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:

1. Food processing equipment, particularly in beer brewing, milk processing, and wine making

2. Kitchen benches, sinks, troughs, equipment, and appliances

3. Architectural trim and molding

4. Automotive and aerospace structural use

5. Construction material in large buildings

6. Chemical containers, including for transport

7. Heat exchangers

8. Nuts, bolts, screws, and other fasteners in the marine environment

9. Dyeing industry

10. Woven or welded screens for mining, quarrying & water filtration

Standards:

1. ASTM/ASME:  S30403

2. EURONORM:  1.4303

3. AFNOR:  Z2 CN 18.10

4. DIN:  X2 CrNi 19 11

1. Resistance

 Corrosion Resistance:

1. 
   

2. Resistance to corrosion in oxidizing environments is a result of the 18 to 19% chromium that the 304 alloys contain.

3. Resistance to moderately aggressive organic acids is a result of the 9 to 11% nickel that the 304 alloys contain.

4. 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.

5. 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:

1. Good oxidation resistance in intermittent service to 1600°F and in continuous service to 1690°F.

2. Continuous use of 304 in the 800-1580°F range is not recommended if subsequent aqueous corrosion resistance is important.

3. Grade 304L is more resistant to carbide precipitation and can be heated into the above temperature range.

1. 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:

1. To forge, heat uniformity to 2100 / 2300 °F

2. Do not forge below 1700 °F

3. Forging can be air cooled without danger of cracking

Processing – Cold Forming:

1. 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.

2. 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:

1. 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.

1. Properties

Chemical Properties:CMnSiPSCrNiN304L0.03max2.0max0.75max0.45max0.03maxmin: 18.0 max: 20.0min: 8.0 max: 12.00.10 max

Mechanical Properties:GradeTensile Strength ksi (min)Yield Strength 0.2% ksi (min)Elongation %Hardness (Brinell) MAXHardness (Rockwell B) MAX304L70254020192

Physical Properties:

Density lbm/in3Thermal Conductivity (BTU/h ft. °F)Electrical Resistivity (in x 10-6)Modulus of Elasticity (psi x 106Coefficient of Thermal Expansion (in/in)/ °F x 10-6Specific Heat (BTU/lb/ °F)Melting Range (°F)at 68°F: 0.2859.4 at 212°F28.3 at 68°F289.4 at 32 – 212°F0.1200 at 68°F to 212°F2500 to 259012.4 at 932 °F39.4 at 752°F10.2 at 32 – 1000°F49.6 at 1652 °F10.4 at 32 – 1500°F