GB/T 713.7 022Cr25Ni6Mo2N S22553 Pressure Vessel Stainless Plate
GB/T 713.7 022Cr25Ni6Mo2N: what it is and who uses it
022Cr25Ni6Mo2N S22553 is listed in GB/T 713.7-2023, the Chinese standard for pressure equipment stainless steel plate, as a standard duplex grade with about 50/50 austenite and ferrite. As a GB/T 713.7-2023 stainless plate it is ordered by vessel and heat-exchanger shops that design to GB/T 150 and the TSG 21 safety rules, and by EPC contractors who must deliver Chinese-code equipment abroad. There is no exact ASTM A240 twin; the closest foreign grade is S31200.
Reading the designation: the leading digits give the carbon level (≤ 0.030%); the element symbols that follow give the approximate contents of the main alloying elements in percent. S22553 is the unified numeric code (ISC). The grade is new in the 2023 edition: it was not part of GB/T 24511-2017, so older drawings will not call for it and the designer must reference GB/T 713.7-2023 directly. In short, S22553 stainless steel is the GB/T 713.7 designation of this grade. Mills sell 022Cr25Ni6Mo2N stainless steel under several product standards, but only GB/T 713.7 certifies it for pressure equipment. Every 022Cr25Ni6Mo2N pressure vessel plate is tested and certified to the 2023 edition.
SHH STEEL produces and exports stainless plate from Shanghai, works as a sales agent for mills including TISCO, Baosteel and POSCO, and runs its own processing warehouse for cutting and polishing. 022Cr25Ni6Mo2N is part of our GB/T 713.7-2023 pressure vessel stainless plate range; for the general-purpose version of the same grade see GB/T 4237 022Cr25Ni6Mo2N S22553.
Why designers specify S22553
Material selection for a Chinese-code pressure vessel starts with the design conditions: medium, temperature, pressure and the minimum design metal temperature. Duplex grades are chosen when a designer needs about twice the proof strength of an austenitic grade together with resistance to chloride stress-corrosion cracking, which allows thinner walls and lighter vessels. GB/T 150 lists the permitted plate standards and allowable stresses, and the material must be supplied with a certificate that ties every plate to its heat. Because 022Cr25Ni6Mo2N is listed in GB/T 713.7-2023, it can be used directly under GB/T 150 without a separate material evaluation, which saves time on approvals compared with a foreign grade.
Who buys it
Our customers for this grade include pressure vessel fabricators in China and Southeast Asia, EPC contractors building Chinese-designed plants in the Middle East, Africa and Central Asia, and maintenance teams that need like-for-like replacement plate for equipment originally built to GB/T 24511 or GB/T 713.7. Export buyers often need the plate certified to GB/T 713.7 and checked against an ASTM or EN grade at the same time, which we arrange with the mill before rolling.
What the standard covers for this grade
| Item | GB/T 713.7-2023 requirement / SHH STEEL supply |
|---|---|
| Standard | GB/T 713.7-2023 (in force since 1 March 2024; replaces GB/T 24511-2017) |
| Grade / unified code | 022Cr25Ni6Mo2N / S22553 |
| Steel class | Austenitic-ferritic (duplex) |
| Chemical composition | Table 14 (heat analysis); product analysis deviations per GB/T 713.1 |
| Mechanical properties | Table 17: Rp0.2 ≥ 450 MPa, Rm ≥ 640 MPa, A ≥ 25% |
| Product forms | Hot-rolled thick plate, hot-rolled plate and strip, cold-rolled plate and strip, width ≥ 600 mm |
| Thickness (Table 1) | 0.30 – 8.00 mm cold rolled; 2.00 – 14.0 mm hot-rolled strip; 6.00 – 100 mm hot-rolled thick plate |
| Delivery condition | Solution treated (Annex C gives the regime) |
| Edge / accuracy | EC trimmed or EM untrimmed; PT.A or PT.B thickness accuracy |
| Density | about 7.8 (Annex A) |
| Certificate | EN 10204 3.1; 3.2 with third-party witness on request |
The table is a summary; the purchase order should cite the full standard and edition. Clause 4.2 of GB/T 713.7 requires the surface finish to be named on the order, and the edge and thickness-accuracy codes decide the tolerance class used for acceptance. For coil-cut plate, flatness and camber follow the general rules of GB/T 713.1, which every part of GB/T 713 refers to.
