Experimental Study On Laser Cladding Process And Properties Of Mining Pick

The mining pick is a cutting tool on a roadheader.During the mining process,the pick collides with coal seam and hard materials mixed in the coal seam,and fails due to periodic shear stress,compressive stress and impact load,thus greatly reducing the service life of the mining pick and increasing the cost of coal mining.In recent years,improving pick surface performance and prolonging pick service life have become the main research contents of many experts and scholars.At present,laser cladding technology is one of the main technologies for metal surface repair and strengthening.In this paper,42 CrMo,the component material of pick,is used as the base material,and a wide spot direct output semiconductor laser is used to carry out experimental research in the way of coaxial powder feeding.firstly,the mechanism of improving the performance of the cladding layer,the causes of crack generation and the elimination methods are summarized and analyzed,and it is determined that WC particles and Mo simple substance are added to the Fe-based cladding layer to improve the performance of the Fe-based cladding layer and avoid the generation of crack defects.Then,a variety of test parameters are designed to carry out experiments.The test parameters are determined by comparing the morphology and performance of each cladding layer.A variety of cladding layers are prepared by using the test parameters.By comparing and analyzing the surface morphology,hardness,friction coefficient and wear amount of each cladding layer,the cladding layer with better performance is selected.Through flaw detection tests on each cladding layer,the cladding layer with few cracks or no cracks is selected.Combining the two screening results,a variety of laser cladding layers with high performance,few cracks and no cracks are obtained.Finally,by comparing the properties of various high-performancecladding layers with almost no cracks and few defects again,the cladding layer with the best comprehensive properties is obtained,the average hardness is about 765 HV,the stabilized hardness reaches 825 HV,the friction coefficient is about 0.4,and the wear amount is 3.8 mg.Compared with 42 CrMo matrix,its hardness is 3.2-3.4 times of the matrix hardness,the friction coefficient is reduced by about 27%,and the wear amount is reduced by about 62%.The test results show that the Fe+15%WC+10%Mo cladding layer prepared by adding 15% WC and 10% Mo to Fe alloy powder can obviously improve the pick surface performance,delay pick failure,and provide experimental and theoretical basis for laser cladding technology in surface modification.