Through the Design Of Experiment (DOE), the simulation model of glass flush and lifting torque, the key quality characteristics of Flush Door system, was established, and the significant factors affecting response variables were analysed, and the system robustness before and after tolerance optimization was simulated by Monte Carlo. The Simulation results show that the determination coefficient (R²) of glass flush and lifting torque are 0.968 6 and 0.963 9 respectively, which indicates the models agree well with experimental data. After tolerance optimization, the product out-of-tolerance rates of glass flush and lifting torque are reduced from 0.62% and 1.71% to 0 respectively. At the same time, the redistribution of the tolerance zones has reduced the product out-of-tolerance rates by 0.60% and 1.67% respectively, significantly improving the robustness of the system tolerance design.

In order to improve the visual, auditory, olfactory, tactile and other subjective feelings brought by the passenger car seal strip, this paper, through the study and discussion of the automotive seal strip extrusion process, clarified the general review content of the seal strip extrusion process in the trial production stage, so that the external seal strip can follow a unified evaluation standards in the design and manufacturing process. The paper systematically introduced raw materials, classification, structure and properties of seal strips as well as the key points of process control in the process of extrusion, so as to meet the following requirements including seal strip Product Verification(PV) tests, functional requirements for vehicle sealing, vehicle appearance and exterior trims.

This paper summarized the research status and existing problems of automobile lightweight technologies at home and abroad from 3 aspects of structure lightweight, lightweight materials and manufacturing processes lightweight, mainly including the basic principle and research progress of size optimization, topological optimization and shape optimization in automobile structure lightweight, performance characteristics of lightweight materials and high-strength materials in material lightweight and application in automobile, basic principle and existing problems of manufacturing processes including hydraulic molding, laser welding and thermal forming. In terms of the current development trend, structural integration, research and development of lightweight materials with better comprehensive performance and adoption of more advanced manufacturing processes are important approaches to achieve automobile lightweight.

Taking the magnesium alloy rear door of passenger car as the research object, the finite element software Comsol Multiphysics was used to establish the galvanic corrosion model of magnesium-steel dissimilar materials and simulate its galvanic corrosion behavior, the corrosion mechanism of magnesium-steel was analyzed by combining the results of electrochemical testing and corrosion morphology. Meanwhile, 4 anti-galvanic corrosion measures were formulated by combining the corrosion mechanism. These 4 anti-corrosion methods, including reducing electrolyte concentration, magnesium alloy surface treatment, reducing cathode area and adding aluminum alloy transition layer between magnesium and steels, can effectively inhibit the galvanic corrosion between magnesium and steels.

Cr⁶⁺ is widely applied in automotive metal coating and leather, Cr⁶⁺ test is an indispensable index for the test of prohibited substances on automobiles. In order to test Cr⁶⁺ content in the metal coating of automotive materials, a rapid semi-quantitative detection procedure was established by the test strip method. Compared with ultraviolet method and point test method in QC/T 942—2021 Test Methods of Hexavalent Chromium in Automotive Materials, results of the strip test method are basically consistent with traditional qualitative and quantitative test methods. The advantage of strip test method is that the test can be completed within 5 minutes, far less than that of the traditional method that takes 4 to 8 hours. Meanwhile, operation of the test is simple, which saves large amount of test consumables and reduces waste discharge.

An investigation was conducted on the wrinkling of the paint coating on the weld sealant, it was determined that the cause of the wrinkling was poor wetting of the paint on the surface of the sealant. Through verification of material compatibility, influence of plasticizers, baking of sealants, comparison of different formulas of sealants and cross comparison of different film thicknesses in the middle surface coating, it is found that the cause for poor wetting is the thin film thickness of the paint coating. The fluctuation of robot spraying is the main cause for the thin film thickness. However, considering reducing the cost of spare parts and reducing the risk of sagging and foaming, the wrinkling problem was ultimately solved by improving the material’s wettability and an anti-recurrence solution was proposed.

For central black spot defect of molded bearing steel wire, the annealing state and hot-rolled state wire rod samples were tested by means of low acid leaching, metallographic analysis, Scanning Electron Microscopy (SEM) microstructure observation and energy spectrum analysis. By investigation of smelting and rolling process, it is confirmed that the central black spot problem is caused by poor heat preservation of heating agent, causing carbide segregation by element C and Cr concentration at the casting head. According to the causes of the defect, this paper proposed corresponding field process improvement measures, including changing the heating agent to strengthen the heat preservation of the casting head, reduce the pouring superheat, the central black spot defect was finally solved and the qualified rate of the product was increased.

Thermodynamic calculation software Thermo-Calc was used to calculate the influence of the change of Nb and Ti content on the precipitation behavior of carbon nitride, the composition of 1 800 MPa hot-formed steel was determined. The equilibrium phase diagram, the precipitation temperature of the main precipitated phase, the change of element content with temperature and the growth behavior of the precipitated phase were calculated, the basic data of the main phase composition and phase transformation characteristics were obtained. The mechanical properties and 3 point bending properties of microalloy 1 800 MPa hot stamping steel have been tested. The test results show that the steel has good toughness. The microstructure of the hot formed steel after quenching was characterized by Electron Back Scattering Diffraction (EBSD). The characterized results show that the small austenitic grains and small martensitic blocks are the main causes for the high toughness of the 1 800 MPa hot formed steel. Finally, the delayed fracture sensitivity of the hot-formed steel was measured by hydrogen filling and slow drawing method. The measured results show that the hot stamping steel has excellent delayed fracture sensitivity when the hydrogen filling time is less than 2 h.

This paper studied and demonstrated feasibility of bio-based and degradable Polylactic Acid (PLA) as a substitute of petroleum-based engineering plastics in the fabrication of automotive interior parts. Through 1 year-damp-heat aging test, PLA demonstrated sufficient hydrolysis resistance and weather resistance, meeting the long-time service requirements of automotive interior parts. Through molding and performance verification as a ceilisng lamp shell, PLA was also confirmed to be suitable in automotive interior part design and development.

The hybrid excitation rotor has higher process requirements in the production process. This paper discussed hybrid excitation rotor from 3 perspectives, i.e. how to correctly install the magnetic steel polarity in the manufacturing process, the identification of the magnetic polarity of the excitation coil and slip ring in the process inspection and the effect of different magnetic steel materials on the performance improvement. Through the combination of magnetic steel and claw pole arrays, a dedicated inspection equipment was designed to verify the excitation coil during the inspection process, different materials of magnetic steel were used for performance testing of the generator. The results show that combining the positive and negative poles of the excitation coil with the magnetic steel to form a Haier Beck array can effectively improve the output power of the generator, aluminum iron boron material has a better effect on improving electrical performance compared to ferrite.