Effect of Mill Scale on Laser Cutting Quality of Various Thick Steel Plates

Abstract

Laser cutting provides more precise and higher quality cuts than other thermal cutting processes, and is adaptable to automation requirements. On the other hand, laser cutting with oxygen assist gas of thick steel plates is a complex process in which various factors affect laser cutting quality compared to the thin plates. When laser cutting of the plate with mill scale is performed, the mill scale on the surface of plate generally plays a role in supporting stable laser cutting, although self-burning may also occur due to peeling of the mill scale. Therefore, this paper focuses on the mill scale and investigates the effects of the adhesion, thickness, and surface roughness of the mill scale on the laser cutting quality. As a result, it was found that the laser cutting quality is higher when the adhesion of the mill scale is high, the thickness of the mill scale is between 20 μm and 40 μm, and the surface roughness is small.

Keywords:

• Laser cutting
• Thick steel plate
• Mill scale
• Adhesion
• Surface roughness
• EPMA
• Segregation

Acknowledgment

The authors would like to express their deep appreciation to Mr. Takami Masui of the Mie Prefectural Industrial Research Institute for his assistance in surface roughness measurement and Mr. Shoji Nakamura of the Engineering Department, Faculty of Engineering, Mie University for his assistance in EPMA analysis.