Heat and product analysis limits for 022Cr25Ni6Mo2N
The S22553 chemical composition is the heat (melting) analysis the mill reports for each heat, and it must meet GB/T 713.7-2023 Table 14 in weight percent.
| Element | 022Cr25Ni6Mo2N heat analysis, % (Table 14) | Why it matters |
|---|---|---|
| C | ≤ 0.030 | Strength, weldability and sensitization risk |
| Si | ≤ 1.00 | Deoxidation; in heat-resisting grades, oxidation resistance |
| Mn | per Table 14 | Austenite stability and hot workability |
| P | ≤ 0.030 | Kept low for weld soundness |
| S | per Table 14 | Kept low for toughness and weld cracking resistance |
| Cr | 24.00 – 26.00 | Passive film and oxidation resistance |
| Ni | 5.50 – 6.50 | Austenite stability and toughness |
| Mo | 1.50 – 2.50 | Pitting and crevice resistance |
| N | 0.10 – 0.20 | Strength and pitting resistance |
The product analysis is a check on the finished plate. Clause 7.2.2 of GB/T 713.7 refers to GB/T 713.1 for the permitted deviations; the values below are the customary GB/T 222 / ASTM A480 deviations applied to 022Cr25Ni6Mo2N and should be confirmed against the edition cited in the contract.
| Element | Heat analysis limit (%) | Permitted deviation | Product analysis limit (%) |
|---|---|---|---|
| C | ≤ 0.030 | +0.005 | ≤ 0.035 |
| Si | ≤ 1.00 | +0.05 | ≤ 1.05 |
| Mn | per Table 14 | by agreement | by agreement |
| P | ≤ 0.030 | +0.005 | ≤ 0.035 |
| S | per Table 14 | by agreement | by agreement |
| Cr | 24.00 – 26.00 | −0.25 / +0.25 | 23.75 – 26.25 |
| Ni | 5.50 – 6.50 | −0.1 / +0.1 | 5.40 – 6.60 |
| Mo | 1.50 – 2.50 | −0.05 / +0.1 | 1.45 – 2.60 |
| N | 0.10 – 0.20 | −0.01 / +0.02 | 0.090 – 0.220 |
PREN (Cr + 3.3Mo + 16N) calculated from the minimum chemistry is 30.6. Notes to the table state that compositions were adjusted compared with GB/T 3280 and GB/T 4237, so a general-purpose certificate does not automatically meet GB/T 713.7.
Product (check) analysis and PMI
Product (check) analysis is the chemistry measured on a sample taken from the finished plate rather than from the ladle, and it is how a buyer proves the plate matches the certificate.
Under GB/T 713.7 the mill reports the heat analysis as standard. A product analysis is made when the purchase order calls for it, and the result is judged against the heat limits widened by the permitted deviations shown above. Deviations apply to one side of a range only; a heat may not exceed both the lower and upper limit of the same element. Elements marked ‘by agreement’ have no tabulated deviation and should be settled in the contract.
SHH STEEL runs positive material identification (PMI) on every plate in our Shanghai warehouse before it ships. PMI by handheld XRF confirms Cr, Ni, Mo and other alloying elements; it cannot measure carbon or nitrogen, so when low carbon matters we arrange laboratory spark-OES or combustion analysis through our steel testing service. Product analysis results are added to the 3.1 certificate or reported by the third-party inspector on a 3.2 certificate.
Sampling and acceptance
Samples for product analysis are taken across the thickness or from millings so that the result represents the whole plate, not only the surface. If a product analysis falls outside the permitted range, the usual practice under GB/T 713.1 is to retest on additional samples before the plate or batch is rejected. We keep retained samples from tested heats for a period agreed with the customer, which helps when questions arise during fabrication or inspection.
