Stainless Steel CG3M-AC (Spheroidize annealed)
Heat-treated state
ASTM CG3M · UNS J92999 · EN 1.4508
Only for non-critical, non-corrosive duty; residual segregation and interdendritic phases lower corrosion resistance and toughness versus solution annealed.
Values for the AC condition
Other CG3M tempers and conditions
CG3M is listed in 3 conditions; see the grade overview at CG3M.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SADefault Solution annealed | Standard supply condition for ASTM A743/A744 CG3M castings; maximum corrosion resistance and ductility. | 275 | 530 | 40 | 150 HB | — |
ACThis page Spheroidize annealed | Only for non-critical, non-corrosive duty; residual segregation and interdendritic phases lower corrosion resistance and toughness versus solution annealed. | 285 | 520 | 28 | 160 HB | 2.1 % IACS |
hot isostatically pressed then solution annealed | Chosen for pressure-critical pump/valve castings where shrinkage porosity must be closed for higher fatigue life and better radiographic quality. | 285 | 550 | 45 | 150 HB | 2.1 % IACS |
What is CG3M-AC?
CG3M-AC is CG3M heat treated to AC — only for non-critical, non-corrosive duty; residual segregation and interdendritic phases lower corrosion resistance and toughness versus solution annealed. CG3M-AC has a yield strength of 285 MPa (41.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 74% of stainless steel grades. Elongation at break is 28% and the elastic modulus is 193 GPa (28 Msi). CG3M-AC has a density of 7.98 g/cm³ (0.288 lb/in³), heavier than 85% of stainless steel grades. It melts at 1,400°C (2,552 °F). SA is the default condition FabDigit quotes; AC is available on request or by drawing note.
Advantages
- Readily welded — 80/100, better than 80% of stainless steel grades
Limitations
- Limited formability — 20/100, worse than 86% of stainless steel grades
- Hard to polish — 60/100, worse than 80% of stainless steel grades
- Limited service temperature — 400°C (752 °F), worse than 78% of stainless steel grades
CG3M-AC properties
Typical room-temperature values for CG3M-AC; 22 are specific to this condition. Other listed values are CG3M reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
CG3M-AC has a density of 7.98 g/cm³ (0.288 lb/in³), heavier than 85% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical14
CG3M-AC has a yield strength of 285 MPa (41.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 74% of stainless steel grades. Elongation at break is 28% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
CG3M-AC is rated for continuous service to 400°C (752 °F). It conducts heat at 14.5 W/m·K (8.38 BTU/hr·ft·°F), worse than 72% of stainless steel grades. Thermal expansion is 16.2 µm/m·K (9 µin/in·°F).
Electrical3
CG3M-AC conducts electricity at 2.1 % IACS, worse than 73% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (66/100), better than 59% of stainless steel grades.
Sustainability4
Producing a kilogram of CG3M-AC takes about 55 MJ of energy and emits 4.5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 75%.
Manufacturability8
CG3M-AC's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability very good (80/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CG3M-AC
Is CG3M easy to machine?
Machine like CF3M/316L cast stainless: rigid setup, sharp positive-rake carbide, low speed with heavy feed, flood coolant and no dwelling to avoid work-hardened glazing.
Can CG3M be welded?
Excellent — GTAW/SMAW with ER316L/E316L-15 (or matching CG3M/ER317L for full Mo match); low carbon means no post-weld solution anneal is needed, keep interpass low and avoid full-ferrite-free deposits to limit hot cracking.
Can CG3M be formed, bent or molded?
Sand or investment cast only; allow ~2.5 % shrinkage with generous risering and chills, then solution anneal and water quench for corrosion service.
What surface finishes work on CG3M?
Grit blast, pickle and passivate per ASTM A967 (citric or nitric); electropolishing gives the best cleanliness for pulp/chemical duty — no anodizing.
CG3M 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 grade, avoids sensitization | ≤ 0.03 | 0.02 |
| Mn | ≤ 1.5 | 0.8 |
| Si | ≤ 1.5 | 1 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Cr | 18 – 21 | 19.5 |
| Ni | 9 – 13 | 11 |
| Mohigher than CF3M (2–3 %) | 3 – 4 | 3.5 |
| Fe | balance | — |
CG3M-AC — frequently asked
What is CG3M-AC used for?
CG3M-AC is typically used for welded chemical process castings, corrosive fluid handling components, pump casings and impellers for acid service, valve bodies and bonnets, pulp bleach plant fittings and scrubber and absorber internals. In short: weldable high-Mo cast austenitic; low-carbon CG8M; better corrosion than CF3M.
What is the yield strength of CG3M-AC?
CG3M-AC has a typical yield strength of 285 MPa (41.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 74% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is CG3M-AC easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% of stainless steel grades). Machine like CF3M/316L cast stainless: rigid setup, sharp positive-rake carbide, low speed with heavy feed, flood coolant and no dwelling to avoid work-hardened glazing.
Can CG3M-AC be welded?
Yes — weldability is rated very good (80/100). Excellent — GTAW/SMAW with ER316L/E316L-15 (or matching CG3M/ER317L for full Mo match); low carbon means no post-weld solution anneal is needed, keep interpass low and avoid full-ferrite-free deposits to limit hot cracking.
What surface finishes work on CG3M-AC?
Grit blast, pickle and passivate per ASTM A967 (citric or nitric); electropolishing gives the best cleanliness for pulp/chemical duty — no anodizing.
Can CG3M-AC be formed, bent or molded?
Sand or investment cast only; allow ~2.5 % shrinkage with generous risering and chills, then solution anneal and water quench for corrosion service.
What is the maximum service temperature of CG3M-AC?
CG3M-AC 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 CG3M-SA and CG3M-AC?
SA is the default condition — standard supply condition for ASTM A743/A744 CG3M castings; maximum corrosion resistance and ductility. AC: only for non-critical, non-corrosive duty; residual segregation and interdendritic phases lower corrosion resistance and toughness versus solution annealed. Yield strength is 275 MPa in SA versus 285 MPa in AC.
Sources
- ASTM A743/A743M — Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application — ASTM (2019)
- ASTM A744/A744M — Castings, Iron-Chromium-Nickel, Corrosion Resistant, for Severe Service — ASTM (2019)
- Steel Castings Handbook, Supplement 8 — High Alloy Data Sheets, Corrosion Series — SFSA (2004)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.15 — Casting — ASM International (2008)
- UNS J92999 alloy record — SAE/ASTM Unified Numbering System (2018)
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.