Research On Key Machining Process For A Certain Type Of Superalloy Casing

At present,the material of caitridge receiver is mainly difficult-to-machine materials such as superalloy,so how to effectively improve the processing quality and processing efficiency has become an urgent problem.Firstly,it is aimed at the problem of serious tool wear during turning of superalloy parts and in order to select the right tool material.GH4169 was machined using PCD(polycrystalline diamond),CBN(cubic boron nitride)and coated cemented carbide tools,then the cutting performance of the three tools was studied in the aspects include the tool wear,chip morphology,machining quality.The results show that the coated cemented carbide tool wears the least.The outer diameter of the helical chip processed by the three tools is:PCD<coated carbide<CBN.The surface roughness of coated cemented carbide processing is the smallest.Therefore,the coated carbide has better cutting performance.Secondly,according to the preferred tool material,the wear law,cutting force and surface roughness of cemented carbide tools under different turning distances are studied.The results show that with the increase of cutting distance,the wear area of the rake face is gradually enlarged.The F_x,F_y and F_z increase first and then decrease as the cutting distance increases.The surface roughness of the workpiece decreases with the increase of cutting distance.Then,in order to optimize the hole-making process of superalloy,different hole-making processes like conventional drilling and helical milling were conducted on the superalloy(MSRR7197).Combining the deformation mechanism of the hole wall material,the influence of both hole-making processes on the processing quality of the MSRR7197 were investigated.The experimental results demonstrate that the axial force for the helical milling is about 1/10of that for the drilling.Compared with drilling,the tool wear of helical milling are smaller.The hole wall quality of helical milling is better than that of the drilling.In addition,the helical milling can get smaller roundness deviations and aperture deviations.Finally,aiming at the problem that the existing fixture has large accumulation error and low efficiency,a hydraulic positioning fixture for thin-walled rotary parts is proposed,which can realize one-time clamping and multi-process processing.The fixture mainly comprises a base,a positioning sleeve,positioning plates,a cylindrical positioning ring,a sheet positioning ring and a locking mechanism.