本文選題：先進高強度鋼板 + U型彎曲�。� 參考：《湘潭大學》2017年碩士論文

【摘要】：由于節(jié)能、環(huán)保等綠色制造的需要,汽車輕量化已成為未來汽車持續(xù)發(fā)展的主題之一。先進高強度鋼板因其高強度、低密度、碰撞吸能等優(yōu)異性能成為輕量化汽車使用最廣泛的材料。但是,隨著高強鋼板強度的增加,汽車零件生產(chǎn)過程中模具和板料表面會產(chǎn)生劃痕、粘著和凹坑等粘模行為,降低了模具的使用壽命,并使成形零件的表面質量變差。熱擴散法碳化物覆層處理(TD)作為一種富有前景的表面抗磨損處理技術在汽車行業(yè)得到廣泛應用。本文以汽車用先進高強度鋼板DP780為研究對象,采用U型彎曲成形試驗方法,對Cr12及經(jīng)TD處理制備VC鍍層的Cr12模具表面粘模機理進行了系統(tǒng)研究,并基于FEM-Archard磨損模型定量評估了DP780先進高強度鋼板彎曲成形過程中的粘模行為。試驗結果表明:無鍍層Cr12模具表面在彎曲次數(shù)N=3時就出現(xiàn)輕微的劃痕,N=33時出現(xiàn)嚴重的粘模行為并伴有大量的粘結瘤,粘模行為是粘著磨損;TD處理VC鍍層模具在成形初期(N=30)也發(fā)生了輕微的微觀粘模,嚴重粘模出現(xiàn)的臨界Ry值為1.554μm;嚴重粘模首次出現(xiàn)的區(qū)域為模具圓角60-70°區(qū)域,隨后往其兩側擴展到模具圓角其它區(qū)域;其磨損機制在初期以犁溝和劃痕為主,磨損較嚴重的區(qū)域為0-10°和30-50°,隨后DP780鋼板表面產(chǎn)生較深的劃痕和橫向的裂紋,材料脫落轉移到模具表面形成粘結瘤,此時以粘著磨損為主。當彎曲次數(shù)N=660,模具和板料表面均出現(xiàn)寬而深的溝槽和凹坑,此時磨損機制以磨粒磨損為主。與Cr12模具相比,TD處理的Cr12模具具有更優(yōu)異的抗成形粘模性能。通過Abaqus有限元模擬軟件耦合Archard磨損模型預測了不同工藝參數(shù)條件下DP780高強度鋼板彎曲成形粘模行為的變化規(guī)律。模擬結果表明:基于FEM-Archard磨損模型預測的彎曲成形粘模區(qū)域與試驗結果相吻合;另外,凹模圓角形狀對模具表面粘模行為有一定影響,偏差-橢圓弧比標準圓弧、偏差圓弧和橢圓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 擄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 擄and 30-50 擄, 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.
【學位授予單位】：湘潭大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TG306;TG142.1

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本文編號：1962614