347 is a niobium-stabilized austenitic steel similar to 321 but with better high-temperature strength. It prevents intergranular corrosion after exposure to high temperatures.
Key Properties
Stabilization: Niobium prevents chromium carbide precipitation.
High Temp: Good mechanical properties up to 800°C.
Weldability: Excellent for heavy gauge welding without post-weld annealing.
Ductility: Good formability for complex high-temp parts.
Common Applications
Aerospace: Exhaust manifolds and firewalls.
Refining: Catalytic cracking equipment and expansion joints.
Boilers: Superheater tubes and high-temp piping.
Automotive: Thermal oxidizers and exhaust components.

302 is an austenitic stainless steel similar to 304 but with slightly higher carbon content. It offers good corrosion resistance and excellent formability, often used in springs and general fabrication.
Key Properties
Corrosion: Good resistance to oxidation and mild acids, similar to 304.
Formability: Excellent ductility for deep drawing and bending.
Strength: Higher carbon provides slightly higher strength than 304.
Weldability: Good weldability using standard methods.
Common Applications
Springs: High-quality springs and wire forms.
Fasteners: Bolts, nuts, and screws.
Kitchenware: Sinks, cookware, and food processing equipment.
Architecture: Decorative trim and building facades.

405 is a lower-cost ferritic stainless steel with aluminum addition instead of titanium. It offers moderate corrosion resistance and good weldability, often used where high polish is not required.
Key Properties
Weldability: Better weldability than other ferritic grades due to aluminum.
Corrosion: Moderate resistance to atmospheric corrosion and fresh water.
Cost: Economical alternative to 430 for less demanding uses.
Ductility: Good formability for simple shapes.
Common Applications
Industrial: Drip pans, quench tanks, and annealing boxes.
Automotive: Underbody components and non-visible trim.
Construction: Roofing and siding for agricultural buildings.
General: Parts requiring moderate heat and corrosion resistance.

409 is a titanium-stabilized ferritic stainless steel designed specifically for automotive exhaust systems. It offers good oxidation resistance at high temperatures and excellent formability.
Key Properties
Heat Resistance: Resists oxidation in exhaust gas environments up to 600-700°C.
Weldability: Titanium stabilization improves weld zone toughness.
Cost: Lower cost than austenitic grades like 304/409M.
Formability: Good ductility for complex exhaust shapes.
Common Applications
Automotive: Exhaust manifolds, catalytic converter shells, and tailpipes.
Agriculture: Grain dryer components and silo vents.
Construction: Heat exchangers and HVAC ducting.
Industrial: Conveyor belts for heat treatment.

302HQ strip is an austenitic alloy optimized for cold heading. Modified from 302/304 grades, it features a low work-hardening rate, allowing severe deformation without cracking.
Key Properties
Cold Heading: "HQ" means High Quality for heading. Excellent ductility allows significant deformation without fracturing, superior to standard 304 for fasteners.
Strength: Soft enough for forming but achieves high tensile strength after cold working.
Corrosion: Similar to AISI 304; resists oxidation and rust in mild environments.
Magnetism: Non-magnetic when annealed; slightly magnetic after cold work.
Common Applications
Widely used for room-temperature shaping:
Fasteners: Screws, bolts, nuts, rivets.
Electronics: Pins, connectors, lead frames.
Auto Parts: High-strength precision components.
Household: Zippers, hooks, formed accessories.

410 is a general-purpose martensitic stainless steel that can be heat-treated to achieve high hardness and tensile strength. It offers moderate corrosion resistance for non-critical industrial applications.
Key Properties
Hardness: Can be hardened by heat treatment to achieve high tensile strength.
Wear Resistance: Excellent resistance to abrasion and wear after hardening.
Corrosion: Moderate resistance to mild atmospheres, fresh water, and steam.
Machinability: Good machinability in the annealed condition.
Common Applications
Fasteners: High-strength bolts, nuts, screws, and studs.
Pumps & Valves: Shafts, bushings, valve seats, and trim components.
Automotive: Pump parts, turbine blades, and non-critical engine components.
Cutlery: Knife blanks, surgical instrument components, and razor blades.

