630 (17-4PH / S17400) vs 616 (S42200): Precipitation-Hardening Stainless Steel Comparison
At FULLERKREG, we supply precision fasteners and engineered components in a wide range of precipitation-hardening (PH) stainless steels. 630 / 17-4PH (S17400) and 616 (S42200) are two of the most widely specified PH stainless grades for high-strength fastener, aerospace, and industrial applications — both offering significantly higher strength than standard austenitic stainless steels, but with different alloy systems, heat treatment responses, and application profiles.
This guide provides a direct technical comparison of both grades per their respective ASTM standards, covering chemical composition and the full range of mechanical properties by heat treatment condition and bar size.
Alloy Overview
- 630 / 17-4PH (S17400) — A martensitic precipitation-hardening stainless steel with chromium, nickel, copper, and niobium additions. Achieves a wide range of strength levels through age-hardening conditions H900 through H1150D. One of the most widely used PH stainless steels globally. Governed by ASTM A564 S17400.
- 616 (S42200) — A martensitic precipitation-hardening stainless steel with chromium, nickel, molybdenum, vanadium, and tungsten additions. Designed for elevated-temperature service with superior creep resistance compared to 630. Governed by ASTM A565 S42200.
Chemical Composition Comparison
All values are weight percent (%). Min = minimum required; Max = maximum allowed per respective ASTM standard.
630 / 17-4PH — S17400 (ASTM A564)
| C | Mn | P | S | Si | Cr | Ni | Cu | Nb | |
|---|---|---|---|---|---|---|---|---|---|
| Min | — | — | — | — | — | 15.00 | 3.00 | 3.00 | 0.15 |
| Max | 0.07 | 1.00 | 0.040 | 0.030 | 1.00 | 17.50 | 5.00 | 5.00 | 0.45 |
616 — S42200 (ASTM A565)
| C | Mn | P | S | Si | Cr | Ni | Mo | V | W | |
|---|---|---|---|---|---|---|---|---|---|---|
| Min | 0.20 | 0.50 | — | — | — | 11.00 | 0.50 | 0.90 | 0.20 | 0.9 |
| Max | 0.25 | 1.00 | 0.025 | 0.025 | 0.50 | 12.50 | 1.00 | 1.25 | 0.30 | 1.25 |
Mechanical Properties — 630 / 17-4PH (S17400) by Condition
630 is available in multiple age-hardening conditions. Higher condition numbers (e.g., H1150) indicate higher tempering temperatures, resulting in lower strength but improved ductility and toughness.
| Condition | Bar Size / Notes | Tensile Strength Rm (N/mm²) min | Yield Strength Rp0.2 (N/mm²) min | Elongation A (%) min | Reduction of Area (%) min | Hardness HRC min |
|---|---|---|---|---|---|---|
| H900 | <75 mm | ≥1310 | ≥1170 | ≥10 | ≥40 | ≥40 |
| H900 | 75–200 mm | ≥1310 | ≥1170 | ≥10 | ≥35 | ≥40 |
| H1025 | ≤200 mm | ≥1070 | ≥1000 | ≥12 | ≥45 | ≥31 |
| H1075 | ≤200 mm | ≥965 | ≥795 | ≥14 | ≥45 | ≥31 |
| H1150 | ≤200 mm | ≥930 | ≥725 | ≥16 | ≥50 | ≥28 |
| H1150D | — | ≥860 | ≥725 | ≥16 | ≥50 | 24–33 |
Mechanical Properties — 616 (S42200)
| Tensile Strength Rm (N/mm²) min | Yield Strength Rp0.2 (N/mm²) min | Elongation A (%) min | Reduction of Area (%) min | Hardness HRC |
|---|---|---|---|---|
| ≥965 | ≥760 | ≥13 | ≥30 | 302–352 HB |
Key Differences at a Glance
| Parameter | 630 / 17-4PH (S17400) | 616 (S42200) |
|---|---|---|
| Governing standard | ASTM A564 | ASTM A565 |
| Steel family | Martensitic PH stainless (Cu-Nb) | Martensitic PH stainless (Mo-V-W) |
| Cr content (%) | 15.0–17.5 | 11.0–12.5 |
| Ni content (%) | 3.0–5.0 | 0.5–1.0 |
| Key alloying additions | Cu (3–5%), Nb (0.15–0.45%) | Mo (0.9–1.25%), V (0.2–0.3%), W (0.9–1.25%) |
