procurement of protection sleeve or shields for high pressure boiler tubes in 1 x 210 mw unit atps chachai. procurement of protection sleeve or shields for high pressure boiler tubes in 1 x 210 mw unit atps chachai. , protection sleeve / shield for eco coil with suitable c clamps-3 nos. for each shield ) item no. d ( id-44mm, l-2000 mm thickness- 2.5 mm ) as per drawing no. bms / 259 material: corton steel gr.a material compostion 1 ) cortonsteel gr.a:- c-0.12% ( max ) , cr-0.5-1.25%, ni-0.65% ( max ) , si-0.25-0.7% ( max ) , mn-0.2-0.5%, cu-0.25-0.4%, p-0.0-0.15% s-0.03% max, tensile strength 470-630mpa