Experimental Study Of Laser Impact Peening To Improve The Oxidation Resistance Of The Inner Wall Of TP347H Steel Collectors

TP347H steel heating surface tube has a variety of failure conditions in boiler service operation,including intergranular corrosion,stress corrosion cracking,tissue aging,oxidation corrosion,original defects and martensitic transformation.Especially in the operation environment of high temperature and high pressure supercritical water,TP347H as the high temperature heating surface of boiler pipe is easy to occur rapid oxidation and spalling,resulting in unplanned shutdown of the power plant.In order to improve the application of TP347H material in power plant boiler,laser shock strengthening technology is used to treat the surface of the material.The effect of laser shock strengthening on the oxidation resistance of TP347H was studied.The content of this study is mainly divided into two parts:one is to detect and analyze the performance of laser shock strengthened sample,and study the influence mechanism of laser shock strengthened technology on the performance of TP347H material;On the other hand,the oxidation test of the sample in supercritical water environment was carried out to analyze the oxidation mechanism and discuss the influence of laser shock strengthening technology on the oxidation resistance of the material.To test and analyze the properties of the sample,the microhardness,grain size and residual stress of the material were studied.For the oxidation test under supercritical water environment,the oxidation weight gain,surface morphology,phase composition,cross section morphology and element distribution were studied,and compared with the samples TP347H,HR3C and Super304H without laser shock reinforcement.The properties of TP347H material strengthened by laser shock and its oxidation mechanism under supercritical water environment were studied theoretically,and some references were provided for steel selection for power station.This paper will study how to improve the oxidation resistance of the inner wall of TP347H steel collector by laser shock strengthening.The results of this study provide technical support for improving the performance of materials in extreme environments.