Scale formation, properties and de-scaling in steelmaking

<p>During continuous castings, reheating, and hot rolling, slab surfaces are exposed to atmospheres containing oxidizing gases which results in scale formation. Inefficient removal of the formed scale during reheating affects product surface quality. The effect of steel composition and operating parameters on scale formation and scale removal efficiencies were investigated. Experimental investigations were carried out using a thermogravimetric (TGA) apparatus designed to replicate the combustion gas atmosphere and temperature in actual industrial slab reheat furnaces. Report on oxidation kinetics, scale structure and properties, and descaling were conducted on laboratory cast and industrial samples. Different characterization techniques were used to analyze in-depth formed scale structure.</p><p>Results on scale formation studies showed that sample chemistry, reheating parameters and sample surface condition significantly affected the development of scale structure and its properties particularly in the subsurface scale layer region. The studies showed that major alloying elements (Mn, Si,), micro alloying (Al) elements, and impurities (Cu, Ni, Cr) modified the properties of the formed scale and its kinetics mechanism. Complexity of scale formation due to alloying elements and impurities in steel and cast slab surface condition affected its efficient removal using hydraulic descaling. Samples with high alloying elements of Si and Mn were characterized by strong adhesion and complex root penetrations in the subsurface scale region which decreased descaling efficiency. Descaling hydraulic parameters and surface pretreatment that improved scale removal efficiency were suggested”--Abstract, page iv.</p>

Name thesis:degree_name

Ph. D. in Materials Science and Engineering

Grantor

Missouri University of Science and Technology

Author dc:creator

• Osei, Richard

• Descaling
• Oxidation Kinetics
• Oxide Phases
• Reheating
• Scale Structure
• Water Jet Impact Factor
• Metallurgy

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/3157

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-4162