STAINLESS STEEL FORGINGS - Nickel Institute · PDF fileSTAINLESS STEEL FORGINGS. 1 ... By forging the fitting, ... work-hardening rate for better cold-forming qualities than Type 304,

STAINLESS STEEL FORGINGS

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Contents Introduction ............................................................ 5

Forging Terminology .............................................. 9

Design Considerations ......................................... 13

Tolerances ........................................................... 17

Quality Descriptions and Special Requirements .......................................... 21

Nondestructive Product Inspections........................................................... 23

Typical Properties of Wrought Stainless Steel ........................................24

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FORGING RANGES FOR STAINLESS STEELS

Temperature, °F 1400 1600 1800 2000 2200 2400

Type 440C

Type 347 & 348

Type 321

Type 440B

Type 440A

Type 310

Type 310S

Type 329

Type 317

Type 316L

Type 316

Type 309S

Type 309

Mo

re D

iffi

cult

to

Ho

t W

ork

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Type 303

Type 303 Se

Type 305

Type 302 & 304

Type 431

Type 414

Type 420F

Type 420

Type 416

Type 410

Type 446

Type 443

Type 430F

⇐

Ea

sie

r to

Ho

t W

ork

Type 430

Note: This chart does not take into consideration aspects of hot working such as heating and cooling practices, scaling rate, grain size, billet size and equipment. It should not be used as a basis for selecting materials without metallurgical advice.

8.132F

C−=

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Source: METAL PROGRESS, June 1974

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Preface

Designers select stainless steels first on the basis of corrosion resistance, then on the basis of strength and other mechanical properties. In the interest of achieving optimum quality at the most economical cost, designers do not overlook a third factor, manufacturing. Fabrication is important even in early stages of design, and forging is one method of fabrication that designers regularly consider.

The reason for this is that stainless steels have advantages that are difficult

to duplicate, and forging enhances these advantages, which include:

Corrosion and Heat Resistance The principal advantage of stainless steels is resistance to corrosion by moisture, atmospheric conditions, many acids, and other aggressive environments at low or high temperature. Strength Parts made of stainless steel are often stronger and tougher than parts made of mild steels or nonferrous metals. Grain Structure A unique feature of forgings is the continuous grain flow that follows the contour of the part, as illustrated by the top drawing. In comparison is the random grain structure of a cast part (center) and the straight-line orientation of grain in a machined part (bottom). From this simple fact. stem many secondary advantages inherent in forged stainless steels:

Strength where needed. Through grain refinement and flow, forging puts the strength where it's needed most. Lighter weight. Higher strength-to-weight ratio permits the use of thinner, lighter weight sections – without sacrificing safety. Improved mechanical properties. Forging develops the full impact resistance, fatigue resistance, ductility, creep-rupture life, and other mechanical properties of stainless steels. Repeatable dimensions. Tolerances of a few thousandths are routinely maintained from part to part, simplifying final fixturing and machining requirements. Efficient metal utilization. Forging cuts waste because it reduces metal removal. Structural uniformity. Forgings are sound, nonporous, and uniform in metallurgical structure.

Availability Wide choice of stainless steel types. With few exceptions all stainless steels can be forged, as suggested by the chart (opposite page) and by the many applications illustrated in this booklet. Wide range of sizes and shapes. Forgers make stainless steel parts from a few ounces in weight to hundreds of pounds; smaller than one inch to parts many feet long. Special operations such as extrusion, drawing, piercing, and coining further enhance forging capabilities.

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The three components shown here are for aircraft applications, illustrating one often overlooked aspect of stainless steels: Because of their high strength-to-weight ratios, stainless steels serve for light-weight design applications just as well as other light-weight materials. For example, the long part, above, is a structural compo-nent for the cargo version of the Boeing 747 Jumbo Jet. It is forged of Type S15500 precipitation hardening stainless steel, measures about 23" long, and weighs 8 pounds. Below that is a 4.2-pound bracket forged of Type 410 stainless steel. It is a motor mount bracket for the 250-Series aircraft engines produced by Detroit Diesel, Allison Division of General Motors Corporation. The bottom photograph is a 7-pound component for the F-4 Phantom Jet pro-duced by McDonnell Douglas Corporation. It is forged of Type S13800 precipitation -hardening stainless steel. Forging achieves the best in strength-to-weight ratios in stainless steel parts. Courtesy Consolidated Industries, Inc., Cheshire, Connecticut

This mechanical linkage part illustrates the extent to which forging reduces machining. Not only is it a difficult shape to machine, but machining would result in considerable (about 40%) metal scrap. The part is Type S17400 precipitation hardening stainless steel that combines high strength and hardness with excellent corrosion re-sistance. Courtesy Cornell Forge Company, Chicago, Illinois

This bearing housing for a rocket aircraft was forged to minimize machining and to provide optimum mechanical properties. Stain-less steel was selected for its resistance to corrosion. The stainless steel is Type 410, and the part was impression die forged on a 2500-pound hammer. Courtesy Cornell Forge Company, Chicago, Illinois

The forging bar for this helicopter sling hook is first bent then impres-sion die forged on a 2,000-pound hammer. Grain flow is in the shape of the hook for maximum strength, which is essential for a part like this subjected to high stresses during maximum loading. The stain-less steel is Type S17400. Courtesy Endicott Forging & Mfg. Co., Inc., Endicott, New York

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By way of introduction . . . . .

What is stainless steel? Stainless steel is not just one material but a family of many different, but

related corrosion resistant steel alloys containing about 10.5% chromium and up. Other alloying elements beside chromium may be present in stainless steel. These include nickel, manganese, molybdenum, and others.

American Iron and Steel Institute (AISI) designates 57 stainless steels as

standard compositions. All are listed in Table 1 on page 24. A more detailed description of each type is contained in the AISI publication, “Steel Products Manual–Stainless and Heat Resisting Steels.”1 Also, many special analysis stainless steels are produced in the United States that do not have AISI designation numbers. Many of these are identified in technical literature, such as in the ASTM Data Series Booklet DS 45.2

Corrosion resistance is the outstanding characteristic of stainless steels and

the principal reason for their use. These steels are not immune to attack in all environments; however, their performance is outstanding when compared with ordinary steel and other common metals. Table 2 on page 32 gives some indication of the relative corrosion resistance of stainless steels to seven typical environments.

How are stainless steels identified?

Those not familiar with stainless steels often ask this question, because there are different terms used that tend to cause confusion. For example, the terms austenitic, martensitic, ferritic, and precipitation hardening serve to identify categories of stainless steels on the basis of their metallurgical structure. Design and product engineers should recognize these terms and understand what they mean, because the stainless steels so classified tend to have similar characteristics with respect to corrosion resistance, hardenability, and fabricability.

AISI stainless steels are identified by a system of numbers that are in either

200, 300, or 400 Series. The 200 Series stainless steels contain chromium, nickel, and manganese; the 300 Series contain chromium and nickel; while the 400 Series are straight-chromium stainless steels. This numbering system is the one by which most people today identify stainless steels, such as Type 304 or Type 316, etc.

A new Unified Numbering System (UNS) has been developed that applies

to all commercial metals, including steels, nonferrous metals, and even to rare earths. The Society of Automotive Engineers (SAE)3 and the American Society for Testing and Materials (ASTM)4 developed the system, and AISI is cooperating in the effort to have UNS apply to all steels. Accordingly, UNS numbers appear with the AISI type numbers in Table 1. Note in this table that five of the stainless steels are identified by UNS numbers only.

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The operational environment inside a jet engine consists of three basic ingredients . . . heat, pressure, and airflow. All three can only be described as severe. No wonder, then, that so many inside components for jet engines are forgings, such as the fuel-nozzle support shown here. This 4" high, 1½ pound forging is mounted in the combustion chamber, or burner, of huge turbofan jet engines used to power one of the popular wide-body airliners. Jet fuel flows through the support to a sophisticated nozzle, which sprays the fuel into the burner, where it is ignited and converted into thrust energy. Made of Type 347 stainless steel, this support takes shape in four forging operations: upset, bent, blocked, and then finish-forged and trimmed in a closed-impression die. As-forged weight is 2½ pounds. After being machined at the nozzle tip and mounting flange, the support is drilled from each end to form the fuel-flow passage. Note that the body, between tip and flange, remains in the asforged condition. The bottom part, below the bend, sits directly in the engine airflow, which is compressed and heated to 800-1100°F. Type 347 stainless steel contains columbium and tantalum and is recommended for parts exposed to temperatures between 800 and 1650°F. Courtesy Ontario Corporation, Muncie, Indiana, and The Forging Industry Association

Pipeline fabricators use forged Weldolet® fittings (top photograph) in making branch connections to a main pipe run. For example, the photograph (lower left) shows a typical fixture for attaching the forged fittings to a pipe section. The fixture serves a dual purpose: It holds the fittings in position for welding, and it clamps the pipe to prevent deflection caused by the weld heat. The other photograph shows an installation in a municipal sewage treatment plant. The fittings are attached to the horizontal pipe tee sections. Attached to each fitting will be a small-diameter pipe and porous ceramic air diffuser. When operating, air will be forced out through the diffusers to bubble up through the raw sewage in the tank. By forging the fitting, optimum mechanical properties are achieved and minimum machining will be required for the intricate shape. Stainless steel Types 304 or 316 provide strength and resistance to corrosion. Courtesy Bonney Forge Division Gulf + Western Manufacturing Company

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Why so many stainless steels? Early uses of stainless steels were usually such applications as gun

barrels, cutlery, and nitric acid tanks. As industry began to exploit the full potential of these corrosion and heat resistant steels, however, new compositions were developed to accommodate requirements for greater resistance to corrosion, greater strength levels, different fabricating characteristics, resistance to elevated temperature, etc. For instance, Type 304 serves as a general-purpose stainless steel for a broad range of applications from cookware to chemical plant equipment. There is Type 316 with greater resistance to pitting corrosion than Type 304, especially in marine (salt water) environments. Type 305, on the other hand, has a lower work-hardening rate for better cold-forming qualities than Type 304, while Type 303 is more machinable than Type 304.