Mechanical properties of 022Cr25Ni6Mo2N plate
The S22553 mechanical properties are the room-temperature values that GB/T 713.7-2023 Table 17 sets for solution treated plate.
| Property | GB/T 713.7 S22553 (Table 17) |
|---|---|
| Rp0.2, MPa | ≥ 450 |
| Rm, MPa | ≥ 640 |
| A, % | ≥ 25 |
| Hardness | HBW ≤ 295, HRC 31 max |
Elongation for thickness ≤ 3.00 mm is measured on A50 mm specimens per GB/T 228.1 P5. Design stresses are not taken from this table directly: the vessel designer uses the allowable-stress tables of GB/T 150.2, which are derived from these minimums and from the elevated-temperature data in Annex D where given.
How designers use these values
The room-temperature minimums are the basis of the allowable stresses in GB/T 150.2. The designer takes the lower of the stress derived from tensile strength and the stress derived from proof strength, applies the code safety factors, and for elevated temperatures uses the temperature-dependent proof strength. For duplex grades the high proof strength usually means the tensile-strength term governs, and the upper temperature limit in the code must be respected. Hardness limits on the certificate are a quick check that the plate has been correctly heat treated: a plate above the maximum hardness has usually been under-treated or cold worked.
Testing frequency
Tensile and hardness tests are made per batch as defined in the inspection rules of GB/T 713.7 clause 9 and GB/T 713.1. A batch is plate from the same heat, the same thickness and the same heat-treatment condition. When the order calls for testing of each plate or each rolled plate, state this explicitly, as it affects cost and lead time.
Annealing / solution treatment
S22553 heat treatment solution treatment is the final heat treatment that sets the structure and properties of the plate, and GB/T 713.7-2023 Annex C gives the recommended regime for 022Cr25Ni6Mo2N. Mills typically solution treat this grade at about 1 020 – 1 100 °C followed by rapid cooling to keep the austenite/ferrite balance and avoid sigma and chi phases. The actual temperature and cooling method are recorded on the mill certificate.
Clause 7.1.2 allows hot-rolled strip 14.0 – 25.0 mm thick to be levelled and heat treated sheet by sheet. After heavy cold forming or hot forming of heads, the fabricator should follow GB/T 150.4 on whether re-treatment is needed; for duplex plate, any re-treatment must be a full solution treatment; stress relieving in the 300 – 1 000 °C range causes embrittling phases.
What can go wrong
An incorrectly heat-treated plate shows up as high hardness, low elongation or, in corrosion tests, as intergranular attack. Slow cooling or holding in the range of about 700 – 950 °C forms sigma and chi phases that sharply reduce toughness and corrosion resistance, so cooling must be fast. When we receive plate, our engineers check the heat-treatment record on the certificate against Annex C and the hardness result before releasing the material.
Phase balance and service temperature limits
Phase balance is the ratio of austenite to ferrite in 022Cr25Ni6Mo2N, which the mill controls through chemistry and solution treatment to give the grade its strength and stress-corrosion resistance.
| Point | Guidance |
|---|---|
| Typical ferrite | About 40 – 60% after solution treatment; ferrite measurement by agreement |
| Upper limit | Usually about 250 – 300 °C in pressure codes because of 475 °C embrittlement |
| Lower limit | Set by the design code; impact testing at the minimum design temperature as agreed |
| Intermetallics | Sigma and chi form at about 700 – 950 °C; avoid slow cooling and over-long heating |
Confirm both limits against GB/T 150 and the project specification before choosing duplex.
Buyers comparing the S31200 PREN with this grade should use the same formula and the minimum chemistry of each standard, since the ranges differ slightly.
Design checklist for this service
- Confirm the minimum and maximum design metal temperatures against the limits in GB/T 150 for this material.
- State on the order every test that the design relies on, because tests that are ‘by agreement’ are not performed unless they are written into the contract.
- Check that weld procedures, filler metals and any post-weld treatment are qualified for the same temperature range as the base metal.
- Keep the mill certificate, the inspection report and the weld records together in the vessel data book, as required for registration with the special-equipment authority.
