Type ASTM 440A, UNS S44002 high carbon martensitic SS strips, coils, sheets, plates
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.
Stainless Type 440A attains a hardness of Rockwell C 56 and maximum toughness when heat treated.
440A has been used for pivot pins, dental and surgical instruments, cutlery, valve parts, etc.
This steel makes fair permanent magnets.
Stainless Type 440A is not usually recommended to elevated temperature applications
since corrosion resistance is reduced when used in the annealed condition or hardened
and tempered above about 800ºF (427°c).
Stainless Type 440A has corrosion resistance generally similar to that of Type 410.
It has resisted corrosion from mild atmospheres, fresh water, steam, ammonia,
many petroleum products and organic materials, and several mild acid environments.Stainless Type 440A has a moderate degree of corrosion resistance in the annealed condition,
which has made it useful for such parts as pivot pins where the points only are hardened.
Better corrosion resistance is obtained by hardening and tempering below about 800ºF (427°c).
For optimum corrosion resistance, surfaces must be free of scale, lubricants, foreign particles,
and coatings applied for drawing and heading.
After fabrication of parts, cleaning and/or passivation should be considered.
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 C56/57 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).
This steel should be handled like high-speed tool steel. Preheat to 1400/1500ºF (760/816°c),
then heat slowly and uniformly to 1900/2200ºF (1038/1204°c).
Do not forge below 1700ºF (927°c), and reheat as often as necessary.
Cool in a furnace if possible or in warm dry lime or ashes.
Anneal after forging; cool to room temperature before annealing.
If annealed for maximum softness, this steel can be moderately cold formed, headed and upset.
For most machining operations, this steel cuts best when in the dead soft annealed condition.
Due to its high carbon content it machines somewhat like high-speed steel.
The use of carbide or ceramic tools is suggested.
Because chips are tough and stringy, chip curlers and breakers are important.
We are looking forward to your enquiries.
Please call +86 151 9025 7143, skype: paul_luhongxiang or send an email to
export @ ahoneststeel dot com