Study Of Internal Friction On Masteel's Automotive Sheets Of A Series Of Steels

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.