GB/T 4237 015Cr21Ni26Mo5Cu2 S31782 Stainless Steel Plate Supplier
What is GB/T 4237 015Cr21Ni26Mo5Cu2 (S31782) stainless steel plate?
015Cr21Ni26Mo5Cu2 is China’s 904L (N08904): 23–28% nickel, 4–5% molybdenum and 1–2% copper on a 19–23% chromium base. It was developed for sulfuric acid and stays one of the best stainless choices for dilute to medium sulfuric and phosphoric acid.
How to read the name: under GB/T 20878 the leading ‘015’ is the carbon code (here C ≤0.020%), then Cr21 = about 21% chromium; Ni26 = about 26% nickel; Mo5 = about 5% molybdenum; Cu2 = about 2% copper. S31782 is the unified numeric code (ISC) used in GB/T 4237-2015. Note that GB/T 20878-2024 has since assigned the code S39042; this page follows GB/T 4237-2015, the plate standard in force.
SHH STEEL produces and exports austenitic stainless plate from China, works as a sales agent for leading stainless mills, and runs its own processing warehouse for cutting and surface finishing. 015Cr21Ni26Mo5Cu2 is part of our GB/T 4237 stainless plate range; for comparison, see our ASTM A240 Type 904L page.
Corrosion behaviour and intergranular corrosion tests
Super austenitic grades are chosen when 316L and 317L pit or crevice-corrode: seawater, bleach plant filtrates, hot brines, sulfuric and phosphoric acids with chloride.
PREN of 015Cr21Ni26Mo5Cu2 from the GB/T 4237 limits: 32.2 – 35.9. PREN is a ranking tool for pitting in chlorides, not a guarantee; temperature, crevices, deposits and weld finish matter as much.
Intergranular corrosion testing is not compulsory for this grade in GB/T 4237-2015; when required, the method (GB/T 4334, ASTM A262 or A923 for duplex) and acceptance are agreed in the order.
For critical service, order ASTM G48 Method A (ferric chloride pitting) or Method C/E (critical pitting temperature) tests on the plate heat. We arrange them at the mill or an independent laboratory.
If service is harsher than 015Cr21Ni26Mo5Cu2 can handle, the next step up in this batch is GB/T 4237 015Cr20Ni18Mo6CuN S31252.
015Cr21Ni26Mo5Cu2 chemical composition (heat analysis)
| Element | 015Cr21Ni26Mo5Cu2 heat analysis, % (Table 15) | Why it matters |
|---|---|---|
| C | ≤ 0.020 | Carbon. Low values protect welds from carbide precipitation; higher values add hot strength or hardenability. |
| Si | ≤ 1.00 | Silicon. Deoxidizer; in heat-resistant grades it builds a protective scale. |
| Mn | ≤ 2.00 | Manganese. Deoxidizer; in Mn-bearing grades it replaces nickel and keeps nitrogen in solution. |
| P | ≤ 0.045 | Phosphorus. Impurity, kept low for toughness and weld cracking resistance. |
| S | ≤ 0.035 | Sulfur. Impurity; low sulfur improves pitting resistance, hot workability and polishability. |
| Cr | 19.00 – 23.00 | Chromium. Forms the passive film; the main driver of corrosion and oxidation resistance. |
| Ni | 23.00 – 28.00 | Nickel. Stabilizes austenite, improves toughness and resistance to reducing acids. |
| Mo | 4.00 – 5.00 | Molybdenum. Raises pitting and crevice resistance in chlorides (×3.3 in PREN). |
| Cu | 1.00 – 2.00 | Copper. Improves resistance to sulfuric acid and, in ferritics, general corrosion and formability. |
| N | ≤ 0.10 | Nitrogen. Strengthens, stabilizes austenite and adds pitting resistance (×16 in PREN). |
| PREN (Cr + 3.3Mo + 16N) | 32.2 – 35.9 (minimum – mid-range) | Calculated from the limits above, not a requirement of GB/T 4237 |
Values are maximum unless a range is given. The mill reports the ladle (heat) analysis on the certificate; this is the figure to compare with Table 15.
