Debasis Ni and their effect for producing high tensile steel had their share of problems of failures in many LPG operating plants in 1960-70's. A spate of failures occurred in 1970 with Japanese steels wtih Ni additions in LPG/Propoane service. In fact, Japanese developed HTS - with 1% Ni addition for reducing tonnage in LPG construction Spheres / Bullets in th 1960's. Following a spate of failures (due to SSCC) researchers, manufcturers and welding institute in Japan (1970) did a lot of survey of all vessels supplied / in operation at that time from service prone failures due to SSCC - with addition of Ni - 1%. Later HST were modified to supply without Ni addition. Trust this will help you C.V.Srinivasan Nishi Engineers Pvt Ltd India June 23, 2007 E-mail: nishi@vsnl.com >It has been established that "Ni" more than 1% in CS or LTCS >has v. adverse effect w.r.t. SSCC in wet aq. H2S environment >under low pH . > >Any body has come acroos any FAilure or Failure >Investigation due to this Ni Effect may please share the >incidence aspectss for common interest. >regards