SUS 631 vs 17-7PH stianless steel plate
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SUS 631 vs 17-7PH stianless steel plate: What's the difference?
Here is a detailed comparison between SUS 631 and 17-7PH stainless steel plate, covering their chemical composition, mechanical properties, standards, and applications. These two designations refer to essentially the same material under different standards-SUS 631 is the Japanese equivalent of the American 17-7PH stainless steel.
SUS 631 vs 17-7PH Stainless Steel Plate: Comparison
1. Standard & Designation
| Feature | SUS 631 | 17-7PH |
|---|---|---|
| Origin | JIS (Japan Industrial Standard) | ASTM / AISI (USA) |
| UNS Number | S17700 | S17700 |
| Other Standards | JIS G4304 (Plate), G4313 (Strip) | ASTM A693, AMS 5528/5529 |
Conclusion: SUS 631 and 17-7PH are the same steel grade under different naming systems (JIS vs ASTM).
2.SUS 631 vs 17-7PH Stainless Steel Plate: Chemical Composition (Typical)
| Element | SUS 631 / 17-7PH Composition |
|---|---|
| Carbon (C) | ≤ 0.09% |
| Chromium (Cr) | 16.0–18.0% |
| Nickel (Ni) | 6.5–7.8% |
| Aluminum (Al) | 0.75–1.50% |
| Manganese (Mn) | ≤ 1.0% |
| Silicon (Si) | ≤ 1.0% |
| Phosphorus (P) | ≤ 0.040% |
| Sulfur (S) | ≤ 0.030% |
➡️ Conclusion: Both grades have identical chemical makeup, emphasizing precipitation hardening elements like Aluminum (Al).
🔹 3. SUS 631 vs 17-7PH Stainless Steel Plate: Mechanical Properties (Typical in CH900 Condition)
| Property | SUS 631 / 17-7PH Plate |
|---|---|
| Tensile Strength | ≥ 1250 MPa |
| Yield Strength (0.2%) | ≥ 1100 MPa |
| Hardness | ~40 HRC |
| Elongation | ≥ 10% |
➡️ Conclusion: Both grades offer high strength and are suitable for structural, aerospace, and spring applications.
🔹 4. Heat Treatment Options
| Condition | Description |
|---|---|
| Condition A | Annealed (soft for cold working) |
| Condition CH900 | Cold worked + aged at 900°F |
| Condition H1150 | Precipitation hardened at 1150°F |
➡️ Conclusion: Both grades can be cold worked and aged to achieve high strength and hardness.
SUS 631 vs 17-7PH Stainless Steel :Surface & Plate Form
| Feature | Detail |
|---|---|
| Available Thickness | 0.5 mm – 50 mm |
| Width & Length | Custom cut, or standard 1000–2000 mm width |
| Surface Finish | 2B, BA, No.1, No.4, or polished |
🔸 17-7PH stainless steel alternative
SUS 631 and 17-7PH stainless steel plate are functionally equivalent, with only regional standard differences. They are interchangeable in most applications and deliver the same high-strength, corrosion-resistant performance when processed and heat-treated correctly.
If you're exporting or sourcing internationally:
Use SUS 631 in Japan or Asian markets.
Use 17-7PH for U.S. or global aerospace/industrial standards.
