... GB, ASTM, API (2)Standard: GB/T 3091-2001 (3)Grade:10#-45#, A53-A369 Standard: GB ... , DIN, ASTM, APIStandard: GB/T 3091-2001, DIN 1626, DIN 1629/3,...Grade: 10#-45 ... , have extreme experience in steel manufacturing. Over the year's technical capabilities and commitment to quality have ... business relationship with clients from all over the world in long term business.LogoZhongtongContact informationEmma ...