GB/T 4237 07Cr17Ni7Al S51770 Stainless Steel Plate Supplier
07Cr17Ni7Al S51770 plate at a glance
07Cr17Ni7Al is 17-7 PH (Type 631, UNS S17700, JIS SUS631): a semi-austenitic precipitation-hardening grade. It is soft and formable in the solution-treated condition, then transformed and aged (TH1050 or RH950) to strengths above 1 200 MPa.
How to read the name: under GB/T 20878 the leading ’07’ is the carbon code (here C ≤0.09%), then Cr17 = about 17% chromium; Ni7 = about 7% nickel; Al = aluminium added. S51770 is the unified numeric code (ISC) used in GB/T 4237-2015.
SHH STEEL produces and exports precipitation-hardening stainless plate from China, works as a sales agent for leading stainless mills, and runs its own processing warehouse for cutting and surface finishing. 07Cr17Ni7Al is part of our GB/T 4237 stainless plate range; for comparison, see our JIS G4305 SUS630 (17-4 PH) page.
GB/T 4237 07Cr17Ni7Al specification details
| 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 | 07Cr17Ni7Al / S51770 |
| Steel class | Precipitation-hardening |
| Chemical composition | Table 19 (heat analysis); product analysis per GB/T 222 |
| Mechanical properties | Tables 24 and 25 |
| 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 | 2 – 16 mm (thicker by mill agreement) |
| Delivery condition | Solution 1 065 °C ± 15 °C; TH1050 or RH950 hardening |
| Surface | Hot rolled, heat treated, pickled (No.1 / 1D) as standard; ground or polished by agreement |
| Density | 7.8 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.
Chemical composition of 07Cr17Ni7Al S51770
| Element | 07Cr17Ni7Al heat analysis, % (Table 19) | Why it matters |
|---|---|---|
| C | ≤ 0.09 | 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 | ≤ 1.00 | Manganese. Deoxidizer; in Mn-bearing grades it replaces nickel and keeps nitrogen in solution. |
| P | ≤ 0.040 | 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 | 16.00 – 18.00 | Chromium. Forms the passive film; the main driver of corrosion and oxidation resistance. |
| Ni | 6.50 – 7.75 | Nickel. Stabilizes austenite, improves toughness and resistance to reducing acids. |
| Al | 0.75 – 1.50 | Aluminium. Ferrite former; in PH grades it forms the NiAl hardening phase. |
| PREN (Cr + 3.3Mo + 16N) | 16.0 – 17.0 (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 19.
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 07Cr17Ni7Al 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 | ≤ 0.09 | ±0.01 | ≤ 0.10 |
| Si | ≤ 1.00 | ±0.05 | ≤ 1.05 |
| Mn | ≤ 1.00 | ±0.03 | ≤ 1.03 |
| P | ≤ 0.040 | +0.005 | ≤ 0.045 |
| S | ≤ 0.030 | +0.005 | ≤ 0.035 |
| Cr | 16.00 – 18.00 | ±0.20 | 15.80 – 18.20 |
| Ni | 6.50 – 7.75 | ±0.10 | 6.40 – 7.85 |
| Al | 0.75 – 1.50 | ±0.10 | 0.65 – 1.60 |
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.
07Cr17Ni7Al S51770 tensile and hardness requirements
07Cr17Ni7Al is ordered in the solution-treated condition (Solution treated 1 065 °C ± 15 °C). The aged values below show what the user can reach after the agreed hardening route (Tables 24 and 25).
| Condition | Rp0.2, MPa | Rm, MPa | A, % | Hardness |
|---|---|---|---|---|
| Solution treated (A) | ≤ 380 | ≤ 1 035 | ≥ 20 | HRB ≤ 92 |
| RH950: 954 °C ± 8 °C → −73 °C ± 6 °C → 510 °C ± 6 °C, 2 – < 5 mm | ≥ 1 310 | ≥ 1 450 | ≥ 4 | HRC ≥ 44 |
| RH950, 5 – 16 mm | ≥ 1 240 | ≥ 1 380 | ≥ 6 | HRC ≥ 43 / HBW ≥ 401 |
| TH1050: 760 °C ± 15 °C → 15 °C ± 3 °C → 566 °C ± 6 °C | per Table 25 (confirm on MTC) | — | — | — |
Bend test, solution-treated plate: D = a (2.0 – < 5.0 mm); D = 3a (5.0 – 7.0 mm).