Selection of the proper grade of stainless steel from the many types

available requires an evaluation based upon four important criteria. Listed in order of importance, they are:

1. Corrosion or Heat Resistances5–the primary reason for specifying stainless steel. The specifier needs to know the nature of the environment and the degree of corrosion or heat resistance required. 2. Mechanical Properties–with particular emphasis on strength at room, elevated, or low temperature. Generally speaking, the combination of corrosion resistance and strength is the basis for selection. 3. Fabrication Operations–and how the product is to be made is a third-level consideration. This includes forging, machining, forming, welding, etc. 4. Total Cost–To put everything into proper perspective, a total value analysis is appropriate that will consider not only material and production costs, but the cost-saving benefits of a maintenance-free product having a long life expectancy. Selection procedures are thoroughly covered in technical publications and

in product literature available from companies represented on the Committee of Stainless Steel Producers. Those companies are listed on the back cover of this publication.

It cannot be over-emphasized that although resistance to corrosion or heat

is the most important factor in selecting a stainless steel, the other considerations help to narrow the list of acceptable grades. Specifiers often face the need to compromise among the four factors to obtain optimum benefits.

With respect to forging, however, there is little need for compromise,

because virtually all stainless steels can be forged. For instance, if Type 304 is selected on the basis of corrosion resistance, it is not necessary to consider an alternate type to get better forgeability.

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One of the largest forgings ever produced, this nuclear reactor lower-core support weighs 110,000 pounds. It was open-die forged from a Type 304 stainless steel ingot weighing 294,000 pounds. The forging is 152¼" in diameter and 20¼" thick, and it replaces a casting that measured about 155" in diameter and 37" high.

As a key part for a nuclear reactor core barrel, the lower-core support is located in that portion of a pressurized water reactor that houses the core internals. The internals position and support nuclear fuel in the reactor. Courtesy Westinghouse Electric Corporation

Fuel pressure and sump valve bracket for an aircraft turbine engine is forged of Type 410 stainless steel for maximum strength, fatigue resistance, and protection against corrosion. Type 410 is a marten-sitic stainless steel that can be hardened by heat treatment. Courtesy McWilliams Forge Company, Rockaway, New Jersey

ACFX 86503 is a railroad tank car for general petroleum and chemi-cal service, having a capacity for 16,162 gallons. Among the many forged parts on this car, several are forged in stainless steel. One is an intricate shape, a stem for a spring operated, pressure safety valve, which is forged of Type S17400 precipitation hardening stain-less steel. The stem is 22 16

3 " long and 2 85 " in diameter, and is

treated to a tensile strength of about 135,000 psi minimum and a hardness of Rc 32/36.

Two components are large “eye” bolts for sealing the manway hatch cover. The bolts are Type 304 or 316 stainless steel, depend-ing on the end use. Stainless steel is used primarily for protection against corrosion. Forgings are used in preference over castings to minimize machining and to provide the best possible mechanical properties.

Courtesy AMCAR Division of ACF Industries, Incorporated.

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Forging terminology6

Open Die Forging

One basic method for plastic (hot) deformation of metal is open die forging (or flat die forging) in which the billet is hammered along its horizontal axis. A rough shape is achieved by repeated hammer blows and manipulation of the billet. Because metal flow is not confined by dies, the technique relies heavily on operator skill and, accordingly, is also known as hand or smith forging.

Closed Die or Impression Die Forging

When metal flow in a forging operation is controlled in three dimensions by a die or dies, it is classified as closed die or impression die forging. Impression die forging accounts for most commercial forging production.

Upset Forging or Upsetting

When plastic deformation of the bar or billet is done along its longitudinal axis, it is called upset forging. In its simplest form, the billet is compressed between flat dies, with the material unrestrained and free to flow in two directions. Upset forging, however, is usually accomplished with some control over metal flow, such as in upsetting, which accounts for a substantial part of forging production. It can be classified as impression die forging. In upsetting, the metal is worked in such a manner that the cross-sectional area in all or part of the stock is increased. There are various types of upsetting. In one method, the top and bottom dies grip the bar or billet, and a heading die moves against the end of the metal to upset or form a head in the shape of the die cavity.

The maximum length of bar that can be upset in a single stroke is limited by

possible buckling of the unsupported portion. For stainless steel, the unsupported portion should not exceed 2½ times the diameter.

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A gear-powered union is used instead of flanges or other bolted connections in high-pressure piping systems, such as hydraulic lines, to save weight, space, and installation time. For instance, a gear-powered union for a 4" pipe size weighs only 22 pounds, whereas its ASA bolted-flange counterpart weighs 300 pounds. Forging the collar gives the best possible strength and reduces the amount of machining needed to complete the part. Note that the exterior of the collar is in the as-forged condition. The stainless steel type depends on end-use conditions. Courtesy McWilliams Forge Company, Rockaway, New Jersey and Resistoflex Corporation

Two impressions on a 2,000-pound hammer shape a round ¾" diameter, Type 410 stainless steel bar into a 2-pound tank periscope mounting bracket. Following anneal, the part is trimmed and bent as shown, then hardened and tempered to a Brinell hardness of 201/ 235. Final inspection is by die penetrant. The completed part has excellent resistance to fatigue failure. Courtesy Endicott Forging & Mfg. Co., Inc., Endicott, New York

Pipeline flanges, fittings, and special components for nuclear power plants, refineries, chemical processing plants, and cryogenic appli-cations are routinely forged of stainless steel Types 304, 304L, 316, and 316L. Square forging billets are supplied in several sizes: 4", 6", and 8" included. Flanges are subjected to high stresses and there-fore need the best possible strength. Courtesy Alloy Flange and Fittings Division Gulf + Western Manufacturing Company

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Thickened sections can be upset anywhere along the length of a bar, not just on its end. For gathering material in the middle of a bar, the heading die is replaced with two sliding dies that move within the grip-die frames. The same length-to-die limits apply, to avoid kinking the bar within the die cavity.

Roll Forging

When reduction in thickness is desired over a long bar, it can be gradually moved in an axial direction between cylindrical rolls, which is called rolling. Large-diameter rolls cause greater lateral spread and less elongation, whereas small-diameter rolls cause greater elongation.

A variation of rolling, is roll forging in which shaped tools that impart a shape

to the work piece are affixed to the rolls.

Extrusion

In extrusion the bar or billet is placed in a die and compressed by the movement of a ram until pressure inside the bar reaches the flow stress. At this point, the workpiece is upset and fills the cavity. As the pressure is further increased, material is forced through an orifice and forms the extruded product.

Stainless steel extrusions are usually limited in size. The cross-sectional

shape must be contained within a circumscribed circle no larger than 5 83 " in

diameter.

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These unique elliptical head forgings are for a new fuel-saving nuclear reactor. Components have to meet strict standards for soundness and cleanliness. Grainflow was carefully controlled to achieve good strength. Stainless steel is used to prevent corrosion and contamination of the liquids that come in contact with the metal surfaces. Courtesy Energy Products Group Gulf + Western Manufacturing Company

This is a cylinder, asforged prior to machining, that is used to actuate a jet engine after-burner closure. Forged from stainless steel alloy Greek Ascoloy (AMS 5616), the forging billet was a 2¾" square bar. The sequence of forging included blanking, impression die forging, and piercing. Courtesy Transue & Williams Steel Forging Corporation, Alliance, Ohio

This seaming chuck for a can-making machine was forged of Type 440C stainless steel, which can be heat treated to the highest hardness of any stainless steel. In the annealed condition, the yield strength is 65,000 psi. The 2½" round bar was upset, hot trimmed, and annealed to a Brinell hardness of about 240 maximum. The component weighs four pounds. Courtesy Endicott Forging & Mfg. Co., Inc., Endicott, New York

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Piercing

Piercing is a method for producing hollow bar, and it is closely related to extrusion.

Precision Forging

Precision forging is normally taken to mean close-to-final form or close-tolerance forging. It is not a special technology of its own, but a refinement of existing practices to a point where the forged part can be used with little or no subsequent machining.

Trimming, Punching, Coining, and Ironing

After the part has been forged, it may undergo additional operations under the general heading of “metalworking other than machining,” which includes trimming away the flash, punching out holes, and improving the surface finish by coining or ironing. Coining and ironing are essentially sizing operations performed in dies. Pressure is applied to obtain closer tolerances, smoother surfaces, and to eliminate draft.

