440A stainless steel
Name: martensitic stainless steel
Standard: AISI, ASTM
Model: 440A
UNS Number: S44002
● 440A features and applications:
440A stainless steel hardened excellent performance, high hardness, compared with 440B and 440C steel, steel with high toughness. Used as cutting tools, measuring tools, bearings.
● 440A chemical composition ①:
Carbon C: 0.60 ~ 0.75
Manganese Mn: ≤ 1.00
Si Si: ≤ 1.00
Chromium Cr: 16.0 ~ 18.0
Ni-Ni ②: -
Phosphorus P: ≤ 0.04
Sulfur S: ≤ 0.03
Mo Mo: ≤ 0.75
Note: ① single value unless otherwise stated herein, are the highest value; ② pipe technology for some time, some types of austenitic stainless steel containing nickel must be slightly higher than the values shown in the table; ③ free; ④ the highest amount of Ta containing 0.10%; ⑤ the highest content of 0.75%; ⑥ the highest content of 0.70%
440A-440B-440C carbon content and hardness by the successive ABC increase (A-0.75%, B-0.9%, C-1.2%). 440C is an excellent high-end stainless steel, hardness is usually to 56-58RC. This three resist rust are good, 440A best, and 440C the least. 440C with the very common.
Martensitic stainless steel chemical composition is characterized in the 0.1% -1.0% C, 12% -27% Cr, based on a combination of different components to add molybdenum, tungsten, vanadium, and niobium and other elements. As the organizational structure for the body-centered cubic structure, and thus a sharp decline in strength at high temperatures. In 600 ℃, high temperature strength of stainless steel in various types of the highest, the highest creep strength. 440A hardened excellent performance, high hardness, compared with 440B and 440C steel, steel with high toughness. 440B for cutting tools, measuring tools, bearings and valves, compared with 440A steel, high hardness, high toughness than 440C steel. 440C has all stainless steel, the highest hardness of heat-resistant steel used for nozzles, bearings. 440F 440C is to improve the performance of steel-cutting steel, used for automatic lathes.
