There are three heat treatment processes for flange forging. Today, let's learn:
Solid solution treatment of flange forging
The solid solution treatment temperature of flange forging is 950-1150 ℃, and the holding time of stainless steel flange is 20-30% longer than that of general alloy steel. For the cooling of flange forging, attention should be paid to the rapid cooling of carbide formation temperature range (450-850 ℃); There are many kinds of cooling methods, mainly when the chromium content of the raw material of quench flange is greater than 22%, and the nickel content is higher and the carbon content is greater than 0.08; Stainless steel with carbon content of flange raw material not greater than 0.08% but effective size greater than 3mm shall be water-cooled. The carbon content of flange raw material shall not be greater than 0.08%, and the effective size shall be less than 3mm. The stainless steel shall be air-cooled. Thin parts with flange size less than 0.5mm can be air cooled.
Stabilization treatment of flange forging
Stabilization treatment is a heat treatment method for austenitic stainless steel flanges containing nd or Ti. 1) Stabilization treatment temperature of flange forging: higher than the dissolution temperature of chromium carbide (450-870 ℃) and lower or slightly higher than the dissolution temperature of tic and NBC (750-1120 ℃). 870-950 ℃ is generally recommended.
2) Holding time: 2-4 hours (according to workpiece shape, alloy elements, etc.).
The insulation time of 25mm in thickness or diameter shall be 2 hours, and 1 hour shall be added if it exceeds.
3) Cooling: small cooling rate, such as air cooling or furnace cooling.
Stress relief annealing of flange forging
1) The stress relief annealing process of austenitic stainless steel flange shall be selected according to the material, service environment, purpose of stress relief and workpiece shape and size of austenitic stainless steel flange. 2) The purpose of stress relief annealing is to remove residual stress, reduce stress corrosion cracking and ensure the stability of the final dimension of the flange.
