304L Stainless Steel (S30403)

Alloy  304L a T-300 series stainless steel austenitic, which has a minimum of 18% chromium and 8% nickel. Type 304L has a carbon maximum is 0.030. It is the standard “18/8 stainless” that is commonly found in pans and cooking tools. Alloys 304L is the most versatile and widely used alloy in the stainless steel family. Ideal for a wide variety of home and commercial applications, Alloys 304L 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 S30403

Applications:

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

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

Standards:

• ASTM/ASME:  S30403
• EURONORM:  1.4303
• AFNOR:  Z2 CN 18.10
• DIN:  X2 CrNi 19 11

 

Resistance

 Corrosion Resistance:

• Resistance to corrosion in oxidizing environments is a result of the 18 to 19% chromium that the 304 alloys contain.
• Resistance to moderately aggressive organic acids is a result of the 9 to 11% nickel that the 304 alloys contain.
• At times, alloy 304L may show a lower corrosion rate than the higher carbon Alloy 304; otherwise, the 304, 304L, and 304H may be considered to perform uniformly in most corrosive environments.
• Alloy 304L is preferred for use in environments sufficiently corrosive to cause intergranular corrosion of welds and heat-affected zones on susceptible alloys.

Heat Resistance:

• Good oxidation resistance in intermittent service to 1600°F and in continuous service to 1690°F.
• Continuous use of 304 in the 800-1580°F range is not recommended if subsequent aqueous corrosion resistance is important.
• Grade 304L is more resistant to carbide precipitation and can be heated into the above temperature range.

• Processing

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. preservation of corrosion resistance
2. avoidance of cracking

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.
• Properties

Chemical Properties:

	C	Mn	Si	P	S	Cr	Ni	N
304L	0.03max	2.0max	0.75max	0.45max	0.03max	min: 18.0 max: 20.0	min: 8.0 max: 12.0	0.10 max

Mechanical Properties:

Grade	Tensile Strength ksi (min)	Yield Strength 0.2% ksi (min)	Elongation %	Hardness (Brinell) MAX	Hardness (Rockwell B) MAX
304L	70	25	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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