Flash

Flash is necessary metal in excess of that required to completely fill the finishing impression of the dies. It extends out from the forging as a thin plate at the line where dies meet, and it is subsequently trimmed.

Design considerations Parting Line and Parting Plane

The parting line is the line along which forging dies come together. It may be straight or irregular, depending on the complexity of the part being forged. The parting plane (or forging plane) is a plane perpendicular to the direction of forging pressure, which is not necessarily the same as the parting line.

The parting line affects die cost, grain flow, trimming procedure, material

utilization, and the position of locating surfaces for subsequent machining. As a general rule, it is most desirable to position the parting line in one plane. The illustrations show preferred and undesirable parting line locations.

Draft

Draft is the angle normally added to all surfaces perpendicular to the parting line to allow easy removal of the forged part from the die. The most common draft angles for stainless steels are 5 to 7 degrees.

For stainless steels, it is common to apply a smaller draft angle on the

outside surface than on the inside because the outside will shrink away from the die during cooling. Deeper die cavities normally require greater drafts to insure release of the part. Also, a part may have a natural draft that can be utilized by changing the position of the part relative to its parting plane, as illustrated.

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This intricate shaped bearing component for a turbine engine was formerly cast. Significant savings were achieved by making minor changes in design so the part can be forged of Type 410 stainless steel. The part was forged on a 5,000-pound hammer in three impressions. The bar was 2¾" round, ultrasonic tested before forg-ing. The component weighs about 7 pounds. Courtesy Endicott Forging & Mfg. Co., Inc., Endicott, New York

This separator bowl forged of Type 329 stainless steel measures about 24" across the opening, and it weighs 536 pounds after machining. Type 329 is an austenitic-ferritic stainless steel similar to Type 316 in corrosion resistance except that it exhibits superior resistance to stress-corrosion cracking. Courtesy Wyman-Gordon Company, Worcester, Massachusetts

Type 316 stainless steel valve body weighs 2,500 pounds and was forged on a 50,000 ton press. After initial machining, the 12" valve is 24" high and 43" wide. Valve and pump components for high-temperature service, such as in nuclear power generation or chemi-cal processing, need the combined strength and corrosion resis-tance of forged stainless steel. Courtesy Wyman-Gordon Company, Worcester, Massachusetts

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Webs and Ribs A web is a thin section of the forging that is parallel to the forging plane; a

rib is a thin section perpendicular to the forging plane. Both webs and ribs are more difficult to forge than thicker sections because the metal in them cools rapidly, building up resistance to deformation.

Significant weight savings can be realized by avoiding excess metal in webs

and ribs, although there are no hard and fast rules that apply to dimensions. How thin a web can be depends on its smallest longitudinal dimension, and whether the web is confined or unconfined. In an unconfined web, the metal is free to flow in at least one direction during forging. In a confined web, metal flow is impeded by ribs.

Rib height depends primarily on its thickness, and in general, it should not

exceed eight times the width.

Holes and Recesses

To conserve material and reduce final machining, recesses should be forged into the part wherever possible. By forging recesses on opposite sides of a forging, a hole can be created by a relatively economical punching operation. Recess depths are usually limited to no more than their diameter for flat bottoms, and to no more than 1.5 times diameter for round bottom recesses.

Fillet and Corner Radii

One of the most important factors in the design of die forgings is having sufficiently large fillet and corner radii to assure proper metal flow. Also, small radii are more costly to machine into the die. By forging a part in a succession of dies, it is possible to reduce the fillet radius by 50% in each impression. For instance, a three-inch high rib would require a one-inch fillet for one impression. However on the second impression, the fillet radius can be one-half inch, and on the third impression one-quarter inch. A one-quarter inch radius is considered the minimum fillet radius for stainless steels.

Corner radii should also be as large as possible to ease metal flow during

forging, and thus reduce die wear. But the minimums for corner radii are about half those for fillet radii. For stainless steels, the minimum corner radius is one-eighth inch for the corners of bosses and other edges. For rib ends, a radius that will make the end a full semicircle is preferred.

It is also important, for purposes of economy, to keep corner and fillet radii as consistent as possible for any given part to minimize the need for a multiplicity of tool changes while the die is being made.

Grain Flow

Grain flow direction is determined by the size and shape of the bar or billet used for the forging. If, however, the part needs higher strength in one direction than in another, this can be worked out with the forge shop.

It is always good practice to consult with a forge shop before reaching the

final stages of design. To a great extent, design depends on the forging capabilities that are available, such as individual equipment types, press sizes, and production capacities. Also, many forge shops have design services to help with final drawings and specifications.

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Forging has always been the principal method for making blades or buckets for turbine engines. This blade of Type 410 stainless steel is 62" long, about 8" wide (at the airfoil), and it weighs 158 pounds. Blades are subjected to extremes in temperatures and pressures and so benefit greatly from forging. Courtesy Wyman-Gordon Company, Worcester, Massachusetts

Boat manufacturers have switched en masse from brass to stainless steel for marine hardware, much of which is forged of either Type 304 or 316 stainless steel. For salt water marine applications, Type 316 is preferred. The fittings shown here are: 1) swivel/shackle, 2) shackle, 3) eye bolt, and 4) cable clamp. Courtesy Merrill Brothers, Maspeth, New York

The Lockheed L-1011 wide-body jet has a completely self-con-tained, integrated pneumatic system composed of environmental control equipment, engine starters, and auxiliary power unit. A key component in this unit is a swing link, forged of a precipitation hardening stainless steel Type S17400. In the heat treated condi-tion, Type S17400 has a tensile strength of up to 200,000 psi and a hardness of Rc 44. Courtesy McWilliams Forge Company, Rockaway, New Jersey, and Hamilton Standard Division of United Aircraft Corporation

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Tolerances 6

The final dimensions in a series of forged parts will vary slightly from start to finish, and from the dimensions on the drawings. These variations result from several factors, such as die wear, differences in billet volume, and cooling rates.

How closely the forger is asked to control these variations depends on

end-use requirements and economic considerations. For instance, it is possible to hold fairly tight tolerances in precision or “no-draft” forging, but costs will be higher with stainless steels. For one thing, stainless steels have a very narrow range of temperatures at which they can be forged. Consequently, they are within a forgeable range for a short period of time as they cool from the upper to the lower temperature limits. (See chart on page 2.)

The tolerances established for stainless steels by the forging industry are

adequate for most industrial applications.

Length and Width

The length and width (L-W) tolerance is ±0.003 inch per inch, and it applies to all dimensions of length, width and diameters. This tolerance includes allowances for shrinkage, die sinking, and die polishing variations.

Die Wear Tolerances

This tolerance represents the extra material that must be added to the surface of a forged part to accommodate wear of the die. It is applied in addition to the length and width tolerances, and it applies to the dimensions of forged surfaces only-not to center-to-center dimensions. Die wear tolerance factors for stainless steels are:

300 Series-0.007" 400 Series-0.006" 1" = 25.4mm

To apply these tolerances on external dimensions of length, width, and

diameter, multiply the greatest external length of the part by the appropriate factor (above), and add the result to the plus values of the L-W tolerances for individual dimensions.

On internal dimensions of length, width, and diameter, again compute the

tolerance by multiplying the greatest external length by the appropriate factor, but add the result to the minus values of L-W tolerances for individual dimensions.

Die Closure

Die closure tolerances allow for variations from die wear and from incomplete closing of the dies. They are applied to all dimensions perpendicular to the parting plane. The following table shows die closure tolerances for stainless steels.

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By converting to a forging from a completely machined part, The DeLaval Separator Company achieved a combined cost saving of 22% for producing stainless steel milk claw bodies.

The 2 pound milk claw bodies for automatic pipeline milking machines were originally machined from 2 8

7 " diameter bar stock, 2 8

5 " long and weighing 4.83 pounds. During machining, about 2.83 pounds of metal chips were cut away and discarded. Seeking to reduce production costs and metal scrap, DeLaval engineers rede-signed the part to be forged.

Milk claw bodies are now forged from 2" diameter round bar (1), 3 16

7 " long and weighing 3.38 pounds. The forging (2) weighs 3.13 pounds and the machined body (3) weighs 2 pounds. The scrap by this method is about 50% less than the previous method.

Also, by eliminating some machining operations and cutting down on machining time, tool costs decreased and productivity increased 60%. The combined savings totaled 22%, with no sacrifice to quality.

The milk claw body is made of Type 303 stainless steel, which is a free-machining grade.

Courtesy Cape Ann Tool Company, Pigeon Cove, Massachusetts, and The Forginq Industry Association

A familiar sight to travelers in New York is the Sikorsky S-61L helicopter, shown here landing at the Wall Street Heliport in New York City. It carries 30 passengers at a cruising speed of 140 miles per hour, and it is powered by two 1,500 horsepower turbine en-gines.

Directional control in a helicopter is achieved by the rotating rud- der, barely visible at the tail. A key component in the control linkage of the S-61L is a rod end, which is forged of a precipitation hardening stainless steel, Type S15500.

A precipitation hardening stainless steel can be hardened by a single low-temperature heat treatment (900-1150°F) that virtually eliminates scaling and distortion. Type S15500 has good forgeability and good transverse mechanical properties.

