Stainless Steel CA6N
ASTM CA6N · UNS J91650
CA6N is a low-carbon, higher-nickel cast martensitic stainless (UNS J91650, ASTM A743 Gr.
Reference datasheet — CA6N 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 N+T condition
CA6N tempers and conditions
CA6N is supplied in 5 conditions, soft to hard. N+T is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition, used between rough machining and final heat treatment or before major weld repair. | 560 | 760 | 24 | 18 HRC | 2.3 % IACS |
N+T | Pick when maximum impact toughness, lower hardness for machining, or NACE-type hardness limits matter more than peak strength. | 720 | 860 | 22 | 24 HRC | — |
As fabricated | Foundry as-cast state only; brittle untempered martensite that must be normalized and tempered before use. | 900 | 1,100 | 9 | 37 HRC | 2.1 % IACS |
N+TDefault Normalized and tempered | Standard ASTM A743 CA6N supply condition: maximum strength with useful toughness for pump/valve pressure parts. | 930 | 1,020 | 19 | 31 HRC | — |
hot isostatically pressed, then normalized and tempered | For critical fatigue- or pressure-rated castings where internal porosity must be closed; same strength as N+T with better ductility and fatigue scatter. | 940 | 1,030 | 22 | 31 HRC | 2.2 % IACS |
What is CA6N?
CA6N is a low-carbon, higher-nickel cast martensitic stainless (UNS J91650, ASTM A743 Gr. CA6N) that trades carbon for nickel to gain toughness and weldability without the molybdenum of CA6NM. Normalized and tempered it reaches about 930 MPa yield, 1020 MPa tensile, 19% elongation and 300 HB (31 HRC), making it one of the strongest CA castings, with service limited to 400 °C. Machinability is low (score 32) and the alloy is casting-only; CA6NM is the nearest alternative where the Mo addition is needed for chloride or cavitation service. CA6N has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F). CA6N has a yield strength of 930 MPa (135 ksi) and a tensile strength of 1,020 MPa (148 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 19% and the elastic modulus is 200 GPa (29 Msi).
What is CA6N used for?
- Pump and valve bodies needing improved toughness
- Weld-repaired castings
- Corrosion-resistant structural castings
Advantages
- High strength — 930 MPa (135 ksi), better than 98% of stainless steel grades
- Conducts heat well — 25 W/m·K (14.4 BTU/hr·ft·°F), better than 93% of stainless steel grades
- Low embodied carbon — 3.6 kg CO₂/kg, better than 83% of stainless steel grades
Limitations
- Limited formability — 15/100, worse than 91% of stainless steel grades
- Limited ductility — 19%, worse than 81% of stainless steel grades
- Limited service temperature — 400°C (752 °F), worse than 78% of stainless steel grades
CA6N properties
Typical room-temperature values for CA6N-N+T; bars are the position among stainless steel grades.
Physical3
CA6N has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
CA6N has a yield strength of 930 MPa (135 ksi) and a tensile strength of 1,020 MPa (148 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 19% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
CA6N is rated for continuous service to 400°C (752 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), better than 93% of stainless steel grades. Thermal expansion is 10.6 µm/m·K (5.89 µin/in·°F).
Electrical3
CA6N conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 71% of stainless steel grades.
Sustainability4
Producing a kilogram of CA6N takes about 53 MJ of energy and emits 3.6 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 75%.
Manufacturability8
CA6N's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability good (62/100); formability poor (15/100).
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. CA6N is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CA6N
Is CA6N easy to machine?
Machine in the annealed or high-tempered state with rigid setups, sharp carbide inserts, positive rake and heavy flood coolant; work-hardens and gums up at low speed like other 12Cr martensitics.
Can CA6N be welded?
Weldable with matching low-C 12Cr-Ni or 410NiMo filler; preheat 100–150 °C, keep interpass below ~150 °C, and post-weld temper at 595–620 °C to restore toughness — never leave weld metal untempered.
Can CA6N be formed, bent or molded?
Casting alloy only: good fluidity for pumps, valve bodies and hydro turbine runners, but design generous risers and radii to avoid shrinkage porosity and hot tears; full normalize-and-temper after any weld repair.
CA6N 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 |
|---|---|---|
| Clow carbon keeps martensite tough and weldable | ≤ 0.06 | 0.04 |
| Mn | ≤ 0.5 | 0.35 |
| Si | ≤ 1 | 0.6 |
| P | ≤ 0.02 | 0.02 |
| S | ≤ 0.02 | 0.01 |
| Cr | 10.5 – 12.5 | 11.5 |
| Nihigh Ni suppresses delta ferrite and boosts toughness | 6 – 8 | 7 |
| Moresidual only — CA6N is not Mo-alloyed (unlike CA6NM) | ≤ 0.5 | 0.2 |
| Fe | balance |
What surface finishes work on CA6N?
Passivate per ASTM A967 or electropolish for corrosion service; takes a good mechanical polish, and can be hard chrome plated or nitrided below the tempering temperature.
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 CA6N in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- J91650
- ASTM
- A743 Gr. CA6N
How much does CA6N cost?
CA6N 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.
CA6N — frequently asked
What is CA6N used for?
CA6N is typically used for pump and valve bodies needing improved toughness, weld-repaired castings and corrosion-resistant structural castings. In short: highest-strength CA6 grade; tougher, weldable martensitic; mo-free CA6NM alternative.
What is the yield strength of CA6N?
CA6N has a typical yield strength of 930 MPa (135 ksi) and a tensile strength of 1,020 MPa (148 ksi) — stronger than 98% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is CA6N easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% of stainless steel grades). Machine in the annealed or high-tempered state with rigid setups, sharp carbide inserts, positive rake and heavy flood coolant; work-hardens and gums up at low speed like other 12Cr martensitics.
Can CA6N be welded?
Yes — weldability is rated good (62/100). Weldable with matching low-C 12Cr-Ni or 410NiMo filler; preheat 100–150 °C, keep interpass below ~150 °C, and post-weld temper at 595–620 °C to restore toughness — never leave weld metal untempered.
What surface finishes work on CA6N?
Passivate per ASTM A967 or electropolish for corrosion service; takes a good mechanical polish, and can be hard chrome plated or nitrided below the tempering temperature.
Can CA6N be formed, bent or molded?
Casting alloy only: good fluidity for pumps, valve bodies and hydro turbine runners, but design generous risers and radii to avoid shrinkage porosity and hot tears; full normalize-and-temper after any weld repair.
What is the maximum service temperature of CA6N?
CA6N is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between CA6N N+T and CA6N-ANN?
N+T is the default condition — standard ASTM A743 CA6N supply condition: maximum strength with useful toughness for pump/valve pressure parts. ANN: softest condition, used between rough machining and final heat treatment or before major weld repair. Yield strength is 930 MPa in N+T versus 560 MPa in ANN.
How much does CA6N cost?
CA6N 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 (Gr. CA6N) — ASTM International (2021)
- ASTM A781/A781M — Common Requirements for Steel and Alloy Castings — ASTM International (2020)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (cast stainless steels) — ASM International (1990)
- Steel Castings Handbook, Supplement 8 — High Alloy Data Sheets, Corrosion Series — Steel Founders' Society of America (2004)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
- UNS J91650 alloy record — SAE/ASTM Unified Numbering System (2019)
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.