022Cr25Ni6Mo2N equivalent grades: ASTM, EN, former China
A 022Cr25Ni6Mo2N equivalent grade is a grade in another standard with similar chemistry and properties, not an interchangeable certificate.
| Standard system | Equivalent / closest grade |
|---|---|
| GB/T 713.7-2023 | 022Cr25Ni6Mo2N, S22553 |
| ASTM A240 / ASME SA-240 | UNS S31200 (closest, not identical) |
Equivalence is by alloy family, not certificate. Replacing S22553 with a foreign grade in a Chinese-code vessel needs approval from the designer and, where required, the special-equipment inspection authority; the reverse also applies to ASME or PED equipment built from GB/T plate.
Welding and fabrication of 022Cr25Ni6Mo2N
Welding of 022Cr25Ni6Mo2N is done by GTAW, SMAW, GMAW or SAW with 2209-type filler metal. Heat input is typically held in a window of about 0.5 – 2.5 kJ/mm with interpass at or below about 100 – 150 °C, so the weld and HAZ keep a sound phase balance. Pickle and passivate welds for corrosive service.
Weld procedures are qualified to NB/T 47014 for Chinese-code equipment, or to ASME IX for export projects. Cold forming of heads and shells is normal for this grade; duplex plate needs about twice the forming force of austenitic plate and has more springback. Plasma, laser and waterjet cutting are all suitable; remove heat-tinted edges before welding.
Practical welding notes
- Clean the joint area with stainless-only brushes and solvent; carbon steel contamination causes rust spots.
- Use argon with a small nitrogen addition for root and shielding gas to keep the weld austenite level.
- Avoid autogenous welds without filler, as they give too much ferrite.
- Do not stress relieve; any heat treatment must be a full solution treatment.
Our warehouse can supply bevelled edges and cut blanks ready for welding, which reduces work in the fabrication shop.
Corrosion resistance and PREN of 022Cr25Ni6Mo2N
Corrosion resistance of 022Cr25Ni6Mo2N is set by its chromium, molybdenum and nitrogen content: it combines good chloride pitting resistance with excellent chloride stress-corrosion cracking resistance. Its minimum PREN is 30.6.
For welded parts in sensitizing media, an intergranular corrosion test to GB/T 4334 can be ordered. Hydrotest water chloride content should be controlled as required by GB/T 150.4.
Media guide
| Medium | Typical suitability |
|---|---|
| Chloride cooling water | Good; strong SCC resistance |
| Seawater | Limited, depends on temperature |
| Organic acids | Good |
| Sour service | Per project specification |
The table is general guidance. Final material selection should be based on the actual medium, temperature and concentration, and where possible on plant experience or corrosion testing.
Where this plate goes
Applications of 022Cr25Ni6Mo2N follow from its strength and corrosion behaviour as a pressure equipment stainless steel plate. Typical uses:
- Chemical tankers and storage tanks
- Heat exchangers with chloride cooling water
- Pressure vessels in oil and gas
- Pulp and paper digesters
Buyers specifying 022Cr25Ni6Mo2N for these jobs often compare it with GB/T 713.7 022Cr23Ni5Mo3N S22053 and GB/T 713.7 03Cr25Ni6Mo3Cu2N S25554; the comparison table on this page shows the differences.
Other GB/T 713.7 grades buyers request alongside it: GB/T 713.7 022Cr25Ni7Mo4N S25073.
Selection guidance by application
For storage tanks and low-pressure vessels the decision is usually driven by corrosion resistance and cost, and the plate thickness is moderate. For high-pressure or large-diameter vessels, strength becomes important and duplex plate often allows a thinner wall than austenitic plate, which reduces weight, welding time and cost. For heat exchangers the tube sheets, shells and channels often use different grades, and we can supply all of them in one order with consistent certification.
Choosing between 022Cr25Ni6Mo2N and its neighbours
On S22553 vs S31200, the two grades are close in chemistry but not identical, so they should not be treated as interchangeable. The table compares the grades buyers most often weigh it against, using GB/T 713.7-2023 values.
