GB/T 9711.1-1997 |
石油天然氣工業輸送鋼管交貨技術條件 第1部分 A級鋼管 The first Part of Oil-Gas industrial Transportatio Steel Pipes onsignment Technical Qualification Level A Steel Pipes |
螺旋焊管、
直縫埋弧焊管、
直縫高頻焊管 Spirsl-seam,
Steel Pipes,Longitudinal-seam submerged-arcSteel pipes,
High-Frequency Longitudinal-seam
Steel Pipes |