440A stainless steel properties and applications

440A stainless steel properties and applications

440A stainless steel

UNS number: S44002

●440A features and applications:

●440A chemical composition ① :

Carbon C: {{0}}.60~0.75

Mn: Less than or equal to 1.00

Si: Less than or equal to 1.00

Chromium: 16.0~18.0

Nickel Ni② : -

P: Less than or equal to 0.04

Sulfur S: Less than or equal to 0.03

Molybdenum Mo: Less than or equal to 0.75

Note: a single value is the highest value unless otherwise indicated; When used in some pipe making processes, the nickel content of some types of austenitic stainless steel must be slightly higher than the value shown in the table; ③ at will; ④ The maximum Ta content is {{0}}.10%; ⑤ The highest content is 0.75%; ⑥ The highest content is 0.70%

The carbon content and hardness of 440A-440B-440C are progressively increased from A-B-C (A-0.75%, B-0.9%, C-1.2%). 440C is a very good high-end stainless steel, hardness usually reaches 56-58RC. The rust resistance of these three kinds of steel is good, 440A is the best, and 440C is the lowest. The 440C is very common.

The chemical composition of Martensitic stainless steel is characterized by the addition of molybdenum, tungsten, vanadium, niobium and other elements on the basis of different composition combinations of {{0}}.1%-1.0%C and 12%-27%Cr. Because the structure is body-centered cubic structure, the strength decreases sharply at high temperature. Below 600 degree , the high temperature strength is the highest in all kinds of stainless steel, and the creep strength is also the highest. 440A has excellent hardening performance, high hardness, and higher toughness than 440B steel and 440C steel. 440B is used for cutting tools, measuring tools, bearings and valves, and has higher hardness than 440A steel and higher toughness than 440C steel. 440C has the highest hardness of all stainless steel and heat-resistant steel for nozzles and bearings. 440F is a steel grade that improves the cutting performance of 440C steel and is used in automatic lathes.