D-M-E #7D-M-E #7

A Unique StainlessA Unique Stainless

Holder Steel from D-M-E.Holder Steel from D-M-E.U.S. Patent # 6,045,633

• During the last 25 years, modified During the last 25 years, modified 420F stainless steels have become a 420F stainless steels have become a standard for mold bases worldwide.standard for mold bases worldwide.

• However, 420F grades possess However, 420F grades possess certain characteristics that are not certain characteristics that are not ideal for mold base applications. ideal for mold base applications.

These characteristics are:These characteristics are:

• brittlenessbrittleness

• inconsistent hardness inconsistent hardness

• crack sensitivitycrack sensitivity

• inhomogeneous microstructureinhomogeneous microstructure

• unsafe weldabilityunsafe weldability

In 1992, an intensive research In 1992, an intensive research

and development program was and development program was

started. The goal was to:started. The goal was to:

Develop a Superior Develop a Superior Stainless Mold Base SteelStainless Mold Base Steel

Experimental stainless steel chemistries, Experimental stainless steel chemistries, were produced as laboratory melts and were produced as laboratory melts and evaluated metallurgically, and from a evaluated metallurgically, and from a machining standpoint.machining standpoint.

Several analyses Several analyses were produced in were produced in 8,000 lb. pilot 8,000 lb. pilot ingots.ingots.

•These pilot heats were further modified These pilot heats were further modified

and extensively tested.and extensively tested.

•The final product, a new and improvedThe final product, a new and improved

D-M-E #7D-M-E #7, was successfully introduced in , was successfully introduced in

1996.1996.

•D-M-E #7D-M-E #7 is a pre - hardened is a pre - hardened free machining 400 series free machining 400 series martensitic stainless steel, martensitic stainless steel, designed and developed designed and developed specifically for improved specifically for improved plastics mold base tooling. plastics mold base tooling.

• D-M-E #7 D-M-E #7 is patented under is patented under U.S.patent # 6,045,633U.S.patent # 6,045,633

Features of Features of D-M-E #7D-M-E #7::

• Improved MachinabilityImproved Machinability

• Improved StabilityImproved Stability

• Improved DuctilityImproved Ductility

• Elimination of Brittle Elimination of Brittle FailuresFailures

• Consistent HardnessConsistent Hardness

• Superior WeldabilitySuperior Weldability

• Improved Plate SurfaceImproved Plate Surface and Appearanceand Appearance

IMPROVED MACHINABILITYIMPROVED MACHINABILITY• Enhanced surface finishes Enhanced surface finishes and threadsand threads when milling, when milling, drilling and tapping compared drilling and tapping compared with 420F.with 420F.

• Increased tool life Increased tool life with with faster machining feeds and faster machining feeds and speeds.speeds.

• Elimination of breakout Elimination of breakout problemsproblems when drilling with when drilling with carbide indexable drills.carbide indexable drills.

IMPROVED STABILITYIMPROVED STABILITY• D-M-E #7 D-M-E #7 plates provide improved plates provide improved dimensional stability after dimensional stability after machining and during molding. machining and during molding. • Special thermal treatments during Special thermal treatments during manufacture provide improved manufacture provide improved uniformity and reduced residual uniformity and reduced residual stresses.stresses.

D-M-E #7 D-M-E #7 plates remain flat and parallelplates remain flat and parallel after extensive machining. after extensive machining.

IMPROVED DUCTILITYIMPROVED DUCTILITY

• D-M-E #7D-M-E #7 shows improved ductility, shows improved ductility, a measure of a steel’s ability to be a measure of a steel’s ability to be deformed prior to fracture.deformed prior to fracture.

• Bend samples were tested to Bend samples were tested to illustrate the improved ductility of illustrate the improved ductility of D-M-E #7D-M-E #7 compared to 420F steels. compared to 420F steels.

BEND TEST RESULTSBEND TEST RESULTS

D-M-E #7D-M-E #7 samples samples cracked after bending 70 cracked after bending 70 degrees, but did not break.degrees, but did not break.

Samples of 420F cracked Samples of 420F cracked and broke into two and broke into two pieces after bending 30 pieces after bending 30 degreesdegrees..

D-M-E #7D-M-E #7 35HRC35HRC420F 35HRC420F 35HRC

MECHANICAL PROPERTIESMECHANICAL PROPERTIES

Material Tensile -ksi

Yield @ .2% - ksi

% El in 2”

% RA BHN HRC Avg. CVN Ft. Lbs

D-M-E #7 155 132 12 32 321 34 16 420F 155 135 9 20 321 34 8

Results of room temperature tensile and Charpy V-notch Results of room temperature tensile and Charpy V-notch impact tests using samples from rolled and heat treated 3” impact tests using samples from rolled and heat treated 3”

gauge plates.gauge plates.

D-M-E #7 D-M-E #7 displays superior ductility and displays superior ductility and notch toughness compared to 420F at notch toughness compared to 420F at

the same strength and hardness levels.the same strength and hardness levels.

ELIMINATION OF BRITTLE ELIMINATION OF BRITTLE FAILURES FAILURES

• D-M-E #7’sD-M-E #7’s increased increased toughness reduces the risk of toughness reduces the risk of plates cracking during the life of plates cracking during the life of the mold, and also reduces the the mold, and also reduces the risk of breakage caused by risk of breakage caused by machining pressures and machining pressures and stresses.stresses.

