The main purpose of heat treatment for 304l stainless steel strip is to avoid hardening after cold rolling. Once hardening occurs, it will affect the mechanical properties of the finished product and cause the performance of the finished product to decline. It can be seen that heat treatment is very important. What are the commonly used heat treatment methods?
The commonly used heat treatment methods for 304l stainless steel strip are as follows:
1. Quenching, the austenite, austenite-ferrite and austenite-martensite varieties of stainless steel are usually heat treated by quenching, which can eliminate the traces left by the hot rolling process.
The specific quenching operation process is to first heat the stainless steel strip in a straight-through furnace. Usually, it needs to be heated to 1050-1150 °C to dissolve the carbides in the material, and then immediately cool. The cooling method is water cooling. It is easy to cause the material to be easily corroded in the future.
Quenching of cold-rolled 304l stainless steel strip can not only be used as heat treatment, but also as final heat treatment, but it should be noted that when quenching is used as final heat treatment, the heating temperature of the material is controlled at 1100 ~ 1150 ℃.
2. Annealing, cold-rolled stainless steel strips such as martensite, ferrite and martensite-ferrite generally need to be annealed.
When annealing, the annealing environment is required, and it is required to be carried out in the electric heating or gas bell furnace of air or protective gas. The annealing temperature is usually 750-900°C, and then it is cooled by air cooling or furnace cooling.
3. Cold treatment, cold treatment is to increase the strength of the stainless steel strip. Cold treatment is to intrude the 304l stainless steel strip after heat treatment or cold rolling into a low temperature medium for a period of time, and the temperature of the low temperature medium needs to be controlled at -40 ~ -70 ℃.
In order to avoid the increase of internal stress after cold treatment and affect the performance of stainless steel strip, it is also necessary to perform tempering treatment at a temperature of 350-500 °C.