Annealing / solution treatment
Recommended heat treatment for 07Cr17Ni7Al (GB/T 4237-2015 Annex C): Solution 1 065 °C ± 15 °C; TH1050 or RH950 hardening.
Precipitation-hardening plate is delivered solution treated (condition A). The hardening treatment is done after machining or forming.
Hardening routes for this PH grade
07Cr17Ni7Al gains strength by precipitation of fine particles during ageing. Annex C gives the solution treatment (Solution 1 065 °C ± 15 °C; TH1050 or RH950 hardening); the ageing route is chosen by the user.
| Condition | Treatment (typical) |
|---|---|
| RH950 | 954 °C ± 8 °C → −73 °C ± 6 °C → 510 °C ± 6 °C |
| TH1050 | 760 °C ± 15 °C → 15 °C ± 3 °C → 566 °C ± 6 °C |
Higher ageing temperature gives lower strength but better toughness and stress corrosion resistance.
Cross-reference to other standards
| Standard system | Equivalent / closest grade |
|---|---|
| China GB/T 4237-2015 | 07Cr17Ni7Al (S51770) |
| ASTM A693 | Type 631 / S17700 (ASTM A693) |
| EN 10088-2 | X7CrNiAl17-7 / 1.4568 |
| JIS G4304 (hot rolled) | SUS631 |
| Common name | 17-7 PH |
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: JIS G4305 SUS630, AISI 301. See also our ASTM A240/A240M and JIS G4305 plate lists.
Welding and fabrication of 07Cr17Ni7Al
PH stainless steels are normally welded in the solution-treated condition with matching filler, then re-solution treated and aged together with the part.
Welding after ageing destroys the precipitates in the HAZ. If ageing after welding is not possible, design the joint for annealed-state strength.
Form in the solution-treated condition only.
How 07Cr17Ni7Al performs in corrosive service
Precipitation-hardening grades have corrosion resistance between 410 and 304 depending on chromium and molybdenum content.
PREN of 07Cr17Ni7Al from the GB/T 4237 limits: 16.0 – 17.0. 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 a GB/T 4237 requirement for precipitation-hardening plate; stress corrosion behaviour depends mainly on the ageing condition chosen.
If service is harsher than 07Cr17Ni7Al can handle, the next step up in this batch is GB/T 4237 07Cr15Ni7Mo2Al S51570.
Applications of 07Cr17Ni7Al plate
Typical uses (after ageing):
- Springs, washers and retaining rings
- Aerospace structural parts and bellows
- Instrument diaphragms
- Knife blades and industrial clips
Buyers specifying 07Cr17Ni7Al for these jobs often compare it with GB/T 4237 07Cr15Ni7Mo2Al S51570 and GB/T 4237 12Cr17Ni7 S30110; the comparison table on this page shows the differences.
International grade pages for the alternatives mentioned above: ASTM A240 Type 301.
Other GB/T 4237 grades buyers request alongside it: GB/T 4237 022Cr12Ni9Cu2NbTi S51290, GB/T 4237 04Cr13Ni8Mo2Al S51380, GB/T 4237 12Cr13 S41010, GB/T 4237 06Cr13 S41008, GB/T 4237 04Cr13Ni5Mo S41595.