HARDNESSHARDNESSHARDNESSHARDNESS• D-M-E #7D-M-E #7 exhibits a more uniform and consistent exhibits a more uniform and consistent

hardness than 420F.hardness than 420F.

• D-M-E #7D-M-E #7 is supplied is supplied heat treated to a heat treated to a standard standard hardness of hardness of 32-36 HRC 32-36 HRC

(BHN 301-340).(BHN 301-340). (Maximum hardness attainable: 40 HRC)(Maximum hardness attainable: 40 HRC)

SUPERIOR WELDABILITYSUPERIOR WELDABILITY• D-M-E #7 D-M-E #7 is safe and easy to weld. is safe and easy to weld.

• D-M-E #7 D-M-E #7 filler metal produces filler metal produces virtually invisible welds, with virtually invisible welds, with consistent properties throughout consistent properties throughout the welded area. the welded area.

• The following two slides illustrate The following two slides illustrate the differences between the the differences between the microstructures and properties of microstructures and properties of welded 420F and welded welded 420F and welded D-M-E #7D-M-E #7..

420F WELD SAMPLE420F WELD SAMPLE

20HRC 54HRC 50HRC 48HRC 35HRC 35HRC

40X Photomicrograph showing undesirable high hardness in 40X Photomicrograph showing undesirable high hardness in heat affected zone near test weld on 420F sample. A 300 heat affected zone near test weld on 420F sample. A 300

series non - hardenable stainless filler metal is typically used series non - hardenable stainless filler metal is typically used when repair welding 420F to minimize risk of cracking.when repair welding 420F to minimize risk of cracking.

Weld Heat Affected Zone Base MetalWeld Heat Affected Zone Base Metal

D-M-E #7 D-M-E #7 WELD SAMPLEWELD SAMPLE

35HRC 35HRC 35HRC 35HRC

40X Photomicrograph showing uniform desirable hardness 40X Photomicrograph showing uniform desirable hardness throughout weld, heat affected zone and base metal of DME #7 throughout weld, heat affected zone and base metal of DME #7

sample, using DME #7 filler metal.sample, using DME #7 filler metal.

Weld Heat Affected Zone Base MetalWeld Heat Affected Zone Base Metal

IMPROVED PLATE SURFACE IMPROVED PLATE SURFACE AND APPEARANCEAND APPEARANCE

• D-M-E #7 D-M-E #7 possesses increased hot ductility possesses increased hot ductility resulting in smoother as rolled plate resulting in smoother as rolled plate surfaces, free of tears and surfaces, free of tears and cracks. Better as cracks. Better as rolled surfaces reduce rolled surfaces reduce the risk of surface cracks the risk of surface cracks remaining after machining.remaining after machining.

• Flat smooth surfaces also Flat smooth surfaces also mean less stock mean less stock removal to produce removal to produce finished sizes, finished sizes, requiring less machining and requiring less machining and lower material costs.lower material costs.

QUALITY CONTROLQUALITY CONTROL• D-M-E #7 D-M-E #7 is manufactured in accordance with is manufactured in accordance with

detailed specifications covering melting, rolling and detailed specifications covering melting, rolling and heat treating.heat treating.

• All production operations are controlled and All production operations are controlled and supervised, providing uniformity and quality in every supervised, providing uniformity and quality in every plate produced.plate produced.

• Standard metallurgical and production testing is also Standard metallurgical and production testing is also performed on all performed on all D-M-E #7D-M-E #7 plates produced, ensuring plates produced, ensuring a consistent product with unmatched quality.a consistent product with unmatched quality.

D-M-E No. 7, pre hardened 400 series Stainless Holder Steel.

D-M-E No. 7, 400 series Stainless Holder Steel is supplied pre heat treated to a standard hardness level of 302 BHN (30 HRC) to 340 BHN (36 HRC).

It is designed to be used at the supplied hardness.

Additional heat treatment is not recommended.

D-M-E No. 7 stainless cannot be heat treated like 420F.

D-M-E guarantees DME No. 7 can be used for mold base applications in the as supplied condition without further heat treatment.

D-M-E No. 7 can be reliably substituted for 420F, DIN 1.2085 and DIN 1.2316 for all applications requiring a hardness level of 302 BHN (30 HRC) to 340 BHN (36 HRC).

General Information:

D-M-E improved prehardened stainless holder steel, D-M-E No. 7, is a modified 400 series prehardened stainless holder steel designed and developed specifically for improved stainless mold base tooling. It is widely used and specified today by leading molders, mold makers and mold base builders throughout North America and abroad.

U.S. patent number 6,045,633 covers D-M-E No. 7

Features of DME No. 7, compared to 420F, include improvements in the areas of:

Stability (steel remains more stable after machining and during the life of the mold)

Mechanical properties (improved ductility and toughness)

Weldability (virtually invisible welds with uniformity throughout the welded area and base metal)

Machinability (improved speeds and feeds, better finishes)

Hardness uniformity (homogeneity, repeatability)

Thermal conductivity (approximately 15% better thermal conductivity)

D-M-E #7D-M-E #7

For improved stainless mold bases.For improved stainless mold bases.U.S. Patent # 6,045,633