304 (UNS S30400) is the most widely used austenitic stainless steel offering:
Excellent corrosion resistance
Good formability and weldability
Non-magnetic properties (when annealed)
Hygienic surface capabilities
Key standards: ASTM A240, EN 1.4301, JIS SUS304
Purchasing Considerations
Specify ASTM A240 certification
Choose between 304/304L based on welding needs
Consider surface finish requirements
Verify dimensional tolerances (ASTM A480)
Common Applications
Food processing equipment
Kitchen appliances and sinks
Architectural panels and trim
Chemical containers
Medical equipment
Automotive trim

Type 410 stainless steel is a martensitic stainless steel (12% chromium alloy) offering:
Good corrosion resistance (moderate)
High strength and hardness (heat-treatable)
Magnetic properties
Excellent machinability
Key standards: ASTM A240 (sheet), AMS 5504, UNS S41000
Key Specifications
Property Value
Density 7.7 g/cm³
Melting Point 1480-1530°C (2700-2790°F)
Thermal Conductivity 24.9 W/m·K
Electrical Resistivity 0.59 μΩ·m
Common Applications
Cutlery and knife blades
Valve components and fasteners
Pump shafts and turbine blades
Mining equipment
Aircraft components

The corrosion resistance of stainless steel primarily comes from the passive film formed on the steel surface by the chromium element (content of at least 10.5%), which isolates the metal from the outside world and prevents oxidation. However, once the passive film is destroyed, the corrosion resistance will decrease. Different grades, such as 304 and 316, can adapt to different corrosive environments by adjusting the chromium and nickel content.

321 (UNS S32100) is a titanium-stabilized austenitic stainless steel offering:
Excellent intergranular corrosion resistance
Good high-temperature strength
Oxidation resistance up to 900°C (1650°F)
Non-magnetic properties
Key standards: ASTM A240, EN 1.4541, JIS SUS321
Corrosion Resistance
Excellent intergranular corrosion resistance
Good oxidation resistance up to 900°C
Similar to 304 in most environments
Pitting Resistance Equivalent (PRE): ~19
Common Applications
Aircraft exhaust systems
Heat exchangers and boiler components
Chemical processing equipment
Pressure vessels
Welded components for high-temperature service

2205 is a duplex (austenitic-ferritic) stainless steel offering:
Superior strength (2x 316L)
Excellent corrosion resistance
Good weldability
High stress corrosion cracking resistance
Key standards: ASTM A240, UNS S32205/S31803, EN 1.4462
Key Specifications
Property Value
Density 7.8 g/cm³
Melting Range 1380-1450°C (2516-2642°F)
Thermal Conductivity 19 W/m·K
Electrical Resistivity 0.80 μΩ·m
Purchasing Considerations
Specify ASTM A240 certification
Request ferrite content verification (30-50%)
Consider surface finish requirements
Verify impact test results for low temp applications
Common Applications
Oil & gas industry (pipelines, pressure vessels)
Chemical processing equipment
Marine and offshore applications
Desalination plants
Pulp and paper industry

904L (UNS N08904) is a super austenitic stainless steel offering:
Exceptional corrosion resistance (superior to 316L)
High molybdenum content (4-5%)
Non-magnetic (austenitic structure)
Excellent weldability and formability
Key standards: ASTM A240 (sheet), EN 1.4539, UNS N08904
Key Specifications
Property Value
Density 8.0 g/cm³
Melting Range 1300-1390°C (2372-2534°F)
Thermal Conductivity 12.9 W/m·K
Electrical Resistivity 0.85 μΩ·m
Common Applications
Chemical processing equipment
Pharmaceutical and food processing
Seawater and marine applications
Oil & gas industry (sour gas service)
Pollution control scrubbers

403 stainless steel is a martensitic stainless steel (12% chromium alloy) primarily used in high-temperature applications. Key characteristics include:
Good corrosion resistance (moderate, not as strong as 304/316)
High strength and hardness (can be heat treated)
Magnetic properties (unlike austenitic grades)
Excellent machinability (better than most stainless steels)
Common Applications
Turbine blades and steam generator parts
Jet engine components
Fasteners and valves
Cutlery and surgical instruments
Nuclear reactor components