激光重熔低温相变合金喷焊层的组织与性能
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摘要
采用等离子喷焊法,在Q235上熔敷自制的低温相变合金粉末,并进行激光重熔处理,研究了激光重熔处理对等离子喷焊层组织和性能的影响。结果表明:等离子喷焊层的组织均为马氏体和少量残余奥氏体,相变温度在200℃～室温,相变获得了约0.5%的膨胀应变,产生残余压缩应力,最大为-189 MPa;激光重熔处理可有效修复等离子喷焊层表面未熔颗粒、孔洞等缺陷,细化组织,促进马氏体相变,增大残余压缩应力,最大可达到-383.3 MPa。和基体材料相比较,等离子喷焊层的硬度增加约2.6倍,耐磨性能提高49.92倍;激光重熔后的硬度增加约3倍,耐磨性能提高约63.19倍。降低马氏体相变温度,可使熔敷金属获得残余压缩应力,提高了熔敷金属的硬度和耐磨性。
The low temperature phase transformation alloy powders were deposited on Q235 by plasma spray welding,and the laser remelting treatment was carried out. The effects of laser remelting treatment on the microstructure and properties of the plasma sprayed cladding were investigated. The results show that the microstructure of plasma spray welding layer is martensite and a small amount of retained austenite. The phase transition temperature is between 200 ℃ and room temperature. About 0.5% of the expansion strain is obtained, and the residual compressive stress appears and its maximum value is-189 MPa. Laser remelting treatment can effectively repair the defects of the plasma spraying layer, such as non remelting particles, holes and other defects. Laser remelting can also refine the microstructure, promote martensitic transformation and increase the residual compressive stress, the maximum can reach -383.3 MPa. Compared with the base material, the hardness of the plasma spray welding layer is increased by about 2.6 times, and the wear resistance is increased by 49.92 times. After laser remelting, the hardness increases about 3 times and the wear resistance increases by about 63.19 times. By reducing the martensitic transformation temperature, the residual compressive stress in the cladding metal can be obtained and then the hardness and wear resistance of the cladding metal improve.
The low temperature phase transformation alloy powders were deposited on Q235 by plasma spray welding,and the laser remelting treatment was carried out. The effects of laser remelting treatment on the microstructure and properties of the plasma sprayed cladding were investigated. The results show that the microstructure of plasma spray welding layer is martensite and a small amount of retained austenite. The phase transition temperature is between 200 ℃ and room temperature. About 0.5% of the expansion strain is obtained, and the residual compressive stress appears and its maximum value is-189 MPa. Laser remelting treatment can effectively repair the defects of the plasma spraying layer, such as non remelting particles, holes and other defects. Laser remelting can also refine the microstructure, promote martensitic transformation and increase the residual compressive stress, the maximum can reach -383.3 MPa. Compared with the base material, the hardness of the plasma spray welding layer is increased by about 2.6 times, and the wear resistance is increased by 49.92 times. After laser remelting, the hardness increases about 3 times and the wear resistance increases by about 63.19 times. By reducing the martensitic transformation temperature, the residual compressive stress in the cladding metal can be obtained and then the hardness and wear resistance of the cladding metal improve.
引文
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[3]陈希章,胡科,袁其兵.激光熔敷原位合成WC增强铁基复合涂层的组织和性能[J].中国表面工程,2016,29(4):118-124.
[4]李爱农,魏成靓,刘娇姣,等.激光熔覆铁基Cr3C2/Mo S2覆层的组织和摩擦磨损性能[J].中国表面工程,2015,28(5):77-85.
[5]Shiozak T,Tamai Y,Urabe T.Effect of residual stresses on fatigue strength of high strength steel sheets with punched holes[J]International Journal of Fatigue.2015,80:324-331.
[6]Chen X Z,Wang J J,Fang Y Y.Investigation of microstructures and residual stresses in laser peened Incoloy800H weldments[J].Optics&Laser Technology,2014,57:159-164.
[7]Chen X Z,Fang Y Y,Li P,et al.Microstructure,residual stress and mechanical properties of a high strength steel weld using low transformation temperature welding wires[J].Materials&Design,2015,65:1214-1221.
[8]Ooi S W,Garnham J E,Ramjuna T I.Low transformation temperature weld filler for tensile residual stress reduction[J].Materials&Design,2014,56:773-81.
[9]王文先,霍立兴,张玉凤,等.相变温度对焊接残余应力的影响规律及机理分析[J].中国机械工程,2003(3):72-75.