440B stainless steel is a high carbon martensitic stainless steel containing good strength, moderate corrosion resistance and ability to obtain and maintain wear resistance and excellent resistance.

Applications:
Suitable for applications requiring a combination of excellent wear resistance with moderate corrosion resistance. 440B stainless steel is commonly used in the oil, gas, marine, food and medical industries. Typical applications include valve components, knives, bearings, surgical tools and cutlery.

Hardness (HB):265max

Hot Working: Hot working for grade 440B stainless steel takes place by pre-heating the steel to 760°C (1400°F) which is then followed by slowly increasing the temperature range to 1038-1204°C (1900-2200°F). After the hot working process, the material is then cooled slowly at room temperature followed by complete annealing.

Cold Working: 440B stainless steel can be slightly cold worked by common cold working methods.

Forging:Heat slowly and uniformly to 1180°C, allowing sufficient time for the steel to become heated through. Be careful not to overheat as this can cause a loss of toughness and ductility. Do not forge below 1010°C reheating if necessary. After forging cool slowly in furnace or thermoinsulating material, then anneal immediately. Air cooling after forging 440B may cause cracking.
Annealing: 440B stainless steel is annealed at 843-871°C (1550-1600°F) and then cooled very slowly in a furnace.
Hardening: 440B stainless steel is heated at 760°C (1400°F), soaked at 1010°C (1850°F) and finally cooled in oil or air.
Tempering: 440B stainless steel is tempered at 148°C (300°F) to obtain maximum properties and the maximum hardness that can be obtained is RC58.
Welding: Welding is not generally recommended for grade 440B stainless steel as it tends to harden in air. If this steel grade is welded the recommended temperature is 260°C (500°F) and for the post weld treatment the recommended temperature is 732-760°C (1350-1400°F). The post weld treatment should take place for 6 h and then the material should be cooled slowly in a furnace to avoid cracking. Similar high heat inputs and filler metal should be used during operations.
Machinability: 440B stainless steel is best machined in the annealed condition. Chip breakers are used to handle tough, stringy chips of grade 440B stainless steel. Ceramic or carbide tooling is best suited for this grade 440B stainless steel.

EN 10204/3.1 with all relevant data reg. chem. composition, mech. properties and results of testing.