Stainless steel valve materials are mainly divided into 304, 316, 304L, 316L, 321 and other stainless steel materials. However, the material on the valve body does often appear CF8, CF8M, CF3, CF3M and so on.

There are many customers because it is written on the contract that it is a ball valve: DN50, 304, 20 sets. But when the goods arrived at the scene, it was found that there was no digital material such as 304 on the valve. Customers will have questions and ask why there is no 304 mark on the valve. The material element of 304 appears only in the “Valve Product Quality Certificate”. Here I will explain to you the difference between CF8 and 304.

CF8 is a standard material drafted by ASTM A351 for stainless steel casting materials (American Society for Testing and Materials). It is a standard name for material casting. 304 is also a name introduced by the United States, and the Japanese name for this is SUS304. The chemical composition of the material is ≤0.08 ≤1.00 ≤2.00 ≤0.05 ≤0.03 18.00-20.00 8.00~10.50, 304 is forged or forged material. Such as steel pipes, steel plates, forgings, forgings.

CF8 and 304 are called 0Cr18Ni9 in China, and SUS304 in Japan. However, due to the continuous progress of the country, the standards of materials are constantly in line with international standards. As we see now. CF8, 304, 0Cr18Ni9 materials are almost close. Therefore, according to custom and easy to remember, whether it is casting, forging, forging, we call it 304. The mechanical properties and chemical composition are almost the same. But strictly speaking, the stainless steel valve should still be called CF8.

CF8, CF8M, CF3, CF3M are stainless steel castings in the American Standard ASTM A351 standard

CF8M is equivalent to China’s ZG0Cr17Ni12Mo2. Corresponds to 316 stainless steel.
CF8 is equivalent to China’s ZG0Cr18Ni9. Corresponds to 304 stainless steel.

  • CF3 is equivalent to 304L
  • CF3M is equivalent to 316L

Chemical Composition of CF8 CF8M CF3 CF3M

GradeC碳Mn锰Si硅P磷S硫 Ni镍Cr铬MO钼
 CF30.031.502.000.040.04 8.0〜12.017.0〜21.0
CF3M0.031.501.500.040.04 9.0〜13.017.0〜21.0 2.00〜3.00