高温高压水环境下690TT合金传热管微动磨损研究

Study on Fretting Wear of 690TT Alloy Heat Transfer Tube in High Temperature and High Pressure Water Environment

蒸汽发生器(SG)的完整性对于核电站的安全运行十分重要。在运行过程中,SG二次侧流动会使得传热管产生微动磨损,导致管壁减薄甚至破裂,从而影响到核电站的高效安全运行。针对该问题,本文通过试验研究,模拟在高温高压水环境中SG传热管材料690TT合金的微动磨损行为。系统地研究了循环周次和位移幅值对690TT合金传热管微动磨损损伤机制以及磨损性能的影响。结果表明,循环周次对磨损行为和损伤机制影响不大,但影响材料磨损性能评估,需通过差分法计算得到准确的材料磨损系数。位移幅值对传热管的磨损行为和损伤机制影响较大。振幅由20μm增加到150μm时,磨损系数会增大,磨损机制从以黏着磨损为主,逐渐变成磨粒磨损、剥层磨损和氧化磨损。

Steam generator(SG)is the key component of primary and secondary circuits in pressurized water reactor(PWR)nuclear power plant.Its integrity is very important for the safe operation of PWR nuclear power plant.During operation,the secondary side flow of SG will cause the vibration of the heat transfer tube,which will lead to the collision between the heat transfer tube and the supporting parts,resulting in the fretting wear of heat transfer tube.With the increase of the service life of SG,fretting wear between the heat transfer tube and the supporting parts causes the failure phenomenon of heat transfer tube to increase gradually,leading to the tube wall thinning or even rupture,thus affecting the efficient and safe operation of nuclear power plant.For the fretting wear phenomenon of SG heat transfer tube,the fretting wear behavior of 690TT alloy SG heat transfer tube under high temperature and high pressure water environment through experimental research was simulated in the paper.The fretting wear test system independently developed in China,was used for fretting wear test of tubular and plate friction pairs under high temperature and high pressure water environment.After the test was completed,the wear volume,the three-dimensional morphology of the wear marks and the section profile of the wear parts were analyzed by using the white light interferometer,and the wear coefficient of the 690TT alloy heat transfer tube under high temperature and high pressure water environment was calculated.The effects of the fretting cycle and displacement amplitude on fretting wear damage mechanism and wear performance of 690TT alloy heat transfer tube were systematically studied.The results show that the fretting cycle has little influence on fretting wear behavior and damage mechanism,but it has influence on the evaluation of material wear performance.It is necessary to calculate the exact material wear coefficient by difference method.The displacement amplitude has great influence on the fretting wear behavior and damage mechanism of the heat transfer tube.When the amplitude increases from 20μm to 150μm,the wear coefficient increases from 1.014×10-13 Pa-1 to 3.653×10-13 Pa-1.Under high temperature and high pressure water environment,fretting wear condition is very complicated.A variety of wear mechanisms,including adhesive wear,fatigue wear,stripping wear and oxidation wear,cause fretting wear damage.When the amplitude is small,the main wear mechanism is adhesive wear,and the characteristic region is adhesive wear.When the amplitude increases,the wear mechanism changes to oxidation wear,stripping wear and abrasive wear.