Jiangyin Donghao Stainless Steel Pipe Co., Ltd  
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304L UNS S30403 stainless steel is a variation of the 18% chromium – 8% nickel austenitic alloy, the most familiar and most frequently used alloy in the stainless steel family. This alloy may be considered for a wide variety of applications and exhibits good corrosion resistance, ease of fabrication, excellent formability, and high strength with low weight. Type 304L is a lower carbon variant of Grade 304 – the steel can be welded without the resulting issue of carbon precipitation precipitation of chromium carbide as heat is applied during the welding process which depletes the chromium element of the steel thus reducing its anti-corrosive/oxidation effectiveness.

As a result, Type 304L stainless steel is a sort after material for use in severely corrosive conditions. Weld annealing is only necessary in applications where stress loads are excessive. This steel Grade is found in a variety of commercial sectors, particularly in the chemical industry. 304 & 304L have similar properties and in certain cases are stocked with Dual Certification, where it is concluded that each item has properties and a composition which comply with both steel types. Grade 304H cannot be included in this equation due to the steel's higher carbon content which is intended for use in elevated temperature applications.

Benefits of using 304L stainless steel
  • Low carbon content eliminates carbon precipitation in the welding process
  • Can be used in severe corrosive environments
  • Weld annealing only required in high stress applications
  • Very similar to Type 304

C Si Mn P S Cr Mo Ni N Cu
max. 0,03 max. 1,00 max. 2,00 max. 0,045 max. 0,03 18 - 20 - 8 -12 - -

General Properties
Chemical Composition
Resistance to Corrosion
Physical Properties
Mechanical Properties
Heat Treatment
304/304L/304LN/304H Tubing and Pipe

Chemical Composition
Carbon 0.03 max
Chromium 18 - 20
Iron Balance
Manganese 2 max
Nickel 8 - 12
Phosphorus 0.045 max
Silicon 1 max
Sulphur 0.03 max
General Information
Principal Design Features
A low carbon version of type 304 stainless. 304L is used almost interchangeably with 304 but is preferred for welding operations. It offers a good combination of strength, corrosion resistance and fabricability.
The list is endless. Almost every conceivable industry uses some of this material in some way. Everything from stovetops to ball point pen barrels to flatware to fasteners has been fabricated from this alloy.
Slow speeds and heavy feeds will minimize this alloys tendency to work harden. Due to long stringy chips, the use of chip breakers is advisable. Many companies now offer premium machinability grades, such as CarTech with their Project 70 and 7000 series.
All fusion and resistance processes have been successfully employed in welding 304. AWS E/ER308 or 312 filler metal is recommended. Its low carbon, means that the is less carbide precipitation at the weld boundaries resulting in stronger welds.
Hot Working
Forging, heading and other hot working should follow uniform heating to 2100-2300 F (1149-1260 C). Rapid cooling is necessary to attain maximum corrosion resistance in finished parts.
Cold Working
Readily fabricated by most cold working methods, 304L may require intermediate annealing to avoid cracking or tearing from radical deformation. Full annealing should follow any operation to reduce internal stress and optimize corrosion resistance.
1850-2050 F (1010-1121 C) followed by rapid cooling.
This alloy does not respond to heat treatment. Cold work will cause an increase in both hardness and strength.
Physical Properties
Density (lb / cu. in.) 0.29
Specific Gravity 7.9
Specific Heat (Btu/lb/Deg F - [32-212 Deg F]) 0.12
Electrical Resistivity (microhm-cm (at 68 Deg F)) 432
Melting Point (Deg F) 2650
Modulus of Elasticity Tension 28
Mechanical Properties
Form Plate
Condition Test Specimen Annealed
Temper 70
Tensile Strength 79
Yield Strength 33