【作者】 张志波；

【导师】 于宁；

【作者基本信息】 东北大学 ， 材料物理与化学， 2009， 硕士

【摘要】 本文包括绪论、内耗原理、实验过程、含碳量不同的汽车钢板的力学谱及其力学性能、不同冲压成形性能DC01汽车钢板的力学谱研究、DC04汽车钢板的力学谱以及结论等7章内容。在介绍了研究背景、目标、意义和实验过程之后,详细地描述了论文的实验结果、讨论、结论。本文测量了马鞍山钢铁公司生产的含0.025-0.050wt%C的DC01汽车钢板、不同冲压性能低碳铝镇静钢汽车板、DC04(IF)汽车板和参比的进口钢汽车板室温至350℃的力学谱。研究发现内耗谱特征明显不同的IF钢板和铝镇静汽车板,其n90值、r90值有明显的差异。而内耗谱特征相同、阻尼峰参量也相近的汽车钢板,它们的n90值、r90值很相近。并通过观测部分汽车钢板样品的金相和力性等发现马钢生产的DC01铝镇静钢出现冲压变形滑移带、“橘皮”等有问题汽车板和未出现上下屈服点的常规板,在金相上没有明显差异,却呈现出内耗峰数目不同、阻尼参数有差异等特征明显不同的力学谱：常规板有包括Snoek峰、B峰和Snoek-Ke-Koster (SKK)峰的三峰谱；有Liiders bands的钢板,呈只有Snoek峰和SKK峰、但峰明显高的双峰谱；而出现“橘皮”的汽车板,则呈峰都很低但有4-5个内耗峰的多峰谱。此外,也对DC04钢板的室温到约230℃的阻尼现象进行了研究。论文讨论了研究钢板的力学谱特征和内耗峰的本质,并结合钢板的金相结果、成分、工艺参数和力学谱,对含碳量不同的汽车钢板的力学性能进行了分析。对不同冲压成形性能汽车钢板冶金因素与钢板冲压性能的关系以及汽车钢板冲压成形“起皱”(wrinkling)等问题做了一些分析。同时也确定了DC04钢的从室温到约230℃的阻尼为一种由变形缺陷引起的内耗。更多还原

【Abstract】 The paper is composed of the introduction, the related internal friction theory, experiment procedure, mechanical spectra studies of automotive sheets with different the carbon content, the stamping properties of the DC01 steels, the internal friction of DC04 automotive sheets and conclusions, including all seven chapters. The results, discussion, conclusions of the paper are described in detail after intriducing the research background, objectives, significance and experimental process.It is found, by the measurements of the internal friction in a temperature range from room temperature to 350℃of the DC01 sheets containing 0.025-0.050wt% C, low-carbon Al-killed steel automotive sheets with varied stamping properties, and DC04 (IF) sheets which were all produced by the Masteel Corp. along with the received sheets of import sheets, and by metallgraph observation and mechanical measurements of a part of the sheets, that the values of n90 and r90 of the IF steel and Al-killed steel plates, whose internal friction spectrums are obviously different, are different. While friction spectrums and the damping peak parameters are similar, values of n90 and r90 of car plates are closed. In addition, there are obviously different characters of mechanical spectra of the steels with different stamping properties. The mechanical spectrum of the normal sheet presents three small peaks including Snoek peak, B peak and Snoek-Ke-Koster (SKK) peak and one of the sheets with Liiders bands exhibits double peaks, i.e., Snoek peak and SKK peak. There are 4-5 very small multi-peaks for the sheets with orange skin deforming, although there is no significant difference in metallograph for these sheets. Furthermore, the internal friction of DC04 steel from room temperature to 230℃is studied too.Spectral characteristics and the mechanical nature of the internal friction peak of steel are discussed. Based on research results of the steel microstructure, composition, process parameters and mechanical spectroscopy, mechanical properties of the car sheets with different carbon content are analyzed. The relationship of automotive sheets with different stamping performance between metallurgical properties and stamping performance and the problem of metal forming "wrinkles" (wrinkling) of automobile sheet were investigated. Finally, the internal friction of DC04 from room temperature to 230℃was certain to be interrelated with defect of deformed.更多还原