等离子喷涂法改善焊接结构的疲劳性能

采用低碳钢涂层对1Cr18Ni9Ti不锈钢横向与纵向角焊缝接头进行喷涂处理,测试了涂层的显微硬度和结合强度,并分别在焊接状态和喷涂处理状态下进行疲劳对比试验.试验结果表明,等离子喷涂层的显微硬度、结合强度约为火焰喷涂层的2倍.等离子喷涂后1Cr18Ni9Ti接头疲劳性能明显改善.横向接头焊接状态试件的疲劳强度为169.8 MPa,火焰喷涂试件为186.2 MPa,等离子喷涂试件为213.8 MPa,与焊接状态试件相比,等离子喷涂试件的疲劳强度提高25.9%,火焰喷涂试件提高9.7%.纵向接头焊接状态试件的疲劳强度为91.1 MPa,等离子喷涂试件为100.4 MPa,等离子喷涂后疲劳强度提高10.2%.

Fatigue properties improvement of welded structures by plasma spraying process

The plasma spraying process was used to improve fatigue properties of stainless steel 1Cr18Ni9Ti welded joints.Low carbon steel powder was used.The microhardness and coating-substrate adhesive strengths were measured.The fatigue tests of the cruciform joints welded by TIG welding and longitudinal joints welded by arc-welding under tensile load(R=0) were carried out at the welding and spraying conditions.Tests results show that the microhardness and coating-substrate adhesive strengths of plasma sprayed coatings are approximately 1 times larger than that of flame sprayed coatings.Plasma spraying process is effective to improve fatigue life of welded joints.For the cruciform joints,the fatigue strength of the welded specimens is 169.8 MPa,and that of the flame sprayed and plasma sprayed specimens are 186.2 MPa and 213.8 MPa,respectively.The fatigue strength of the plasma sprayed specimens has been increased by 25.9%,and that of the flame sprayed has been increased by 9.7%.For the longitudinal joints,the fatigue strength of the as welded specimens is 91.1 MPa,and that of the plasma sprayed specimens are 100.4 MPa,which is increased by 10.2%.