What is an appropriate temperature for the solution heat treatment of 10 mm thick austenitic stainless steel?
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I’m seeking advice from fellow forum members: For an austenitic stainless steel head with a thickness of 10 mm, is it necessary to carry out solution heat treatment after it has been formed by spinning? If solution heat treatment is to be carried out, what temperature is appropriate to use? The relevant literature specifies a wide range of temperatures for solution heat treatment, generally between 1050 and 1100 degrees. For 10 mm thick austenitic stainless steel, I would appreciate it if you could advise me on the appropriate temperature to use for solution heat treatment.
Each austenitic stainless steel has a specified solubilization temperature range, as required by the material standards.
Cold spinning; no solution treatment required
For 10mm stainless steel, either cold stamping or cold spinning can be used; it depends on the diameter – generally, cold stamping is sufficient. The cold forming deformation rate does not exceed the standard requirements, so heat treatment is generally not necessary. Why is solution treatment still required?
The purpose of solubilization treatment for stainless steel is to dissolve carbides in austenite as much as possible at high temperatures, and to retain a single-phase austenitic structure through rapid cooling, thereby improving the corrosion resistance of the stainless steel. The heating temperature for solution treatment is generally between 1050–1150°C; the lower limit is used when the carbon content is low, while the upper limit is used when it is high. Due to the poor thermal conductivity of stainless steel, the holding time during solution treatment is relatively long; the calculation for this holding time is 1–2 minutes per millimeter. When heating stainless steel, it is particularly important to prevent carbon pickup, as this will increase the tendency of intergranular corrosion in the stainless steel. Therefore, oil residues on the surface of the workpiece must be removed before heating, in order to maintain a neutral or slightly oxidizing atmosphere inside the furnace. The problem of coarse grains is mainly addressed by controlling the holding time to prevent excessive heating. Solution treatment is primarily aimed at obtaining a single-phase austenitic structure; therefore, the main issue is to prevent the formation of carbides, while other issues should be secondary. After solution treatment, the structure is generally single-phase austenite, with sometimes a small amount of ferrite present.