- non-magnetic drill collar
- 2016-11-02 15:15
- Non-magnetic collar is a kind of low carbon chromium manganese steel, it is through the strict chemical composition prop
- drill pipe
- 2016-10-26 03:38
- StandardSizeandConnectionsofDrillPipesODGradeWallThicknessUpsetEnds,forWeld-onToolJoints(seenote)ToolJointinchmminchmm27