Stainless Steel 15-7 Mo Condition C
Supply condition
UNS S15700 · AISI/SAE PH15-7Mo · ASTM A693 · also Alloy 632
Cold-rolled hard strip supplied for spring and diaphragm stock, normally aged afterwards to CH900.
Values for the Condition C condition
Other 15-7 Mo tempers and conditions
15-7 Mo is listed in 7 conditions; see the grade overview at 15-7 Mo.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Condition ADefault solution annealed (~1065 °C, air cooled) | Standard mill-supplied soft condition for blanking, forming and welding before hardening. | 415 | 950 | 25 | 13 HRC | 2.1 % IACS |
austenite conditioned at 760 °C (1400 °F), cooled to ≤16 °C | Intermediate martensitic state produced before the 1050 °F age; supplied only as a processing step, straightening/limited forming still possible. | 760 | 1,030 | 10 | 32 HRC | 2.2 % IACS |
Austenite conditioned at 954 °C (1750 °F) + refrigerated to −73 °C | Transformed-to-martensite state preceding the RH950 age; used when maximum aged strength is required. | 860 | 1,170 | 7 | 36 HRC | 2.2 % IACS |
Condition CThis page cold rolled to ~60 % reduction (strip) | Cold-rolled hard strip supplied for spring and diaphragm stock, normally aged afterwards to CH900. | 1,310 | 1,450 | 2 | 43 HRC | 2.1 % IACS |
Austenite conditioned at 760 °C, cooled, then aged 566 °C | The workhorse hardened condition: ~1400 MPa with usable ductility and best toughness of the aged states. | 1,345 | 1,415 | 7 | 45 HRC | — |
Austenite conditioned at 954 °C, refrigerated −73 °C, aged 510 °C | Highest-strength heat-treated condition for springs and highly loaded sheet parts; least ductile and most SCC-sensitive. | 1,520 | 1,620 | 6 | 48 HRC | — |
Condition C strip aged 482 °C | Maximum-strength thin strip/wire condition for springs, bellows and diaphragms; very low ductility. | 1,655 | 1,725 | 2 | 48 HRC | 16 W/m·K |
What is 15-7 Mo Condition C?
15-7 Mo Condition C is 15-7 Mo supplied in the Condition C condition — cold-rolled hard strip supplied for spring and diaphragm stock, normally aged afterwards to CH900. 15-7 Mo Condition C has a yield strength of 1,310 MPa (190 ksi) and a tensile strength of 1,450 MPa (210 ksi) — stronger than 99% of stainless steel grades. Elongation at break is 2% and the elastic modulus is 200 GPa (29 Msi). 15-7 Mo Condition C 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). Condition A is the default condition FabDigit quotes; Condition C is available on request or by drawing note.
Advantages
- High strength — 1,310 MPa (190 ksi), better than 99% of stainless steel grades
Limitations
- Limited ductility — 2%, worse than 100% of stainless steel grades
- Difficult to machine — 20/100, worse than 98% of stainless steel grades
- Limited formability — 10/100, worse than 95% 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
15-7 Mo Condition C properties
Typical room-temperature values for 15-7 Mo Condition C; 22 are specific to this condition. Other listed values are 15-7 Mo reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
15-7 Mo Condition C 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).
Mechanical16
15-7 Mo Condition C has a yield strength of 1,310 MPa (190 ksi) and a tensile strength of 1,450 MPa (210 ksi) — stronger than 99% of stainless steel grades. Elongation at break is 2% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
15-7 Mo Condition C is rated for continuous service to 315°C (599 °F). It conducts heat at 16.3 W/m·K (9.42 BTU/hr·ft·°F), better than 68% of stainless steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
15-7 Mo Condition C conducts electricity at 2.1 % IACS, worse than 73% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 62% of stainless steel grades.
Sustainability4
Producing a kilogram of 15-7 Mo Condition C takes about 68 MJ of energy and emits 5.4 kg of CO₂ — more than 80% of stainless steel grades. Typical recycled content is 30%.
Manufacturability7
15-7 Mo Condition C's machinability is poor (20/100, worse than 98% of stainless steel grades); weldability poor (30/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 15-7 Mo Condition C
Is 15-7 Mo easy to machine?
