Study On Tangential And Impact Wear Properties Of 2.25Cr-1Mo Alloy Steel Heat Transfer Tube

The nuclear power plant is a facility that converts nuclear fission energy into electrical energy with appropriate equipment.Reactor is the key design of nuclear power plant,which is used to realize the conversion of nuclear energy to thermal energy.The steam generator of nuclear power plant is the equipment used for heat exchange inside the reactor.The vibration of the heat transfer tube of the nuclear power steam generator will lead to the wear between the heat transfer pipe and the support plate,which will lead to the failure of the heat transfer tube.The failure of heat transfer tube will seriously affect the safe operation of nuclear power plant.Therefore,it is of great significance to study the wear behavior of steam generator heat transfer tube for prolonging the service life of steam generator and the safe operation of reactor.In this paper,the tangential fretting wear and impact wear behavior and damage mechanism of 2.25Cr-1Mo alloy steel,the material of nuclear steam generator heat transfer tube,were studied.The fretting operation characteristics,friction coefficient and the interface response behavior of impact wear of heat transfer tube materials under different influencing factors were analyzed.The main conclusions are as follows:(1)The tangential fretting wear study shows that the fretting operation state of the heat transfer tube is changed with the increase of load.With the increase of the load,the friction force increases,and the wear volume and wear depth both increase.When the load increases to 20 N,the wear volume and wear depth decrease with the increase of the load.The wear mechanism changes from abrasive wear,layered spalling to adhesive wear and oxidation wear.The increase of load leads to the adhesion of the interface,which inhibits fretting wear.(2)The impact wear test results show that the impact kinetic energy has a great influence on the response behavior of the wear interface.The peak impact force and energy absorption rate increase with the increase of impact kinetic energy.When the impact kinetic energy is large,the surface material of the wear mark is easier to be removed,but at the same time,the surface of the wear mark also becomes smooth.The worn surface hardened during the impact wear process under the larger impact kinetic energy.The oxygen content on the surface of wear marks increases with the increase of impact energy.(3)The influence of high temperature on the operating characteristics of tangential fretting wear is significant,but the influence on the interface response behavior of impact wear is small.In the fretting wear process,the oxide layer is formed at high temperature(225℃ or above),and the wear volume and wear depth decrease to a certain extent compared with 25℃.The wear mechanism under fretting wear is mainly oxidized wear and adhesion,while the impact wear is mainly layered spalling,oxidized wear and accompanied by cracks.In the process of impact wear,the variation of wear volume and wear depth is similar to fretting wear.Oxides or wear particles produced in the process of fretting wear and impact wear at high temperature can reduce the wear on the material surface to some extent.