Martensitic high carbon stainless steel sheets 440A
This high-carbon high-chromium martensitic stainless steel is designed to provide stainless properties with excellent hardness.
It has moderate corrosion resistance as-annealed which has permitted its use in mild environments.
In some respects it behaves similarly to tool steels.
Type 440A attains a hardness of Rockwell C 56 and maximum toughness when heat treated.
Type 440A has been used for pivot pins, dental and surgical instruments, cutlery, valve parts, etc.
Chemistry data ( in weight % )
For maximum softness, this steel should be heated uniformly to 1550/1600ºF (843/871°c).
Soak and cool very slowly in the furnace. Brinell approximately 223.
Intermediate or process annealing treatment---heat uniformly to 1350/1400ºF (732/760°c).
May be cooled in the furnace or air cooled. Brinell hardness about 230.
Preheat to 1400/1500ºF (760/816°c), then heat to 1850/1950ºF (1010/1066°c); soak; quench in warm oil or cool in air.
Do not overheat.
When overheated, full hardness cannot be obtained.
Hardness of approximately Rockwell C 56/57 will be obtained on this steel.
To remove peak stresses and yet retain maximum hardness temper at least one hour at 300/350ºF (148/176°c).
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