Machine in Condition A with rigid setups, positive rake carbide and heavy coolant (work-hardens strongly); after TH1050/RH950 expect grinding or low-feed carbide finishing only, so rough to near net size before aging.
Can 15-7 Mo be welded?
GTAW/resistance welding is practical with matching or 17-7 PH filler and no preheat, but the joint must receive the full austenite-conditioning + aging cycle to recover strength; avoid welding in the aged condition.
Can 15-7 Mo be formed, bent or molded?
Form, blank and draw only in Condition A allowing for high springback and dimensional growth (~0.5 %) during aging; hardened tempers are essentially non-formable.
What surface finishes work on 15-7 Mo?
Passivate per AMS 2700/ASTM A967 after machining; grit-blast or pickle scale from heat treatment, and use bright-dip/electropolish or mechanical polish for cosmetic surfaces (no anodizing).
15-7 Mo 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 | ≤ 0.09 | 0.07 |
| Mn | ≤ 1 | 0.5 |
| Si | ≤ 1 | 0.4 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Cr | 14 – 16 | 15.2 |
| Ni | 6.5 – 7.75 | 7.1 |
| Mo | 2 – 3 | 2.5 |
| Alprecipitation hardener (NiAl) | 0.75 – 1.5 | 1.1 |
| Fe | balance | — |
15-7 Mo Condition C — frequently asked
What is 15-7 Mo Condition C used for?
15-7 Mo Condition C is typically used for aerospace springs, washers and fittings. In short: high-strength PH stainless.
What is the yield strength of 15-7 Mo Condition C?
15-7 Mo Condition C has a typical yield strength of 1,310 MPa (190 ksi) and a tensile strength of 1,450 MPa (210 ksi) — stronger than 99% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is 15-7 Mo Condition C easy to machine?
Not especially — machinability is rated poor (20/100, worse than 98% of stainless steel grades). Machine in Condition A with rigid setups, positive rake carbide and heavy coolant (work-hardens strongly); after TH1050/RH950 expect grinding or low-feed carbide finishing only, so rough to near net size before aging.
Can 15-7 Mo Condition C be welded?
Not readily — weldability is rated poor (30/100). GTAW/resistance welding is practical with matching or 17-7 PH filler and no preheat, but the joint must receive the full austenite-conditioning + aging cycle to recover strength; avoid welding in the aged condition.
What surface finishes work on 15-7 Mo Condition C?
Passivate per AMS 2700/ASTM A967 after machining; grit-blast or pickle scale from heat treatment, and use bright-dip/electropolish or mechanical polish for cosmetic surfaces (no anodizing).
Can 15-7 Mo Condition C be formed, bent or molded?
Form, blank and draw only in Condition A allowing for high springback and dimensional growth (~0.5 %) during aging; hardened tempers are essentially non-formable.
What is the maximum service temperature of 15-7 Mo Condition C?
15-7 Mo Condition C 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 15-7 Mo Condition A and 15-7 Mo-CH900?
Condition A is the default condition — standard mill-supplied soft condition for blanking, forming and welding before hardening. CH900: maximum-strength thin strip/wire condition for springs, bellows and diaphragms; very low ductility. Yield strength is 415 MPa in Condition A versus 1,655 MPa in CH900.
Can FabDigit make parts in 15-7 Mo Condition C?
Yes — 15-7 Mo Condition C is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- AMS 5520 — Steel, Corrosion and Heat Resistant, Sheet, Strip and Plate 15Cr-7Ni-2.5Mo-1.1Al — SAE International (2020)
- AMS 5657 — Steel, Corrosion Resistant, Bars and Wire, 15Cr-7Ni-2.5Mo-1.1Al — SAE International (2018)
- ASTM A693 — Precipitation-Hardening Stainless and Heat-Resisting Steel Plate, Sheet, and Strip — ASTM (2016)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- MMPDS — Metallic Materials Properties Development and Standardization, PH stainless section — Battelle/FAA (2023)
- PH 15-7 Mo semi-austenitic precipitation-hardening stainless datasheet — Cleveland-Cliffs (AK Steel) / Carpenter Technology (2021)
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.