Product (check) analysis tolerances
A check analysis drilled from the finished plate may differ slightly from the heat analysis. GB/T 4237 refers to GB/T 222 for the permitted deviations; the table applies them to the 015Cr21Ni26Mo5Cu2 limits. Deviations apply to one side of a range only, never to both sides in the same heat.
| Element | Heat analysis limit (%) | Permitted deviation | Product analysis limit (%) |
|---|---|---|---|
| C | ≤ 0.020 | +0.005 | ≤ 0.025 |
| Si | ≤ 1.00 | ±0.05 | ≤ 1.05 |
| Mn | ≤ 2.00 | ±0.04 | ≤ 2.04 |
| P | ≤ 0.045 | +0.010 | ≤ 0.055 |
| S | ≤ 0.035 | +0.005 | ≤ 0.040 |
| Cr | 19.00 – 23.00 | ±0.20 (min) / ±0.25 (max) | 18.80 – 23.25 |
| Ni | 23.00 – 28.00 | ±0.20 | 22.80 – 28.20 |
| Mo | 4.00 – 5.00 | ±0.10 | 3.90 – 5.10 |
| Cu | 1.00 – 2.00 | ±0.05 (min) / ±0.10 (max) | 0.95 – 2.10 |
| N | ≤ 0.10 | ±0.01 | ≤ 0.11 |
Where the table says ‘by agreement’, the deviation is not tabulated for that content level and should be agreed in the contract, usually by reference to ASTM A480 Table A1.1.
Mechanical properties at room temperature
| Property | 015Cr21Ni26Mo5Cu2 (Table 20) |
|---|---|
| Proof strength Rp0.2, MPa | ≥ 220 |
| Tensile strength Rm, MPa | ≥ 490 |
| Elongation A, % | ≥ 35 |
| Hardness HRB | ≤ 90 |
| Hardness HV | ≤ 200 |
Values apply to plate in the delivery heat-treated condition, tested transversely per GB/T 228.1. Hardness is checked by one method chosen by the mill.
015Cr21Ni26Mo5Cu2 equivalent grades: ASTM, EN, JIS
| Standard system | Equivalent / closest grade |
|---|---|
| China GB/T 4237-2015 | 015Cr21Ni26Mo5Cu2 (S31782) |
| GB/T 20878-2024 code | S39042 |
| ASTM A240/A240M | 904L / N08904 |
| EN 10088-2 | X1NiCrMoCu25-20-5 / 1.4539 |
| JIS G4304 (hot rolled) | SUS890L |
| Common name | 904L |
Equivalent grades are close in chemistry and properties but are never identical: limits on carbon, nitrogen and residual elements differ. For dual or multiple certification the heat must meet every standard named on the order, and we confirm that from the heat chemistry before quotation.
Related pages: ASTM A240 Type 904L, AISI 904L. See also our ASTM A240/A240M and JIS G4305 plate lists.
Where this grade sits on the super austenitic ladder
The high-alloy austenitics of GB/T 4237 step up in molybdenum and nitrogen. Pitting resistance follows PREN closely; nickel mainly helps in acids and against phase precipitation.
| Grade | Mo, % | N, % | PREN min |
|---|---|---|---|
| 015Cr21Ni26Mo5Cu2 S31782 | 4.00 – 5.00 | ≤ 0.10 | 32.2 |
| GB/T 4237 015Cr20Ni18Mo6CuN S31252 | 6.00 – 6.50 | 0.18 – 0.25 | 42.2 |
| GB/T 4237 015Cr20Ni25Mo7CuN S38926 | 6.00 – 7.00 | 0.15 – 0.25 | 41.2 |
| GB/T 4237 022Cr21Ni25Mo7N S38367 | 6.00 – 7.00 | 0.18 – 0.25 | 42.7 |
| GB/T 4237 022Cr24Ni17Mo5Mn6NbN S34553 | 4.00 – 5.00 | 0.40 – 0.60 | 42.6 |
| GB/T 4237 015Cr24Ni22Mo8Mn3CuN S32652 | 7.00 – 8.00 | 0.45 – 0.55 | 54.3 |
015Cr21Ni26Mo5Cu2: 904L.
