OD:20-660MM ,WT:5-60MM Standard: GB8163-2008 ,Material: 20#OD:20-660MM WT:5-60MM,Standard: Tianjin large seamless, small seamless, baotou, hengyang, chengdu, exist issues now days, baosteel, anshan, metallurgical steel, wuhan, etc. Product material for: # 20, 35 #, 45 #, 20 G, 20 A, 40, 45 Mn2 Mn2, 27 SiMn, 40 MnB, 20 MnVB, 20 Cr, 30 Cr, 35 Cr, 40 Cr, 45 Cr, 50 Cr, 38 CrSi, 12 CrMo, 20 CrMo, 35 ...