... 4.Standard:GB,ANSI,JIS,DIN and so on TechnicsSeamless Elbow, Welded ElbowSize1/2"-48"(DN15-DN1200)VarietiesSCH5,SCH10,SCH20,SCH30 ... ,Gost17375MateriaCarbon steel: ASTM A234 GR WPB , ST37.2 , ST35.8……Alloy steel: A234 WP5/WP9/WP11/WP22/WP91, A420 WPL6, A860 ... &CFR, CIFPAYMENTTT or L/CCERTIFICATESGB/T19001-2008-ISO 9001:2008 seamless pipe fitting elbow a234 wpb sch40,80,xs,xxs