... 4.Standard:GB,ANSI,JIS,DIN and so on TechnicsSeamless Elbow, Welded ElbowSize1/2"-48"(DN15-DN1200)VarietiesSCH5,SCH10,SCH20,SCH30 ... 2312/JIS2313/ DIN2615 /GB-12459/GB-T13401,Gost17375MateriaCarbon steel: ASTM A234 GR WPB , ST37.2 , ST35.8……Alloy steel: A234 WP5/WP9 ... L/CCERTIFICATESGB/T19001-2008-ISO 9001:2008 seamless pipe fitting elbow a234 wpb sch40,80,xs,xxs