Stainless Steel Properties
Nickel Alloys Chemical Composition
Stainless Steel Application
An austenitic stainless steel, which 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 and tableware.
It is the most widely used austenitic stainless steel. Popularly known as 18/8 stainless steel, it has excellent corrosion resistance and forming characteristics. Used in chemical, petrochemical and fertiliser industries and as equipment in dairy, food processing, pharmaceutical industries, in hospitals, households as kitchenware, cryogenic vessels and as heat exchangers, for machinery in paper, pulp, textile and beverage sectors.
An austenitic stainless steel similar to AlSI 304 with less carbon (0.03%max) is used in place of AISI 304 for improved resistance to inter-granular corrosion. It is used for parts and structures which cannot be heat treated for stress relieving after welding.
AISI 309 / AISI 309S
These are austenitic stainless steels which are strong and tough. Because of their higher nickel and chromium content, these are used for applications requiring high scaling resistance and corrosion resistance. They find their use for air heaters, annealing boxes, bake oven equipment, boiler oven equipment, boiler baffle plates, carburising boxes, chemical processing equipment, dryers,exhaust manifolds, furnace parts, gas turbine parts, heat exchangers, jet engine parts, oil burner parts, oven equipment, petroleum refining equipment, etc.
These are austenitic types with higher chromium and nickel content than 309/309S. Because of their relatively high creep strength and mechanical properties at higher temperatures these steels find their applications for higher temperatures and severe service conditions. Used for air heaters, annealing boxes, ovens, carburizing boxes, fire box sheets, furnace linings, furnace stacks and dampers, gas turbine parts, heat exchangers, kiln linings, nozzle diaphragm assemblies for turbo jet engines, oil burner parts, paper mill equipment, oil refinery equipment, recuperators and so on.
An austenitic stainless steel with 2.0 to 3.0% Mo. which improves corrosion resistance and imparts hot strength characteristics. Used for applications requiring resistance to pitting corrosion in halogen atmospheres. Typical applications: architectural trims, marine exteriors, chemical processing equipment, food processing equipment, petroleum refining equipment, pharmaceutical equipment, photographic equipment, pulp and paper processing equipment, textile finishing equipment, etc.
An austenitic stainless steel modification of type AISI 316 (contains a maximum of 0.03 percent carbon) with reduced tendency towards carbide precipitation without addition of a stabilizing element. Recommended for parts which cannot be heat treated after welding.
AISI 317 / AISI317L
These are austenitic stainless steels which are modifications of type AISI 316/AIS1316L and offer increased chromium, nickel and molybdenum ranges for improved corrosion resistance. The steels were developed to resist attack of sulphurous acid compounds. They resist pitting in phosphoric and acetic acids. Application include paper pulp handling equipment, process equipment for producing photographic chemicals, bleaching solutions and handling s lphurous, acetic, formic, citric and tartaric acids. They have the best corrosion resistance to body acids and blood and are recommended for surgical bone applications.
An austenitic stainless steel similar to AISI 304 but stabilized with titanium to avoid inter-granular corrosion. Type AISI 321 resists scaling and vibration fatigue. It is used for aircraft exhaust stacks and manifolds, pressure vessels, large mufflers for stationery diesel engines, carburetors, expansion bellows, stack liners, fire walls, etc.
An austenitic stainless steel similar to AISI 321 but stabilised by Columbium which does not appreciably reduce the overall corrosion resistance. Recommended in the range of 420° to 900°C for parts fabricated by welding and which cannot be subsequently annealed. Applications include airplane exhaust stacks, welded tanks for chemicals, heat resistors, jet engine parts, expansion bellows, etc.
It is the lowest alloyed straight Chromium ferritic stainless steel. It replaces carbon steels and low alloy steels where heat, corrosion resistance and higher strength are required and where appearance is secondary. It is used for fins in heater tubes, transformer and capacitor cases, dry fertilizer spreaders, automotive exhaust system including mufflers, resonators, silencers, pipes and emission control units, high pressure agricultural spray tanks, culverts, shipping containers and farm equipment.
AISI 410 / 410S
AISl 410 is the most commonly used 12% Chromium martensitic stainless steel. Excellent combination of toughness and strength can be developed through proper heat treatment. This steel has better corrosion resistance in the hardened condition. 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 operating below 650°c, micrometer parts, tray supports, caps and vaporizers in petroleum fractionating towers, lining for reaction chambers, coal screens, fishing tackles, keys, lamp brackets, rulers and tapes, wall screens, steam turbine buckets, blades, bucket covers, pump parts, petrochemical equipment and press plates. Type AISI 410S is a low carbon modification of AlSI 410.
This Steel contains min. 0.5% 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.
AISI 430 with 16-18% Cr. is inferior to AISI 304 as regards deep drawability. Though it does not have good corrosion resistance properties as the Cr-Ni steels, it is used under less severe corrosive atmospheres for chemical processing equipment, furnace parts, heat exchangers, oil burner parts, petroleum refining equipment. pyrometers, protection tubes, recuperators, rubber plant machinery, scientific apparatus, storage vessels, tubing, television cones, electrical appliances, solar water /heaters, air conditioners, kitchenware, household appliances, decorative trims, parts for washing machines etc.