| Grade | Key chemistry, % | Rp0.2 min, MPa | Rm, MPa |
|---|---|---|---|
| GB/T 713.7 S22553 | C ≤ 0.030, Cr 24.00 – 26.00, Ni 5.50 – 6.50, Mo 1.50 – 2.50, N 0.10 – 0.20 | 450 | ≥ 640 |
| GB/T 713.7 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 | 450 | ≥ 620 |
| GB/T 713.7 03Cr25Ni6Mo3Cu2N S25554 | C ≤ 0.04, Cr 24.00 – 27.00, Ni 4.50 – 6.50, Mo 2.90 – 3.90, N 0.10 – 0.25 | 550 | ≥ 760 |
| GB/T 713.7 022Cr25Ni7Mo4N S25073 | C ≤ 0.030, Cr 24.00 – 26.00, Ni 6.00 – 8.00, Mo 3.00 – 5.00, N 0.24 – 0.32 | 550 | ≥ 800 |
How to choose
Start from the corrosion requirement and the design temperature, then compare strength, availability and cost. A higher-alloy grade is only worth its price when the medium or temperature needs it; a lower-alloy grade that is readily available often gives a shorter lead time. Lean duplex grades replace 304/316 on cost, standard duplex covers most chloride duties, and super duplex is reserved for seawater and hot chlorides. Our engineers can review your design conditions and suggest the most economical grade that meets the code.
Dimensions and plate weight
| Dimension | Typical supply |
|---|---|
| Thickness | 0.30 – 8.00 mm cold rolled; 2.00 – 14.0 mm hot-rolled strip; 6.00 – 100 mm hot-rolled thick plate |
| Width | 600 – 2 100 mm strip; up to 4 800 mm thick plate |
| Length | Cut to length or coil |
| Tolerances | GB/T 708 / GB/T 709, PT.A or PT.B |
| Weight | thickness (mm) × density (g/cm³) = kg/m²; density about 7.8 (Annex A) |
Weight example: a 10 mm plate at 7.9 – 8.0 g/cm³ weighs about 79 – 80 kg/m². Ask for cut-to-size blanks to reduce scrap on heads and shells.
Tolerance and flatness notes
PT.A is the normal thickness accuracy class; PT.B gives a tighter tolerance and is useful when the designer has little corrosion allowance or when plates are rolled into shells with close fit-up requirements. Flatness depends on thickness and width, and cut-to-length plate from coil is usually flatter than as-rolled thick plate. For heads and dished ends, ask us for circular blanks cut to the developed diameter, which reduces handling and scrap at the fabricator.
Surface finish and processing
| Finish | Description | Availability for this grade |
|---|---|---|
| No.1 | Hot rolled, heat treated, pickled | Hot-rolled plate |
| 2B | Cold rolled, heat treated, skin passed | Cold-rolled sheet, by mill |
| 2D | Cold rolled, heat treated, matt | Cold-rolled sheet, by mill |
| No.4 | Mechanically polished | On request in our warehouse |
We offer steel cutting services and stainless surface finishing services in our Shanghai warehouse.
Choosing a finish
No.1 is the standard finish for hot-rolled pressure vessel plate; it is suitable for shells, heads and parts that will be pickled or machined after fabrication. Cold-rolled 2B is used for thin vessels, liners and parts where a smoother surface helps cleaning. Polished finishes are specified for hygienic vessels in food and pharmaceutical plants, where surface roughness limits are part of the design. Plates can be supplied with PE film protection to prevent scratching during fabrication.
Testing and certification
- Heat chemical analysis on every heat; product analysis by agreement
- Tensile test and hardness per Table 17
- Ferrite content and ASTM A923-type intermetallic test by agreement
- Intergranular corrosion (GB/T 4334) and UT on request
- 100% PMI and dimensional check by SHH STEEL
- EN 10204 3.1 certificate; 3.2 with SGS, BV, TUV or a named inspector
Every test result appears on the certificate with the heat number, so the plate can be traced from mill to finished vessel.
Third-party inspection
For export projects, a 3.2 certificate is often required. In that case an independent inspector witnesses sampling and testing at the mill and countersigns the certificate. We coordinate SGS, BV, TUV, Lloyd’s or a client-named inspector, and we schedule witness points so that inspection does not delay rolling. In our warehouse we check dimensions, flatness, surface condition and marking, and repeat PMI on each plate before packing.