Cutting, forming and welding 015Cr21Ni26Mo5Cu2 plate
Weld super austenitic plate with over-alloyed nickel-base filler (ERNiCrMo-3, ERNiCrMo-10 or ERNiCrMo-13 class). Matching filler leaves Mo-depleted dendrite cores that pit before the parent metal.
Heat input ≤1.5 kJ/mm, interpass ≤100 °C, full argon back purge, and pickling of the whole weld zone. Avoid autogenous (no-filler) GTAW on wetted surfaces.
Cutting: we cut 015Cr21Ni26Mo5Cu2 by plasma (up to about 150 mm), laser (thin plate) or waterjet, and remove the heat-affected edge by machining where the drawing requires it.
How 015Cr21Ni26Mo5Cu2 plate is heat treated
Recommended heat treatment for 015Cr21Ni26Mo5Cu2 (GB/T 4237-2015 Annex C): 1 030 – 1 180 °C, rapid cooling.
Super austenitic plate must be quenched fast from the solution temperature to keep sigma and chi phases out of the structure. Hot-formed heads are re-annealed at the same temperature.
Specification summary
| Item | GB/T 4237-2015 requirement / SHH STEEL supply |
|---|---|
| Standard | GB/T 4237-2015 Hot rolled stainless steel plate, sheet and strip (current edition, replaces GB/T 4237-2007) |
| Grade / unified code | 015Cr21Ni26Mo5Cu2 / S31782 |
| Steel class | Austenitic |
| Chemical composition | Table 15 (heat analysis); product analysis per GB/T 222 |
| Mechanical properties | Table 20 |
| Product forms | Hot-rolled thick plate (3.0 – 200 mm in the standard), hot-rolled wide strip and cut plate (2.0 – 25.4 mm) |
| Our usual thickness range | 3 – 50 mm |
| Delivery condition | 1 030 – 1 180 °C, rapid cooling |
| Surface | Hot rolled, heat treated, pickled (No.1 / 1D) as standard; ground or polished by agreement |
| Density | 8.0 g/cm³ |
| Certificate | EN 10204 3.1 mill certificate; 3.2 with third-party inspection on request |
Sister grades on the same standard are listed under GB/T 4237; cold-rolled sheet of the same chemistry is ordered to GB/T 3280, and all our plate lines sit in stainless steel sheets and plates.
Applications of 015Cr21Ni26Mo5Cu2 plate
Severe-service applications:
- Sulfuric acid coolers, tanks and pickling equipment
- Phosphoric acid evaporators and fertilizer plants
- FGD scrubbers and wet stacks
- Seawater-cooled heat exchangers (moderate temperature)
- Pulp and paper bleach plants
- Pharmaceutical and fine chemical vessels
Buyers specifying 015Cr21Ni26Mo5Cu2 for these jobs often compare it with GB/T 4237 015Cr20Ni18Mo6CuN S31252 and GB/T 4237 06Cr18Ni12Mo2Cu2 S31688; the comparison table on this page shows the differences.
International grade pages for the alternatives mentioned above: AISI 254 SMO, AISI 254 SMO, ASTM A240 Type 317L, ASTM A240 Type 2205.
015Cr21Ni26Mo5Cu2 compared with related grades
The table compares 015Cr21Ni26Mo5Cu2 with the grades buyers most often weigh it against. Strength values are GB/T 4237-2015 minimums; PREN is calculated from the minimum chemistry.