Courtesy McWilliams Forge Company, Rockaway, New Jersey, and Sikorsky Aircraft Division of United Aircraft Corporation

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Die Closure Tolerances

Area at Trim Line (square inches)

Under 10

10-30

30-50

50-100

100-500

500- 1000

Over 1000

300 Series Stainless Steels (inch) 16

1 323 8

1 325 16

3 41 16

5

400 Series Stainless Steels (inch) 32

1 161 32

3 81 16

3 41 16

5

To apply these tolerances: On parts with no projections beyond six inches from the parting line, add the appropriate value from the table to the plus tolerances of all dimensions perpendicular to the parting plane. On parts with projections greater than six inches from the parting line, apply the above tolerance and length tolerance of ±0.003 inch per inch. This extra tolerance applies only to extensions beyond six inches.

Match

This tolerance allows for the lateral misalignment of a point on one die in relation to a corresponding point on the other die. It is measured parallel to the parting line.

Match tolerances are applied independently of all other tolerances, and

should be measured on areas of the part that are unaffected by die wear. Match tolerances vary with the total weight of the forged part after trimming, but are constant for all of the stainless steels. Typical values are given in the table. They represent the displacement of a point in one die half from a corresponding point in the other die half.

Weight of part after trimming (pounds)

Radius

These tolerances are specified as variations from the nominal radius shown on the drawing. They are relatively independent of metal used, and standard production tolerance is ±½ of the nominal radius.

If corner radii are affected by later removal of draft by trimming, broaching, or

punching, however, the minus part of the radius tolerance does not apply.

Straightness

These tolerances allow for the deviation of flat surfaces and centerlines from a straight line, and are applied in addition to all other tolerances. Because they are largely a function of cooling variations, straightness tolerances are highly dependent on part shape–particularly for parts made of stainless steels. No industry standards exist, and straightness tolerances should be worked out with the forge shop.

Match Tolerances

2-5

5-25

25-50

50-100

100-200

200-500

500-1000

over 1000

Displacement (inch)

20

Cut-away view shows internal components of a wedge gate valve used widely in petroleum and chemical processing. Down through the center of the valve extends the stem, which, when the wheel is turned, operates the valve disc. At one end of the threaded stem is a Tee-head, which connects to the wedge disc. The tee-head is forged integral with the stem for increased strength at the highly stressed point where the stem meets the tee. Upset forging eliminates machining on these parts, which are made of stainless steel Types 304 or 316. Wedge discs for gate valves are also economically forged. Stem courtesy Commercial Stamping & Forging Inc., Chicago, Il-linois

Valve courtesy Crane Co.

Disc courtesy Endicott Forging & Mfg. Co., Inc., Endicott, New York

Sometimes materials handling slings are subjected to elevated temperatures and corrosive environments, in which case the sling components must be of a corrosion and heat resistant material. This hook, made from a 1" round bar that was first bent and then impres-sion die forged, is stainless steel Type 347. After forging and anneal-ing, the hook was die penetrant tested and a small hole was drilled on the shoulder. Weight of the finished component is 1¼ pounds. Courtesy CM Chain Division, Columbus Mckinnon Corporation and Endicott Forging & Mfg. Co., Inc., Endicott, New York

21

Flash Extension

These tolerances specify the allowable amount of flash extending from the body of the forged part. Flash tolerances vary with the weight of the forged part after trimming, but are relatively constant for all stainless steels. Typical values are contained in this table.

Flash Extension Tolerances Weight of part after trimming (pounds)

Flash extension range (inch)

under 10 0- 321

10-25 0- 323

25-50 0- 81

50-100 0- 163

100-200 0- 41

200-500 0- 165

500-1000 0- 83

over 1000 0- 21

Quality descriptions and special requirements

Stainless steels are available which are capable of meeting certain special quality tests or special requirements.

The production of such steels normally requires exacting steelmaking practices, extensive testing prior to shipment, or both. The selection of heats or portions of heats as well as additional discard may be necessary.

The processing method used to meet those tests and requirements may

vary among the producers.

Magnetic Particle Inspection Quality

This quality designation, sometimes described as “Aircraft Quality,” applies to steels for highly stressed parts of aircraft and for other similar or corresponding purposes requiring steel of a special quality.

A typical procedure for the magnetic particle method of inspection is

described in ASTM E 45, Recommended Practice for Determining Inclusion Content of Steel. It consists of suitably magnetizing the steel and applying a prepared magnetic powder which adheres to it along lines of flux leakage. On properly magnetized steel, flux leakage develops along surface or subsurface nonuniformities.

This method of inspection is applicable to most types of stainless steels in

the 40d Series. It is not appropriate for use with the free-machining types since they contain nonmetallic sulfide or selenide inclusions in large numbers. Steels in the 200 and 300 Series do not respond to magnetic particle inspection because they are essentially nonmagnetic.

The magnetic particle test was developed for, and is used primarily on, fully

machined or ground surfaces or finished parts.

Turbine Quality

Turbine quality is the term sometimes applied to Type 403, since this grade has been employed in the manufacture of blading for steam turbines, for compressor blading in gas turbines, as well as for other applications not related to turbines where parts are subject to high static or dynamic stresses.

22

The by-pass valve body is for a pneumatic flow transmitter. Made of Type 316 for corrosive service, the part was forged on a 2750-pound hammer. Three impressions were required to form a 2 8

3 " round bar into this unusual shape. Courtesy Endicott Forging & Mfg. Co., Inc., Endicott, New York, and Taylor Instrument Process Control Division Sybron Corporation

Steam pumps are subjected to vibration, temperature, moisture, and the erosive effects of steam. Conse-quently, parts such as this valve are made of stainless steel. This 2½ pound valve of Type 410 stainless was forged from a 2¼" round bar in three impressions. Strength and reduced machining requirements were principal considerations for forging. Courtesy Endicott Forging & Mfg. Co., Inc., Endicott, New York, and Worthington Pump, Inc.

23

Mirror-Finish Quality

This quality designation applies to stock for cutlery that must be capable of being polished to an extremely high mirror finish as a final operation. A sample of steel is either machined or forged to a flat, and then machined or ground and polished to simulate actual expected conditions of manufacture used in the finished part. Ultrasonic Quality

Stainless steel plates, bars, billets, blooms, slabs, and forgings can be ultrasonically tested for quality when size, shape, and grain size permit adequate transmission and reception of sound waves.

Nondestructive product inspections Ultrasonic Nondestructive Testing

Ultrasonic testing of stainless steel plates, bars, billets, blooms, slabs, and forgings is applicable in a wide range of sizes. Ultrasonic testing, as used herein, is confined to the pulse echo reflection method employing either the direct contact or the immersion inspection technique.

The accuracy of ultrasonic testing depends to a large extent on the surface

condition of the piece to be inspected, particularly when the direct contact method is used. In general, surfaces should be clean and free from rough or loose scale.

The surface is considered satisfactory if adequate transmission of the sound

waves can be maintained during inspection. No further criteria of surface smoothness are required. In order to achieve proper transmission of the sound energy in some instances special cleaning, grinding or other operation is required. In order to perform satisfactory inspection, it should be recognized that such special operations may be required.

Internal conditions, such as grain size, segregation or structure may impose

restrictions which limit or prevent ultrasonic inspection. Reference standards are established as benchmarks by which ultrasonic

indications from discontinuities are evaluated to determine their acceptability. The exact dividing line between acceptance and rejection in terms of the reference standards is customarily given in the documents pertaining to the specific order. There are several generally used standards for evaluation of discrete indications. The standard selected depends upon the particular application and the dictates of the specific order. It is suggested that the stainless steel producer be consulted for detailed information.

Liquid Penetrant Nondestructive Inspection

Liquid penetrant inspection is sometimes used as an aid to visual examination in detecting surface discontinuities on critical products. In this technique a liquid penetrant–which is either fluorescent or colored by a dye–is applied to the surface, and enters any discontinuities by capillary action. After sufficient time has been allowed, excess penetrant is removed from the surface. A developer is then applied to draw penetrant from the discontinuities to the surface, where it becomes visible either because of its intense color or its fluorescence under ultraviolet light.

Penetrant inspection can be very sensitive and thus readily detect

discontinuities which might be overlooked in visual inspection. However, the penetrant cannot enter discontinuities not open to the surface, so the technique cannot be used to detect subsurface defects. Penetrant inspection can be used only to locate discontinuities, and cannot be used to determine depth. The inspection technique is not suited to surfaces so rough that excess penetrant cannot be completely removed, or to inspection of products such as hot-rolled bars that are expected to contain some surface discontinuities.

