Study On Local Squeeze Process-assisted HPDC For Reducing Porosity Of The Engine Bracket

With the development of the automobile lightweight manufacturing,auto parts products in the design process was loss weight and become complex,it has brought about great challenge to the traditional way of die casting.For XXX car engine right bracket,although its small size,but the structure is relatively complex,traditional die-casting casting pressure can't effectively affect its porosity,so the local porosity exposed in the solidification and take a direct impact on the performance of the bracket.For manufacturers,if they can be reasonably and effectively reduce the gas pore defect in die casting,it will produce a great impact on the strength of bracket and improve the production efficiency.It is very important to improve the vehicle performance.The purpose of this article is to seek a reasonable way to reduce the gas pore defect of engine.The research method in this article is that the theory analysis and CAE simulation combine with experimental analysis.The results of the study is that through research on the theory of CAE,process effect on gas pore mechanism,effect of pressure theory,etc.It is to seek methods which can improve porosity defect of the engine bracket and establish a CAE analysis,mold design,process optimization and local extrusion auxiliary system,reduce blow hole defects of the lightweight aluminum alloy parts based on production methods.This article main research work is:(1)In this article,the forming theory of pore and shrinkage in High Pressure Die Casting(HPDC)was analyzed.The die-casting molding process were analyzed in detail,and understanding the selection of process parameters on the influence of porosity defects.The process scope was determined.At the same time,the mathematical equations of CAE simulation on the die-casting molding were introduced.It provided a certain theoretical basis for the prediction of subsequent pore defects and solutions.(2)Using MAGMA software for automobile engine of High Pressure Die Casting(HPDC)mounts to numerical simulation,the author estimated the defects in verify the stent type and position which is consistent with the actual production test.Results show that the higher porosity in casting was the cause of the higher die joint,uneven thickness,the gate early solidification and those gas pore was difficult to discharge,And the distal cannot get the better effect of pressure,so we can found the formation of gas pore defect.(3)Through the die casting process parameters(Casting pressure,High speed casting speed,high speed range,etc.)were optimized,the optimum combination was established.The optimization results showed that low porosity defect of the products can be obtained relatively when the high speed is 3.5m/s,high speed range is 200 mm,casting pressure is 100 MPa.But local gas pore defect still large,and the high porosity wasn't still accepted.Process optimization on the influence of the local porosity defect was not particularly evident,while the porosity defect reduced slightly,but the porosity is still in the scope of unqualified.It does not reduce the blowhole defects to the greatest extent.(4)The way of local squeeze casting technology is put forward to reduce gas pore defect by analyzing local squeeze casting device,According to the characteristics of the engine support concrete structure,it was analyzed in detail of the design in squeeze pin,squeeze pin set and squeeze cylinder.Local squeeze process parameters were optimized in the meantime,and the problem of gas pore defect was solved around the far end bearing gas pore.Finally,which were verified with X-ray real-time imaging technology.The results showed that we could get castings that the surface is smooth and internal gas pore defect is better when the casting pressure is 100 MPa,extrusion pressure is 360 MPa,the starting time of squeeze is 1s,the duration of squeeze is 5s.The biggest gas pore diameter was 0.5mm.Engine support production way was founded which the combination of local squeeze casting technology,high pressure die casting and CAE.The porosity of Engine support was reduced to 0.6% and the production efficiency was obviously improved.