汽车用先进高强钢板弯曲成形粘模机理研究

发布时间：2018-06-01 03:05

本文选题：先进高强度钢板 + U型弯曲　；参考：《湘潭大学》2017年硕士论文

【摘要】：由于节能、环保等绿色制造的需要,汽车轻量化已成为未来汽车持续发展的主题之一。先进高强度钢板因其高强度、低密度、碰撞吸能等优异性能成为轻量化汽车使用最广泛的材料。但是,随着高强钢板强度的增加,汽车零件生产过程中模具和板料表面会产生划痕、粘着和凹坑等粘模行为,降低了模具的使用寿命,并使成形零件的表面质量变差。热扩散法碳化物覆层处理(TD)作为一种富有前景的表面抗磨损处理技术在汽车行业得到广泛应用。本文以汽车用先进高强度钢板DP780为研究对象,采用U型弯曲成形试验方法,对Cr12及经TD处理制备VC镀层的Cr12模具表面粘模机理进行了系统研究,并基于FEM-Archard磨损模型定量评估了DP780先进高强度钢板弯曲成形过程中的粘模行为。试验结果表明:无镀层Cr12模具表面在弯曲次数N=3时就出现轻微的划痕,N=33时出现严重的粘模行为并伴有大量的粘结瘤,粘模行为是粘着磨损;TD处理VC镀层模具在成形初期(N=30)也发生了轻微的微观粘模,严重粘模出现的临界Ry值为1.554μm;严重粘模首次出现的区域为模具圆角60-70°区域,随后往其两侧扩展到模具圆角其它区域;其磨损机制在初期以犁沟和划痕为主,磨损较严重的区域为0-10°和30-50°,随后DP780钢板表面产生较深的划痕和横向的裂纹,材料脱落转移到模具表面形成粘结瘤,此时以粘着磨损为主。当弯曲次数N=660,模具和板料表面均出现宽而深的沟槽和凹坑,此时磨损机制以磨粒磨损为主。与Cr12模具相比,TD处理的Cr12模具具有更优异的抗成形粘模性能。通过Abaqus有限元模拟软件耦合Archard磨损模型预测了不同工艺参数条件下DP780高强度钢板弯曲成形粘模行为的变化规律。模拟结果表明:基于FEM-Archard磨损模型预测的弯曲成形粘模区域与试验结果相吻合;另外,凹模圆角形状对模具表面粘模行为有一定影响,偏差-椭圆弧比标准圆弧、偏差圆弧和椭圆弧具有更好的抗成形粘模性能。
[Abstract]:Due to the need of green manufacturing, such as energy saving and environmental protection, automobile lightweight has become one of the themes of automobile sustainable development in the future. Advanced high strength steel plate has become the most widely used material for lightweight automobile because of its high strength, low density, collision energy absorption and other excellent properties. However, with the increase of the strength of high strength steel plate, the die and sheet surface will produce scratches, adhesions and pits during the manufacturing process of automobile parts, thus reducing the service life of the die and making the surface quality of the formed parts worse. Thermal Diffusion Carbide coating treatment (TD) has been widely used in automobile industry as a promising anti-wear treatment technology. In this paper, taking advanced high strength steel plate DP780 for automobile as the research object, the surface adhesion mechanism of Cr12 and Cr12 die prepared by TD treatment has been studied systematically by using U-shaped bending forming test method. Based on the FEM-Archard wear model, the bonding behavior of DP780 advanced high strength steel sheet during bending process was quantitatively evaluated. The test results show that the surface of the uncoated Cr12 die has serious adhesion behavior and a large number of bonding nodules when the bending times N = 3 are slightly scratched on the surface of the mould. The bonding behavior of the die is adhesive wear, TD treatment VC coating die has a slight micro adhesion in the early forming stage, the critical Ry value of the serious adhesion die is 1.554 渭 m, and the first time region of the serious adhesion die is the round corner 60-70 掳region of the die. The wear mechanism was mainly furrow and scratch at the initial stage, and the more serious wear areas were 0-10 掳and 30-50 掳, then deeper scratches and transverse cracks appeared on the surface of the DP780 plate. The material is removed and transferred to the surface of the mould to form a bond, which is mainly adhesive wear. Wide and deep grooves and pits appear on the surface of die and sheet when the bending times N ~ (60), and the wear mechanism is mainly abrasive wear. Compared with Cr12 die, Cr12 die treated by TD has better forming resistance. The Abaqus finite element simulation software coupled with the Archard wear model was used to predict the change of bonding behavior of DP780 high strength steel sheet under different process parameters. The simulation results show that the die area predicted by FEM-Archard wear model is in agreement with the experimental results, and the shape of the groove has a certain influence on the die surface adhesion behavior, and the deviation to ellipse arc ratio is standard arc. Deviation arc and elliptical arc have better anti-forming properties.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG306;TG142.1

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