Stainless steel CF8 vs CF8M

CF8 & CF8M Stainless steel is a type of low-carbon steel that is resistant to corrosion and rusting. It is made from iron, chromium, and other elements, such as nickel, carbon, molybdenum, and nitrogen. The chromium content in stainless steel is at least 10.5%, which creates a chromium oxide layer on the surface that protects the material from further oxidation.

Cast stainless steel ASTM A531 CF8 is the equivalent lost-wax investment casting alloy of AISI 304 stainless steel.

Cast stainless steel ASTM A531 CF8M is the cast equivalent of type 316 stainless steel, mainly be casted by silica sol lost-wax investment casting process.

CF8 and CF8M chemical composition in ASTM A351, ASTM A743 or ASTM A744 standards are same.

ASTM A351 Standard Specification for Castings, Austenitic, for Pressure-containing Parts

ASTM A743 Standard Specification for Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application

ASTM A744 Standard Specification for Castings, Iron-Chromium-Nickel, Corrosion Resistant, for Severe Service

Stainless steel alloys
Grades	C	Mn	P	S	Si	Cr	Ni	Mo
CF8	0.08	1.5	0.04	0.04	2	18~21	8~11
CF8M	0.08	1.5	0.04	0.04	2	18~21	9~12	2~3
CF3	0.03	1.5	0.04	0.04	2	17~21	8~12
CF3M	0.03	1.5	0.04	0.04	1.5	17~21	9~13	2~3
All values are maximums unless a range is provided

ASTM A 531 CF8 and CF8M stainless steel alloy is the most common austenitic stainless steel, which are with a mixture primarily composed of Cr, Ni and Mo, offering good corrosion resistance and excellent formability, making them widely used in various applications, such as pump and valve, marine, chemical processing, food, aircraft and automotive.

Especially, CF8M, which equal to 316, is with 2~3% Mo, which improves the alloy’s resistance to acids, alkalis, and chloride pitting. The more corrosion resistance of 316 (CF8M) allows it to be used in highly acidic environments that other steels can’t tolerate without incurring damage. And ASTM 316 can be used in sea and marine applications because 316 can withstand exposure to salt and chlorides without breaking down.

Baoding Guokun, with 25 years casting experience, can produce various stainless steel investment casting for various industries. Lost wax investment casting process can produce complex parts that are near-net shape. The stainless steel lost-wax casting parts manufactured by Baoding Guokun is with complex shapes, tight and accurate tolerances that have a standard of +/-0.005, fine surface finish 125 μin (3.2 μm Ra), minimal machining to reduce time and cost and cost-effective.

No.	Water Glass Casting	Silica sol casting
1. Main metal	carbon steel, cast steel, alloy steel, etc	Stainless steel, alloy steel, etc
2. Casting tolerance	CT7-CT9	CT5-CT6
3. Surface Finish	12.5	6.3
4. Application	valve casting, mining casting, agricultural casting, railway casting, etc	Furniture or door casting, medical casting, valve casting, pump castings, etc
5. Advantage	Competitive prices	Fine surface finish and high precision