309S
Brief introduction
309S stainless steel is a highly alloyed austenitic stainless steel used for its excellent oxidation resistance, high-temperature strength, and creep resistance. The lower nickel content of Stainless Steel 309, compared to Stainless Steel 310, improves its resistance to hydrogen sulfide (H2S) attack at high temperatures. It is tough and ductile and can be readily fabricated and machined. SS 309S is the low-carbon version, and is recommended for applications where sensitization and subsequent corrosion by high temperature gases or condensates during shutdown may pose a problem.

Chemical composition

C	Si	Mn	Cr	P	S	Ni
≤0.08	≤1.00	≤2.0	22.0-24.0	≤0.045	≤0.03	12.0-15.0

Physical property

Tensile Strength	Yeild Strength	Elongation	Reduction of Area	Density
≥515MPa	≥205MPa	≥40%	≥50%	7.98g/cm3

Application
stainless steel 309s is used for its high-temperature oxidation resistance and resistance to H2S attack for applications such as furnace parts, muffles, retorts, firebox sheets, high-temperature containers, catalytic converters, and exhaust systems, radiant tubes, fluidized bed coal combusters, petroleum refineries and steam boilers, thermowells, carbon saggers, paper mill equipment, power boiler tube hangers, anchor bolts, gladd forming equipment, food processing industry.

310S
Brief introduction
310S stainless steel is a highly alloyed austenitic stainless steel designed for elevated-temperature service. The high Cr and Ni contents enable this alloy to resist oxidation in continuous service at temperatures up to 1200°C, provided reducing sulfur gases are not present. In intermittent service, it can be used at temperatures up to 1030°C as it resists scaling and has a relatively low coefficient of expansion. This alloy has superior resistance, compared to both SS 304 and SS 309, in carburizing and reducing environments.

Chemical composition

C	Si	Mn	Cr	P	S	Ni
≤0.08	≤1.00	≤2.0	24.0-26.0	≤0.035	≤0.03	19.0-22.0

Physical property

Tensile Strength	Yeild Strength	Elongation	Reduction of Area	HB	Density
≥520MPa	≥205MPa	≥40%	≥50%	≤187	7.98g/cm3

Application
SS 310 types are used for their high-temperature oxidation resistance in applications such as furnace parts and shafts, mufflers, radiant tubes, ammonia converters, carbon saggers, power boiler tube hangers, brazing fixtures, glass forming equipment, chemical process industry, food processing.