Mechanical adhesion energy of thermal oxide scale on 0.01 and 0.12 wt.% Si-containing hot-rolled steels

High Temperature Corrosion Research Centre, Department of Materials and Production Technology Engineering, Faculty of Engineering, King Mongkut’s University of Technology North Bangkok, 1518, Pracharat 1 Road, Wongsawang, Bangsue, Bangkok, 10800, Thailand

^* Corresponding author: thanasak.n@eng.kmutnb.ac.th

Abstract

The mechanical adhesion energy of thermal oxide scales plays a critical role in the quality and efficiency of the hot rolling process, as the formation of oxide scales on steel surfaces can lead to defects that adversely affect material performance. This study aims to investigate the adhesion behavior of thermal oxide scales on as-received hot-rolled steels containing 0.01 wt.% Si and 0.12 wt.% Si, utilizing a tensile testing machine equipped with an observation setup and acoustic emission monitoring. Results indicate that the average scale thickness for the 0.01 wt.% Si and 0.12 wt.% Si steels were 10.83 ± 0.76 µm and 8.13 ± 1.08 µm, respectively, with the oxide scales consisting of hematite, magnetite, wustite, and iron. The strain associated with initial scale spallation was measured to calculate mechanical adhesion energy, revealing values of 5.46 ± 0.01% for 0.01 wt.% Si and 7.08 ± 0.20% for 0.12 wt.% Si. The computed mechanical adhesion energy ranged from 1093 J/m² to 1565 J/m², demonstrating that higher silicon content correlates with enhanced scale adhesion. Consequently, the scale on the higher Si-containing steel proved more challenging to remove after the hot rolling process, which has significant implications for processing and surface quality in steel manufacturing.