Used in oil and gas industry, construction, engineering, power station, cylinder, automobile. Used in oil and gas industry, construction, engineering, power station, cylinder, automobile. Standard: GB/T3087,3639,5310,5312,6479,6725,8162,8163,18248; ASTM A53,A106,A179,A192,A213,A335,A519;API 5L,5CT,5D; NACE MR0175; DIN1629,2448,10210,10297,17175Steel Grade: 20#,20G,16Mn,15CrMoG,37Mn,30CrMo,34CrMo4 ...