24

Table 1

Typical Properties of Wrought Stainless Steel

Mechanical Properties of Annealed Material at Room Temperature

Nominal Properties of Annealed Material at Low Temperature

AISI Type

(UNS)

Typical Composition, % (a) Max. (if not designated otherwise)

Form (b)

Tensile

Strength, 1000 Psi

Yield Strength (0.2% Offset),

1000 Psi

Elonga- tion in

2 In., %

Hard- ness

Tem- pera- ture, °F

Tensile

Strength, 1000 Psi

Yield

Strength, 1000 Psi

Elonga- tion in

2 In., %

Reduc- tion in Area,

%

Izod impact

Strength, Ft-Lb

Austenitic

201

S20100)

(c) 16-18 Cr, 3.5-5.5 Ni, 0.15 C, 5.5-7.5 Mn, 1.0 Si, 0-060 P, 0.030 S, 0.25 N

Sheets Strips Tubing

115 115 115

55 55 55

55 55 55

Rb 90 Rb 90 Rb 90

��

+ 70 – 300

– – – – 110 - 120 38 - 70

202 (520200)

17-19 Cr, 4-6 Ni, 0.15 C, 7.5-10.0 Mn, 1.0 Si, 0.060 P, 0.030 S, 0.25 N

Sheets Strips Tubing

105 105 105

55 55 55

55 55 55

Rb 90 Rb 90 Rb 90

��

+ 70 – 100 – 300 – 423

100 145 200 220

55 95

150 170

55 38 15 5

–

110 - 120 –

42 - 120 –

205

(S20500)

16.5-18 Cr, 1-1.75 Ni, 0.12-0.25 C, 14-15.5 Mn, 1.0 Si, 0.060 P, 0.030 S, 1-1.75 Mo, 0.32-0.40 N

Plates 120 69 58 Rb 98

��

– – – – Charpy

200

301

(530100)

16-18 Cr, 6-8 Ni, 0.15 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S

Plates Sheets Strips Tubing

105 110 110 105

40 40 40 40

55 60

50 50

Bhn 165 Rb 85 Rb 85 Rb 95

��

+ 70 + 32 – 40 – 80 – 320

105 155 180 195 275

40 43 48 50 75

60 53 42 40 30

70 64 63 62 57

100 110 110 110 110

302 (530200)

17-19 Cr, 8-10 Ni, 0.15 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S

Bars Plates Sheets Strips Tubing Wire

85 90 90 90 85 90

35 35 40 40 35 35

60 60 50 50 50 60

Bhn 150 Rb 80 Rb 85 Rb 85 Rb 85 Rb 83

��

+ 70 + 32 – 40 – 80 – 320 – 423

94 122 145 161 219 250

37 40 48 50 68

125

68 65 60 57 46 41

78 76 73 70 70 55

110 110 110 110 110 –

302B

(530215)

17-19 Cr, 8-10 Ni, 0.15 C, 2.0 Mn, 2.0-3.0 Si, 0.045 P, 0.030 S

Bars Plates Sheets Strips Tubing

90 90 95 95 85

40 40 40 40 35

50 50 55 55 50

Rb 85 Rb 85 Rb 85 Rb 85 Rb 95

��

+ 70 Not applicable. Silicon added to type 302 for oxidation resistance

90

303

(S30300)

17-19 Cr, 8-10 Ni, 0.15 C, 2.0 Mn, 1.0 Si, 0.20 P, 0.15S min, 0.60 Mo (optional)

303Se (S30323)

17-19 Cr, 8-10 Ni, 0.15 C, 2.0 Mn, 1.0 Si, 0.20P,0.060S,0.15Semin

Bars Tubing Wire

90 80 90

35 38 35

50 53 50

Bhn 160 Rb 76

��

+ 70 + 32 – 40 – 80 – 320 – 452

100 114 145 162 235 267

40 40 40 40 37 –

67 61 45 40 35 30

67 65 62 60 52 37

85 90 100 106 125 –

304

(S30400)

18-20 Cr, 8-10.50 Ni, 0.08 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S

FBars Plates Sheets Strips Tubing Wire

85 82 84 84 85 90

35 35 42 42 35 35

60 60 55 55 50 60

Bhn 149 Bhn 149 Rb 80 Rb 80 Rb 80 Rb 83

304L (S30403)

18-20 Cr, 8.12 Ni, 0.03 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S


79 81 81 78

33 39 39 34

60 55 55 55

Bhn 143 Rb 79 Rb 79 Rb 75

��

+ 70 + 32 – 40 – 80 – 320 – 423

95 130 155 170 221 243

35 34 34 34 39 50

65 55 47 39 40 40

71 68 64 63 55 50

110 110 110 110 110 110

S30430 17-19 Cr, 8-10 Ni, 0.08 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S, 3-4 Cu

Wire 73 31 70 RB 70

��


240

304N

(530451)

18-20 Cr, 8-10.5 Ni, 0.08 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S, 0.10-0.16 N

Bars Sheets

90 90

42 48

55 50

Bhn 180 Rb 85

��

– – – – –

305

(530500)

17-19 Cr, 10.50-13 Ni, 0.12 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S

Plates Sheets Strips Tubing Wire

85 85 85 80 85

35 38 38 36 74

55 50 50 56 60

Rb 80 Rb 80 Rb 80 Rb 77

��

+ 70 – – – – 110

308 (S30800)

19-21 Cr, 10-12 Ni, 0.08 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S


85 85 85 85 85 95**

30 30 35 35 35 60**

55 55 50 50 50 50**

Rb 80 Bhn 150 Rb 80 Rb 80 Rb 80

��

+ 70 – – – – 110

(a) Single values are maximums, except as noted; (b) Forms listed are only those for which mechanical properties are given. Most types are available in many forms; (c) Austenitic, hardenable by cold working; not hardenable by heat treatment. Ferritic, not hardenable by heat treatment or cold working. Martensitic, hardenable by heat treatment; (d) Followed by rapid cooling. H is hardening temperature; T is tempering; (e) Stabilizing temperature, 1550 to 1650 °F; (f) Retarded cool; (g) Full anneal, followed by slow cooling; (h) Low anneal; (i) Tempering within the range of 800 to 1100 °F is not recommended because of resulting low and erratic impact properties and reduced corrosion resistance. Time at temperature and temperatures may vary depending on part size; (j) Retarded cool and anneal.

25

Mechanical Properties at Elevated Temperatures

Creep Strength Scaling TemperatureThermal Treatment

Load for 1% Elongation in 10,000 Hr, 1000 Psi

1000 °F

1100 °F

1200 °F

1300 °F

1500 °F

Max Con-

tinuous Service in Air, °F

Max Inter-

mittent Service in Air, °F

Initial

Forging Tempera- ture, °F

Annealing Tempera- ture, °F (d)

Stress-Relief

Annealing Temperature,

°F

Melting Range, °F

AISI

Type (UNS)

Characteristics and

Applications

– – – – – 1550 1450 2100-2250 1850-2050 – –

201 (520100)

High work hardening rate; low-nickel equivalent of type 301.

– – – – – 1550 1450 2100-2250 1850-2050 – –

202 (520200)

General purpose low-nickel equivalent of type 302.

– – – – – – – 2250 1950 – –

205 (S20500)

Lower work-hardening rate than Type 202. Used for spinning and special drawing operations.

19 12.5 8 4.5 1,8 1650 1500 2100-2300 1850-2050 400-750 2250-2590

301

(530100)

High work hardening rate; used for structural applications where high strength plus high ductility is required in railroad cars, trailer bodies, aircraft structurals.

20 12.5 7.5 4.3 1.5 1650 1500 2100-2300 1850-2050 400-750 2550-2590

302

(S30200)

General purpose austenitic stainless steel for trim, food handling equip-ment, aircraft cowling, antennas, springs, architectural, cookware.

– – 7 4.5 1 1750 1600 2050-2250 1850-2050 – 2500-2550

302B (530215)

More resistant to scale than type 302. Used for furnace parts, still liners, heating elements.

303 (S30300)

Free-machining modification of type 302 for heavier cuts. Used for screw machine products, shafts, valves.

16.5 11.5 6.5 3.5 0.7 1650 1400 2100-2350 1850-2050 400-750 2550-2590 303Se (S30323)

Free-machining modification of type 302, for lighter cuts and where hot working or cold heading may be in-volved.

304

(530400)

Low-carbon modification of type 302 for restriction of carbide precipitation during welding. Used for chemical and food processing equipment, recording wire.

20 12 7.5 4 1.5 1650 1550 2100-2300 1850-2050 400-750 2550-2650 304L (530403)

Extra-low-carbon modification of type 304 for further restriction of carbide precipitation during welding.

– – – – – – – 2100-2300 1850-2050 – 2550-2650 S30430 Has lower work-hardening rate than Type 305; is used for severe cold-heading applications.

– – – – – – – 2100-2300 1850-2050 – 2550-2650

304N

(S30451)

Higher nitrogen than Type 304 to increase strength with minimum effect on ductility and corrosion resistance.

19 12.5 8 4.5 2 1650 – 2100-2300 1850-2050 – 2550-2650

305

(530500)

Low work hardening rate; used for spin forming and severe drawing opera-tions. Used for nuclear energy appli-cations.

– – – – – 1700 1550 2100-2300 1850-2050 – 2550-2590

308

(530800)

Higher alloy steel having higher cor-rosion and heat resistance. Primarily used for welding filler metals to com-pensate for alloy loss in welding.

* Composition for Type 310 tubing varies slightly from AISI values. ** Soft temper. For standard compositions, refer to ASTM A213.

