Stainless steels are high-alloy steels which have higher corrosion resistance compared to other steels due to the presence of large amounts of chromium. Based on their crystalline structure, they are further divided into ferritic, austenitic, and martensitic steels.
Grade 309 stainless steel has high corrosion resistance and strength compared to 304 stainless steel. The following datasheet gives an overview of grade 309 stainless steel.
Grade 309 stainless steel can be machined similar to that of 304 stainless steel.
Grade 309 stainless steel can be welded using fusion or resistance welding methods. Oxyacetylene welding method is not preferred for welding this alloy.
Grade 309 stainless steel is hot worked at 1177°C (2150°F) followed by reheating at 982°C (1800°F). It can be then quenched rapidly. Post-work annealing can be done to restore its corrosion resistance property.
Grade 309 stainless steel can be headed, upset, drawn, and stamped even though it has high work hardening rate. Annealing is performed after cold working in order to reduce internal stress.
Grade 309 stainless steel is annealed at 1038-1121°C (1900-2050°F) followed by quenching in water.
Grade 309 stainless steel does not react to heat treatment. Strength and hardness of this alloy can be increased by cold working.
Grade 309 stainless steel is used in the following applications:
Fire box sheets
Other high temperature containers.