| Grade (GB/T 4237) | Key chemistry, % | PREN min | Rp0.2 min, MPa | Rm min, MPa |
|---|---|---|---|---|
| 015Cr21Ni26Mo5Cu2 S31782 | C ≤ 0.020, Cr 19.00 – 23.00, Ni 23.00 – 28.00, Mo 4.00 – 5.00, N ≤ 0.10, Cu 1.00 – 2.00 | 32.2 | 220 | 490 |
| GB/T 4237 015Cr20Ni18Mo6CuN S31252 | C ≤ 0.020, Cr 19.50 – 20.50, Ni 17.50 – 18.50, Mo 6.00 – 6.50, N 0.18 – 0.25, Cu 0.50 – 1.00 | 42.2 | 310 | 655 |
| GB/T 4237 015Cr20Ni25Mo7CuN S38926 | C ≤ 0.020, Cr 19.00 – 21.00, Ni 24.00 – 26.00, Mo 6.00 – 7.00, N 0.15 – 0.25, Cu 0.50 – 1.50 | 41.2 | 295 | 650 |
| GB/T 4237 022Cr19Ni13Mo3 S31703 | C ≤ 0.030, Cr 18.00 – 20.00, Ni 11.00 – 15.00, Mo 3.00 – 4.00, N ≤ 0.10 | 27.9 | 205 | 515 |
| GB/T 4237 022Cr23Ni5Mo3N S22053 | C ≤ 0.030, Cr 22.00 – 23.00, Ni 4.50 – 6.50, Mo 3.00 – 3.50, N 0.14 – 0.20 | 34.1 | 450 | 655 |
| GB/T 4237 06Cr18Ni12Mo2Cu2 S31688 | C ≤ 0.08, Cr 17.00 – 19.00, Ni 10.00 – 14.00, Mo 1.20 – 2.75, Cu 1.00 – 2.50 | 21.0 | 205 | 520 |
904L is not a 6Mo grade: in warm seawater or high-chloride brines its crevice resistance is below 254 SMO-type steel. Weld with ERNiCrMo-3 or matching 385/904L filler and keep heat input low to avoid hot cracking in this fully austenitic alloy. GB/T 20878-2024 recodes it as S39042.
Surface finish and processing
| Finish | Description | Availability for this grade |
|---|---|---|
| No.1 / 1D | Hot rolled, heat treated, pickled; the GB/T 4237 standard surface | Standard |
| Shot-blasted + pickled | Uniform matte for welded structures | On request |
| Ground | Ground surface for defect removal or UT | On request |
| 2B / BA | Cold-rolled finishes (ordered as GB/T 3280 sheet, not hot-rolled plate) | Sheet only |
Our warehouse cuts plate to size (plasma, laser, waterjet, saw), bevels weld edges, polishes and applies PVC protective film. Processed plate ships with the original mill heat number marked. Ask for cut pieces of other stainless steel products at the same time to consolidate freight.
Dimensions and plate weight
| Dimension | Typical supply |
|---|---|
| Thickness | 3 – 50 mm |
| Width | 1 000 / 1 219 / 1 250 / 1 500 / 1 800 / 2 000 mm; wider by mill order |
| Length | 2 000 / 2 438 / 3 000 / 6 000 mm or cut to size |
| Flatness | Per GB/T 4237; ≤15 mm per metre for plate up to 25 mm unless agreed tighter |
| Thickness tolerance | Per the GB/T 4237 dimensional tolerance tables (normal or higher accuracy as ordered) |
| Edge | Mill edge or cut edge |
Weight: plate mass in kg/m² = thickness (mm) × density (8.0 g/cm³). A 10 mm 015Cr21Ni26Mo5Cu2 plate weighs about 80.0 kg/m²; a 1 500 × 6 000 × 10 mm plate about 720 kg.
Inspection, tests and mill certificates
- Heat chemical analysis on every heat; product analysis by agreement
- Tensile test (Rp0.2, Rm, A) per batch
- Hardness test
- ASTM G48 pitting test when specified
- Ultrasonic testing (NB/T 47013.3 or ASTM A578) when specified
- Positive material identification (PMI) on every plate leaving our warehouse
- Visual and dimensional inspection; third-party inspection (SGS, BV, TÜV, Intertek) at the buyer’s request
Certificates follow EN 10204 3.1 as standard. Where plate is also certified to ASME SA240 or ASTM A240, both standards are shown on one certificate.
Mill sourcing and lead time
015Cr21Ni26Mo5Cu2 is a mainstream grade at Chinese stainless mills. We supply it from our own stock and processing warehouse, and by mill order from major producers such as TISCO and Baosteel Stainless, for which we act as a sales agent. Stock plate ships in about 1–2 weeks after cutting; mill orders typically take 30–60 days depending on thickness and rolling schedule.
Every plate is traceable to its heat number, and copies of the mill certificates stay on file for repeat orders and audits. The same mills also supply our ASTM A240, ASME SA240, JIS G4305 and AISI plate ranges, so mixed-standard orders can ship together.
