GB/T 4237 06Cr19Ni9NbN S30478 Stainless Steel Plate Supplier
GB/T 4237 06Cr19Ni9NbN: what it is and who uses it
06Cr19Ni9NbN is a high-strength 304 variant: 0.15–0.30% nitrogen plus up to 0.15% niobium and manganese to 2.50%. Niobium nitrides pin the grain, so GB/T 4237-2015 can require 275 MPa proof strength and 585 MPa tensile in the solution-treated state.
How to read the name: under GB/T 20878 the leading ’06’ is the carbon code (here C ≤0.08%), then Cr19 = about 19% chromium; Ni9 = about 9% nickel; Nb = niobium added; N = nitrogen added. S30478 is the unified numeric code (ISC) used in GB/T 4237-2015. Older drawings and Chinese buyers may still write the pre-2007 name 0Cr19Ni10NbN.
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. 06Cr19Ni9NbN is part of our GB/T 4237 stainless plate range; for comparison, see our AISI 304N page.
What the standard covers for this grade
| 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 | 06Cr19Ni9NbN / S30478 |
| 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 – 120 mm (to 200 mm by mill order) |
| Delivery condition | ≥ 1 040 °C, water quench or other rapid cooling |
| Surface | Hot rolled, heat treated, pickled (No.1 / 1D) as standard; ground or polished by agreement |
| Density | 7.93 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.
06Cr19Ni9NbN chemical composition (heat analysis)
| Element | 06Cr19Ni9NbN heat analysis, % (Table 15) | Why it matters |
|---|---|---|
| C | ≤ 0.08 | 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 | ≤ 2.50 | 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 | ≤ 0.030 | Sulfur. Impurity; low sulfur improves pitting resistance, hot workability and polishability. |
| Cr | 18.00 – 20.00 | Chromium. Forms the passive film; the main driver of corrosion and oxidation resistance. |
| Ni | 7.50 – 10.50 | Nickel. Stabilizes austenite, improves toughness and resistance to reducing acids. |
| N | 0.15 – 0.30 | Nitrogen. Strengthens, stabilizes austenite and adds pitting resistance (×16 in PREN). |
| Nb | ≤ 0.15 | Niobium. Stabilizes carbon, refines grain and adds high-temperature strength. |
| PREN (Cr + 3.3Mo + 16N) | 20.4 – 22.6 (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 06Cr19Ni9NbN 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 | ≤ 0.08 | ±0.01 | ≤ 0.09 |
| Si | ≤ 1.00 | ±0.05 | ≤ 1.05 |
| Mn | ≤ 2.50 | ±0.04 | ≤ 2.54 |
| P | ≤ 0.045 | +0.010 | ≤ 0.055 |
| S | ≤ 0.030 | +0.005 | ≤ 0.035 |
| Cr | 18.00 – 20.00 | ±0.20 | 17.80 – 20.20 |
| Ni | 7.50 – 10.50 | ±0.10 (min) / ±0.15 (max) | 7.40 – 10.65 |
| N | 0.15 – 0.30 | ±0.01 (min) / ±0.03 (max) | 0.14 – 0.33 |
| Nb | ≤ 0.15 | ±0.05 | ≤ 0.20 |
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.
06Cr19Ni9NbN S30478 tensile and hardness requirements
| Property | 06Cr19Ni9NbN (Table 20) |
|---|---|
| Proof strength Rp0.2, MPa | ≥ 275 |
| Tensile strength Rm, MPa | ≥ 585 |
| Elongation A, % | ≥ 30 |
| Hardness HBW | ≤ 241 |
| Hardness HRB | ≤ 100 |
| Hardness HV | ≤ 242 |
Strength minimums apply to solution-treated plate tested transverse to rolling. Actual mill results are usually well above these minimums and are reported on the certificate.
Which variant to order: standard, L, H or N?
Each 18-8 base grade in GB/T 4237 comes in several variants. L (C ≤0.030%) is for welded parts in corrosive service, H (C 0.04–0.10%) for creep strength, N for higher strength.
| Grade | Order it for |
|---|---|
| GB/T 4237 06Cr19Ni10 S30408 | Standard 304 for general fabrication |
| GB/T 4237 022Cr19Ni10 S30403 | Welded parts in corrosive service |
| GB/T 4237 07Cr19Ni10 S30409 | Pressure parts above about 500 °C (creep) |
| GB/T 4237 06Cr19Ni10N S30458 | Higher strength, thinner walls |
| GB/T 4237 022Cr19Ni10N S30453 | Low carbon plus nitrogen strength |
| 06Cr19Ni9NbN S30478 | Highest strength 304 variant (Nb + N) |
06Cr19Ni9NbN sits in this family as 304N2 / XM-21.
