Rebuilding of the tool joint diameter by welding
In the course of drilling operations, drill pipe tool joints are subject to the greatest wear. The greater the vertical deviation during drilling, the greater is the wear of tool joint pats in a drilling string.
Often customers face such a situation, when the pipe is still premium class, while the tool joint is worn so much that it implies rejection of the pipe to the 2nd or 3d class. This problem can be solved through welding along the whole length of the tool joint a wire similar in composition and properties to the tool joint material.
The process is semi-automated, the operator controls all the operations. After that, non-destructive testing is carried out in order to check the tool joint for lack of welding penetration, cavities appearing in the process of rebuilding.
Then the pipe is delivered to the turning shop where the tool joint is drilled through to the diameter determined by standards. Then non-destructive testing is run again, and after that the thread connection is repaired.
That way the pipe is given a second life. It is natural, that the expenses on this procedure are much lower than the price of a new drill pipe, particularly in case of special alloys, such as VM95SS, L80SS and others, with increased concentration of chromium and alloying elements.