| With the advent of the automobile era,automobiles have become an important part of people's production and life,which has brought great convenience to people.At the same time,it has also created conflicts between energy and the environment.As the use of automobiles increased,energy consumption become larger,and severe environmental problems are gradually intensified.Therefore,the development of lightweight automobiles is extremely important to human society.In today's automotive manufacturing materials,aluminum has the lowest quality,so replacing steel with aluminum has become the current direction of lightweight vehicle development,and is also the key to the improvement of heavy vehicles.In addition,from a practical point of view,China is still in the primary stage in the implementation of lightweight heavy-duty vehicles,and has not formed advanced technology.This subject mainly carried out the design of aluminum alloy rods on the lightweight body of automobiles,and studied the application of 4500-ton die casting machine in the forming of aluminum alloy rods,designed the die casting mold of aluminum alloy rods,and then designed the mold to carry out manufacturing to achieve product production,and finally inspected the defects and performance of die-cast aluminum alloy rods.The research contents were as follows:(1)Through the design of aluminum alloy rods for automobile lightweight bodies,and comparative analysis of the lightweight effect of two commonly used aluminum alloy materials,combined with Ansys finite element software for aluminum alloy rods under different working conditions Simulation.The study found that excepted for the front and rear axle positions,the original steel rods were used at the bottom of the car body,and other parts can be replaced with aluminum alloy rods.The aluminum alloy rods mainly bear the load under bending conditions and bendingtorsion conditions.The linking method of different rods was symmetrically connected by four rivets.If the aluminum alloy extrusion was 6000 Al.Mg.Si series aluminum alloy,the quality of the vertical extrusion rod was reduced by 45.8%;The quality of the lateral extrusion of the connecting rod has been reduced by 58.8%.If YL104 series aluminum alloy was selected for aluminum alloy die casting,the quality of vertical die casting components was reduced by 54.6%;IVthe quality of oblique die casting components was reduced by 65%.Combined with Ansys finite element simulation software to check the strength of aluminum alloy rods under bending conditions and bending-torsion conditions,it was found that under bending conditions,the maximum stress of extruded members was 224.357 MPa,and the highest bearing stress of die-cast members was 142.35MPa;under bending-twisting conditions,the maximum stress of the extruded member was 237.326 MPa,and the maximum stress of the die-cast member was136.918 MPa,which were all smaller than the extruded 6000 Al.Mg.Si series' s the strength limit of aluminum alloy was 405 MPa,and the strength limit of die-casting YL104 series aluminum alloy was 202 MPa.(2)The application of 4500-ton die-casting machine in lightweight automobile aluminum alloy rods was studied,the die-casting mold for aluminum alloy rods was designed,and the corresponding die-casting process was explored.The research obtained that the aluminum alloy rods were produced by vacuum die casting to ensure the quality of the rods,and a 4500-ton vacuum die casting machine was modified to ensure the production efficiency and quality.Designed the die-casting mold of aluminum alloy rods and combined with CAE simulation technology,determined the casting technology plan for the design of the die-casting mold,the arrangement of the vacuum exhaust channel and the setting of the specific parameters of the die-casting process,and explored the use of combined cores to reduce the difficulty of manufacturing the mold,and the flat thimble mechanism was set into the deep and narrow position of the molded parts to ensure the smooth production of the product.(3)By manufacturing the designed die-casting mold,the precision requirements of the mold were analyzed,and the product forming process was explored.The research showed that the accuracy of the shape and position tolerance of the mold was determined during the manufacturing process of the mold,and the matching size and surface roughness were Ra3.2.Formulated part forming process flow and mold assembly process flow,and set the corresponding real-time mold accuracy and tightness detection.In the production of aluminum alloy rods,the type of die casting machine and the process parameters of the specific die casting process were determined.The product with the vacuum set at 337? 413 mbar wasoptimal;after the die-casting rod was formed,it was annealed at 175 ? for 2.5h Treatment,followed by air cooling.(4)The size,surface and internal defects and mechanical properties of aluminum alloy die-casting molding members were tested.It was found that the size and related requirements of the die-cast rods after the treatment had reached the requirements for the use of automobile rods;through the inspection of the surface and internal quality of the die-cast rods,it was found that after the modification of the mold,the vacuum of the mold was improved.The surface quality was obviously improved;through the internal inspection of X-ray,which was found that the vacuum die-casting process can avoid the occurrence of internal pores in the rod and improve the quality of the die-cast rod.Through testing the mechanical properties of die-casting rods,it was found that the surface hardness of aluminum alloy rods using vacuum die-casting process was 137.4HV,the hardness of aluminum alloy rods without vacuum die-casting process was 128.85 HV,and the hardness was increased by 6.6%;the tensile strength and the maximum bearing capacity of the rod heat-treated by vacuum die-casting were 194.80 MPa,and 19084 N respectively,the elongation was 2.0%,its performance was better than other treatment methods. |
PDF Full Text Request