Difference between 304 and 321 stainless steel

Difference between 304 and 321 stainless steel

The main difference between 304 and 321 stainless steel is that 304 does not contain Ti, and 321 contains Ti. Ti can avoid stainless steel sensitization. In short, it is to improve the service life of stainless steel in high temperature practice. That is to say, in high temperature environment, 321 stainless steel plate More suitable than 304 stainless steel plate. Both 304 and 321 are austenitic stainless steels, and their appearance and physical functions are very similar, with only slight differences in chemical composition.

First of all, 321 stainless steel is required to contain a small amount of titanium (Ti) element (according to ASTMA182-2008 norms, its Ti content should not be less than 5 times the carbon (C) content, but not less than 0.7%. Note, 304 and 321 The carbon (C) content is 0.08%), while 304 does not contain titanium (Ti).

Second, the requirements for nickel (Ni) content are slightly different, 304 is between 8% and 11%, and 321 is between 9% and 12%.

Third, the requirements for chromium (Cr) content are different, 304 is between 18% and 20%, and 321 is between 17% and 19%.