Stainless Steel CA40
ASTM CA40 · UNS J91153
CA40 is the higher-carbon version of CA15 (UNS J91153, ASTM A743 Gr.
Reference datasheet — CA40 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 H+T 650 condition
CA40 tempers and conditions
CA40 is supplied in 6 conditions, soft to hard. H+T 650 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 — choose for rough machining of complex castings before final hardening. | 415 | 640 | 24 | 200 HB | — |
Normalized and tempered | Best-toughness heat treatment; use where impact and weld repair matter more than hardness. | 530 | 720 | 22 | 20 HRC | — |
H+T 650Default Austenitized 980–1010 °C, air/oil quenched, tempered 620–675 °C | Standard ASTM A743 CA40 supply condition — balanced 690 MPa-class strength with usable ductility and corrosion resistance. | 620 | 795 | 18 | 24 HRC | — |
As fabricated | Shipping/intermediate condition only — as-cast martensite is hard and crack-prone; always heat treat before service. | 650 | 900 | 5 | 43 HRC | 2.8 % IACS |
Quenched, tempered 480–590 °C | Higher-strength option; avoid the 400–550 °C band where temper embrittlement and reduced corrosion resistance occur unless toughness is secondary. | 790 | 1,000 | 13 | 33 HRC | — |
Quenched, tempered 260–370 °C | Pick for wear surfaces, valve seats and pump wear rings where hardness ≥ 38 HRC matters and impact loading is low. | 1,000 | 1,300 | 7 | 41 HRC | — |
What is CA40?
CA40 is the higher-carbon version of CA15 (UNS J91153, ASTM A743 Gr. CA40, SCS2A), where the added carbon raises attainable hardness and strength after hardening and tempering at the cost of toughness. Typical values are 620 MPa yield, 795 MPa tensile, 18% elongation and 250 HB (24 HRC), with service to 550 °C, and it is used for wear-resistant cast valve and pump parts. Machinability (score 40) and corrosion resistance (score 38) are both below CA15, and welding is difficult; choose CA15 or CA6NM when weld repair or toughness matters more than hardness. CA40 has a density of 7.61 g/cm³ (0.275 lb/in³), lighter than 96% of stainless steel grades. It melts at 1,480°C (2,696 °F). CA40 has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 795 MPa (115 ksi) — stronger than 88% of stainless steel grades. Elongation at break is 18% and the elastic modulus is 200 GPa (29 Msi).
What is CA40 used for?
- Valve seats and trim
- Wear rings
- Pump parts
- Cutlery-grade castings
Advantages
- Low embodied carbon — 2.9 kg CO₂/kg, better than 98% of stainless steel grades
- High electrical conductivity — 3 % IACS, better than 95% of stainless steel grades
- High strength — 620 MPa (89.9 ksi), better than 88% 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 — 8/100, worse than 97% of stainless steel grades
- Needs corrosion protection — 38/100, worse than 95% of stainless steel grades
- Difficult to weld — 28/100, worse than 90% of stainless steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 88% of stainless steel grades
- Limited ductility — 18%, worse than 83% of stainless steel grades
CA40 properties
Typical room-temperature values for CA40-H+T 650; bars are the position among stainless steel grades.
Physical3
CA40 has a density of 7.61 g/cm³ (0.275 lb/in³), lighter than 96% of stainless steel grades. It melts at 1,480°C (2,696 °F).
Mechanical16
CA40 has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 795 MPa (115 ksi) — stronger than 88% of stainless steel grades. Elongation at break is 18% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
CA40 is rated for continuous service to 550°C (1,022 °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 10.4 µm/m·K (5.78 µin/in·°F).
Electrical3
CA40 conducts electricity at 3 % IACS, better than 95% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (38/100), worse than 95% of stainless steel grades.
Sustainability4
Producing a kilogram of CA40 takes about 40 MJ of energy and emits 2.9 kg of CO₂ — less than 97% of stainless steel grades. Typical recycled content is 75%.
