... International (GB) T8162, T8163, T3087, 10#20# specification 1/ 2" -34", SCH10-SCHXXX wall thickness. 1 general purpose of seamless steel pipe ... pipe GB / T8162-1999, grades: 10, 20, 35# # #, 45, #, specifications: 6-720* 1-70mm 10 Seamless steel pipes conveying fluid GB / ... pressure boiler pipe steel grade GB3087-1999, 10, 20: # #, specifications: 6-720* 1-70mm 12 High pressure boiler tube steel: ...