GET A QUOTE

Stainless Steel 304/304L

 

Stainless Steel 304/304L

Material

Stainless Steel
Nickel Alloy
Duplex/Super Duplex Stainless Steel
Engine Valve Steels

Alloy 304/304L (UNS S30400/S30403) is the most widely used "18-8" chromium-nickel austenitic stainless steel. It is a cost-effective and versatile corrosion-resistant alloy suitable for a wide range of general-purpose applications. It is common for 304L to be dual certified as both 304 and 304L. The low carbon content in 304L, combined with the addition of nitrogen, allows it to meet the mechanical properties of 304 stainless steel. Alloy 304/304L exhibits resistance to atmospheric corrosion, as well as moderately oxidizing and reducing environments. It also has excellent resistance to intergranular corrosion in the as-welded condition. Additionally, Alloy 304/304L maintains good strength and toughness at cryogenic temperatures. In the annealed condition, Alloy 304/304L is non-magnetic. However, it may become slightly magnetic as a result of cold working or welding. It can be easily welded and processed using standard shop fabrication practices.

 

Applications

  • Chemical and Petrochemical
    Processing—pressure vessels, tanks, heat exchangers, piping systems,flanges, fittings, valves and pumps
  • Food and Beverage Processing
  • Medical
  • Mining
  • Petroleum Refining
  • Pharmaceutical Processing
  • Power Generation—nuclear
  • Pulp and Paper

Standards

ASTM........A 240
ASME........SA 240
AMS..........5511/5513
QQ-S........766
 
 

Corrosion Resistance

Alloy 304/304L stainless steel demonstrates good resistance to atmospheric corrosion, as well as resistance to various organic and inorganic chemicals in moderately oxidizing to moderately reducing environments. The high chromium content in the alloy provides resistance to oxidizing solutions, including nitric acid up to 55% weight at temperatures up to 176°F (80°C).

The alloy also resists moderately aggressive organic acids such as acetic acid. The presence of nickel in the alloy contributes to its resistance to moderately reducing solutions, such as pure phosphoric acid, at any concentration in cold solutions, and up to 10% diluted hot solutions. It can also operate successfully in caustic solutions without chlorides. However, Alloy 304/304L does not perform well in highly reducing environments containing chlorides and sulfuric acid.

Alloy 304/304L performs well in fresh water service with low chloride levels (less than 100ppm). However, at higher chloride levels, the grade becomes susceptible to crevice corrosion and pitting. In such severe conditions, an alloy with a higher molybdenum content, such as 316/316L, is recommended. Alloy 304/304L is not recommended for use in marine environments.

In most cases, the corrosion resistance of Alloys 304, 304L, and 304H will be roughly equal in various corrosive environments. However, in environments that are corrosive enough to cause intergranular corrosion of welds and heat-affected zones, Alloy 304L should be used due to its low carbon content, which helps mitigate such corrosion.

Lowest Temperature (°F) at Which the Corrosion Rate Exceeds 5mpy

CORROSION
ENVIRONMENT		 Type
304/304H		 Type
316L		 2205
(UNS S32205)		 2507
0.2% Hydrochloric Acid >Boiling >Boiling >Boiling >Boiling
1% Hydrochloric Acid 86p 86 185 >Boiling
10% Sulfuric Acid — 122 140 167
60% Sulfuric Acid — <54 <59 <57
96% Sulfuric Acid — 113 77 86
85% Phosphoric Acid 176 203 194 203
10% Nitric Acid >Boiling >Boiling >Boiling >Boiling
65% Niitric Acid 212 212 221 230
80% Acetic Acid 212p >Boiling >Boiling >Boiling
50% Formic Acid ≤50 104 194 194
50% Sodium Hydroxide 185 194 194 230

83% Phosphoric Acid +
2% Hydrofluoric Acid

 113 149 122 140
60% Nitric Acid +
2% Hydrocloric Acid		 >140 >140 >140 >140
50% Acetic Acid +
50% Acetic Anhydride		 >Boiling 248 212 230
1% Hydrochloric Acid +
0.3% Ferric Chloride		 68p 77p 113ps 203ps
10% Sulfuric Acid +
2000ppm Cl- + N2		 — 77 95 122
10% Sulfuric Acid +
2000ppm Cl- + SO2		 — <<59p <59 104
WPA1, High Cl- Content <<50 ≤50 113 203
WPA2, High F- Content <<50 ≤50 140 167

ps = pitting can occur
ps = pitting/crevice corrosion can occur

WPA P2O5 CL- F- H2SO4 Fe2O3 Al2O3 SiO2 CaO MgO
1 54 0.20 0.50 4.0 0.30 0.20 0.10 0.20 0.70
2 54 0.02 2.0 4.0 0.30 0.20 0.10 0.20 0.70

