A6 Tool Steel

A6 de-carb free tool steel is an air hardening tool steel with higher manganese and lower chromium and carbon than A2, offering moderate wear resistance and toughness. It has the advantage of hardening from a lower austenitizing temperature for easy heat treatment. A6 hardens with very little movement or distortion. A6 offers medium resistance to softening at elevated work temperatures, medium to high resistance to decarburization, and has good machinability. One main advantage of A6 is its deep hardening with high safety in hardening.

ANALYSIS

A.I.S.I. A6 conforms to ASTM A681

APPLICATIONS

Typical applications for A6 tool steel are blanking dies, forming dies, trim dies, stamping dies, coining dies, notching dies, bending tools, rim rolls, punches, cams, thread roll dies, spindles, retaining rings, master hobs, precision tools, mandrels, compression molds, plastic molds requiring high hardness, ball screws, lead screws, general purpose tooling, etc

HEAT TREATING

FORGING

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 1600°F. After forging, cool slowly in lime, mica, dry ashes or furnace. A6 should always be annealed after forging.

ANNEALING

Heat slowly to 1350°-1375°F, hold until entire mass is heated through, and cool slowly in the furnace (20F per hour) to about 1000°F, after which cooling rate may be increased. Suitable precautions must be taken to prevent excessive carburization or decarburization.

STRESS RELIEVING

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

Preheating is often not necessary depending on the size and complexity of the part. If a preheat is desirable, a 1200°-1250°F temperature should be used. Heat slowly.

HARDENING

Parts at room temperature or as pre-heated should be placed in a hardening furnace operating at 1525°-1600°F. After parts have reached the furnace temperature, hold 20 minutes for small parts and up to 45 minutes for large parts

QUENCHING

A6 is a deep hardening tool steel and will reach full hardness by cooling in freely circulating air.

TEMPERING

A single temper (one hour at temperature for small pieces; proportionately longer time for larger sizes) is usually all that is required with tempering carried out in the range of 300°-1000°F. For most applications, the best combination of hardness and toughness is accomplished at 350°-400°F. Specimens 1 inch square by 3 inches long were air hardened from 1550°F and tempered at various temperatures for two hours. The resulting harnesses were as follows:

TOLERANCES

SPEEDY METALS ITEMS