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304 Stainless Steel

Penn Stainless inventory includes Alloy 304 (UNS S30400), in sheet, sheet coil, plate, plate coil, round bar, processed flat bar and tubular products. Alloy 304 is ideally suited for home and commercial applications.

 

General Properties

Alloy 304 a T-300 series stainless steel austenitic, which has a minimum of 18% chromium and 8% nickel. Type 304 has a maximum carbon of 0.07% . It is the standard “18/8 stainless” that is commonly found in pans and cooking tools. Alloy 304 is the most versatile and widely used alloy in the stainless steel family. Ideal for a wide variety of home and commercial applications, Alloy 304 exhibits excellent corrosion resistance and has a high ease of fabrication, outstanding formability. The austenitic stainless steels are also considered to be the most weldable of the high-alloy steels and can be welded by all fusion and resistance welding processes.

Specifications: UNS S30400

Applications:

Alloy 304 Stainless Steel is used in a wide variety of home and commercial applications, including:

  • Kitchen benches, sinks, troughs, equipment, and appliances
  • Chemical containers, including for transport
  • Food processing equipment, particularly in beer brewing, milk processing, and wine making
  • Heat exchangers
  • Architectural trim and molding
  • Woven or welded screens for mining, quarrying & water filtration
  • Automotive and aerospace structural use
  • Nuts, bolts, screws, and other fasteners in the marine environment
  • Construction material in large buildings
  • Dyeing industry

Standards:

  • ASTM/ASME: UNS S30400 / S30403
  • EURONORM: 1.4301 / 1.4303
  • AFNOR: Z5 CN 18.09 / Z2 CN 18.10
  • DIN: X5 CrNi 18 10 / X2 CrNi 19 11

Corrosion Resistance:

  • Resistance to moderately aggressive organic acids is a result of the 9 to 11% nickel that the 304 alloys contain.
  • Resistance to corrosion in oxidizing environments is a result of the 18 to 19% chromium that the 304 alloys contain.
  • The 304, 304L, and 304H may be considered to perform uniformly in most corrosive environments.

Heat Resistance:

  • Continuous use of 304 in the 800-1580°F range is not recommended if subsequent aqueous corrosion resistance is important.
  • Good oxidation resistance in intermittent service to 1600°F and in continuous service to 1690°F.

Properties of 304 Alloy

Welding Characteristics:

Excellent welding properties; post-weld annealing is not required when welding thin sections. Two important considerations in producing weld joints in the austenitic stainless steels are:

  1. avoidance of cracking
  2. preservation of corrosion resistance

Processing – Hot Forming:

  • To forge, heat uniformity to 2100 / 2300 °F
  • Do not forge below 1700 °F
  • Forging can be air cooled without danger of cracking

Processing – Cold Forming:

  • Its austenitic structure allows it to be deep-drawn without intermediate annealing, Making this the stainless steel grade of choice in the manufacturing of sinks, hollow-ware and saucepans.
  • These grades work harden rapidly. To relieve stresses produced in severe forming or spinning, parts should be full annealed or stress relief annealed as soon as possible after forming.

Machinability:

  • The use of chip breakers is advised since the chips can be stringy. Stainless steel work harden rapidly, heavy positive feeds, sharp tooling, and a rigid set-up should be used.of cut below the work-hardened layer resulting from the previous passes.

Chemical Properties:

C Mn Si P S Cr Ni N
304 0.07max 2.0max 0.75max 0.045max 0.03max min: 18.0 max: 20.0 min: 8.0 max: 10.5

Mechanical Properties:

Grade Tensile Strength ksi (min) Yield Strength 0.2% ksi (min) Elongation % Hardness (Brinell) MAX Hardness (Rockwell B) MAX
304 75 30 40 201 92

Physical Properties:

Density
lbm/in3
Thermal Conductivity
(BTU/h ft. °F)
Electrical
Resistivity
(in x 10-6)
Modulus of
Elasticity
(psi x 106
Coefficient of
Thermal Expansion
(in/in)/
°F x 10-6
Specific Heat
(BTU/lb/
°F)
Melting
Range
(°F)
at 68°F: 0.285 9.4 at 212°F 28.3 at 68°F 28 9.4 at 32 – 212°F 0.1200 at 68°F to 212°F 2500 to 2590
12.4 at 932 °F 39.4 at 752°F 10.2 at 32 – 1000°F
49.6 at 1652 °F 10.4 at 32 – 1500°F

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