External leakage from pipes screw connections due to swells of pipe screw to prevent accidents, after processing pipe threads per to clarify the test methods and acceptance criteria.
For external leakage accident prevention from the tube screw connection according to the swell of pipe thread processing, to clarify the inspection method and judgment criteria per tube screw after machining.
To prevent the accident from leakage of external screw connection with the screw machining, machining and inspection method to clarify the criteria of the screw.