Abstract
Corrosion tests were conducted on 18Cr‐2Mo titanium‐stabilized ferritic stainless steel aged at 620°C for various time periods. Sensitivity to intergranular corrosion was detected in the Streicher test but not in the Strauss or Warren tests. The corrosion resistance in 45% boiling formic acid and in dilute chloride solution (
, 90°C) was unaffected by aging at 620°C. Pitting potentials in molars 
at 25°C were also unaffected by the 620°C heat‐treatment. Corrosion tests were also performed with the same 
stainless steel aged at 475°C for 240, 2400, and 4800 hr (
steel is embrittled after 240 hr at 475°C). The 475°C heat‐treatment affected corrosion resistance to boiling formic acid. Corrosion resistance started to deteriorate after 2400 hr aging and was seriously impaired after 4800 hr aging. Pitting potentials were rendered less noble by the 475°C treatment. The 475°C embrittlement did not result in sensitization to intergranular corrosion in any environment as contrasted to the 620°C treatment which did sensitize the steel to intergranular corrosion in the Streicher test.