ASTM A351 CF8 & CF8M are the common cast stainless steel grades in all the stainless steel foundries. They are similar, but not complete the same. Specialised in stainless steel investment casting process, CFS Foundry usually casts A351 CF8 and CF8M stainless steel components for various applications.
In this article, we will help you to understand the differences between these two alloys, and how to select a proper alloy for your design.
ASTM A351 CF8 is the equivalent investment cast alloy of AISI 304 stainless steel, which belongs to austenitic stainless steel that presents good strength and ductility. As the chemical composition of CF8 includes approximately 18% chromium and 8% nickel by weight, it is also known as 18/8 stainless steel.
For its good cavitation resistance, CF8 is primarily used to cast stainless steel components like pump impellers, some important parts for water handling application. It also provides strong oxidation resistance and corrosion resistance especially in some special medias such as hydrocarbons, liquid oxygen, organic liquids, nitric acid, sodium carbonate, etc, so it is also an ideal cast alloy to produce some parts like stainless steel valves fittings, stainless steel flanges, stainless steel mixing agitators and propellers, stainless steel spray nozzles, etc.
ASTM A351 CF8M is an upgraded austentic stainless steel alloy of CF8, which contains molybdenum element. The equivalent cast stainless steel alloy is AISI 316 stainless steel. Compared to CF8 stainless steel, The presence of molybdenum in CF8M increases the corrosion resistance and the resistance to pitting by chlorides.
CF8M stainless steel is the proper alloy to cast stainless steel parts that require excellent corrosion resistance that CF8 can not provide. It can be used to produce parts include stainles steel valve components, marine boat hardwares, other pressure-containing parts, food machinery parts, etc.
In summary, ASTM A351 CF8M stainless steel castings shows better corrosition resistance, while CF8 stainless steel castings have lower cost. The selection of these two alloys mainly depend on the working environment. If you are unfamilar with them, CFS can recommend a good alloy for your cast stainless steel product according to our rich casting experience.
When CFS foundry was created in China over 30 years ago, the company’s sole focus was on the production of high quality stainless steel castings mainly in ASTM A351 CF8 & CF8M stainless steel alloys using investment casting process. these two alloys take up most of the stainless steel castings that go through our stainless steel foundry. Besides we can also cast stainless steel in other alloys like CF3, CF3M, CG8M, etc.
As an ISO9001:2008 accredited company, all the castings can be supplied in finish machined status and are fully tested before delivery to suit our customers’ requirements. Any inquiry on CF8 or CF8M stainless steel casting, pls feel free to contact our foundry!