Manufacturability8
CA40's machinability is fair (40/100, better than 72% of stainless steel grades); weldability poor (28/100); formability not recommended (8/100).
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. CA40 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CA40
Is CA40 easy to machine?
Machine in the annealed or high-temper condition with rigid setups, sharp carbide (C2/C6) tooling, positive rake and generous flood coolant; above ~35 HRC switch to ceramic/CBN or grinding.
Can CA40 be welded?
Weldable only with care: preheat 200–315 °C, use 410/410NiMo or austenitic 309 filler, maintain interpass temperature, and temper immediately after welding to avoid hydrogen and quench cracking.
Can CA40 be formed, bent or molded?
Sand or investment cast with generous risering and controlled cooling; slow cool through the martensite range and stress-relieve/anneal before shakeout stresses cause cracking — no cold forming.
CA40 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 |
|---|---|---|
| Chigher C than CA15 — source of extra hardness | 0.2 – 0.4 | 0.3 |
| Mn | ≤ 1 | 0.6 |
| Si | ≤ 1.5 | 0.9 |
| P | ≤ 0.04 | |
| SCA40F free-machining variant raises S deliberately | ≤ 0.04 | |
| Cr | 11.5 – 14 | 12.8 |
| Ni | ≤ 1 | 0.5 |
| Moresidual; not intentionally added | ≤ 0.5 | |
| Fe | balance |
What surface finishes work on CA40?
Passivate per ASTM A967 after machining to restore the chromium oxide film; takes hard chrome plating, nitriding or a bright mechanical polish, but never anodize.
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 CA40 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- J91153
- ASTM
- A743 Gr. CA40
- Also called
- ZG2Cr13
- Similar grades
- SCS2A
How much does CA40 cost?
CA40 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.
CA40 — frequently asked
What is CA40 used for?
CA40 is typically used for valve seats and trim, wear rings, pump parts and cutlery-grade castings. In short: hardest standard CA grade; wear-resistant cast martensitic; lower toughness than CA15.
What is the yield strength of CA40?
CA40 has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 795 MPa (115 ksi) — stronger than 88% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is CA40 easy to machine?
Not especially — machinability is rated fair (40/100, better than 72% of stainless steel grades). Machine in the annealed or high-temper condition with rigid setups, sharp carbide (C2/C6) tooling, positive rake and generous flood coolant; above ~35 HRC switch to ceramic/CBN or grinding.
Can CA40 be welded?
Not readily — weldability is rated poor (28/100). Weldable only with care: preheat 200–315 °C, use 410/410NiMo or austenitic 309 filler, maintain interpass temperature, and temper immediately after welding to avoid hydrogen and quench cracking.
What surface finishes work on CA40?
Passivate per ASTM A967 after machining to restore the chromium oxide film; takes hard chrome plating, nitriding or a bright mechanical polish, but never anodize.
Can CA40 be formed, bent or molded?
Sand or investment cast with generous risering and controlled cooling; slow cool through the martensite range and stress-relieve/anneal before shakeout stresses cause cracking — no cold forming.
What is the maximum service temperature of CA40?
CA40 is rated for continuous use to about 550°C (1,022 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CA40 H+T 650 and CA40-A?
H+T 650 is the default condition — standard ASTM A743 CA40 supply condition — balanced 690 MPa-class strength with usable ductility and corrosion resistance. A: softest condition — choose for rough machining of complex castings before final hardening. Yield strength is 620 MPa in H+T 650 versus 415 MPa in A.
How much does CA40 cost?
CA40 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)
- ASTM A487/A487M — Steel Castings Suitable for Pressure Service — ASTM International (2020)
- Steel Castings Handbook, Supplement 8 — High Alloy Data Sheets, Corrosion Series — Steel Founders' Society of America (2004)
- 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)
- GB/T 2100 / GB/T 8492 (ZG2Cr13 ) (2017)
- JIS G 5121 — Corrosion-resistant steel castings (SCS2A) — JSA (2003)
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.