06Cr19Ni9NbN equivalent grades: ASTM, EN, JIS
| Standard system | Equivalent / closest grade |
|---|---|
| China GB/T 4237-2015 | 06Cr19Ni9NbN (S30478) |
| Former Chinese name | 0Cr19Ni10NbN |
| ASTM A240/A240M | XM-21 / S30452 |
| EN 10088-2 | — |
| JIS G4304 (hot rolled) | SUS304N2 |
| Common name | 304N2 |
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: AISI 304N, ASTM A240 Type 304N. See also our ASTM A240/A240M and JIS G4305 plate lists.
Choosing between 06Cr19Ni9NbN and its neighbours
The table compares 06Cr19Ni9NbN 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 |
|---|---|---|---|---|
| 06Cr19Ni9NbN S30478 | C ≤ 0.08, Cr 18.00 – 20.00, Ni 7.50 – 10.50, N 0.15 – 0.30, Nb ≤ 0.15 | 20.4 | 275 | 585 |
| GB/T 4237 06Cr19Ni10N S30458 | C ≤ 0.08, Cr 18.00 – 20.00, Ni 8.00 – 10.50, N 0.10 – 0.16 | 19.6 | 240 | 550 |
| GB/T 4237 06Cr19Ni10 S30408 | C ≤ 0.07, Cr 17.50 – 19.50, Ni 8.00 – 10.50, N ≤ 0.10 | 17.5 | 205 | 515 |
| GB/T 4237 05Cr19Ni10Si2CeN S30450 | C 0.04 – 0.06, Cr 18.00 – 19.00, Ni 9.00 – 10.00, N 0.12 – 0.18, Si 1.00 – 2.00 | 19.9 | 290 | 600 |
| GB/T 4237 06Cr17Ni12Mo2N S31658 | C ≤ 0.08, Cr 16.00 – 18.00, Ni 10.00 – 14.00, Mo 2.00 – 3.00, N 0.10 – 0.16 | 24.2 | 240 | 550 |
This is a niche grade in Chinese mills and normally a mill order rather than stock. Allow for the higher strength when shearing and bending: 30% minimum elongation, harder than 304 (HBW ≤241).
Corrosion behaviour and intergranular corrosion tests
Austenitic 18-8 grades resist atmospheric corrosion, fresh water, foods, nitric acid and most organic acids. They are vulnerable to chlorides (pitting, crevice and stress corrosion cracking above about 60 °C).
PREN of 06Cr19Ni9NbN from the GB/T 4237 limits: 20.4 – 22.6. 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.
If service is harsher than 06Cr19Ni9NbN can handle, the next step up in this batch is GB/T 4237 06Cr17Ni12Mo2N S31658.
How 06Cr19Ni9NbN plate is heat treated
Recommended heat treatment for 06Cr19Ni9NbN (GB/T 4237-2015 Annex C): ≥ 1 040 °C, water quench or other rapid cooling.
Solution treatment dissolves carbides and restores full corrosion resistance and ductility. Hot forming should finish above about 900 °C and be followed by a new solution anneal if the part is used in corrosive service.
Fabrication guidance
Austenitic 18-8 plate welds well with every arc process (SMAW, GTAW, GMAW, SAW, FCAW). Use ER308L/E308L filler for 304 and 304L, ER347 where the joint must resist sensitization at high carbon, and ER308H for H grades.
Keep interpass temperature below about 150 °C, avoid preheat, and remove heat tint by pickling or brushing with stainless brushes. Distortion is higher than with carbon steel because thermal expansion is about 50% greater and conductivity much lower; plan tacking sequence and fixtures.
Cold forming: austenitic plate bends to tight radii (inside radius ≈ thickness for most gauges) but springs back more than carbon steel.
Finishes and warehouse services
| 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 |
| No.4 / brushed | Abrasive finish, grit 150–180 | Warehouse processing, thin plate |
| HL (hairline) | Long continuous lines, decorative | Warehouse processing, thin plate |
| 8K mirror | Polished reflective finish | Warehouse processing, limited sizes |
| 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.
06Cr19Ni9NbN plate sizes
| Dimension | Typical supply |
|---|---|
| Thickness | 3 – 120 mm (to 200 mm by mill order) |
| 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 (7.93 g/cm³). A 10 mm 06Cr19Ni9NbN plate weighs about 79.3 kg/m²; a 1 500 × 6 000 × 10 mm plate about 714 kg.
