Stainless Steel 17-6PH-H950
Precip hard
AISI/SAE 17-6PH · UNS S17600 · also Alloy 635
H950 = aged 510 °C (950 °F) / 1–4 h, air cool
High-strength aerospace condition for fasteners, shafts and spring elements with acceptable ductility.
Values for the H950 condition
Other 17-6PH tempers and conditions
17-6PH is listed in 7 conditions; see the grade overview at 17-6PH.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Stock/supply condition: machine, form and cold-head here, then age in one step with minimal distortion. | 760 | 965 | 12 | 30 HRC | — |
Aged 593 °C (1100 °F) for 4 h | Maximum-ductility overaged condition for weldments and parts needing best SCC resistance at ~1000 MPa. | 900 | 1,035 | 15 | 33 HRC | — |
Aged 565 °C (1050 °F) / 4 h, air cool | Overaged, toughest useful strength level — choose for thick sections, impact loading or chloride-bearing service. | 1,035 | 1,140 | 13 | 37 HRC | — |
Cold drawn, Condition A | Cold-drawn spring wire supplied for coiling and subsequent single-step age hardening. | 1,070 | 1,240 | 6 | 40 HRC | 2.1 % IACS |
Aged 540 °C (1000 °F) / 4 h, air cool | Balanced condition: ~1240 MPa with better toughness and stress-corrosion margin than H950. | 1,140 | 1,240 | 11 | 41 HRC | — |
H950This page Aged 510 °C (950 °F) / 1–4 h, air cool | High-strength aerospace condition for fasteners, shafts and spring elements with acceptable ductility. | 1,240 | 1,345 | 9 | 44 HRC | — |
Aged 482 °C (900 °F) for 1 h, peak hardness | Peak-strength aging for springs and small fasteners where hardness matters more than toughness or SCC margin. | 1,275 | 1,380 | 8 | 45 HRC | — |
What is 17-6PH-H950?
17-6PH-H950 is 17-6PH in the H950 condition — high-strength aerospace condition for fasteners, shafts and spring elements with acceptable ductility. 17-6PH-H950 has a yield strength of 1,240 MPa (180 ksi) and a tensile strength of 1,345 MPa (195 ksi) — stronger than 99% of stainless steel grades. Elongation at break is 9% and the elastic modulus is 200 GPa (29 Msi). 17-6PH-H950 has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,400°C (2,552 °F). A is the default condition FabDigit quotes; H950 is available on request or by drawing note.
Advantages
- High strength — 1,240 MPa (180 ksi), better than 99% of stainless steel grades
Limitations
- Limited ductility — 9%, worse than 99% of stainless steel grades
- Difficult to machine — 24/100, worse than 93% of stainless steel grades
- Limited formability — 12/100, worse than 93% of stainless steel grades
- Difficult to weld — 30/100, worse than 88% of stainless steel grades
- Limited service temperature — 315°C (599 °F), worse than 85% of stainless steel grades
17-6PH-H950 properties
Typical room-temperature values for 17-6PH-H950; 17 are specific to this condition. Other listed values are 17-6PH reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
17-6PH-H950 has a density of 7.8 g/cm³ (0.282 lb/in³), heavier than 50% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical14
17-6PH-H950 has a yield strength of 1,240 MPa (180 ksi) and a tensile strength of 1,345 MPa (195 ksi) — stronger than 99% of stainless steel grades. Elongation at break is 9% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
17-6PH-H950 is rated for continuous service to 315°C (599 °F). It conducts heat at 16 W/m·K (9.24 BTU/hr·ft·°F), better than 58% of stainless steel grades. Thermal expansion is 10.8 µm/m·K (6 µin/in·°F).
Electrical3
17-6PH-H950 conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (57/100), worse than 66% of stainless steel grades.
Sustainability4
Producing a kilogram of 17-6PH-H950 takes about 56 MJ of energy and emits 5 kg of CO₂ — more than 59% of stainless steel grades. Typical recycled content is 35%.
