METALS

OBJECTIVE: AM24.02

Identify, cut, drill, bend, shape, file, and grind cold metals.

Identifying Metals

Ferrous contain iron– must be painted Nonferrous has no iron Metals

ColorWeightTextureUseShapeSpark test

Identifying Metals

Spark TestCast iron- red linesHigh carbon steel- yellow lines/star burstsWrought iron- straw colored lines w/o bursts

Galvanized steel should not be cut or welded

Drilling

Center punch Drill- use oil Use round file to smooth hole

OBJECTIVE: AM25.01 Examine oxy-fuel procedures.

Oxy-Fuel Procedures

Used to cut through metal, heat for bending, or for welding

Fuels include propane, propylene, or acetylene

Acetylene is most often used Oxygen enhances the flame-will not

burn

Oxy-Fuel

Use soapy water to check for leaks in hoses

Acetylene pressure should be less than 15psi

Open the acetylene valve ¼ to ½ turn Only use spark lighter

Types of Flames

When first lit, you have a carbonizing flame

Oxygen is adding to make a neutral flame

Extra oxygen makes an oxidizing flame for special applications where extra heat is needed

Arc Welding AC- inexpensive welder used most of

the time DC- generator operated, used where

power is not available Some welders are both AC and DC

Welding

TIG- Tungsten Inert Gas Good for welding stainless steel &

aluminum Gas supply is helium & argon

MIG Welding Metallic Inert Gas Wire feed welder Can be used as automatic welder

Welding Equipment

Helmet leather gloves leather aprons leather welding jacket leather boots

Welding Equipment

Chipping hammer Clamps Vise grip clamps

Electrodes

Rods covered in flux Have a classification system

Example: E6011

Electrodes

6011 is good for all purpose work 6013 is also good but only has medium

penetration

Welding Procedures

Metal should be cleaned before welding ¼” or thicker metal should be beveled &

place 1/16 to 1/8” apart

Setting the Amperage

Amperage too low causes a narrow, high bead with poor penetration.

Amperage too high caused a flat bead with excessive spatter.

Correct amperage helps make a uniform bead with bead width and penetration depth equal to each other.

Welding in the flat position When the electrode sticks, wiggle it back

and forth Tapping or scratching methods can be

used to strike an arc Arc length should be the same as the

diameter of electrode.