SS 301
An austentic stainless steel, because of its ability to attain high strength and ductility through moderate or severe cold working, can be used for automobile trims, conveyor belts, transportation cars such as railway coaches, metal fixtures for construction purposes, roof drainage products, storm door-frames, table-ware etc.
SS 304
It is the most widely used austentic stainles steel. It has excellent corrosion resistance and forming characteristics. Used in chemical, petro-chemical and fertiliser industries, and as equipment in dairy, food processing, pharmaceutical industries in hospitals, households as kitchen wares, sinks, cutlery, cryogenic vessels and as heat exchangers in air-conditioning, refrigeration, for madhinmery in paper, pulp, textile beverage sectors etc.
SS 304L
It is used in place of SS 304 for improved resistance to inter-granular corrosion. It is used for parts and structures which can not be heat trteated for stress relieving after welding. Has less tendency to work harden.
SS 310S
These are austentic types with higher Chromium and Nickel content. Because of their relatively hiofh creep strength and mechanical properties at higher temperatures these steel find application for higher temperatures and severe service conditions. Used for air heaters, annealing boxes, ovens, carburising boxes, fire box sheets furnace linigs, furnace stacks and dampers, gas turbine parts, heat exchangers kiln lining, nozzle diaphragm assemblies for turbo jet engines, oil burner parts, paper mill equipment, oil refinery equipment, recuperators etc.
SS 316
An austentic stainless steel with 2.0 to 3% Mo. which improves corrosion resistance against halogens imparts hot strength charactersistics. Used for applications requiring resistance to pitting corrosion and halogen atmospheres. Typical applications : architectural trims, marine exteriors, chemical processing equipment, food processing equipment, petroleu, refining equipment, pharmaceutical equipment, photyographic equipment, pulp and paper processing equipment, textile finishing equipment, pollution control etc.
SS 316 L
Recommended in place of 316 when weldability has to be improved.
SS 321
An austentic stainless steel similar to SS 304 but stabilized with titanium to avoid inter-granular corrosion. Type SS 321 resists scaling and vibration fatigue. It is used for aircraft exhaust stacks and manifolds pressure vessels, large mufflers for stationary dieselengines, carburetors, expansion bellows, stack liners, fire walls, super heaters etc.
SS 409/409 M
It is the lowest alloyer straight Chromium ferritic stainless steel. It replaces carbon steels and low alloy steel where some amount of heat or corrosion resistance and higher strength is required and where appearance is secondary. It is used fo fins is heater tubes, automotive exhaust systems including mufflers, resonators, silencers, pipes and emission contro units, high pressure agricultural spray tanks, culverts, shipping continers, farm equipment etc.
SS 410S
SS410 is the most commonly used 12% Chromium Stainless Steel. Excellent combination of toughness and strength can be developed. It is a good choice when good formability and high strength are required and the end use demands resistance to mildly corrosive environment. It is used for furnace parts and burners operatin below 650 O.C micrometer parts, tray supports, caps and vaporisers in petrolium fractionation toeres, lining for reaction chambers, coal screens filshing tackles, keys , brackets, rules and tapes, wall screens, stream turbine buckets blades, bucket covers, pump parts, petro-chemical equipment, press plates, etc.
SS 420
This steel contains min 0.15% C and 12 % Cr. It can be thermally hardened to develop very high strength, Extremely useful for cutlery. Other applications include vegetable choppers, scissors, shears, tweezers, hand tools, dental and surgical instruments, etc.
SS 430
SS 430 with 17% Cr. is inferior to SS 304 as sregards deep durability. Though it does not have good corrosion resistance properties as the Cr-Ni steels, it is used under less severe corrosive atmospheres for chemical processin equipment, furnace parts, heat exchangers, oil burner parts, petroleum rolling equimpent, pyrometers, protection tubes, recuperators, rubber plant machinery, scientific apparatus, storage vessels, tubing, television cones, electrical appliances, solar water heaters, air conditioners, kitchen ware, household appliances, decorative trims, parts for washing machines etc.
Welding
Selection of Welding Processes
General guidelines for selection of appropriate method of welding for different types of stainless steels in different thickness, keeping in view the advantages and limitations of the welding processes, are given below.
Selection of welding processes for stainless steels.