As such, magnetic particle inspection for the screw thread of the drill collar is very necessary and important.

因而钻铤内外螺纹的磁粉检测十分必要和重要。

youdao

As such, magnetic particle inspection for the screw thread of the drill collar is very necessary and important.

因而钻铤内外螺纹的磁粉检测十分必要和重要。

youdao