Process Study On Low Pressure Castings In 1-mold-2-products Of Aluminum Alloy Engine Cylinder Head

With the continuous requirement of environmental protection and automobile emissions for society,light-weighting,thinning,precision and integration are reflected in more and more products,especially the core components of engine such as cylinder head and cylinder block.And with the design and appearance of the third generation integrated exhaust engine cylinder head,gravity casting process is becoming more and more difficult to satisfy the matching between product design and casting process of the cylinder head,so the development of new casting technologies has become inevitable.Because of the high dimensional accuracy,high utilization rate of metal castings,smooth filling,compact and good mechanical properties,Low pressure casting has become an important technique in the domestic automobile industry casting.Good combination is obtained between the superior filling,perfect feeding characters and the manufacturing process which the current mainstream design needs..The research object in this paper is a aluminum alloy cylinder head used in the two-cylinder engine.Firstly based on the theory analysis on casting technology of the 1-mold-2-products for cylinder head,this work studies the feasibility of the above-mentioned process;then through the calculation and analysis,preliminary determine the 1-mold-2-products of aluminum alloy engine cylinder head of low pressure casting process parameters.Secondly,using low pressure casting numerical simulation theory,based on the 3D design software Pro/Engineer and low pressure casting simulation software AnyCasting,the cylinder head entity into AnyCasting software,numerical simulation of low pressure castings in 1-mold-2-products of aluminum alloy engine cylinder head:filling process are analyzed to determine the best filling time and pressure;the solidification process are analyzed to determine the temperature field distribution,and the problems that may appear on the filling and solidification process are analyzed;the distribution of the SDAS(secondary dendrite arm spacing)are predicted after the solidification.The SDAS formation in different position is analyzed,proved that the low pressure castings in 1-mold-2-products of aluminum alloy engine cylinder head solidification and temperature field distribution are reasonable.At the same time,based on the low pressure die and low pressure casting equipment,production validation and product quality testing are proceed of the 1-mold-2-products of aluminum alloy engine cylinder head of low pressure casting,including alloy smelting,making sand core products,cylinder head casting and post-processing,finally produce the as-cast cylinder heads;quality inspection including tensile strength test,dimension conformance test,hardness test,SDAS measurement,density test,XRD test,spectrum test.The results proved that the quality of cylinder head and the indicators meet the technical requirementsIn addition,comparison and analysis are made between the low pressure cylinder head casting and gravity castings on the properties such as SDAS,tensile strength,hardness and porosity.The results show the low pressure casting is more suitable for such product than gravity casting.