Stainless Steel CG8M
ASTM CG8M · UNS J93000
CG8M (J93000, ASTM A351/A743) is a higher-molybdenum cast austenitic stainless steel, the cast counterpart of wrought 317, supplied solution treated at 290 MPa yield, 550 MPa tensile strength, 40% elongation and 170 HB.
Reference datasheet — CG8M 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 ST condition
CG8M tempers and conditions
CG8M is supplied in 3 conditions, soft to hard. ST is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Only for non-corrosive structural use or as an intermediate state; interdendritic carbides reduce corrosion resistance and toughness. | 285 | 530 | 28 | 180 HB | 2 % IACS |
STDefault Solution annealed | Standard supply condition for all CG8M castings — maximum corrosion resistance and ductility. | 290 | 550 | 40 | 170 HB | 2 % IACS |
hot isostatically pressed then solution treated | Choose for thick-section or fatigue-critical castings where internal microporosity must be closed. | 300 | 570 | 48 | 175 HB | 2 % IACS |
Supply forms, finishes and certifications
Ways CG8M is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
A351-ST | A351 CG8M ST | Certification |
A744-ST | A744 CG8M ST | Certification |
What is CG8M?
CG8M (J93000, ASTM A351/A743) is a higher-molybdenum cast austenitic stainless steel, the cast counterpart of wrought 317, supplied solution treated at 290 MPa yield, 550 MPa tensile strength, 40% elongation and 170 HB. Engineers select it over CF8M when pitting and crevice attack in chemical, pulp and flue gas service govern, with a corrosion resistance score of 70 and service to 650 °C. It is available as sand and investment castings, including HIP'd and A744 pressure-retaining conditions. The extra molybdenum raises cost and it work-hardens when machined; CF8M is the cheaper option in milder media, and CG3M the low-carbon version for welded assemblies. CG8M has a density of 7.98 g/cm³ (0.288 lb/in³), heavier than 85% of stainless steel grades. It melts at 1,370°C (2,498 °F). CG8M has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 72% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 193 GPa (28 Msi).
What is CG8M used for?
- Pulp and paper process equipment
- Chemical process valves
- Flue gas desulfurization components
Limitations
- Hard to polish — 60/100, worse than 80% of stainless steel grades
- Limited formability — 25/100, worse than 78% of stainless steel grades
- Low electrical conductivity — 2 % IACS, worse than 77% of stainless steel grades
CG8M properties
Typical room-temperature values for CG8M-ST; bars are the position among stainless steel grades.
Physical3
CG8M has a density of 7.98 g/cm³ (0.288 lb/in³), heavier than 85% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical16
CG8M has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 72% of stainless steel grades. Elongation at break is 40% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
CG8M is rated for continuous service to 650°C (1,202 °F). It conducts heat at 14 W/m·K (8.09 BTU/hr·ft·°F), worse than 80% of stainless steel grades. Thermal expansion is 16 µm/m·K (8.89 µin/in·°F).
Electrical3
CG8M conducts electricity at 2 % IACS, worse than 77% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 68% of stainless steel grades.
Sustainability4
Producing a kilogram of CG8M takes about 55 MJ of energy and emits 4.5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 70%.
Manufacturability8
CG8M's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability good (65/100); formability poor (25/100).
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. CG8M is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CG8M
Is CG8M easy to machine?
Gummy and work-hardening: use rigid setups, positive-rake carbide, 60–110 m/min, heavy feeds and flood coolant, avoid dwelling to prevent glazing.
Can CG8M be welded?
Readily welded with ER317L/E317L-15 filler (GTAW/SMAW); keep interpass temperature low and use low-carbon filler to limit sensitization — no post-weld heat treatment needed for thin sections, re-solution treat heavy repairs.
Can CG8M be formed, bent or molded?
Sand or investment cast with generous risers and chills — wide freezing range and 2.0–2.5% solidification shrinkage promote centerline microporosity; solution treat ≥1040 °C and water quench.
CG8M 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 | ≤ 0.08 | 0.06 |
| Mn | ≤ 1.5 | 1 |
| Si | ≤ 1.5 | 1.2 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.04 | 0.02 |
| Cr | 18 – 21 | 19.5 |
| Ni | 9 – 13 | 11 |
| Mo | 3 – 4 | 3.5 |
| Fe | balance |
What surface finishes work on CG8M?
Pickle and passivate (ASTM A967) or electropolish for chemical service; shot-blast/grind gate marks first — casting skin porosity limits mirror polish, and no anodizing applies.
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 CG8M in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- J93000
- Also called
- Cast 317
How much does CG8M cost?
CG8M 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.
CG8M — frequently asked
What is CG8M used for?
CG8M is typically used for pulp and paper process equipment, chemical process valves and flue gas desulfurization components. In short: cast 317 equivalent; higher pitting resistance than CF8M; chemical and pulp service.
What is the yield strength of CG8M?
CG8M has a typical yield strength of 290 MPa (42.1 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 72% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is CG8M easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% of stainless steel grades). Gummy and work-hardening: use rigid setups, positive-rake carbide, 60–110 m/min, heavy feeds and flood coolant, avoid dwelling to prevent glazing.
Can CG8M be welded?
Yes — weldability is rated good (65/100). Readily welded with ER317L/E317L-15 filler (GTAW/SMAW); keep interpass temperature low and use low-carbon filler to limit sensitization — no post-weld heat treatment needed for thin sections, re-solution treat heavy repairs.
What surface finishes work on CG8M?
Pickle and passivate (ASTM A967) or electropolish for chemical service; shot-blast/grind gate marks first — casting skin porosity limits mirror polish, and no anodizing applies.
Can CG8M be formed, bent or molded?
Sand or investment cast with generous risers and chills — wide freezing range and 2.0–2.5% solidification shrinkage promote centerline microporosity; solution treat ≥1040 °C and water quench.
What is the maximum service temperature of CG8M?
CG8M 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 CG8M-ST and CG8M ST-HIP?
ST is the default condition — standard supply condition for all CG8M castings — maximum corrosion resistance and ductility. ST-HIP: choose for thick-section or fatigue-critical castings where internal microporosity must be closed. Yield strength is 290 MPa in ST versus 300 MPa in ST-HIP.
How much does CG8M cost?
CG8M 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 A744/A744M — Castings, Iron-Chromium-Nickel, Corrosion Resistant, for Severe Service — ASTM International (2021)
- ASTM A351/A351M — Castings, Austenitic, for Pressure-Containing Parts — ASTM International (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (Cast Stainless Steels) — ASM International (1990)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
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.