Study On The Coating Performance Of H13Steel Surface By EDM

H13steel is one of the most widely applied hot die steel, it is usually used to produce die-casting die which is made by Aluminum alloy or magnesium alloy. Its mainly failure mode is thermal erosion, thermal fatigue and thermal aluminum because of splat cooling and heating in the service process. Therefore the use of surface strengthening technology to increase the performance and service life of hot die is a valid solution. ESD is a technology uses spark discharge effect to infiltrine the electrode material into the workpiece surface so as to form a alloying coating, it becomes hot off the press in the field of surface engineering because of advantages of simple devices, flexible, environmental protection, energy saving and high coating anchoring strength.In order to increase the hardness wear resistance and corrosion resistance of the H13steel’s surface, using the DZ-4000(Ⅲ) spark deposition/bead weld machine, using argon as shielding gas, using scanning electron microscope, X-ray diffractometer, microhardness tester et al to analyzing the impact what the micro hardness, phase, performance, and technological parameter of the layer on the thickness and surfaceness.The WC-8Co electrode was used to be deposited on the surface of H13steel. The best process parameters:deposition time is16Min, deposited voltage is80V, deposition frequency is2000Hz and deposition capacitance is180uμF. Analysis showed that the WC-8Co deposition layer is tigh, no obvious pores、cracks and other defects. Its internal has hard phase such as Fe3W3C、(CrFe)7C3etc. Test results showed that the hardness is1352.4Hv (2.1times of the substrate), the thickness is71.5μm and the roughness of surface (SRa) is135.9612μm.The Deloro50electrode was used to be deposited on the surface of H13steel. The best process parameters:deposition time is5Min, deposited voltage is80V, deposition frequency is3500Hz and deposition capacitance is240μF. Analysis showed that the deloro50deposition layer is tigh, no obvious pores、cracks and other defects. Its internal has hard phase such as FeNi3etc. Test results showed that the hardness is988.3Hv (1.5times of the substrate), the thickness is206.5μm and the roughness of surface (SRa) is26.1649μm. The Deloro50and WC-8Co electrode was used to be deposited on the surface of H13steel. Results showed that WC-8Co electrode failed to form stable deposition layer on Deloro50coating in experiment1. Deloro50and WC-8Co material interaction is poor, WC-8Co electrode materials were flake or granular dispersed to splash.The Deloro50is deposited on the WC-8Co layer which can form stable composite layers. Tts internal has hard phase containing such as FeNi3、Cr2Fe6.7Mo0.1Ni1.3Si0.3etc. Test results showed that the hardness is1109.5Hv (1.7times of the substrate), the thickness is139.7μm and the roughness of surface (SRa)is10.1μm.