904L is a high-alloy austenitic stainless steel with very high chromium, nickel, molybdenum, and copper content, offering superior corrosion resistance in highly aggressive environments especially sulfuric acid.
Key Properties
Corrosion: Exceptional resistance to sulfuric acid, phosphoric acid, and chlorides.
Pitting Resistance: High PREN value (>35) for superior pitting and crevice resistance.
Weldability: Good weldability with standard methods; no post-weld heat treatment required.
Formability: Excellent ductility for deep drawing and complex fabrication.
Common Applications
Chemical: Sulfuric acid storage tank internals, process piping supports, and heat exchanger baffles.
Pharmaceutical: Reaction vessel internals, processing line supports, and CIP system components.
Marine: Seawater cooling system brackets and offshore component mounts.
Pollution Control: Flue gas desulfurization (FGD) equipment supports and scrubber internals.

310S is a high-alloy austenitic stainless steel with 25% chromium and 20% nickel, offering exceptional oxidation resistance and creep strength for continuous service up to 1100°C.
Key Properties
High Temp: Excellent oxidation resistance up to 1100°C continuous service.
Creep Strength: Superior creep and rupture strength at elevated temperatures.
Low Carbon: Reduced carbide precipitation improves weldability and corrosion resistance.
Non-Magnetic: Austenitic structure remains non-magnetic in solution-treated condition.
Common Applications
Heat Treatment: Furnace components, radiant tubes, annealing covers, and kiln furniture.
Petrochemical: Fluidized bed combustors, coal gasifier internals, and reformer tubes.
Power Generation: Boiler tube hangers, superheater supports, and incinerator components.
Food Processing: High-temperature cooking equipment and sterilization chambers.

321 is a titanium-stabilized austenitic stainless steel offering superior resistance to intergranular corrosion after exposure to temperatures between 425-860°C, making it ideal for welded components and moderate high-temperature service.
Key Properties
Stabilization: Titanium addition prevents chromium carbide precipitation during welding and heating.
High Temp: Good oxidation resistance up to 860°C intermittent service.
Weldability: Excellent for heavy gauge welding without post-weld annealing.
Corrosion: Similar to 304 in mild environments, superior in oxidizing acids.
Common Applications
Aerospace: Jet engine exhaust manifolds, expansion joints, and afterburner components.
Petrochemical: Process piping, heat exchanger tubes, and reactor internals.
Power Generation: Boiler components, superheater tube supports, and chimney liners.
Chemical: Welded vessels, storage tanks, and acid handling equipment.

301L is a low-carbon variant of 301 with nitrogen addition, offering superior weldability and formability while maintaining high work-hardening rate for structural applications in rail transit and automotive.
Key Properties
Low Carbon: Reduced carbide precipitation improves weldability and intergranular corrosion resistance.
Work Hardening: Exceptional work-hardening rate (~14 MPa per 1% reduction) for high strength through cold working.
Formability: Excellent ductility for deep drawing and complex fabrication.
Non-Magnetic: Austenitic structure remains non-magnetic in annealed condition.
Common Applications
Rail Transit: Subway and high-speed train car body structures, interior panels, and luggage racks.
Automotive: Exhaust system components, structural reinforcements, and decorative trim.
Electronics: Mobile phone internal frames, spring contacts, and EMI shielding components.
Construction: Elevator cabins, architectural cladding, and structural fasteners.

301 is a metastable austenitic stainless steel with exceptional work-hardening rate, achieving tensile strength up to 1275 MPa through cold working, widely used in springs, fasteners, and structural components.
Key Properties
Work Hardening: Highest work-hardening rate among austenitic grades (~14 MPa per 1% reduction).
Strength Range: Seven temper grades from Annealed (515 MPa) to Full Hard (1275+ MPa).
Magnetic Behavior: Becomes increasingly magnetic with cold working due to austenite-to-martensite transformation.
Formability: Good ductility in annealed condition for bending and forming operations.
Common Applications
Springs: Vehicle suspension springs, conveyor belt springs, and industrial spring components.
Fasteners: High-strength bolts, nuts, screws, and aerospace fasteners.
Rail Transit: Train car body structures, decorative trim, and structural reinforcements.
Electronics: EMI shielding, connector springs, and battery contacts.

409 is a titanium-stabilized ferritic stainless steel offering good corrosion resistance and excellent formability at a lower cost than austenitic grades. It is widely used in automotive exhaust systems and agricultural equipment.
Key Properties
Ferritic Structure: Magnetic with good resistance to stress corrosion cracking.
Stabilization: Titanium addition improves weldability and high-temperature performance.
Cost Efficiency: Lower nickel content makes it more economical than 304/316.
Formability: Good ductility for bending and fabrication.
Common Applications
Automotive: Exhaust manifolds, catalytic converter shells, and mufflers.
Agriculture: Grain handling equipment and fertilizer spreaders.
Construction: Non-structural decorative trim and indoor applications.
Appliances: Washing machine drums and dishwasher interiors.