Type

Journal Article

Authors

Patrick Biggs
Sumsun Naher
Dermot Brabazon

Subjects

Engineering

Topics
materials amorphous mechanical engineering tool steel glazing h13 laser processing xrd

Glazing of tool dies for semi-solid steel forming (2008)

Abstract This paper describes an analysis conducted into the effect of CO2 laser processing parameters on the surface modification and heat treatment of steels. The CO2 laser and in house developed apparatus for movement of the samples allowed for high speed surface heat treatment. The operation of these components in conjunction allowed a wide variation in the heat treatments and sample properties to be obtained. In particular, the mechanism to pass the steel samples at high speeds (700 — 1200 mm/s), kept the focus spot exposure times below 1 x 10-3 s. Laser power from 825 to 1050W and continuous beam mode were used. Both laser hardened and laser glazed samples were analysed using optical microscopy, Vickers and micro hardness testing, and XRD. The samples showed functionally graded surface morphologies and corresponding hardness and stiffness responses. For more rapidly process samples three layers of distinct hardness were noted. In all cases crystal and property modification to approximately 500ttm was found. Results show how the laser treatment is directly related to the hardness profile through the surface and resultant microstructures. The results from all the samples show increased hardness due to (a) the formation of martensite and ferrite in the laser hardened samples and (b) a complete microstructural transformation to an amorphous state in the glazed samples. It is noted that the higher stiffness and hardness of the glazed samples can expect to result in a more wear resistant coating for the semi-steel forming process. The amorphous layer may also be expected to act as a thermal barrier to the higher temperatures encountered in semi-solid steel forming.
Collections Ireland -> Dublin City University -> Publication Type = Article
Ireland -> Dublin City University -> DCU Faculties and Centres = DCU Faculties and Schools
Ireland -> Dublin City University -> Status = Published
Ireland -> Dublin City University -> DCU Faculties and Centres = DCU Faculties and Schools: Faculty of Engineering and Computing: School of Mechanical and Manufacturing Engineering
Ireland -> Dublin City University -> Subject = Engineering: Mechanical engineering
Ireland -> Dublin City University -> DCU Faculties and Centres = DCU Faculties and Schools: Faculty of Engineering and Computing
Ireland -> Dublin City University -> Subject = Engineering: Materials
Ireland -> Dublin City University -> DCU Faculties and Centres = Research Initiatives and Centres: Materials Processing Research Centre (MPRC)
Ireland -> Dublin City University -> Subject = Engineering
Ireland -> Dublin City University -> DCU Faculties and Centres = Research Initiatives and Centres

Full list of authors on original publication

Patrick Biggs, Sumsun Naher, Dermot Brabazon

Experts in our system

1
Sumsun Naher
Dublin City University
Total Publications: 56
 
2
Dermot Brabazon
Dublin City University
Total Publications: 162