| This paper focuses on the problems encountered in the Tianjin DongyiMagnesium Product CO. LTD. in the product and extrusion development, and takesAZ31B magnesium alloy profile as the object for study along with the comparisonwith6063aluminum alloy profile which is well known as the profile in application onhigh speed train. In this paper, the finite element analysis and experimental tests of themagnesium alloy’s replacement of the aluminum alloy are completed. Based on this,an improvement design of the structure of the luggage rack on trains is proposed. Andthe goal of the design is to uniform distribution of stresses, reduce the profile weight,reduce the difficulty of processing and improve the life of an extrusion die. At last, therelationship of AZ31B magnesium alloy hot extrusion molding process in the stressfield, temperature field, strain field and pressure curve with mold structure isdiscussed under a FE method to provide theoretical guidance for magnesium hotextrusion. The main research achievements are shown as follows:According to the real working condition on trains, the criteria for the strengthcalculation of the luggage rack is proposed by series of tests on tensile, bending,compression and impact toughness performance of the AZ31B magnesium, which hadprovided data support for the following FE analysis.The luggage strength analysis: Firstly, the strength FE analysis of the6063aluminum luggage rack is completed and the correctness of the finite element analysismethod is verified by tests on the real luggage rack. Secondly, on this basis, thestrength FE analysis of the AZ31B magnesium luggage rack is completed and theconclusion that AZ31B magnesium luggage rack is save is proposed.The structure design of AZ31B magnesium profile: In order to homogenizestress distribution, reduce the profile weight and reduce the difficulty of processingand to improve extrusion mold life, a series size of the different cross-section of theprofile molds is established. The improved structure of the profile is gained by thestrength FE analysis on the series size of the different cross-section molds. The design parameters of the forming dies: Firstly, referencing to the principle ofaluminum alloy extrusion die design, the extrusion FE analysis is completed by takingluggage rack profile as the extrusion object and AZ31B magnesium alloy extrusionprocess parameters (extrusion speed, extrusion temperature, extrusion ratio) and themold stress field, temperature field, strain field and the relationship between eachfield is gained by the DEFORM-3D software. Secondly, the best extrusion solution isobtained by changing the forming die design parameters (welding chamber height, thesize of the weld angle, fillet radii and adding flow blocking block, etc.). On this basis,the die stress distribution and the quality of extrusion profile is improved which hasprovided a theoretical guidance for the repairing mode and actual production to thecompany. |
