Application of tightening curve in quality of threaded joint

Threaded joint is one of the most widely used connection mode in automobile manufacturing. The reliability of the threaded joint determines the function of the vehicle and even the safely of human life. How to ensure of the reliability of threaded joint become an important issue in automobile manufacturing. The threaded joint have many failure defects (stick-slip, clamping stagnation) that can't be detected by manual inspection and common tightening tools. But the characteristics of the tightening curve can be used to identify the defects, so the tightening curve of several major defects are described in the paper, other manufacturing enterprise can refer to detect hidden defects and quickly find the cause. It also provides a theoretical basis for implementation of tightening curve monitoring and automatic identification and alarm.