I was wondering whether anyone is still recommending shot peening for mitigating Chloride SCC or Polythionic Acid SCC? If you do, is it recommended for fabrication and/or during welding repair of austenitic stainless steels? I noticed that this is not mentioned in NACE RP0170-2004. Thanks,

Alani Luis is correct, in his observation and from his experience, that shot peening may not be regularly applied (to induce compressive stresses) for SS components from mitigating SCC or Polythionic acid SCC. However, for external application on SS piping or vessels affected with embedded steam tracing ( wrapped with mineral wool insulation over the saturated steam tracing lines) where leaching of chlorides had given problem, shot peening of weld and piping (affected areas) had been / could be done. Shot peening or even sand blast cleaning were known to have improved life of SS pipng compoents or SS vessels with steam tracing lines embedded. We have successfully improved perfomance of affected SS piping or SS vessels with steam traced lines and with mineral wool insulation where chloride SCC had already initiated. This had improved the affected piping or SS vessels till planned replacement of the vessel / piping was done. For inside of SS piping or for inside of SS vessels affected by SCC or Polythionic acid SCC this might not have been done (from my knowledge). Trust this will help you C.V.Srinivasan Nishi Engineers Pvt Ltd India Jan 2, 2007 E-mail: nishi@vsnl.com/nishi@hathway.com > >From my knowledge, shot penning, improves somewhat the >surface hardness properties of a metallic surface. > >Shot penning, is a process which applies tension of >compression in metallic surfaces, applying over them, high >speed metallic sandblasting, increasing the resistance, >eliminating the fatigue and corrosion in plain and helical >springs, stabilizing bars of automobiles, gears of exchange >broker, crowns, transmission gears, airplanes parts, and oil >and mine perforating drills. > >I have never heard of shot penning, to mitigate HCL SCC or >polyethionic acid SCC > >Regards > >Luis