Study On The Key Technology Of High-Melting Metal Arc Spraying Shell Preparation

Arc spraying for rapid tooling technology is an advanced manufacturingtechnology on the basis of rapid prototyping combined with arc spraying technology.High melting steel-based moulds become a hot point at present. This paper makes aoptimization study of high-melting rapid tooling process by theory combined with test,and trial-produces a high-melting automobile bonnet tool.Make a research about the effect of spray current, spray voltage, wire feedingvoltage on the arc, obtain the quantitative relation of them, the voltage of spraying3Cr13is determined; make a quantitative study on the relation of spray current andcoating temperature through adjusting wire feed rate to change spray current, researchthe effect of spray current on the spray coating temperature. Spraying current isdetermined initially. Study the effect of initial pressure and grain size on the axialvelocity and temperature field of jet by means of simulation and test, make aquantitative analysis on the change process of high-speed particle velocity andtemperature in the jet flow, and obtain the distribution picture of jet flow velocity andtemperature.Analyze the effect of spray velocity and temperature on the coating stress bysimulation. Simulate the whole transformation process of molten drop with differentvelocity under comprehensive consideration of hydrodynamic force and heat transferfeature in the molten drop, and get the flat degree of molten drop under different sprayvelocity directly. Study the thermal stress distribution of coating and substrate usinglayered model and Birth and Death element method; obtain the effect of temperaturedifference between the coating and substrate on the thermal stress in the coating.Propose some reasonable advice on reducing the coating stress, and provide referenceon the selection of spray process parameters connecting the results of molten dropvelocity and temperature distribution under different spray process parameters.Study the effect of spray distance and substrate preheating temperature on thebond strength between substrate and substrate. Conduct the experiment underdifferent process conditions (contain different spray distance and substrate preheatingtemperature), test the bond strength between coating and substrate, study the effect ofprocess condition on the bond strength, and observe the flat state of particle underdifferent process conditions using scanning electron microscope. Study the relation of bond strength and substrate surface roughness through a measuring method of surfaceroughness.Make use of3Cr13and Chlorine oxygen cement substrate under the optimization of sprayprocess parameter, trial-produce a automobile bonnet tool. The test shows that the thickness oftool shell is5mm, and the hardness is HRC48.