Among the many austenitic stainless steel materials, 309 stainless steel has a higher chromium and nickel content than ordinary 18-8 austenitic stainless steel, so its heat and corrosion resistance is also relatively better, and can be used continuously at temperatures of up to 1090°C.
309 austenitic stainless steel
309 stainless steel can be used for the production of furnace components, furnace plates, high-temperature containers and welding wire. The material can also be used for many further applications using its heat resistance properties.
309 stainless steel plates should be forged at a temperature of around 1175°C and the forging temperature should not be lower than 980°C. After forging, the small forgings should be quickly air cooled or directly water quenched. For optimum corrosion resistance, annealing should also be carried out after forging.
Heat treatment annealing of 309 stainless steel should be carried out at a temperature of 1040-1120°C.
The machinability of this material is similar to that of other 18-8 austenitic stainless steels. Maximum feed rates and slow speeds provide optimum cutting performance. Cold working on the product also improves the surface finish.
In terms of weldability, 309 stainless steel can be welded by shielded fusion and resistance methods, but oxyacetylene welding should be avoided to prevent carbon absorption in the weld seam. The risk of weld cracking is minimal. If filler metal is required, 309 or 309L bars are recommended. Post-weld annealing will prevent intergranular corrosion from occurring.
Similar to 309 stainless steel, 310 stainless steel has a significantly higher chromium and nickel content than normal 18-8 austenitic stainless steel.
It is a high temperature austenitic stainless steel and can be used continuously at temperatures up to 1150°C and intermittently at temperatures up to 1090°C. It has good resistance to oxidation, carburising and sulphur containing environments. It has also proven good resistance to the marine environment.
310 stainless steel sheet should be forged at around 1175°C and not below 980°C. Small parts should be fast air cooled or water quenched directly after forging. The best corrosion resistance is obtained if the parts are annealed after forging.
310 stainless steel parts should be annealed at 1040 – 1120°C and water quenched.
310 stainless steel can be welded by shielded fusion and resistance methods, again without the use of oxyacetylene welding, which prevents carbon absorption in the weld seam. The risk of weld cracking is minimal. If filler metal is required, 310 root rod is recommended. Annealing after the welding process will prevent intergranular corrosion from occurring.