Experimental Study On Abrasion Resistance And Weldability Of Wear Resistant Steel Used In Construction Engineering

High strength low alloy wear-resistant steel not only high strength and good toughness and good wear resistance,is widely used in engineering machinery and equipment;NM360 is the domestic engineering machinery has been standardized by one of the high strength wear-resistant steel series,Hardox400 wear-resistant steel plate is a typical product of the world’s largest maker of Swedish steel Ake Lund ltd..Therefore,the study of two kinds of wear resistant steel at home and abroad,the difference between the performance of the construction machinery enterprises to provide an important reference for material selection and manufacturing.Firstly,the microstructure and mechanical properties of NM360 and Hardox400 two kinds of high strength steel are studied;then under different loads,two kinds of wear-resistant steel for abrasion resistance test,comparing the wear resistance of two kinds of wear-resistant steel,observation of wear surface morphology by scanning electron microscopy,the wear mechanism was analyzed;the HAZ maximum hardness test and Y analysis of the oblique groove of the minimum preheat temperature of two kinds of wear-resistant steel cold cracking tendency and crack of welding crack test;finally,the reasonable welding specification of two kinds of wear resistant steel is welded,and the change of the microstructure and properties of welded joints,the study.The results show that the microstructure of NM360 is tempered martensite microstructure,the microstructure of Hardox400 is martensite and bainite,and the grain size is small.NM360: σb=1084 MPa,δ=14.93%,Ψ=68.54%;Hardox400:σb=1202 MPa,δ=17.35%,Ψ=68.52%,showed good mechanical properties.The strength and hardness of Hardox400 was slightly higher than NM360;under the same conditions,the wear rate of NM360 is about Hardox400 1.4 ~ 1.5 times,a large number of worn surface furrows,showed that two kinds of wear-resistant steel wear mechanism is micro cutting,high hardness Hardox400 furrow depth and broadband are less than the low hardness and wear resistance of NM360.Hardox400 are better than that of NM360.The experiments show that the NM360 and Hardox400 have the same welding properties(except for the different preheating temperature):(1)HAZ maximum hardness and oblique Y groove weld crack test showed that NM360 and Hardox400 have greater tendency to cold cracking,using appropriate preheating temperature can effectively avoid cold crack;(2)NM360 and Hardox400 welded joint tensile test fracture is located in the weld,and the impact of the weld seam is less than other regions of the weld joint.The distribution law of hardness value of joint: HAZ>Base Metal>Weld,and there is a slight softening phenomenon in the welded joint.