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http://dx.doi.org/10.12656/jksht.2020.33.3.107

A Study on Dimensional Change after Heat Treatment and Optimal Chemical Composition of Steels with 1200 MPa Tensile Strength for Automotive Subframe  

Jeong, Woo Chang (School of Mechanical and Automotive Engineering, Daegu Catholic University)
Publication Information
Journal of the Korean Society for Heat Treatment / v.33, no.3, 2020 , pp. 107-116 More about this Journal
Abstract
Four air hardening steels with carbon, silicon, manganese, chromium, and molybdenum variations have been used in this study to find out the optimal chemical compositions of steels with over 1200 MPa tensile strength for automotive subframe. The dimensional changes after heat treatment were determined for two automotive parts with open and closed cross sections using 3D scanner. When four steels were austenitized at 900℃ for 30 seconds, cooled at 3℃/s, reheated to 450℃ for 10 seconds followed by air cooling to simulate hot-dip galvanizing treatment showed ultra high tensile strength over 1200 MPa. Rear floor cross member with open cross section revealed much bigger dimensional changes than subframe with closed cross section after heat treatment at 900℃ for 20 minutes followed by air cooling.
Keywords
Automotive subframe; Ultra-high strength steel; Heat treatment; Dimensional change; Chemical composition;
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