26

Table 1 continued

Typical Properties of Wrought Stainless Steel (Continued)



AISI Type

(UNS)

Typical Composition, % (a) Max. (if not designated otherwise)

Form (b)

Tensile

Strength, 1000 Psi

Yield Strength (0.2% Offset),

1000 Psi

Elonga- tion in

2 In., %

Hard- ness


Tensile

Strength, 1000 Psi

Yield

Strength, 1000 Psi

Elonga- tion in

2 In., %


%

Izod Impact

Strength, Ft. Lb

309

(S30900)

22-24 Cr, 12-15 Ni, 0.20 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S

3095

(S30908)

22-24 Cr, 12-15 Ni, 0.08 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S


95 95 90 90 90

105**

40 40 45 45 45

70**

45 45 45 45 45

35**

Rb 83 Bhn 170Rb 85 Rb 85 Rb 85 Rb 98**

��

+ 70 – – – – 110

310 (531000)

24-26 Cr,19-22 Ni, 0.25 C, 2,0 Mn, 1.5 Si, 0.045 P, 0.030 S

310S

(531008)

24-26 Cr, 19-22 Ni, 0.08 C, 2.0 Mn,1.5 Si, 0-045 P, 0.30 S

Bars Plates Sheets Strips

*Tubing Wire

95 95 95 95 95

105**

45 45 45 45 45

75**

50 50 45 45 45

30**

Rb 89 Bhn 170RI 85 Rb 85 Rb 85 Rb 98**

��

+ 70 + 32 – 40 – 80 – 320 – 423

86 85 95

100 152 176

37 32 39 40 74

108

55 64 57 55 54 56

70 75 75 75 64 61

110 110 110 110 85 –

314 (S31400)

23-26 Cr, 19-22 Ni, 0.25 C. 2.0 Mn, 1.5-3.0 Si, 0-045 P, 0.030 S

Bars Plates Sheets

100 100 100

50 50 50

45 45 40

Bhn 180Ban 180Rb 85

��

Not applicable. High silicon added to type 310 for carburization resistance

316 (S31600)

16-18 Cr, 10-14 Ni, 0.08 C, 2.0 Mn,1.0 Si, 0.045 P, 0.030 S, 2.0-3.0 Mo


80 82 84 84 85 80

30 36 42 42 35 30

60 55 50 50 50 60

Rb 78 Bhn 149Rb 79 Rb 79 Rb 85 Rb 78

316L (S31603)

16-18 Cr, 10-14 Ni, 0,03 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S, 2.0-3.0 Mo


81 81 81 80

34 42 42 35

55 50 50 55

Bhn 146Rb 79 Rb 79 Rb 78

��

+ 70 + 32 – 40 – 80 – 320 – 423

85 90

104 118 185 210

37 39 41 44 75 84

65 60 59 57 59 52

76 75 75 73 76 60

110 110 110 110

– –

316E

(S31620)

16-18 Cr, 10-14 Ni, 0.08 C, 2.0 Mn, 1.0 Si, 0.20 P, 0.10 S min, 1.75-2.50 Mo

gars Sheets

82 85

35 38

51 60

Bhn 143Rb 85

� � �

– – – – –

316N (531651)

16-18 Cr, 10-14 Ni, 0.08 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S, 2-3 Mo, 0.10-0.16 N

gars Sheets

90 90

42 48

55 48

Bhn 180Rb 85

� � �

– – – – –

317

(531700)

18-20 Cr, 11-15 Ni. 0.08 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S, 3.0-4,0 Mo

Bars Plates Sheets Strips Tubing

85 85 90 90 85

40 40 40 40 35

50 50 45 45 40

Bhn 160Bhn 160Rb 85 Rb 85 Rb 85

��

Same as type 316

317L

(531703)

18-20 Cr, 11-15 Ni, 0.03 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S, 3-4 Mo

Plates Sheets Tubing

85 86 86

35 38 50

55 55 55

Rb 80 Rb 85

� � � � �

– – –

321

(S32100)

17-19 Cr, 9-12 Ni, 0.08 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S (Ti, 5×C min)


85 85 90 90 85

95**

35 30 35 35 35

65**

55 55 45 45 50

40**

Bhn 150Bhn 160Rb 80 Rb 80 Rb 80 Rb 89**

��

+ 70 – 32 – 40 – 80 – 320 – 423

89 99

117 130 208 238

37 38 44 45 64 92

62 58 58 57 44 35

76 73 70 68 57 –

110 110 115 117 110

–

329 (S32900)

25-30 Cr, 3-6 Ni, 0.10 C , 2.0 M n, 1.0 Si, 0.040 P, 0.030 S, 1-2 Mo

Bars Strips

105 105

80 80

25 25

Bhn 230Bhn 230

� � �

– Charpy

40

330

(N08330)

17-20 Cr, 34-37 Ni, 0.08 C, 2.0 Mn, 0.75-1.50 Si, 0.040 P, 0.030 S


85 90 80 80

42 38 38 38

45 45 40 40

Rb 80 Rb 80

� � �


240


27




1000 °F

1100 °F

1200 °F

1300 °F

1500 °F

Max Con-

tin uous Service in Air, °F

Max Inter-


Initial



Stress-Relief


°F

Melting Range, °F

AISI Type

(UNS)

Characteristics and Applications

309 (530900)

Used for its high temperature strength and scale resistance in aircraft heaters, heat treating equipment, annealing covers, furnace parts. 16.5 12.5 10 6 3 1950 1850 2050-2250 1900-2050 – 2550-2650

3095

(530908)

Low-carbon modification of type 309, for welded construction.

310

(531000)

Higher elevated temperature strength and scale resistance than type 309. Used for heat exchangers, furnace parts, combustion chambers, welding filler metals. 33 23 15 10 3 2050 1900 2000-2250 1900-2100 400-750 2550-2650

3105

(531008)

Low-carbon modification of type 310, for welded construction.

20 13 7.5 5 2.5 – – 1900-2050 2100 – –

314 (531400)

More resistant to scale than type 310.

316 (S31600)

Higher corrosion resistance than types 302 and 304, high creep strength. Used for chemical and pulp handling equip-ment, photographic and food equip-ment.

25 11.4 11.6 7.5 2.4 1650 1550 2100-2300 1850-2050 400-750 2500-2550

316L (531603)

Extra-low-carbon modification of type 316, for welded construction where in-tergranular carbide precipitation must be avoided.

– – – – – – – 2200 2000 – 2500-2550

316E

(531620)

Higher phosphorus and sulfur than Type 316 to improve machining and nonseizing characteristics; is suit able for automatic screw machining.

– – – – – – – 2100-2300 1850-2050 – 2500-2550

316N

(531651)

Higher nitrogen than Type 316 to in-crease strength with minimum effect on ductility and corrosion resistance.

23 16.8 11.2 6.9 2.0 1700 1600 2100-2300 1850-2050 – 2500-2550

317

(531700)

Higher corrosion and creep resistance than type 316.

– – – – – – – 2250 1900-2000 – 2500-2550

317L

(531703)

Extra low-carbon modification of Type 317 far restriction of carbide precipitation during welding.

18 17 9 5 1.5 1650 1550 2100-2300 1750-2050 400-750(e) 2550-2600

321 (532100)

Stabilized for weldments subject tc severe corrosive conditions and for service from 800 to 1600 F. Used for aircraft exhaust manifolds, boiler shells, process equipment, expansion joints.

– – – – – – – 2000 1750-1800 H1350 –

329

(532900)

Austenitic/ferritic with general cor-rosion resistance similar to Type 316 but with better resistance to stress-corrosion cracking; capable of age hardening.

– – – – – – – 2100-2150 1950-2150 – 2550-2600

330

(N08330)

Has good resistance to carburization and to heat and thermal shock.

* Composition for Type 310 tubing varies slightly from AISI values. ** Soft temper.

For standard compositions, refer to ASTM A213.

28

Table 1 continued

Typical Properties of Wrought Stainless Steel (Continued)



AISI Type

(UNS)

Composition, % (a)

Max. (if Typical not designated otherwise)

Form (b)

Tensile

Strength, 1000 Psi

Yield Strength(0.2% Offset),

1000 Psi

Elonga- tion in

2 In., %

Hard- ness


Tensile

Strength, 1000 Psi

Yield

Strength, 1000 Psi

Elonga- tion in

2 In., %


%

Izod Impact

Strength, Ft-Lb

347 (S34700)

17-19 Cr, 9-13 Ni, 0.08 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S (Cb+Ta, 10×C min)

348 (S34800)

17-19 Cr, 9-13 Ni, 0.08 C, 2.0 Mn, 1.0 Si, 0.045 P, 0.030 S (Cb+Ta, 10×C min but 0.10 Ta max), 0.20 Co


90 90 95 95 85 100**

35 35 40 40 35 70**

50 50 45 45 45 40**

Bhn 160 Bhn 160 Rb 85 Rb 85 Rb 85 Rb 95**

��

+ 70 + 32 – 40 – 80 – 320 – 423

93 105 117 130 200 228

38 42 44 45 47 55

55 62 63 57 43 39

69 72 71 70 65 53

110 110 117 110

95 60

384 (S38400)

15-17 Cr, 17-19 Ni, 0.08 C, 2.0 Mn, 1.0 Si, 0045 P, 0.030 S

Wire 75 35 55 Rb 70 ��

– – – – – –

Ferritic (c) 405 (S40500)

11.5-14.5 Cr, 0.08 C, 1.0 Mn, 1.0 Si, 0.040 P, 0.030 S, 0.1-0.3 AI

Bars Plates Sheets Tubing Wire

70 65 65 65 90**

40 40 40 40

75**

30 30 25 25 15**

Bhn 150 Bhn 150 Rb 75 Rb 80

��

+ 70 Approximately same as type 410 in

annealed condition 20 - 35

409

(S40900)

