... A234 WPB ,ANSI B16.96. Surface treatment: Transparent oil, rust-proof black oil or hot galvanized.7.Standard:ASMEB16.9,MSSSP-43 ... ,SH3408,SH3409,HG/T21635 ,HG/T216318. Applications rang : such as oil, chemical industry, water conservancy, electric power, boiler, machinery, metallurgy, sanitary construction ...