What to put on a 022Cr25Ni6Mo2N purchase order
- Standard and edition: GB/T 713.7-2023
- Grade and code: 022Cr25Ni6Mo2N / S22553
- Thickness, width, length and quantity
- Edge EC or EM; thickness accuracy PT.A or PT.B
- Surface finish (clause 4.2)
- Extra tests: impact temperature, IGC, UT, product analysis
- Certificate type: EN 10204 3.1 or 3.2
Send the list to SHH STEEL and we return a quotation with mill, lead time and stock options.
Common ordering mistakes
- Citing GB/T 24511 instead of GB/T 713.7-2023 on new orders.
- Leaving out the surface finish, which clause 4.2 requires.
- Not stating impact test temperature when the design needs it.
- Ordering to GB/T 4237 for pressure parts; GB/T 4237 plate is not certified for pressure equipment.
A short technical review before order placement avoids these problems, and our engineering team does this free of charge.
Mill sourcing and lead time
022Cr25Ni6Mo2N is produced by a smaller number of Chinese mills; we place mill orders through the producers we represent and confirm minimum quantities per thickness. Lead time is typically 30-40 days for mill production (production can be scheduled within 30-40 days), and we confirm the rolling slot with the quotation.
Every plate is traceable to its heat number, and copies of the mill certificates stay on file for repeat orders and audits. Mixed-grade and mixed-standard orders can be consolidated in one shipment.
Packing and export documents
Plates are packed on steel or fumigated wooden pallets with waterproof wrapping, edge protectors and steel straps, and each bundle carries labels with grade, standard, heat number, size and weight. Export documents include the commercial invoice, packing list, mill certificates, certificate of origin and, when required, inspection certificates. We ship from Shanghai port in containers or break bulk, and can consolidate mixed grades in one shipment.
FAQ
- What is S22553 stainless steel?
- S22553 is the unified numeric code for 022Cr25Ni6Mo2N, a duplex stainless grade listed in GB/T 713.7-2023 for pressure equipment plate. It is supplied solution treated with Rp0.2 ≥450 MPa and Rm ≥ 640 MPa per Table 17.
- What is the ASTM equivalent of 022Cr25Ni6Mo2N?
- There is no exact ASTM A240 equivalent for 022Cr25Ni6Mo2N; the closest grade is S31200. Export projects therefore usually buy it to GB/T 713.7 directly, with a 3.2 certificate.
- What is the yield strength of S22553 plate to GB/T 713.7?
- Rp0.2 is at least 450 MPa at room temperature, with Rm ≥ 640 MPa and A ≥25%, per GB/T 713.7-2023 Table 17. Design allowable stresses are taken from GB/T 150.2, not directly from these minimums.
- Was S22553 in GB/T 24511?
- No. S22553 was added in GB/T 713.7-2023 and was not listed in GB/T 24511-2017. Drawings must reference GB/T 713.7-2023 to use this grade.
- What thickness of 022Cr25Ni6Mo2N plate can you supply?
- GB/T 713.7 covers 0.30 mm to 100 mm in widths of 600 mm and over. Cold-rolled sheet runs 0.30 – 8.00 mm and hot-rolled thick plate 6.00 – 100 mm; availability by thickness depends on the mill.
- What is the PREN of 022Cr25Ni6Mo2N?
- The PREN of 022Cr25Ni6Mo2N calculated from minimum chemistry is about 30.6. PREN = Cr + 3.3Mo + 16N is a ranking tool; actual pitting resistance depends on temperature and medium.
Conclusion
GB/T 713.7 022Cr25Ni6Mo2N (S22553) is a duplex pressure-vessel plate grade. It is defined by Table 14 chemistry (C ≤ 0.030, Cr 24.00 – 26.00, Ni 5.50 – 6.50, Mo 1.50 – 2.50, N 0.10 – 0.20) and Table 17 properties of Rp0.2 ≥450 MPa, Rm ≥ 640 MPa and A ≥25%. Typical uses include chemical tankers and storage tanks, heat exchangers with chloride cooling water and pressure vessels in oil and gas.
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 022Cr25Ni6Mo2N 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 713.7 022Cr23Ni5Mo3N S22053 and GB/T 713.7 03Cr25Ni6Mo3Cu2N S25554, our GB/T 713.7-2023 category and GB/T 4237 022Cr25Ni6Mo2N S22553. Send your sizes and quantities for a quotation.
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