Corrosion of Stainless Steel in High Temperature Water

The Corrosion of AISI Type 304 (or 304 L) stainless steel in high temperature water (300°C, 87 kg/cm2, 1000 hr) was investigated in connection with the carbon content, surface preparation, heat treatment, cold working, etc. An X-ray diffractometer was used to investigate the ferrite formation caused by cold working. The corrosion results were compared with those in boiling 40% and 65% nitric acid, 5% sulfuric acid and copper sulfate-sulfuric acid solutions. These results are summarized as follows; (1) The carbon contents and heat treatments do not affect appreciably the corrosion resistance of Type 304 (or 304 L) stainless steel in high temperature water. However, the corrosion is affected significantly by the surface finish. (2) The degree of cold working does not have a direct relation to the corrosion resistance in high temperature water. However, the ferrite caused by cold working accelerates the corrosion significantly. (3) A consistent relation is found between the corrosion in boiling 5% sulfuric acid and in high temperature water. However, the corrosion in boiling nitric acid has a poor consistent relation with the corrosion in high temperature water.