A351 CF8M vs 316 ss
Apr 15, 2026
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What is the difference between CF8M and SS 316?
CF8M is defined in ASMT A351, ASMT A743 and ASTM A744, which are for casting purpose only. SS316 is defined in ASTM A240 and ASTM A276, it's for plate, sheet, strip or stainless steel bars. Another grade is named as F316, which is from ASTM A182 for Forged parts only.
What is the material of A351 CF8M?
ASTM A351 CF8M is a commonly used austenitic stainless steel casting alloy designed for pressure-containing parts. It is the cast equivalent of wrought 316 stainless steel (containing 18-21% Chromium, 9-12% Nickel, and 2-3% Molybdenum), providing excellent corrosion resistance, particularly against pitting in chloride-rich environments.
What is SS 316 material?
SS 316 (Stainless Steel 316) is an austenitic stainless steel containing 16–18% chromium, 10–14% nickel, and 2–3% molybdenum, with a maximum of 0.08% carbon. The addition of molybdenum significantly enhances its corrosion resistance, especially against chlorides, acids, and marine environments. It can be processed into various practical product forms, including plates, coils, pipes, bars, and wires. For detailed chemical composition and free samples, please contact our factory immediately.
What is A351 CF8M equivalent to?
ASTM A351 CF8M is primarily equivalent to AISI 316 stainless steel (wrought) and European standard EN 1.4408. It is an austenitic cast stainless steel, often referred to as molybdenum-bearing stainless steel due to its 2–3% Mo content, which provides superior corrosion resistance in chloride environments compared to CF8 (304).
A351 CF8M vs 316 ss:Classification & Standards
| Feature | ASTM A351 CF8M | AISI 316 Stainless Steel |
| Product Form | Castings (Valves, Pump bodies, Fittings) | Wrought (Seamless/Welded Pipes, Sheets, Bars) |
| Microstructure | Austenitic + Ferrite (3% – 12%) | Fully Austenitic |
| Common Standards | ASTM A351, A743, A744 |
ASTM A312 (Pipe), A240 (Plate), A182 (Forging)
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Manufacturing methods: CF8M is manufactured using a casting process (ASTM A351), and typically has a higher chromium and nickel content to compensate for casting defects. 316 stainless steel is manufactured using a forging process (ASTM A240/A276), resulting in a smoother and more uniform microstructure.
A351 CF8M vs 316 ss：Chemical Composition Comparison (%)
| Element | CF8M (Cast) | AISI 316 (Wrought) |
| Carbon (C) | 0.08 max | 0.08 max |
| Manganese (Mn) | 1.50 max | 2.00 max |
| Silicon (Si) | 1.50 max (to aid castability) | 0.75 – 1.00 max |
| Chromium (Cr) | 18.0 – 21.0 | 16.0 – 18.0 |
| Nickel (Ni) | 9.0 – 12.0 | 10.0 – 14.0 |
| Molybdenum (Mo) | 2.0 – 3.0 | 2.0 – 3.0 |
A351 CF8M vs 316 ss：Mechanical Properties
| Property | A351 CF8M (Cast) | AISI 316 (Wrought/Annealed) |
| Tensile Strength (MPa) | ≥ 485 (70 ksi) | ≥ 515 (75 ksi) |
| Yield Strength (MPa) | ≥ 205 (30 ksi) | ≥ 205 (30 ksi) |
| Elongation (%) | ≥ 30% | ≥ 40% |
| Hardness (HBW) | ~170 | ~160 |
Are A351 CF8M and 316 ss magnetic?
A351 CF8M (cast) is generally slightly magnetic due to intentional ferrite content for weldability, while wrought 316 stainless steel is typically non-magnetic. Both are austenitic, but CF8M can contain 5–20% magnetic ferrite, making it exhibit weak magnetism, while 316 usually remains non-magnetic unless cold-worked.
Is CF8M the same as 304?
No, CF8M is not the same as 304 stainless steel. While both are austenitic stainless steels used in castings (valves, pumps), CF8M is the cast equivalent of 316 stainless steel, while CF8 is the cast equivalent of 304. CF8M contains molybdenum for higher corrosion resistance, unlike 304/CF8.
ASTM A351 CF8M Supplier
GNEE ensures that if you purchase 316 stainless steel pipes from us, the matching CF8M valves will be chemically compatible with your specific corrosive environment.
For CF8M castings, we can provide ferrite content testing to ensure the ferrite content is within the range of 3%-12%, thus achieving optimal weldability. Both cast and forged products are fully EN 10204 3.1 certified to ensure project traceability.
Pipes/Tubes: Seamless pipes, welded pipes (ERW/EFW), specifications covering SCH 5S to SCH XXS.
Others: 316 stainless steel medium and heavy plates, cold-rolled sheets, round bars, flat bars.
ASTM A351 CF8M (Casting Products) Industrial Valves: Cast steel ball valves, gate valves, globe valves, check valves, and butterfly valves.
Note：If your piping system involves extensive field welding, it is recommended to choose 316L (Low Carbon) pipes with CF8M valves to minimize carbide precipitation in the weld heat-affected zone. In marine engineering or high-chloride environments, ensure that the Mo content of the CF8M is above 2.0% (GNEE standards typically control it above 2.1%) to ensure pitting corrosion resistance.
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