Research On The Remanufacture Repair Technology For Engine Cylinders

The study of this paper was based on WD615 cylinder block’s thrust bearing seat.The technology of arc cold welding by electrode was designed to repair cylinder block’s thrust bearing seat.Firstly,thewelding process is designed to determine the welding process parameters,and the repaired sample was evaluated by quality evaluation system.Secondly,thewelding technology process parameters were optimized based on experiments.Finally,the engine’s durability experiments were applied to test the samples’ reliability.1.The repairing planfor cylinder’s thrust bearing seat was developed.The structure and the materialof the block’s bearing,sethe wear-out valueand temperature distortionwereall analyzedto determine the arc cold welding asthe repair plan.2.The repairing process for cylinder’s thrust bearing seat was designed.The various process parameters were defined and the welding sample was prepared.The quality evaluation system was established based on non-destructive test,mechanical performance test and metallographic examination.The results showed that the white mouth tissue exists in the weld,which is not only bring difficulties formachining process,but also incurcracks and other defects.Therefore,the parameters of the welding repair process should be optimized to eliminate the white tissue in the weld.3.The welding repair process was further optimized.Seven factors whichinfluencedthe quality of the welding were found out,and the preheating temperature,the post-weld tempering temperature and the tempering holding time were taken as the test factors.The orthogonal experiment method of three factors and two levels was designed todetermine the optimal process parameters.Andthe results showed the optimal process parametersare: that preheating temperature is 200℃,the temperature is 800℃,and the time of heat preservation is 120 min.4.The optimized technology of welding repair was verifiedby experiment.The reliability of the repaired part of the cylinder was tested by engine’s cycle endurance test.As the results of experiment showed,the optimized welding process can meet with the demand of engine with relatively stable working conditions.