Chemical Analysis

Weight % (all values are maximum unless a range is otherwise indicated)

Element 304 304H
Chromium 18.0 min.-20.0 max. 18.0 min.-20.0 max.
Nickel 8.0 min.-10.5 max. 8.0 min.-10.5 max.
Carbon 0.08 0.04 min-0.10 max.
Manganese 2.00 2.00
Phosphorus 0.045 0.045
Sulfer 0.030 0.030
Silicon 0.75 0.75
Nitrogen 0.10 0.10
Iron Balance Balance

Physical Properties

Density

0.285 lbs/in3
7.90 g/cm3

Specific Heat

0.12 BTU/lb-°F (32 – 212°F)
502 J/kg-°K (0 – 100°C)

Modulus of Elasticity

29.0 x 106
200 GPa

 

Thermal Conductivity 212°F (100°C)

9.4 BTU/hr/ft2/ft/°F
16.3 W/m-°K

Melting Range

2550 – 2590°F
1398 – 1421°C

Electrical Resistivity

29.1 Microhm-in at 68°C
74 Microhm-cm at 20°C

Mean Coefficient of Thermal Expansion

Temperature Range  
°F °C in/in °F cm/cm °C
68-212 20-100 9.2 x 10-6 16.6 x 10-6
68-932 20-500 10.0 x 10-6 18.0 x 10-6
68-1600 20-870 11.0 x 10-6 19.8 x 10-6

Mechanical Properties

  ASTM
  Typical* Type 304 Type 304H
0.2% Offset Yield Strength, ksi 42 30 min. 25 min.
Ultimate Tensile Strength, ksi 87 75 min. 70 min.
Elongation in 2 inches, % 58 40 min. 40 min.
Reduction in Area, % 70 — —
Hardness, Rockwell B 82 92 max. 92 max.

Fabrication Data

Alloy 304/304L can be easily welded and processed by standard shop fabrication practices.

Cold Forming

The alloy is quite ductile and forms easily. Cold working operations will increase the strength and hardness of the alloy and might leave it slightly magnetic.

Hot Forming

Working temperatures of 1652–2102°F (750–1150°C) are recommended for most hot working processes. For maximum corrosion resistance, the material should be annealed at 1900°F (1038°C) minimum and water quenched or rapidly cooled by other means after hot working.

Machining

Alloy 304/304L is subject to work hardening during deformation and is subject to chip breaking. The best machining results are achieved with slower speeds, heavier feeds, excellent lubrication, sharp tooling and powerful rigid equipment.

Operation Tool Lubrication CONDITIONS
      Depth-mm Depth-in Feed-mm/t Feed-in/t Speed-m/min Speed-ft/min
Turning High Speed Steel Cutting Oil 6 .23 0.5 .019 13-18 42.6-59
Turning High Speed Steel Cutting Oil 3 .11 0.4 .016 20-25 65.6-82
Turning High Speed Steel Cutting Oil 1 .04 0.2 .008 26-31 85.3-101.7
Turning Carbide Dry or Cutting Oil 6 .23 0.5 .019 75-85 246-278.9
Turning Carbide Dry or Cutting Oil 3 .11 0.4 .016 90-100 295.3-328.1
Turning Carbide Dry or Cutting Oil 1 .04 0.2 .008 110-120 360.8-393.7
      Depth of cut-mm Depth of cut-in Feed-mm/t Feed-in/t Speed-m/min Speed-ft/min
Cutting High Speed Steel Cutting Oil 1.5 .06 0.03-0.05 .0012-.0020 18-23 59-75.5
Cutting High Speed Steel Cutting Oil 3 .11 0.04-0.06 .0016-.0024 19-24 62.3-78.7
Cutting High Speed Steel Cutting Oil 6 .23 0.05-0.07 .0020-.0027 20-25 65.6-82
      Drill ø mm Drill ø in Feed-mm/t Feed-in/t Speed-m/min Speed-ft/min
Drilling High Speed Steel Cutting Oil 1.5 .06 0.02-0.03 .0007-.0012 10-14 32.8-45.9
Drilling High Speed Steel Cutting Oil 3 .11 0.05-0.06 .0020-.0024 12-16 39.3-52.5
Drilling High Speed Steel Cutting Oil 6 .23 0.08-0.09 .0031-.0035 12-16 39.3-52.5
Drilling High Speed Steel Cutting Oil 12 .48 0.09-0.10 .0035-.0039 12-16 39.3-52.5
          Feed-mm/t Feed-in/t Speed-m/min Speed-ft/min
Milling Profiling High Speed Steel Cutting Oil     0.05-0.10 .002-.004 12-22 39.4-72.2

Welding

Alloy 304/304L can be readily welded by most standard processes. A post weld heat treatment is not necessary.