Manufacturability7
17-6PH-H950's machinability is poor (24/100, worse than 93% of stainless steel grades); weldability poor (30/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 17-6PH-H950
Is 17-6PH easy to machine?
Machine in Condition A with rigid setups, sharp positive-rake carbide, heavy positive feeds and flood coolant; the alloy work-hardens quickly, so avoid dwelling and expect ~40 % of 1212 rates (drop to ~25 % after H950 aging).
Can 17-6PH be welded?
GTAW/GMAW/EBW with matching or 17-4PH filler is possible, but the Ti-bearing weld metal loses much of its aging response — post-weld solution treat plus re-age wherever full properties are required.
Can 17-6PH be formed, bent or molded?
Cold form, bend, coil or cold-head only in Condition A; aging causes very little distortion or size change, so form to near-net shape first and age last.
What surface finishes work on 17-6PH?
Passivate per ASTM A967 (nitric or citric) after machining; electropolishing improves pitting resistance, and shot peening after aging restores fatigue life — plate only with baking at 190 °C to avoid hydrogen embrittlement.
17-6PH chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | ≤ 0.08 | 0.06 |
| Mn | ≤ 1 | 0.5 |
| Si | ≤ 1 | 0.5 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Cr | 16 – 17.5 | 16.75 |
| Ni | 6 – 7.5 | 6.8 |
| Tiprimary age-hardening element (Ni3Ti) | 0.4 – 1.2 | 0.75 |
| Al | ≤ 0.4 | 0.2 |
| Fe | balance | — |
17-6PH-H950 — frequently asked
What is 17-6PH-H950 used for?
17-6PH-H950 is typically used for springs, fasteners and aerospace structural clips. In short: forms soft, ages hard; low distortion on aging; limited mill availability.
What is the yield strength of 17-6PH-H950?
17-6PH-H950 has a typical yield strength of 1,240 MPa (180 ksi) and a tensile strength of 1,345 MPa (195 ksi) — stronger than 99% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is 17-6PH-H950 easy to machine?
Not especially — machinability is rated poor (24/100, worse than 93% of stainless steel grades). Machine in Condition A with rigid setups, sharp positive-rake carbide, heavy positive feeds and flood coolant; the alloy work-hardens quickly, so avoid dwelling and expect ~40 % of 1212 rates (drop to ~25 % after H950 aging).
Can 17-6PH-H950 be welded?
Not readily — weldability is rated poor (30/100). GTAW/GMAW/EBW with matching or 17-4PH filler is possible, but the Ti-bearing weld metal loses much of its aging response — post-weld solution treat plus re-age wherever full properties are required.
What surface finishes work on 17-6PH-H950?
Passivate per ASTM A967 (nitric or citric) after machining; electropolishing improves pitting resistance, and shot peening after aging restores fatigue life — plate only with baking at 190 °C to avoid hydrogen embrittlement.
Can 17-6PH-H950 be formed, bent or molded?
Cold form, bend, coil or cold-head only in Condition A; aging causes very little distortion or size change, so form to near-net shape first and age last.
What is the maximum service temperature of 17-6PH-H950?
17-6PH-H950 is rated for continuous use to about 315°C (599 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 17-6PH-A and 17-6PH-H900?
A is the default condition — stock/supply condition: machine, form and cold-head here, then age in one step with minimal distortion. H900: peak-strength aging for springs and small fasteners where hardness matters more than toughness or SCC margin. Yield strength is 760 MPa in A versus 1,275 MPa in H900.
Sources
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels and High-Performance Alloys (precipitation-hardening stainless steels) — ASM International (1990)
- SAE AMS 5638 / UNS S17600 — Stainless W (Type 635) chemistry and heat treatment — SAE International (2018)
- ASM Handbook Vol. 13B: Corrosion — Materials (stainless steel corrosion behaviour) — ASM International (2005)
- ASTM A967 — Chemical Passivation Treatments for Stainless Steel Parts — ASTM International (2017)
- MMPDS-style typical room-temperature property tables for PH stainless steels — Battelle / FAA (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.