Title: Effects of laser bending on the microstructural constituents

Authors: Lerato Tshabalala; Sisa Pityana; Richard Mbaya

Addresses: Tshwane University of Technology, Department of Chemical and Metallurgical Engineering, Private Bag X680, Pretoria, 0001, South Africa. ' Tshwane University of Technology, Department of Chemical and Metallurgical Engineering, Private Bag X680, Pretoria, 0001, South Africa. ' Tshwane University of Technology, Department of Chemical and Metallurgical Engineering, Private Bag X680, Pretoria, 0001, South Africa

Abstract: This article will illustrate the correlation between microstructural and microhardness changes in high-strength-low-alloy steel that occur as a result of laser-bending. Laser bending is a process of bending metal shapes using the laser beam to uniformly distribute thermal energy across that target material. The correct thermal distribution in laser bending is achieved by optimum combination of the laser power intensity, scan speed and beam diameter for a specific metal thickness. The effects of the thermal distribution on the stability of metal were elucidated in terms of microstructure and microhardness. Experiments revealed a decrease in properties as a result of laser-bending. The applied heat exceeds the transformation temperature of the fine ferrite grain to austenite. Microstructural constituents on the affected heat treated zones were primarily allotriomorphic ferrite and thus weakened the ferrite grains. This was due to the heat effect on grain growth of the steel that brought about softening.

Keywords: laser bending; automotive manufacturing; automobile industry; microstructure; phase transformation; microhardness; high strength steel; low alloy steel; thermal distribution; the laser power intensity; scan speed; beam diameter; temperature distribution.

DOI: 10.1504/IJMMS.2012.048229

International Journal of Mechatronics and Manufacturing Systems, 2012 Vol.5 No.3/4, pp.214 - 225

Received: 02 Apr 2011
Accepted: 30 Aug 2011
Published online: 21 Aug 2014 *

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