Based on effect of the Cr-rich layer on oxide scales formation process on boiler superheaters and reheaters

the Cr-rich layer retention cleaning method was proposed.Considering the variety of austenitic stainless steels

the complexity of oxide scale condition and the construction difficulties

a novel cleaning medium consisting of various organic acids was developed

which could achieve the aim of Cr-rich layer retention cleaning for various austenitic stainless steels.By losing gravity method

dissolving scale test showed the dissolution rate of Fe oxides layer was ten times higher than that of the Cr-rich layer on austenitic stainless steel

which ensures the Cr-rich layer's retention after long time cleaning.Application of this cleaning medium on TP347 H

Super304and HR3 Csteels shows that

after chemical cleaning for 24 hours

the Fe oxides on TP347 Hand Super304steels could be totally removed

while oxides on HR3 Csteel had left little amount due to the compact structure.The Cr-rich layers of three steels were remained successfully.Moreover

intergranular corrosion didn't occur on the austenitic stainless steel during chemical cleaning using this novel cleaning medium.