1.4404 vs X2CrNiMo17-12-2: Are They the Same Grade?
Leave a message
Two Names, One Stainless Steel Grade
When a procurement document lists both EN 1.4404 and X2CrNiMo17-12-2, it is describing a single material. EN 1.4404 is the European material number defined in the EN 10088 series; X2CrNiMo17-12-2 is the steel name built from chemical composition, a convention inherited from the former DIN designation system. The letter X marks a high-alloy steel, the digit 2 caps carbon at 0.03%, and CrNiMo17-12-2 summarizes the chromium, nickel and molybdenum ranges. Internationally the same grade is called AISI/UNS 316L (UNS S31603), JIS SUS316L or GB 022Cr17Ni12Mo2.
Why the Confusion Happens
A European mill certificate may state 1.4404, an American one UNS S31603, and an Asian one SUS316L, yet all three describe the same product chemistry. Buyers who only know one naming system often request duplicate testing or reject valid stock. Understanding the equivalence prevents ordering errors, redundant certification cost, and project delays.
Chemical Composition According to EN 10088-2
| Element | Range (wt %) |
|---|---|
| Carbon (C) | ≤ 0.03 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 2.00 |
| Phosphorus (P) | ≤ 0.045 |
| Sulfur (S) | ≤ 0.015 |
| Chromium (Cr) | 16.5 – 18.5 |
| Nickel (Ni) | 10.0 – 13.0 |
| Molybdenum (Mo) | 2.00 – 2.50 |
| Nitrogen (N) | ≤ 0.11 |
The 2.0–2.5% molybdenum addition is the decisive difference from grade 304: it raises resistance to pitting and crevice corrosion in chloride-bearing media such as seawater and road-salt atmospheres. The 0.03% maximum carbon keeps the steel immune to sensitization during welding, so heavy sections normally need no post-weld heat treatment.
Mechanical Properties at Room Temperature
| Property | Minimum Value |
|---|---|
| Tensile strength Rm | ≥ 500 MPa |
| Yield strength Rp0.2 | ≥ 200 MPa |
| Elongation A5 | ≥ 40% |
| Brinell hardness HBW | ≤ 215 |
Typical Applications
1.4404 / X2CrNiMo17-12-2 is specified wherever 304 cannot deliver sufficient chloride resistance: marine and offshore piping, food and dairy processing lines, pharmaceutical process vessels, chemical storage tanks, and heat exchangers handling dilute organic or mineral acids. The grade is austenitic and essentially non-magnetic in the annealed condition; it cannot be hardened by heat treatment, and higher strength is achieved only through cold working. It welds readily by TIG, MIG or submerged-arc processes without preheat.
Common Misconceptions
"1.4404 and 1.4435 are identical." Both are 316L-type grades, but 1.4435 (X2CrNiMo18-14-3) carries higher nickel (12.5–15.0%) and molybdenum (2.5–3.0%) limits and is used where tighter pitting resistance or low-permeability requirements apply.
"X2CrNiMo17-12-2 is a DIN-only old name." It remains an active EN 10088 designation and appears on current European mill certificates.
"316L is magnetic." In the annealed condition permeability is near 1.0; only heavy cold work can induce slight magnetism.
Frequently Asked Questions
Is EN 1.4404 the same as 316L?
Yes. 1.4404 is the EN material number of the 316L type; UNS S31603, AISI 316L, JIS SUS316L and GB 022Cr17Ni12Mo2 are equivalent designations.
What does the name X2CrNiMo17-12-2 mean?
X denotes a high-alloy steel, 2 is the maximum carbon content in hundredths of a percent (0.03%), and CrNiMo17-12-2 describes the nominal chromium, nickel and molybdenum contents.
Does 1.4404 require post-weld heat treatment?
No, not for standard wall thicknesses. The 0.03% carbon limit prevents chromium carbide precipitation at grain boundaries during welding, preserving corrosion resistance in the heat-affected zone.
Where is 1.4404 preferred over 304?
Wherever chlorides are present: coastal architecture, marine equipment, pharmaceutical water systems and food processing plant. The molybdenum content is the reason.
Can 1.4404 be supplied with EN 10204 3.1 certification?
Yes. Mill test certificates to EN 10204 3.1 are standard for this grade, giving full traceability of heat, chemistry and mechanical test results.
Which product forms are available?
Sheet, plate, strip, seamless and welded tube, pipe, bar and forgings, normally delivered in the annealed condition with pickled or bright-annealed surfaces.