10.5-11.75 Cr, 0.08 C, 1.0 Mn, 1.0 Si, 0.045 P, 0.045 S, (Ti 6×C, but with 0.75 max)


65 65 65 65

35 35 35 35

25 25 25 25

Rb 75 Rb 75 Rb 75 Rb 75

��

– – – – –

429 (S42900)

14-16 Cr, 0.12 C, 1.0 Mn, 1.0 Si, 0.040 P, 0.030 S

Bars Plates

71 70

45 40

30 30

Bhn 156 Bhn 163

��

– – – – – _

430 (S43000)

16-18 Cr, 0.12 C, 1.0 Mn, 1.0 Si, 0.040 P, 0.030 S


75 75 75 75 75 70

45 40 50 50 40 40

30 30 25 25 25 35

Bhn 155 Bhn 160 Rb 85 Rb 85 Rb 80 Rb 82

��

+ 70 + 32 – 40 – 80 – 320

65 69 76 81 90

–

38 40 41 44 87

–

37 37 36 36

2 –

73 72 72 70

4 –

35 20 10

8 2 –

430F

(543020)

16-18 Cr, 0.12 C, 1.25 Mn, 1.0 Si, 0.060 P, 0.15 S min, 0.60 Mo (optional)

430FSe (S43023)

16-18 Cr, 0.12 C, 1.25 Mn, 1.0 Si, 0.060 P, 0.060 S, 0.15 Se min

Bars Wire

80 95**

55 85**

25 10**

Bhn 170 Rb 92**

��

+ 70 – 100 – 300

– – – – 5 - 50

4 1

434

(543400)

16-18 Cr, 0.12 C, 1.0 Mn, 1.0 Si, 0.040 P, 0.030 S, 0.75-1.25 Mo

Sheets strips Wire

77 77 79

53 53 60

23 23 33

Rb 83 Rb 83 Rb 90

��

– – – – – –

436

(543600)

16-18 Cr, 0.12 C, 1.0 Mn, 1.0 Si, 0.040 P, 0.030 S, 0.75-1.25 Mo (Cb + Ta 5×C min., 0.70 max.)

Sheets Strips

77 77

53 53

23 23

Rb 83 Rb 83

��

– – – – –

442

(544200)

18-23 Cr, 0.20 C, 10 Mn, 1.0 Si, 0.040 P, 0.030 S

Bars 80 45 20 Rb 90 ��

+ 70 – – – – 5 - 15

446

(S44600)

23-27 Cr, 0.20 C, 1.5 Mn, 1.0 Si, 0.040 P, 0.030 S, 0.25 N


80 85 80 80 80 95**

50 55 50 50 50 80**

25 25 20 20 25 15**

Rb 86 Rb 84 Rb 83 Rb 83 Rb 84 Rb 92**

��

+ 70 – – – – 2 - 10

Martensitic 403 (540300)

(c) 11.5-13.0 Cr, 0.15 C, 1.0 Mn, 0.5 Si, 0.040 P, 0.030 S

Bars Sheets Strips Tubing Wire

75 70 70 75 95**

40 45 45 40 80**

35 25 25 35 15**

Rb 82 Rb 80 Rb 80 Rb 80 Rb 92**

��

Same as type 410


29




1000 °F

1100 °F

1200 °F

1300 °F

1500 °F

Max Con-


Max Inter-


Initial



Stress-Relief


°F

Melting Range, °F

AISI Type

(UNS)

Characteristics and Applications

347 (534700)

Similar to type 321.

32 23 16 10 2 1650 1550 2100-2300 1850-2050 400-750(e) 2550-2600 348 (S34800)

Similar to type 321. Used for nuclear energy applications due to low reten-tivity.

– – – – – – – 2100-2250 1900-2100 – 2550-2650

384 (S38400)

Used for severe cold-heading or cold-forming. Lower cold-work hardening rate than type 304. For bolts, rivets, screws, and instrument parts.

8.4 – – – – 1400 1450 1950-2050 Low anneal 1350-1500

– 2700-2790

405 (S40500)

Nonhardenable grade for assemblies where air-hardening types (410 or403) are objectionable.

– – – – – – – – 1625 – 2600-2750

409

(S40900)

General-purpose construction stain-less primarily intended for automo-tive exhaust systems, structural and other applications

– – – – – – – 1900-2050 1450-1550 – 2650-2750

429

(542900)

Improved weldability as. compared to type 430.. For use m nitric acid and nitrogen-bxation equipment.

8.5 4.7 2.6 1.4 – 1550 1650 1900-2050 Low anneal 1400-1500

– 2600-2750

430 (S43000)

General purpose nonhardenable chro-mium type. Used for decorative trim, nitric acid tanks, annealing baskets.

430F

(S43020)

Free-machining modification of type 430, for heavier cuts and screw ma-chine parts.

8.5 4.6 1.9 1.3 – 1500 1600 1950-2100 Low anneal 1250-1400

– 2600-2750 430FSe (S43023)


– – – – – – – 1900-2050 1450-1550 – 2600-2750

434

(S43400)

Modification of type 430 designed for use as automotive trim to resist atmos-pheric corrosion in the presence of winter road-conditioning and dust-laying compounds.

– – – – – – – 1900-2050 1450-1550 – 2600-2750

436 (543600)

Similar to type 434 for general corro-sion- and heat-resistant applications.

8.5 5 1.6 1 0.6 1800 1900 1600-2100 1300 – 2600-2750

442 (544200)

High chromium steel. Usedprincipally for parts which must resist high tem-peraturesin service, without scaling–furnace parts, nozzles, combustion chambers.

– 6.4 2.9 1.4 0.6 0.4 1950 2050 1950-2050 1450-1600 2600-2750

446

(544600)

High resistance to corrosion and scaling at high temperatures especially for in-termittent service. Often used m sul-fur-bearing atmosphere.

Hardening and Tempering,

Temperature, F

11 4.5 2 1.4 – 1300 1450 2000-2200(f) 1500-1650(8) 1200-1400(h) H1700-1850(d)

T 400-1400(1)

2700-2790

403

(540300)

“Turbine quality” grade for steam tur-bine blading and other highly stressed parts.


30

Table 1 continued

Typical Properties of Wrought Stainless Steel (Continued) Mechanical Properties of Annealed Material

at Room Temperature Nominal Properties of Annealed Material

at Low Temperature

AISI Type

(UNS)

Composition, % (a)

Max. (iI Typical not designated otherwise)

Form (b)

Tensile

Strength, 1000 Psi

Yield Strength(0.2% Offset),

1000 Psi

Elonga- tion m

2 In., %

Hard- ness

Tem- pera- ture,

°F

Tensile

Strength, 1000 Psi

Yield

Strength, 1000 Psi

Elonga- tion in

2 In., %

Red uc- tion in Area,

%

Izod Impact

Strength, Ft-Lb

410 (S41000)

11.5-13.5 Cr, 0.15 C, 1.0 Mn, 1.0 Si, 0.040 P, 0.030 S


75 70 70 70 75 75

40 35 45 45 40 40

35 30 25 25 30 30

Rb 82 Bhn 150Rb 80 Rb 80 Rb 82 Rb 82

��

+ 70 + 32 – 40 – 80 – 320

–

110 115 122 128 158 –

87 89 90 94

148 –

21 24 23 22 10 –

68 69 64 60 11 –

85 40 25 25 5 –

414

(S41400)

11.5-13.5 Cr, 1.25-2.50 Ni, 0.15 C, 1.0 Mn, 1.0 Si, 0.040 P, 0.030S

Bars Plates Sheets Strips Wire

115 115 120 120

135**

90 90

105 105 115**

20 20 15 15

10**

Bhn 235Bhn 235Rb 98 Rb 98 Rc 29**

��

+ 70 – – – – 40 - 80

416

(541600)

12-14 Cr, 0.15 C, 1.25 Mn, 1.0 Si, 0.060 P, 0.15 S min, 0.60 Mo (optional)

416Se (S41623)

12-14 Cr, 0.15 C, 1.25 Mn, 1.0 Si, 0.060 P, 0.060 S, 0.15 Se min

Bars Tubing Wire

75 75 75

40 40 40

30 30 20

Rb 82 Rb 82 Rb 82

��

+ 70 – 100 – 300

– – – – 20 - 64

50 3

420 (542000)

12-14 Cr, 0.15 C min, 1.0 Mn, 1.0 Si, 0.040 P, 0 .030 S

Bars Wire

95 95

50 50

25 20

Rb 92 Rb 92

��

+ 70 + 32 – 40 – 80

– – – –

10 10 8 7

420F (S42020)

12-14 Cr, over 0.15 C, 1.25 Mn, 1.0 Si, 0.060 P, 0.15 S Min, 0.60 Mo max (optional)

Bars Wire

95 100

55 80

22 15

Bhn 220Rb 99

��

– – – – – –

422 (542200)

11-13 Cr, 0.50-1.0 Ni, 0.20-0.25 C, 1.0 Mn, 0.75 Si, 0.025 P, 0.025 S, 0.75-125 0.15-0.30 Mo, V, 0.75-1.25 W

