|Analysis||Applications||Heat Treating||Tolerances||Speedy Metals items|
A2 tool steel is a 5% chromium medium alloy cold work tool steel possessing sufficient hardenability to be air hardened to 60 Rc surface hardness level with good depth of hardening. This widely used tool steel has low distortion in heat treatment, good machinability, good toughness for severe service, high abrasion resistance, and deep hardening properties in large sections. A2 has a fully spheroidized structure and has exceptionally low inclusion levels. A2 Plate is supplied in a de-carb free condition and produced oversize to finish to nominal thickness.
|Carbon (C)||Manganese (Mn)|
|Silicon (Si)||Chromium (Cr)||Molybdenum (Mo)||Vanadium (V)||Phosphorus (P)|
A.I.S.I. A2 conforms to ASTM A681, DIN 1.2363, SAE J437, J438
Typical applications for A2 tool steel are blanking, forming, and trim dies, stamping dies, coining dies, thread roller dies, knurls, knurling tools, mandrels, master hobs, cold forming tools, spindles, shear blades, slitter blades, molds, punches, block and ring gauges, punch plates, reamers, brick mold liners, forming rolls, etc.
Heating for forging must be done slowly and uniformly. Soak through at 1900-2000°F and reheat as often as necessary, stopping work when the temperature drops below 1650°F. After forging, cool slowly in lime, mica, dry ashes or furnace. A2 should always be annealed after forging.
Heat slowly to 1550-1600°F, hold until entire mass is heated through, and cool slowly in the furnace (40°F per hour) to about 1000°F, after which cooling rate may be increased. Suitable precautions must be taken to prevent excessive carburization or decarburization.
When desirable to relieve the strains of machining, heat slowly to 1050-1250°F, allow to equalize, and then cool in still air (Strain Relieving).
PREHEAT PRIOR TO HARDENING
Preheat slowly to 1350-1450°F and hold at this temperature until part is uniformly heated.
After thorough preheating, heat to 1750-1800°F. Hold the workpiece at the hardening temperature until it is completely and uniformly heated.
A2 is an air hardening steel and will develop full hardness on cooling in still air. To avoid scaling of the workpiece surface, controlled atmosphere or vacuum furnaces are recommended. If these types of furnaces are not available, salt baths or wrapping the part in stainless steel foil will provide a degree of surface protection in the hardening process, Parts should be allowed to cool to 150°F, or to where they can be held in the bare hand, and then temper immediately.
The tempering temperature may be varied according to the desired hardness. If maximum hardness is desired, tempering should be in the range of 300-400°F, but if a lower hardness is acceptable, tempering at 950°F will give the optimum combination of hardness and toughness. The Rockwell C hardness obtained on specimens 1 inch square when quenched in air from 1775°F and tempered at various temperatures, held for 4 hours, are as follows:
|Tempering Temperature°F||Rockwell C|
|1/4" A-2 De-Carb Free Tool Steel Plate||3/8" A-2 De-Carb Free Tool Steel Plate||1/2" A-2 De-Carb Free Tool Steel Plate|
|5/8" A-2 De-Carb Free Tool Steel Plate||3/4" A-2 De-Carb Free Tool Steel Plate||7/8" A-2 De-Carb Free Tool Steel Plate|
|1" A-2 De-Carb Free Tool Steel Plate||1-1/4" A-2 De-Carb Free Tool Steel Plate||1-1/2" A-2 De-Carb Free Tool Steel Plate|
|1-3/4" A-2 De-Carb Free Tool Steel Plate||2" A-2 De-Carb Free Tool Steel Plate||10.195" A-2 De-Carb Free Tool Steel Plate|