Choosing between 07Cr17Ni7Al and its neighbours
The table compares 07Cr17Ni7Al 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 |
|---|---|---|---|---|
| 07Cr17Ni7Al S51770 | C ≤ 0.09, Cr 16.00 – 18.00, Ni 6.50 – 7.75 | 16.0 | see Table 24 | — |
| GB/T 4237 07Cr15Ni7Mo2Al S51570 | C ≤ 0.09, Cr 14.00 – 16.00, Ni 6.50 – 7.75, Mo 2.00 – 3.00 | 20.6 | see Table 24 | — |
| GB/T 4237 06Cr17Ni7AlTi S51778 | C ≤ 0.08, Cr 16.00 – 17.50, Ni 6.00 – 7.50, Ti 0.40 – 1.20 | 16.0 | see Table 24 | — |
| GB/T 4237 12Cr17Ni7 S30110 | C ≤ 0.15, Cr 16.00 – 18.00, Ni 6.00 – 8.00, N ≤ 0.10 | 16.0 | 205 | 515 |
Forming must be done before transformation; after RH950 the material has only a few percent elongation. GB/T 4237 covers 2.0–16 mm in Tables 24 and 25; thicker plate is not typical.
Sizes, tolerances and weight
| Dimension | Typical supply |
|---|---|
| Thickness | 2 – 16 mm (thicker by mill agreement) |
| 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 (7.8 g/cm³). A 10 mm 07Cr17Ni7Al plate weighs about 78.0 kg/m²; a 1 500 × 6 000 × 10 mm plate about 702 kg.
Surface options and cut-to-size service
| 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.
Quality documents supplied
- 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.
How to order
- Standard and edition: GB/T 4237-2015
- Grade and code: 07Cr17Ni7Al (S51770); 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.
Where our plate comes from
07Cr17Ni7Al 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.
FAQ
- What are TH1050 and RH950 for 07Cr17Ni7Al?
- They are hardening routes for 17-7 PH. TH1050: condition at 760 °C, cool to 15 °C, age at 566 °C. RH950: condition at 954 °C, refrigerate to −73 °C, age at 510 °C. RH950 gives higher strength (≥1 310 MPa proof for 2–5 mm in GB/T 4237-2015).
- What is the chemical composition of 07Cr17Ni7Al?
- Under GB/T 4237-2015 Table 19, 07Cr17Ni7Al (S51770) has C ≤ 0.09, Cr 16.00 – 18.00, Ni 6.50 – 7.75. Phosphorus is limited to ≤0.040% and sulfur to ≤0.030%.
- What is the ASTM equivalent of 07Cr17Ni7Al?
- The closest equivalents of 07Cr17Ni7Al (S51770) are Type 631 / S17700 (ASTM A693) in ASTM, X7CrNiAl17-7 / 1.4568 in EN, SUS631 in JIS (common name: 17-7 PH). Chemistry limits differ slightly, so dual certification depends on the actual heat.
- What strength does 07Cr17Ni7Al reach after ageing?
- 07Cr17Ni7Al is delivered solution treated and aged by the user. RH950: Rp0.2 ≥ 1 310 MPa, Rm ≥ 1 450 MPa; TH1050: Rp0.2 per Table 25 (confirm on MTC) MPa, Rm — MPa.
- Is 07Cr17Ni7Al stainless steel magnetic?
- It depends on condition. 07Cr17Ni7Al is semi-austenitic: in the solution-treated condition A it is mostly austenitic and only weakly magnetic; after transformation and ageing (TH1050, RH950) it is martensitic and strongly magnetic.
- What thickness of 07Cr17Ni7Al plate can you supply?
- Under GB/T 4237 we supply 07Cr17Ni7Al hot-rolled plate in 2 – 16 mm (thicker by mill agreement), 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.
Conclusion
GB/T 4237 07Cr17Ni7Al (S51770) is a precipitation-hardening plate grade, known internationally as 17-7 PH. It is defined by Table 19 chemistry (C ≤ 0.09, Cr 16.00 – 18.00, Ni 6.50 – 7.75) and Tables 24 and 25 properties. Typical uses include springs, washers and retaining rings, aerospace structural parts and bellows and instrument diaphragms. Forming must be done before transformation; after RH950 the material has only a few percent elongation.
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 07Cr17Ni7Al 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 07Cr15Ni7Mo2Al S51570 and GB/T 4237 06Cr17Ni7AlTi S51778, our GB/T 4237 category and the JIS G4305 SUS630 page. Send your sizes and quantities for a quotation.
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