Corrosion of stainless steels in chlorination washer of Indian paper industry

Abstract

Present paper deals with the corrosion evaluation studies in ditlerent phases of chlorination washer of bleach plant. Field tests were conducted on various grades of austenitic stainless-steel in four different Indian paper mills. Investigations included coupon exposure for weight-loss determination, monitoring of process parameters during test period, and post-exposure evaluation/analysis for the degree and nature of corrosion attack. The results showed that gaseous phase is extremely corrosive as conventional grades of stainless-steels (exposed therewith) suffered from heavy metal-loss as well as severe pitting and crevice corrosion. Aggressivity of the other two i.e. wet/dry and liquid phase was, however. lesser than that of gaseous one as negligible to moderate corrosion attack was noticed on test coupons. The performance of various grades of stainless steel was found in the following order