Stainless Steel CG6MMN-SA
Heat-treated state · default condition
ASTM CG6MMN · UNS J93790
SA = solution annealed (≥1040 °C, water quenched) per ASTM A351/A743
Standard supplied condition for all pressure-containing CG6MMN castings; maximum corrosion resistance and full N-strengthened ductility.
Values for the SA condition
Other CG6MMN tempers and conditions
CG6MMN is listed in 3 conditions; see the grade overview at CG6MMN.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefaultThis page Solution annealed (≥1040 °C, water quenched) per ASTM A351/A743 | Standard supplied condition for all pressure-containing CG6MMN castings; maximum corrosion resistance and full N-strengthened ductility. | 350 | 655 | 40 | 190 HB | — |
As fabricated | Only for non-code, non-corrosive service; retained interdendritic carbides/nitrides and residual ferrite reduce ductility and corrosion resistance. | 360 | 620 | 22 | 14 HRC | 2.2 % IACS |
hot isostatically pressed then solution annealed | Choose for critical pump/valve castings where internal microporosity must be closed to raise fatigue life and NDE acceptance. | 365 | 690 | 45 | 190 HB | 2.3 % IACS |
What is CG6MMN-SA?
CG6MMN-SA is CG6MMN heat treated to SA — standard supplied condition for all pressure-containing CG6MMN castings; maximum corrosion resistance and full N-strengthened ductility. CG6MMN-SA has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 655 MPa (95 ksi) — weaker than 52% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 193 GPa (28 Msi). CG6MMN-SA has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 59% of stainless steel grades. It melts at 1,385°C (2,525 °F).
Advantages
- Good corrosion resistance — 75/100, better than 79% of stainless steel grades
Limitations
- Poor heat conductor — 13 W/m·K (7.51 BTU/hr·ft·°F), worse than 85% of stainless steel grades
CG6MMN-SA properties
Typical room-temperature values for CG6MMN-SA; 11 are specific to this condition. Other listed values are CG6MMN reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
CG6MMN-SA has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 59% of stainless steel grades. It melts at 1,385°C (2,525 °F).
Mechanical15
CG6MMN-SA has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 655 MPa (95 ksi) — weaker than 52% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
CG6MMN-SA is rated for continuous service to 650°C (1,202 °F). It conducts heat at 13 W/m·K (7.51 BTU/hr·ft·°F), worse than 85% of stainless steel grades. Thermal expansion is 15.5 µm/m·K (8.61 µin/in·°F).
Electrical3
CG6MMN-SA conducts electricity at 2.3 % IACS, better than 55% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (75/100), better than 79% of stainless steel grades.
Sustainability4
Producing a kilogram of CG6MMN-SA takes about 55 MJ of energy and emits 4.3 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 70%.
Manufacturability8
CG6MMN-SA's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability very good (70/100); formability fair (45/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CG6MMN-SA
Is CG6MMN easy to machine?
Tough and strongly work-hardening — use rigid setups, positive-rake carbide, heavy depth of cut, 15–25 m/min for turning and flood coolant; never dwell or take spring passes.
Can CG6MMN be welded?
Readily welded by GTAW/SMAW with matching CG6MMN or E209/ER209 (or 22Cr-N) filler; keep interpass low, no preheat, and re-solution-anneal heavily welded pressure castings.
Can CG6MMN be formed, bent or molded?
Sand or investment casting with tight nitrogen and ferrite control; provide generous risers and rapid solidification, and always solution treat ≥1040 °C with water quench.
What surface finishes work on CG6MMN?
Pickle and passivate per ASTM A380 after grinding/welding; electropolish for hygienic service — no anodizing, and mechanical finishing is limited by casting skin soundness.
CG6MMN 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 | ≤ 0.06 | 0.05 |
| Mn | 4 – 6 | 5 |
| Si | ≤ 1 | 0.6 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.03 | 0.02 |
| Cr | 20.5 – 23.5 | 22 |
| Ni | 11.5 – 13.5 | 12.5 |
| Mo | 1.5 – 3 | 2.2 |
| Nnitrogen strengthening | 0.1 – 0.3 | 0.2 |
| Nblisted as Cb in ASTM | 0.1 – 0.3 | 0.2 |
| V | 0.1 – 0.3 | 0.2 |
| Fe | balance | — |
CG6MMN-SA — frequently asked
What is CG6MMN-SA used for?
CG6MMN-SA is typically used for high-strength pump and valve castings, marine and offshore components, seawater pump casings and impellers, pressure-retaining valve bodies and bonnets, subsea and deck hardware castings and shaft sleeves and wear rings. In short: strongest cast austenitic here; nitrogen-strengthened marine grade; slow to machine.
What is the yield strength of CG6MMN-SA?
CG6MMN-SA has a typical yield strength of 350 MPa (50.8 ksi) and a tensile strength of 655 MPa (95 ksi) — weaker than 52% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is CG6MMN-SA easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Tough and strongly work-hardening — use rigid setups, positive-rake carbide, heavy depth of cut, 15–25 m/min for turning and flood coolant; never dwell or take spring passes.
Can CG6MMN-SA be welded?
Yes — weldability is rated very good (70/100). Readily welded by GTAW/SMAW with matching CG6MMN or E209/ER209 (or 22Cr-N) filler; keep interpass low, no preheat, and re-solution-anneal heavily welded pressure castings.
What surface finishes work on CG6MMN-SA?
Pickle and passivate per ASTM A380 after grinding/welding; electropolish for hygienic service — no anodizing, and mechanical finishing is limited by casting skin soundness.
Can CG6MMN-SA be formed, bent or molded?
Sand or investment casting with tight nitrogen and ferrite control; provide generous risers and rapid solidification, and always solution treat ≥1040 °C with water quench.
What is the maximum service temperature of CG6MMN-SA?
CG6MMN-SA 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 CG6MMN-SA and CG6MMN-F?
SA is the default condition — standard supplied condition for all pressure-containing CG6MMN castings; maximum corrosion resistance and full N-strengthened ductility. F: only for non-code, non-corrosive service; retained interdendritic carbides/nitrides and residual ferrite reduce ductility and corrosion resistance. Yield strength is 350 MPa in SA versus 360 MPa in F.
Sources
- ASTM A351/A351M — Castings, Austenitic, for Pressure-Containing Parts — ASTM International (2018)
- ASTM A743/A743M — Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application — ASTM International (2019)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (cast stainless steels) — ASM International (1990)
- Steel Castings Handbook — Steel Founders' Society of America / ASM (1995)
- Nitronic 50 / 22Cr-13Ni-5Mn (UNS S20910) alloy data — AK Steel / Armco (Universal Stainless) (2015)
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.