Applying computer simulation in improving heat treating condition of thin high-carbon steel parts

Abstract

The study was carried out using COSMOSFlowWorks® to predict heat treatment conditions for AISI 1085 high-carbon steel sheet that is used to produce automotive parts that require wear resistance and stiffness resulting from controlled moderately high hardness levels. To achieve such properties, flat high-carbon steel parts need to be hardened to produce acicular matrix structures, and the most suitable heat treatment process to harden thin parts without distortion is austempering. In producing hard and stiff thin section parts in this company study the austempering process was performed by soaking at 830ºC and then quenching in a NaCl salt bath at 335ºC. In production hardness testing is performed to ensure that parts have microstructures of lower bainite and martensite instead of upper bainite. To reduce distortion without any effect on hardness, modified austempering conditions were determined using temperature prediction from commercial computational analysis software. This enabled a more suitable production line practice for the production of austempered parts without distortion whilst avoiding reduced hardness.