| Strengthening mechanism | Cu-rich ε-phase precipitation | Mo/V carbide + intermetallic precipitation |
| Available conditions | H900, H1025, H1075, H1150, H1150D | Single tempered condition |
| Tensile Strength range (N/mm²) | 860–1310 (by condition) | ≥965 |
| Yield Strength range (N/mm²) | 725–1170 (by condition) | ≥760 |
| Max service temperature | ~315°C (H900); ~480°C (H1150) | ~540°C (creep-resistant) |
| Corrosion resistance | Good (higher Cr + Ni) | Moderate (lower Cr, no Cu) |
| Magnetic | Yes (martensitic) | Yes (martensitic) |
| Primary applications | Aerospace fasteners, shafting, valves, oil & gas | High-temperature turbine bolting, steam equipment |
Understanding 630 / 17-4PH Heat Treatment Conditions
One of the key advantages of 630 / 17-4PH is its versatility across multiple age-hardening conditions:
- H900 — Highest strength (Rm ≥1310 N/mm²), lowest ductility. Used where maximum strength is the primary requirement. Susceptible to stress corrosion cracking in aggressive environments.
- H1025 — Balanced strength and toughness. A common general-purpose condition for fasteners and structural components.
- H1075 — Improved toughness over H1025 with moderate strength reduction. Good for applications requiring impact resistance.
- H1150 — Highest ductility among standard conditions. Best stress corrosion cracking resistance. Used in sour service and marine environments.
- H1150D — Double-aged at H1150. Further improved toughness and SCC resistance at the cost of some strength. Hardness range 24–33 HRC.
Application Selection Guide
Choose 630 / 17-4PH (S17400) when:
- High strength combined with good corrosion resistance is required across a wide range of conditions
- Flexibility to select the optimal heat treatment condition (H900 through H1150D) for your specific strength/toughness balance is needed
- Service temperature is below ~480°C
- Typical applications: aerospace structural fasteners, aircraft components, oil & gas downhole tools, valve stems, pump shafts, nuclear waste containers, food processing equipment, marine hardware
Choose 616 (S42200) when:
- Elevated-temperature service up to ~540°C requires creep resistance beyond what 630 can provide
- Molybdenum, vanadium, and tungsten additions are needed for high-temperature strength retention
- Steam turbine or power generation bolting specifications call for ASTM A565 compliance
- Typical applications: steam turbine bolting, high-temperature pressure vessel fasteners, power plant flange studs, gas turbine compressor components, elevated-temperature valve stems
FULLERKREG Supply Capabilities
FULLERKREG supplies precision fasteners and engineered components in 630 / 17-4PH and 616:
- Material Test Certificates (MTC) — EN 10204 3.1 / 3.2 available on request
- ASTM A564 / A565 compliance — rod and bar forms for fastener and structural applications
- 630 / 17-4PH in all standard conditions — H900, H1025, H1075, H1150, H1150D per customer specification
- Custom fastener dimensions — non-standard thread forms, head styles, and lengths
- Bulk wholesale pricing — OEM and MRO procurement with competitive lead times
- Global shipping — from our manufacturing base in China to customers worldwide
Need a quote or technical consultation for 630 / 17-4PH or 616 fasteners? Contact FULLERKREG with your specification and our engineering team will respond promptly.
FULLERKREG — Precision Fasteners. Global Standards. Reliable Supply.