Paper Title:

Covering Steel Surface with Carbon Black by CO2 Laser

Periodical Materials Science Forum (Volumes 660 - 661)
Main Theme Advanced Powder Technology VII
Edited by Lucio Salgado and Francisco Ambrozio Filho
Pages 249-252
DOI 10.4028/www.scientific.net/MSF.660-661.249
Citation G. de Vasconcelos et al., 2010, Materials Science Forum, 660-661, 249
Online since October, 2010
Authors G. de Vasconcelos, Gabriela N.P. da Costa, Daniele C. Chagas, Carina Barros Mello, Erica F. Antunes
Keywords Carbon Black (CB), Laser, Laser Hardness, Micro-Hardness, Steel
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Abstract

This study investigate the laser surface hardening in tool steel, avoiding the high reflectivity of the metal to the CO2 radiation by covering the surface sample with black carbon. Hardening process using graphite was effective in many works in the word, although, the particles size of graphite powder was in the range of some micrometers. In order to reduce the particle size, the carbon black was used in the laser thermal treatment of 4340 steel. The microhardness change to 850HV, compared to the substrate of 250HV and the friction coefficient ranged 0.2 and 0.3, because of the covered surface by carbon black. These thin coating of carbon black reduced the wear rate near to a hundred in comparison to the surface without carbon coating.