Stainless Steel CA6N-ANN (Annealed)
Heat-treated state
ASTM CA6N · UNS J91650
Softest condition, used between rough machining and final heat treatment or before major weld repair.
Values for the ANN condition
Other CA6N tempers and conditions
CA6N is listed in 5 conditions; see the grade overview at CA6N.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNThis page 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-ANN?
CA6N-ANN is CA6N heat treated to ANN — softest condition, used between rough machining and final heat treatment or before major weld repair. CA6N-ANN has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 85% of stainless steel grades. Elongation at break is 24% and the elastic modulus is 200 GPa (29 Msi). CA6N-ANN 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). N+T is the default condition FabDigit quotes; ANN is available on request or by drawing note.
Advantages
- Conducts heat well — 25.5 W/m·K (14.7 BTU/hr·ft·°F), better than 95% of stainless steel grades
- Easy to machine — 48/100, better than 88% of stainless steel grades
- High strength — 560 MPa (81.2 ksi), better than 85% of stainless steel grades
- Low embodied carbon — 3.6 kg CO₂/kg, better than 83% of stainless steel grades
Limitations
- Limited service temperature — 400°C (752 °F), worse than 78% of stainless steel grades
CA6N-ANN properties
Typical room-temperature values for CA6N-ANN; 23 are specific to this condition. Other listed values are CA6N reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
CA6N-ANN 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-ANN has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 85% of stainless steel grades. Elongation at break is 24% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
CA6N-ANN is rated for continuous service to 400°C (752 °F). It conducts heat at 25.5 W/m·K (14.7 BTU/hr·ft·°F), better than 95% of stainless steel grades. Thermal expansion is 10.6 µm/m·K (5.89 µin/in·°F).
Electrical3
CA6N-ANN conducts electricity at 2.3 % IACS, better than 55% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (57/100), worse than 66% of stainless steel grades.
Sustainability4
Producing a kilogram of CA6N-ANN 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-ANN's machinability is fair (48/100, better than 88% of stainless steel grades); weldability very good (70/100); formability poor (28/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CA6N-ANN
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.
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.
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 | — |
CA6N-ANN — frequently asked
What is CA6N-ANN used for?
CA6N-ANN 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-ANN?
CA6N-ANN has a typical yield strength of 560 MPa (81.2 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 85% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is CA6N-ANN easy to machine?
Reasonably — machinability is rated fair (48/100, better than 88% 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-ANN be welded?
Yes — weldability is rated very good (70/100). 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-ANN?
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-ANN 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-ANN?
CA6N-ANN 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.