Study On Surface Integrity Of Nickel-base Single Crystal Alloy By EDM Grinding

Nickel-base Single Crystal Alloy has become a kind of important material to manufacture aeroengine hot-end components for its good high-temperature mechanical properties and high-temperature creep properties. However, the application of Nickel-base Single Crystal Alloy brought about a series of problems to processing manufacturing industry. How to process high hardened materials with high precision and efficiency at a low cost has been a problem to be solved immediately. In addition, it was proved by production and practice that many accidents caused by components failure often originated from defects on the surface of components. A large number of relevant literatures were consulted. Combined with the current commonly used processing methods EDM grinding was adopted to process workpiece on the basis of existing research results. The influences of process parameters on surface integrity were researched.It was pointed out that mechanical grinding and EDM machining complemented each other’s advantages. Spark discharge softens the surface materials with heat in micro scale, which reduces the grinding force and improves the efficiency of processing. Subsequently, the layer affected by EDM will be grinding, which will improve the quality of the workpiece surface.Nickel-base Single Crystal Alloy was used as the research object, and EDM grinding was adopted to study the influences of process parameters on surface integrity in this paper. The research contents as follow:(1) In the EDM grinding experiments, pulse duration ton, pulse interval toff, open-circuit voltage U, feed speed v, grinding depth ap was used as experimental factors. Besides, EDM grinding was used to process Nickel-base Single Crystal Alloy to obtain each process parameter’s impact on surface roughness and hardness.(2) Grey correlation analysis method was applied to analyse the influence degree of pulse duration ton, pulse interval toff, open-circuit voltage U, feed speed v, grinding depth ap on surface roughness and hardness. From the above results, the primary and secondary factors were identified.(3) Grey situation decision was applied to find out the satisficing situation on the basis of the established effect of situation sample and unified measure space. That is to say from the perspective of the surface roughness and surface hardness, one was determined from all the experimental schemes to obtain the highest surface integrity.(4) System grey prediction was applied to attain the multivariate linear model of surface roughness and surface hardness with process parameters respectively, which made intelligent prediction a reality.(5) Energy method was used to calculate contribution rate of grinding and EDM to material removal rate on the basis of test results In the process of EDM grinding.