Applications of 06Cr19Ni9NbN plate
Typical end uses we ship this grade for:
- High-strength structural plate for vessels and frames
- Cryogenic equipment that needs strength without cold working
- Pressure parts designed to JIS SUS304N2-type allowables
- Non-magnetic structures
Buyers specifying 06Cr19Ni9NbN for these jobs often compare it with GB/T 4237 06Cr19Ni10N S30458 and GB/T 4237 06Cr17Ni12Mo2N S31658; the comparison table on this page shows the differences.
Testing and certification
- Heat chemical analysis on every heat; product analysis by agreement
- Tensile test (Rp0.2, Rm, A) per batch
- Hardness test
- 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.
What to put on a 06Cr19Ni9NbN purchase order
- Standard and edition: GB/T 4237-2015
- Grade and code: 06Cr19Ni9NbN (S30478); 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.
Mill sourcing and lead time
06Cr19Ni9NbN is produced by a small number of Chinese mills with the melting and heat treatment capability for it. We place mill orders for it through the producers we represent and do not usually hold it in stock. Expect about 45–90 days, with minimum quantities per thickness; we can combine small quantities into one rolling where the mill allows.
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.
What SHH STEEL adds
- Mill-direct prices with our own export documentation
- Own processing warehouse: cutting, bevelling, polishing, PVC film
- PMI and dimensional check before packing
- Mixed-grade shipments across our AISI stainless and GB/T plate ranges
- Technical answers from people who read the standard, not just the price list
SHH STEEL has exported stainless and carbon steel plate to buyers in Asia, the Middle East, Africa, Europe and the Americas.
FAQ
- What is 06Cr19Ni9NbN equivalent to?
- 06Cr19Ni9NbN (S30478) corresponds to JIS SUS304N2 and ASTM XM-21 (S30452). Old Chinese name 0Cr19Ni10NbN. It is a 304 strengthened with N 0.15–0.30% and Nb ≤0.15%, giving 275 MPa minimum proof strength in GB/T 4237-2015.
- What is the chemical composition of 06Cr19Ni9NbN?
- Under GB/T 4237-2015 Table 15, 06Cr19Ni9NbN (S30478) has C ≤ 0.08, Cr 18.00 – 20.00, Ni 7.50 – 10.50, N 0.15 – 0.30, Nb ≤ 0.15. Phosphorus is limited to ≤0.045% and sulfur to ≤0.030%.
- What are the mechanical properties of 06Cr19Ni9NbN plate?
- GB/T 4237-2015 Table 20 requires for 06Cr19Ni9NbN: proof strength Rp0.2 ≥275 MPa, tensile strength ≥585 MPa and elongation ≥30%, hardness ≤241 HBW. Values apply to plate in the delivery heat-treated condition.
- Is 06Cr19Ni9NbN stainless steel magnetic?
- Not in the annealed condition. 06Cr19Ni9NbN is austenitic, so annealed plate is essentially non-magnetic; cold work can induce slight magnetism, mostly at cut and bent edges.
- What thickness of 06Cr19Ni9NbN plate can you supply?
- Under GB/T 4237 we supply 06Cr19Ni9NbN hot-rolled plate in 3 – 120 mm (to 200 mm by mill order), 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.
- How much does a 06Cr19Ni9NbN plate weigh?
- Multiply thickness in mm by the density 7.93 g/cm³ to get kg/m². A 10 mm plate weighs about 79.3 kg/m², so a 1 500 × 6 000 × 10 mm sheet weighs about 714 kg.
Conclusion
GB/T 4237 06Cr19Ni9NbN (S30478) is a 18-8 chromium-nickel austenitic plate grade, known internationally as 304N2 / XM-21. It is defined by Table 15 chemistry (C ≤ 0.08, Cr 18.00 – 20.00, Ni 7.50 – 10.50, N 0.15 – 0.30, Nb ≤ 0.15) and Table 20 properties of at least 275 MPa proof strength and 585 MPa tensile strength. Typical uses include high-strength structural plate for vessels and frames, cryogenic equipment that needs strength without cold working and pressure parts designed to jis sus304n2-type allowables. This is a niche grade in Chinese mills and normally a mill order rather than stock.
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 06Cr19Ni9NbN plate by mill order through the producers we represent, cut to size and finished in our own warehouse, with EN 10204 3.1 certificates. For related grades see GB/T 4237 06Cr19Ni10N S30458 and GB/T 4237 06Cr19Ni10 S30408, our GB/T 4237 category and the AISI 304N page. Send your sizes and quantities for a quotation.
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