Ordering information
- Standard and edition: GB/T 4237-2015
- Grade and code: 015Cr21Ni26Mo5Cu2 (S31782); add the equivalent if dual certification is needed
- Thickness × width × length, quantity in pieces or tonnes
- Thickness tolerance class and flatness if tighter than standard
- Surface finish and protective film
- Tests beyond the standard (IGC, UT, impact, ferrite, PMI, grain size)
- Certificate type (EN 10204 3.1 / 3.2) and inspection body
- Marking, packing (wooden cases, steel pallets) and delivery terms
Send the list to SHH STEEL and we return a quotation with mill, lead time and stock options. Other grades from the same standard can be combined in one shipment; browse GB/T 4237 plate grades.
FAQ
- Is 015Cr21Ni26Mo5Cu2 the same as 904L?
- Yes. 015Cr21Ni26Mo5Cu2 (S31782 in GB/T 4237-2015, S39042 in GB/T 20878-2024) corresponds to UNS N08904, EN 1.4539 and JIS SUS890L. Chemistry: C ≤0.020%, Cr 19–23%, Ni 23–28%, Mo 4–5%, Cu 1–2%.
- What is the chemical composition of 015Cr21Ni26Mo5Cu2?
- Under GB/T 4237-2015 Table 15, 015Cr21Ni26Mo5Cu2 (S31782) has C ≤ 0.020, Cr 19.00 – 23.00, Ni 23.00 – 28.00, Mo 4.00 – 5.00, N ≤ 0.10, Cu 1.00 – 2.00. Phosphorus is limited to ≤0.045% and sulfur to ≤0.035%.
- What are the mechanical properties of 015Cr21Ni26Mo5Cu2 plate?
- GB/T 4237-2015 Table 20 requires for 015Cr21Ni26Mo5Cu2: proof strength Rp0.2 ≥220 MPa, tensile strength ≥490 MPa and elongation ≥35%. Values apply to plate in the delivery heat-treated condition.
- Is 015Cr21Ni26Mo5Cu2 stainless steel magnetic?
- Not in the annealed condition. 015Cr21Ni26Mo5Cu2 is austenitic, so annealed plate is essentially non-magnetic; cold work can induce slight magnetism, mostly at cut and bent edges.
- What thickness of 015Cr21Ni26Mo5Cu2 plate can you supply?
- Under GB/T 4237 we supply 015Cr21Ni26Mo5Cu2 hot-rolled plate in 3 – 50 mm, widths up to 2 000 mm (wider by mill order), cut to size in our warehouse. Thinner material is cold-rolled sheet to GB/T 3280.
- What is the PREN of 015Cr21Ni26Mo5Cu2?
- Using PREN = Cr + 3.3Mo + 16N and the GB/T 4237-2015 limits, 015Cr21Ni26Mo5Cu2 has a PREN of about 32.2 at minimum chemistry and 35.9 at mid-range.
Conclusion
GB/T 4237 015Cr21Ni26Mo5Cu2 (S31782) is a super austenitic / high-alloy austenitic plate grade, known internationally as 904L. It is defined by Table 15 chemistry (C ≤ 0.020, Cr 19.00 – 23.00, Ni 23.00 – 28.00, Mo 4.00 – 5.00, N ≤ 0.10, Cu 1.00 – 2.00) and Table 20 properties of at least 220 MPa proof strength and 490 MPa tensile strength. Typical uses include sulfuric acid coolers, tanks and pickling equipment, phosphoric acid evaporators and fertilizer plants and fgd scrubbers and wet stacks. 904L is not a 6Mo grade: in warm seawater or high-chloride brines its crevice resistance is below 254 SMO-type steel.
Before ordering, state the standard edition, the grade name with its code, and any extra tests, so that the mill certificate matches your design documents. SHH STEEL supplies 015Cr21Ni26Mo5Cu2 plate from stock and by mill order, cut to size and finished in our own warehouse, with EN 10204 3.1 certificates. For related grades see GB/T 4237 015Cr20Ni18Mo6CuN S31252 and GB/T 4237 015Cr20Ni25Mo7CuN S38926, our GB/T 4237 category and the ASTM A240 Type 904L page. Send your sizes and quantities for a quotation.
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