Study Of Laser Cladding On The Surface Of The Mandrel

Mandrel is a important tool in the brass extrusion production. One of the roles is perforation, it is extruding of hot copper ingots in the extrusion. The general depth of perforation is about 250mm or more; the second roles of the mandrel is placed the hole, after perforation, it is still inside the hole, matching with the bottom mold, in order to ensure brass molding accuracy until the end of the extrusion cycle. Mandrel works under the high temperature,high pressure, intense friction and thermal shock effects,poor working conditions, so high requirements is put forward to the die steel performance.The materials of mandrel for copper processing use H13 steel (1Cr5MoSiV1) in a company. When the mandrel working for some time,the surface will occur in varying degrees of wear and tear, so that the size of the copper is difficult to meet the requirements, resulting in perforation of needles discarded.Bring great loss to the enterprise.In the article, By using laser cladding alloy powder(Ni-base dalloys,iron-base dalloy)in the mandrel substrate surface, select the appropriate laser parameters. Through optical microscope, Vickers MicroHardness Tester, friction testing machine to analyze microstructure, the microhardness, as well as wear resistance of coating layer. The result shows that:1,The mandrel substrate has cladding a coating layer, the microstructure of coating layer formed by the fine dendrite structure. And has formed a good metallurgical bond with the substrate.2,Within a certain range of parameters, with the scanning speed and laser power increases, the microhardness of cladding layer is significantly improved, and ladder-like distribution, the microhardness is much higher than the mandrel substrate.3,within a certain range of parameters, with the increase in scanning speed and laser power reduction, the wear resistance of cladding is enhanced.4,Considering the microstructure, microhardness and wear resistance of the laser cladding, when the spot diameter and the preset thickness are unchanged, the most superior technological parameter of the cladding layer :the power of laser cladding is 2 kw, scanning speed for 200-300 mm/min . In the article,laser cladding experiment was successfully implemented in mandrel(H13 steel),which provided experimental basis for the application of repairing in the hot mold, and play a very important role in reducing production costs and improve the economic effects.