At the first appearance, Stainless Steel 304 is very similar to Stainless Steel 321. When comparing the chemical composition of SS 321 and SS 304, it is clear that the chromium (Cr) and nickel (Ni) ranges of these alloys are very similar. So what makes the two Steel different from each other? Let us further discuss their chemical components, physical and mechanical properties and uses.
Stainless Steel 304 Sheets
Stainless Steel 304 is basic austenitic steel with “18/8” chromium-nickel. It is the most commonly used stainless steel. Stainless steel 304 has outstanding resistance to corrosion in a wide range of environments and when in contact with various corrosive media. Pitting and crevice corrosion can occur in chloride-containing environments. Stress corrosion cracking can occur at temperatures above 60 degrees C. Stainless steel 304 has good oxidation resistance up to 870 degrees C in intermittent service and 925 degrees C in continuous service. Fabrication methods, such as forging which require hot working will occur after uniform heating to 1149-1260 degrees C. The fabricated parts should then be cooled rapidly to ensure maximum resistance to corrosion.
Stainless Steel 304 Sheet is widely used in numerous applications which include Food processing equipment, kitchen benches, sinks, Architectural paneling, railings & trim, Chemical containers, Heat Exchangers, Woven or welded screens for mining & water filtration, etc.
Stainless Steel 321 Sheets
Stainless Steel 321 is basic austenitic “18/8” steel stabilized by Titanium additions which reduces or prevents carbide precipitation during welding. SS 321 is used because they are not prone to intergranular corrosion after heating within a range of 425-850 degrees C of carbide precipitation. Stainless Steel 321 is the grade of choice for applications in the range of temperatures up to around 900 degrees C, combining high strength, scaling resistance and phase stability with corresponding aqueous corrosion resistance. SS 321 Sheets have excellent forming and welding characteristics, are readily brake or roll formed and have excellent welding characteristics, excellent durability, even down to cryogenic temperatures. SS 321 performs well in the 425-900 ° C range, and especially where there are subsequent corrosive aqueous conditions.
Stainless Steel 321 Sheets are used for a wide variety of applications which include aircraft exhaust manifolds, expansion joints, bellows, furnace parts, thermal oxidizers, refinery equipment, high temperature chemical process equipment, heating element tubing, heat exchangers, screens for high temperature mineral processing, spiral welded tube for burner pipes and flues.