904L Vs. 316L Stainless Steel: What’s the Difference?

904l vs 316l stainless steel

The 904L super austenitic stainless steel and 316L stainless steel are the good austenitic grades of stainless steels due to their better corrosion resistance.

Both stainless steels used chromium, nickel, and molybdenum as basic chemical elements in their composition.

The 904L super austenitic stainless steel has more chromium, nickel, and molybdenum contents than the grade 316L stainless steel.

Grade 904L and 316l stainless steel materials play a vital role in the petrochemical and chemical processing industries.

In this article, you can learn more about difference between them, and choose the best grade of austenitic stainless steel for your project.

904l super austenitic stainless steel

Grade 904L super austenitic stainless steel also referred to as the UNS N08904/W.Nr. 1.4539 stainless steel.

Like 316L stainless steel, 904L stainless steel is a low-carbon super austenitic stainless steel.

However, its chemical composition includes greater numbers of chromium (19-23%) and nickel (23-28%), which gives the alloy greater corrosion resistance than 316L.

Grade 904L features good activation-passivation conversion ability, excellent corrosion resistance, which is especially pronounced in non-oxidizing acids such as sulfuric acid, acetic acid, formic acid, and phosphoric acid.

With its highly alloyed chemistry nickel and molybdenum, 904L provides good chloride stress corrosion cracking resistance, pitting and general corrosion resistance superior to 316L and 317L molybdenum enhanced stainless steels.

This stainless steel alloy is used extensively in the chemical process industry including the production of phosphate-based fertilizers.

Alloys 904L is available in all standard mill forms including pipe, rod, bar, plate, sheet, strip and foil products.

 

What is 316L Austenitic Stainless Steel?

316l stainless steel

Grade 316L stainless steel is a kind of austenitic stainless steel, a lower carbon variant of 316 stainless steel.

It is also referred to as the UNS S31603/W.Nr. 1.4404 stainless steel.

Both 316 and 316L stainless steels contain molybdenum, but 316L stainless contain more molybdenum than 316 stainless steel. Though 316L features better corrosion resistance than 316, but its mechanical properties are not as good as 316.

Due to the addition of molybdenum in the steel, the overall performance of 316L steel is superior to that of 310S and 304L stainless steel.

In addition to metals like iron and nickel, 316L contains 16-18% chromium and 2-3% of molybdenum. These elements are important because they increase the alloy’s corrosion resistance.

Grade 904L Vs. 316L Stainless Steel Comparison

Let’s see the comparison of grade 904L and 316L stainless steel with their composition and properties.

Chemical Composition Comparison

316L Chemical Composition Display:

316l austenitic stainless steel chemical composition

904L Chemical Composition Display:

904l super austenitic stainless steel chemical composition

Mechanical Properties Comparison

Alloy GradeTensile Strength Rm(MPa)Yield Strength (0.2%Offset) (MPa)Elongation (%)
316L≥485≥170≥40
904L≥490≥220≥35

Equivalent Grades Comparison

ASTM/AISIWERKSTOFF NR.UNSGOSTGBJISDINENOR
316L1.4404S31603022Cr17Ni12Mo2SUS316L
ASTM/AISIWERKSTOFF NR.UNSGOSTGBJISDINENOR
Alloy 904L1.4539N08904015Cr21Ni26SiMo5Cu3SUS904L

Corrosion Resistance Comparison

Due to the difference in chemical composition, 904L stainless steel is more resistant to corrosion than 316L stainless steel, especially in environments containing chloride ions and acidic environments.

Cost Comparison

Both 904L stainless steel and 316L stainless steel are readily accessible for procurement.

Numerous industries and companies opt for the use of 904L stainless steel.

316L stainless steel finds common applications in exhaust manifolds, heat exchangers, jet engine parts, and various other uses.

While 316L may appear more appealing based on numerical considerations alone, owing to its extensive utilization across diverse industries, it is easily procurable and tends to be more budget-friendly. Notably, 904L tends to be approximately 1.5 times more expensive than 316L.

The heightened corrosion resistance of 904L stainless steel reduces the likelihood of deterioration and breakage due to corrosion, translating to fewer necessary repairs throughout its lifespan.

This is particularly advantageous for shipowners seeking to avoid additional costs associated with maintaining compliance with industry environmental and operational standards.

What are the Grade 904L stainless steel and 316L stainless steel Applications?

Applications of 316L stainless steel:

  • Pulp and paper equipment
  • Heat exchanger
  • Dyeing equipment
  • Film processing equipment
  • Pipeline
  • Materials for exterior construction in coastal areas
  • Watch bracelet, case, etc. for advanced watches
  • Equipment for the use of marine, chemicals, dyes, paper, oxalic acid, fertilizer, etc.
  • Food industry
  • Rope
  • Bolts and nuts

Applications of 904L stainless steel:

  • Petroleum and petrochemical equipment
  • Sulphuric acid storage and transport equipment
  • Power plant flue gas desulphurization device
  • Scrubbers and fans in organic acid treatment systems

Which one between Grade 904L stainless steel and 316L stainless steel is better?

904L stainless steel is the best choice for your project.

904L stainless steel offers greater durability than 316L, which makes it more effective and less costly over time (despite a higher initial cost).

Conclusion

Grade 904L stainless steel and 316L stainless steel have some similarities and differences in their compositions.

Both of these stainless steels are most commonly used in industries.

Most people demand these alloys due to their outstanding properties like corrosion resistance, high strength, and toughness.

We specialize in the production of premium-grade stainless steel products. If you have new project today, please do not hesitate to contact our expert team.

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