Things you didn’t know about stainless steel heat treatment

The heat treatment of stainless steel is to improve the processability, eliminate internal stress and prepare a good metallographic structure for the final heat treatment. Stainless steel heat treatment processes include annealing, normalizing, aging, and quenching and tempering. The following explains some of the stainless steel heat treatment processes and methods.

Stainless steel butt weld 180 degree elbows finished in Haihao Group

(1) Austenitic stainless steel

①Solid solution treatment: heating to the solid solution temperature (1050 ~ 1100 ℃), so that all carbides and martensite formed by cold working are melted and transformed into austenite, and then quickly cooled, this heat treatment can get the softest and The most plastic effect.

② Stress relaxation treatment: eliminate internal stress (275 ~ 450 ℃, 0.5 ~ 2h), mechanical properties can be improved.

③ Stabilizing treatment: Heating to 900 ° C will dissolve most of the chromium carbides, so that chromium carbides will no longer be precipitated between the grains.

④ Treatment to eliminate σ-phase: In the case of insufficient chromium in high chromium austenitic stainless steel, σ-phase may be generated during the heat treatment of stainless steel forgings, which will reduce the impact toughness value of steel. Therefore, the temperature of σ-phase formation (500 ~ 970 ° C) should be avoided during heat treatment.

Stainless steel forged threaded elbow A182 F316 90 degree

(2) Martensitic stainless steel

Common heat treatments for martensitic stainless steel are annealing, quenching, and quenching.

The annealed structure is chromium-rich ferrite, which has low mechanical properties and poor corrosion. Therefore, in most cases, this type of steel is used after quenching and tempering.

Due to the different performance requirements of various types of forgings, the tempering heating temperature is not exactly the same.

Forgings that need to withstand impact loads should avoid tempering at 370 ~ 600 ℃.

(3) Precipitation hardened stainless steel

Heat treatment of precipitation hardened stainless steel forgings includes three processes: solid solution treatment, adjustment treatment and aging treatment.

Solid solution treatment: The treatment process is 1000 ~ 1030 ℃, lh, air cooling. The obtained structure is austenite plus a small amount of ferrite.

Adjustment treatment: The purpose of adjustment treatment is to obtain a certain amount of martensite, thereby strengthening the steel.

Aging: It is another way to strengthen precipitation-hardened stainless steel. When the aging temperature is higher than 400 ° C, intermetallic compounds are precipitated from the martensite, which is highly dispersed and plays a role of precipitation hardening. Generally aging at 500 ° C, high hardness and strength can be obtained.

The above is the content of stainless steel heat treatment. We are a professional manufacturer of flanges, pipes and forgings, and have extensive experience in stainless steel heat treatment. If you want to learn about other stainless steel heat treatment (such as ferritic stainless steel, martensitic-ferritic steel). For more information,please click the link: www.haihaoping.com