Bars 145 125 18 Bhn 320 – – – – –

431

(S43100)

15-17 Cr, 1.25-2.50 Ni, 0.20 C, 1.0 1.0 Si, 0.040 Mn, P, 0.030 S

Bars Wire

125 135**

95 115**

20 10**

Bhn 260Rc 29**

��

+ 70 + 32 – 40 – 80

– – – –

50 50 30 17

440A (S44002)

16-18 Cr, 0.60-0.75 C, 1.0 Mn, 1.0 Si, 0.040 P, 0.030 S, 0.75 Mo

Bars Wire

105 105

60 60

20 18

Rb 95 Rb 95

��

– – – – – –

440B

(S44003)

16-18 Cr, 0.75-0.95 C, 1.0 Mn, 1.0 Si, 0.040 P, 0-030 S, 0.75 Mo

Bars Wire

107 107

62 62

18 16

Rb 96 Rb 96

��

– – – – – –

440C

(544004)

16-18 Cr, 0.95-1.20 C, 1,0 Mn, 1.0 Si, 0.040 P, 0.030 S, 0.75 Mo

Bars Wire

110 110

65 65

14 13

Rb 97 Rb 97

��

– – – – – –

Precipitation

S13800

Hardening 12.25-13.25 Cr, 7.5-8.5 Ni, 0.05 C, 0.10 Mn, 0.10 Si, 0.010 P, 0.008 S, 0.90-1.35 Al, 2.0-2.5 Mo, 0.010 N

Bars Plates

160*** 160

120 120

17 17

Rc 33 Rc 33 – – – –

Charpy 60

Charpy 60

S15500 14-15.5 Cr, 3.5-5.5 Ni, 0.07 C, 1.0 Mn, 1.0 Si, 0.040 P. 0.030 S, 2.5-4.5 Cu, (Cb+Ta 0.15-0.45)

Bars Plates Steps

160*** 160 160 160

145 145 145 145

15 15 15 15

Rc 35 Rc 35 Rc 35 Rc 35

– – – –

Charpy 30

Charpy 30

Charpy 30

Charpy 30

S17400 15.5-17.5 Cr, 3-5 Ni, 0.07 C, 1.0 Mn, 1.0 Si, 0.040 P. 0.030 S, 3-5 Cu, (Cb+Ta 0.15-0.45)

Bars Plates Sheets

160*** 160 160

145 145 145

15 15 5

Rc 35 Rc 35 Rc 35

– – – –

Charpy 30

Charpy 30

S17700 16-18 Cr, 6.5-7.75 Ni, 0.09 C, 1.0 Mn, 1.0 Si, 0.040 P, 0.040 S, 0.75-1.50 Al

Bars Plates Sheets

130*** 130 130

40 40 40

10 10 35

Rb 90 Rb 90 Rb 85

– – – – –


31




1000 °F

1100 °F

1200 °F

1300 °F

1500 °F

Ma. Con-


Me- Inter-


Initial



Stress-Relief


°F

Melting Range, °F

AISI Type

(UNS)

Characteristics and Applications Applications

11.5 4.3 2 1.5 – 1300 1450 2000-2200(f) 1500-1650(g) 1200-1400(h)

H1700-1850(d)T 400-1400(i)

2700-2790

410

(541000)

General purpose heat treatable type, for machine parts, pump shafts.

– – – – – 1300 1450 2100-2200 –

1200-1300(h) H1800-1900(d)T 400-1300(i)

–

414

(541400)

Higher hardenability steel for springs, tempered rules, machine parts.

416 (541600)

Free-machining modification of type 410, for heavier cuts.

11 4.6 2 1.2 – 1250 1400 2100-2300(f) 1500-1650(g) 1200-1400(h)

H1700-1850(d)T 400-1400(i)

2700-2790 416Se (S41623)


9.2 4.2 2 1 – 1200 1400 2000-2200(j) 1550-1650(g) 1350-1450(h)

H1800-1900(d)T 300-700

2650-2750

420 (542000)

Higher carbon modification of type 410 often used for cutlery, surgical instruments, valves and other wear-resisting parts.

– – – – – – – 2050-2250 1550-1650(f) H1800-1900(d)T 300-700

2650-2750

420F (542020)

Free-machining modification of type 420.

– – – – – – – 2100 1350-1450 H1900 2675-2700

422 (542200)

High strength and toughness at serv-ice temperatures up to 1200°F, such as far steam turbine blades and fasteners.

6.8 3.5 – – – 1500 1600 2100-2250(j) –

1150-1225(h) H1800-1900(d)T 400-1200(i)

–

431

(S43100)

Special-purpose hardenable steel usedwhere particularly high mechanical properties are required–aircraft fit-tings, heater bars, paper machinery, bolts.

– – – – – 1400 1500 1900-2200(i) 1550-1650(g) 1350-1450(h)

H1850-1950(d)T 300-800

2500-2750

440A (S44002)

Hardenable to higher hardness than type 420 with good corrosion resist-ance. Used for cutlery, bearings, sur-gical tools.

– – – – – 1400 1500 1900-2150(j) 1550-1650(g) 1350-1450(h)

H1850-1950(d)T 300-800

2500-2750

4408

(544003)

Cutlery grade; for finest types of stain-less cutlery, valve parts, and other wear resisting and high hardness parts.

– – – – – 1400 1500 1900-2100(i) 1550-1650(g) 1350-1450(h)

H1850-1950(d)T 300-800

2500-2750

440C (544004)

Yields highest hardnesses of harden able stainless steels farballs, bearings, bearings, races.

– – – – – – – 2150 – H950-1150 2560-2625 513800

Martensitic precipitation hardening (maraging) stainless that can be hardened by a single low-temperature heat treatment.

– – – – – – – 2150 – H900-1150 2560-2625 515500

Martensitic precipitation hardening (maraging) stainless with high strength, hardness, and corrosion resistance.

– – – – – – – 2150 – H900-1150 2560-2625 517400 Similar to 515500 but with slightly higher chromium content.

– – – – – – – 2150 – H900-1050 2560-2625 517700

Semi-austenitic precipitation harden-ing stainless. Can be cold drawn and then hardened by a low-tempera-ture heat treatment,


*** Mechanical properties of the precipita-tion hardening stainless steels are for a solution treated condition.

32

Table 2

Relative Corrosion Resistance of AISI Stainless SteelsAtmospheric Chemical

TYPE Number

UNS Number

Mild Atmos- pheric and

Fresh Water Industrial Marine

Salt Water Mild

Oxidizing Reducing

201 (S20100) x x x x x 202 (S20200) x x x x x 205 (S20500) x x x x x 301 (S30100) x x x x x 302 (S30200) x x x x x 302B (S30215) x x x x x 303 (S30300) x x X

303 Se (S30323) x x X

304 (S30400) x x x x x 304L (S30403) x x x x x (S30430) x x x x x 304N (S30451) x x x x x 305 (S30500) x x x x x 308 (S30800) x x x x x 309 (S30900) x x x x x 309S (S30908) x x x x x 310 (S31000) x x x x x 310S (S31008) x x x x x 314 (S31400) x x x x x 316 (S31600) x x x x X X X

316F (S31620) x x x x X X X

316L (S31603) x x x x X X X

316N (S31651) x x x x x x x 317 (S31700) x x x x x x x 317L (S31703) x x x x x x 321 (S32100) x x x x x 329 (S32900) x x x x X X X

330 (N08330) x x x x x x X

347 (S34700) x x x x x 348 (S34800) x x x x x 384 (S38400) x x x x x 403 (S40300) x X

405 (S40500) x X

409 (S40900) x X

410 (S41000) x X

414 (S41400) x X

416 (S41600) x 416 Se (S41623) x 420 (S42000) x 420F (S42020) x 422 (S42200) x 429 (S42900) x x x x 430 (S43000) x x x x 430F (S43020) x x X

430F Se (S43023) x x X

431 (S43100) x x x X

434 (S43400) x x x x x 436 (S43600) x x x x x 440A (S44002) x x 440B (S44003) x 440C (S44004) x 442 (S44200) x x x x 446 (S44600) x x x x x (S13800) x x x x (S15500) x x x x x (S17400) x x x x x

(S17700) x x x x x

*The “X” notations indicate that a specific stainless steel type may be

considered as resistant to the corrosive environment categories.

This list is suggested as a guideline only and does not suggest or imply a warranty on the part of the American Iron and Steel Institute, the Commit-

tee of Stainless Steel Producers, or any of the member companies rep-resented on the Committee. When selecting a stainless steel for any corrosive environment, it is always best to consult with a corrosion en-gineer and, if possible, conduct tests in the environment involved under actual operating conditions.

References

1. American Iron and Steel Institute, “Steel Products Manual-Stainless and Heat Resisting Steels,” Washington, D.C., 1974

2. American Society for Testing and Materials, “Compilation of Trade Names, Specifications, and Producers of Stainless Alloys and Superalloys,” Data Series DS 45, Philadelphia, Pa., 1969

3. Society of Automotive Engineers, New York, N.Y.

4. American Society for Testing and Materials, Philadelphia, Pa.

5. Climax Molybdenum Company, “A Guide to Corrosion Resistance,” New York, N.Y.

6. Forging Industry Association, “Forging Industry Handbook,” Cleveland, Ohio, 1966

Documents

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