Stainless Steel CA15M
ASTM CA15M · UNS J91151
CA15M is the molybdenum-modified version of CA15 (UNS J91151, ASTM A743 Gr.
Reference datasheet — CA15M is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the NT595 condition
CA15M tempers and conditions
CA15M is supplied in 6 conditions, soft to hard. NT595 is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition for heavy machining or cold straightening before final hardening. | 415 | 640 | 28 | 180 HB | — |
oil/air quench, temper 650–705 °C | Soft-tempered, ≤22 HRC condition for sour service (NACE MR0175) and maximum toughness. | 490 | 690 | 25 | 17 HRC | — |
Homogenized + N&T | For heavy-section or weld-repaired castings needing dendrite/segregation breakdown and uniform properties through thickness. | 540 | 710 | 23 | 19 HRC | 3 % IACS |
NT595Default austenitize ≥1010 °C, air cool, temper 595–650 °C | Standard ASTM A743 supply condition — best balance of strength, ductility and toughness for valve/pump castings. | 550 | 725 | 22 | 20 HRC | — |
Spheroidize annealed | Shipping/intermediate state only — hard, brittle and residually stressed; must be tempered before service. | 690 | 900 | 6 | 41 HRC | 2.8 % IACS |
austenitize ≥1010 °C, quench, temper 260–370 °C | Maximum strength/wear condition for pump wear rings and trim; low toughness, not for sour or impact service. | 830 | 1,035 | 12 | 34 HRC | — |
What is CA15M?
CA15M is the molybdenum-modified version of CA15 (UNS J91151, ASTM A743 Gr. CA15M, 1.4008, GX7CrNiMo12-1), where the Mo addition raises elevated-temperature strength and hardenability. Typical heat-treated properties are 550 MPa yield, 725 MPa tensile, 22% elongation and 225 HB (20 HRC), with service to 650 °C, and it is supplied as sand or investment castings for pumps, valves and turbine hardware. Corrosion resistance remains moderate (score 45) and post-weld tempering is mandatory; use plain CA15 where hot strength is not the limiting factor. CA15M has a density of 7.61 g/cm³ (0.275 lb/in³), lighter than 96% of stainless steel grades. It melts at 1,450°C (2,642 °F). CA15M has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 725 MPa (105 ksi) — stronger than 83% of stainless steel grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi).
What is CA15M used for?
- Steam turbine components
- High-temperature valve parts
- Pump impellers
- Compressor casings
Advantages
- High electrical conductivity — 3 % IACS, better than 95% of stainless steel grades
- Easy to machine — 45/100, better than 84% of stainless steel grades
- High strength — 550 MPa (79.8 ksi), better than 83% of stainless steel grades
- Conducts heat well — 24.2 W/m·K (14 BTU/hr·ft·°F), better than 83% of stainless steel grades
Limitations
- Limited formability — 10/100, worse than 95% of stainless steel grades
- Needs corrosion protection — 45/100, worse than 85% of stainless steel grades
- Difficult to weld — 40/100, worse than 83% of stainless steel grades
- Low fracture toughness — 80 MPa·√m (72.8 ksi·√in), worse than 79% of stainless steel grades
- Limited ductility — 22%, worse than 75% of stainless steel grades
CA15M properties
Typical room-temperature values for CA15M-NT595; bars are the position among stainless steel grades.
Physical3
CA15M has a density of 7.61 g/cm³ (0.275 lb/in³), lighter than 96% of stainless steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
CA15M has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 725 MPa (105 ksi) — stronger than 83% of stainless steel grades. Elongation at break is 22% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
CA15M is rated for continuous service to 650°C (1,202 °F). It conducts heat at 24.2 W/m·K (14 BTU/hr·ft·°F), better than 83% of stainless steel grades. Thermal expansion is 10.8 µm/m·K (6 µin/in·°F).
Electrical3
CA15M conducts electricity at 3 % IACS, better than 95% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 85% of stainless steel grades.
Sustainability4
Producing a kilogram of CA15M takes about 53 MJ of energy and emits 4 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 75%.
Manufacturability7
CA15M's machinability is fair (45/100, better than 84% of stainless steel grades); weldability fair (40/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. CA15M is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CA15M
Is CA15M easy to machine?
Machine in the annealed or high-temper condition with rigid setups, sharp carbide tooling, moderate speeds (60–110 m/min) and heavy coolant; avoid dwelling to prevent work hardening.
Can CA15M be welded?
Weldable with matched 410/410NiMo filler using 200–315 °C preheat, interpass control and mandatory 595–650 °C post-weld temper; underbead martensite cracks without PWHT.
Can CA15M be formed, bent or molded?
Sand or investment cast with generous risering and hot-tearing-tolerant gating; no cold forming — shape by casting plus heat treatment.
CA15M 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 |
|---|---|---|
| CASTM A743 CA15M | ≤ 0.15 | 0.12 |
| Mn | ≤ 1 | 0.6 |
| Si | ≤ 0.65 | 0.5 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.04 | 0.02 |
| Cr | 11.5 – 14 | 12.5 |
| Ni | ≤ 1 | 0.6 |
| Modistinguishes CA15M from CA15 (Mo 0.50 max) | 0.15 – 1 | 0.5 |
| Fe | balance |
What surface finishes work on CA15M?
Takes a good mechanical polish and can be passivated in nitric acid; chrome or electroless-nickel plating requires baking to avoid hydrogen embrittlement in the hardened condition.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel CA15M in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- J91151
- ASTM
- A743 Gr. CA15M
- Similar grades
- 1.4008GX7CrNiMo12-1
How much does CA15M cost?
CA15M is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
CA15M — frequently asked
What is CA15M used for?
CA15M is typically used for steam turbine components, high-temperature valve parts, pump impellers and compressor casings. In short: mo-strengthened CA15; better hot strength than CA15; 650 °C service castings.
What is the yield strength of CA15M?
CA15M has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 725 MPa (105 ksi) — stronger than 83% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is CA15M easy to machine?
Reasonably — machinability is rated fair (45/100, better than 84% of stainless steel grades). Machine in the annealed or high-temper condition with rigid setups, sharp carbide tooling, moderate speeds (60–110 m/min) and heavy coolant; avoid dwelling to prevent work hardening.
Can CA15M be welded?
With care — weldability is rated fair (40/100). Weldable with matched 410/410NiMo filler using 200–315 °C preheat, interpass control and mandatory 595–650 °C post-weld temper; underbead martensite cracks without PWHT.
What surface finishes work on CA15M?
Takes a good mechanical polish and can be passivated in nitric acid; chrome or electroless-nickel plating requires baking to avoid hydrogen embrittlement in the hardened condition.
Can CA15M be formed, bent or molded?
Sand or investment cast with generous risering and hot-tearing-tolerant gating; no cold forming — shape by casting plus heat treatment.
What is the maximum service temperature of CA15M?
CA15M is rated for continuous use to about 650°C (1,202 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CA15M-NT595 and CA15M-QT315?
NT595 is the default condition — standard ASTM A743 supply condition — best balance of strength, ductility and toughness for valve/pump castings. QT315: maximum strength/wear condition for pump wear rings and trim; low toughness, not for sour or impact service. Yield strength is 550 MPa in NT595 versus 830 MPa in QT315.
How much does CA15M cost?
CA15M is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM A743/A743M — Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application — ASTM International (2019)
- EN 10283 — Corrosion resistant steel castings (GX7CrNiMo12-1, 1.4008) — CEN (2010)
- Steel Castings Handbook, 6th ed. (cast corrosion-resistant alloys) — Steel Founders' Society of America / ASM International (1995)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.