904L/UNS N08904/EN 1.4539 Stainless Steel

904L stainless steel pipe, 904L steel sheet

904L (UNS N08904, 1.4539) is a highly alloyed austenitic stainless steel. Its approximate composition is 20% Cr, 25% Ni, 4.0% Mo plus 1.5% Cu, which ensures a pitting resistance equivalent number (PREN) of around 43. It was specifically developed for service in sulphuric acid, mostly in concentrations from 20% to 85%.

904L is austenitic stainless steel. In comparison to 316L, its molybdenum addition gives it superior resistance to localized attack (pitting and crevice corrosion) by chlorides and greater resistance to reducing acids and in particular, its copper addition gives it useful corrosion resistance to all concentrations of sulphuric acid. Its high alloying content also gives it greater resistance to chloride stress corrosion cracking, but it is still susceptible. Its low carbon content makes it resistant to sensitization by welding and prevents intergranular corrosion.

UNS designation: UNS N08904

JIS Equivalent: QS 2025 MC

EN/DIN Numerical Equivalent: EN 1.4539

EN/DIN Symbolical Equivalent: X1NiCrMoCu25-20-5

Available Forms and Specifications

904L seamless pipe/tube: ASTM B677, ASTM A312, ASTM A 213, ASTM A269

904L welded pipe/tube: ASTM A312, ASTM A358 904L Welded pipe

904L stainless steel plate/sheet/coils: ASTM A240, ASTM A480

904L pipe fittings: ASTM B366 bend, ASTM A403,ANSI B16.9

904L Stainless Steel Fasteners: ASTM A479

Chemical Composition

Ni Cr Mo C max Mn max Si max Cu  S P N max
23.0-28.0 19.0-23.0 4.0-5.0 0.02 2.00 1.00 1.0-2.0 0.035 0.035 0.1

Mechanical Properties

Density,g/c㎡ 8.0
Melting range,℃ 1300-1390
Tensile strength, min, Mpa 490
Yield strength, 0.2% offset, min, Mpa 216
Elongation, A5% 35
Hardness, (HR B) 90


  • Petroleum and petrochemical equipment, such as reactors;
  • Storage and transportation equipment of sulfuric acid, such as heat exchanger;
  • Gas desulphurization equipment in power plant, such as absorber tower body, flue, door plate, internal parts, spray system;
  • Scrubber and fan in an organic acid treatment system.

Alloy 904L is widely used in oil and gas industrial, marine industrial, chemical processing, and nuclear industrial. LKALLOY is one of the best vendors of 904L stainless steel pipe, plate, and pipe fittings. We are the leading in supplying superb quality Alloy 904L, which is well known for its excellent strength and good corrosion resistance.

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