Managing method for stud female threads used long period under high temperature on the power plants

장기간 사용된 발전설비용 고온 스터드 암나사부 관리방법

The stud female threads for stud bolts tend to degrade faster by high temperature over 450 C. Therefore, inspection for replacement cycle of stud bolts is used to carry out many kinds of method such as ultrasonic test(UT), magnetic test(MT), wobble test, visual test and hardness test. The visual inspection among those has been only applied for stud female threads generally and wobble test is often used to apply stud bolts. In this paper, wobble test is applied for evaluation of stud female threads on the contrary stud bolts especially. It is also applied three types of inspection method included wobble test on the two sites which is used for each other different operation cycle and three kinds of acquisition data are compared with evaluation methods. From the results, we have studied the characteristic exchanging of integrity evaluation data distribution according to using time and proposed managing method for female thread of stud on the power plants.