Steel 4320

Aging Procedure

Not applicable to this alloy.

Annealing Procedure

Anneal at 1600 F and slow furnace cool.

Cold Workability

The alloy is readily cold worked, in the annealed condition, by conventional methods.

Forgeability

Forge at 2200 F down to 1900 F.

Formability

Forming characteristic are good in the annealed condition.

Hardening Procedure

See "Heat Treatment" and "Tempering". Also hardens by cold working.

Heat Treatability

Heat treatment response is best if the alloy is first normalized at 1650 F and air cooled. It then can be heat treated at 1500 F followed by an oil quench and tempering to desired hardness.

Hot Workability

Hot working may be done at 1900 F down to 1600 F.

Machinability

Machinability is good in the annealed condition, but difficult to machine once the alloy has been hardened by heat treatment. In the hardened condition it is best to use grinding operations.

Principle Design Features

This is an oil hardening chromium, nickel, molybdenum low alloy steel of good strength and toughness, with relatively low carbon content for good weldability.

Tempering Procedure

Tempering temperature depends upon hardness desired. Temper at 400 F to 1300 F. A 400 F temper will give a hardness of approximately 450 Brinell and a 1200 F temper will give 250 Brinell.

Weldability

Weldability of 4320 is good by all conventional methods.