Thermal model with phase change for process parameter determination in laser surface processing

This work presents a 3D computational/mathematical model to solve the heat diffusion equation with phase change, considering metal addition, complex geometry, and thermal properties varying with temperature. The finite volume method was used and the computational code was implemented in C++, using a Borland compiler. Experimental tests considering workpieces of stainless steel AISI 304 were carried out for validation of the thermal model. Inverse techniques based on Golden Section method were used to estimate the heat transfer rate to the workpieces. Experimental temperatures were measured using thermocouples type J—in a total of 07 (seven)—all connected to the welded workpiece and the Agilent 34970A data logger. The workpieces were chamfered in a 45° V-groove in which liquid metal was added on only one weld pass. An innovation presented in this work when compared to other works in scientific literature was the geometry of the weld pool. The good relation between experimental and simulated data confirmed the quality and robustness of the thermal model proposed in this work.

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Metallurgical Aspects of Laser Surface Processing of PM Cr-V Ledeburitic Steel

Advances in Materials Science and Engineering ◽

10.1155/2011/563410 ◽

2011 ◽

Vol 2011 ◽

pp. 1-8 ◽

Cited By ~ 8

Author(s):

Peter Jurči ◽

Jiři Cejp ◽

Jan Brajer

Keyword(s):

Solid Solution ◽

Light Microscopy ◽

Retained Austenite ◽

Surface Melting ◽

Laser Surface ◽

Laser Surface Melting ◽

Surface Processing ◽

Microstructural Changes ◽

Type Steel ◽

Eds Microanalysis

The Vanadis 6 ledeburitic-type steel was laser surface remelted. Microstructural changes and hardness in laser affected material were investigated using light microscopy, SEM, and EDS-microanalysis. It was found that the laser surface melting and subsequent rapid solidifying led to softening of the material, due to presence of retained austenite. The melting of the material begins with the transformation of M7C3-carbide into a liquid and finishes via the dissolution of primary solid solution grains. The solidification proceeded in a reverse manner while the eutectics became often so-called degenerous form.

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Laser Surface Processing for Tailoring of Properties by Optimization of Microstructure

Advances in Civil and Industrial Engineering - Advanced Manufacturing Techniques Using Laser Material Processing ◽

10.4018/978-1-5225-0329-3.ch006 ◽

2016 ◽

pp. 121-171

Author(s):

Jyotsna Dutta Majumdar ◽

Andreas Weisheit ◽

I. Manna

Keyword(s):

Surface Region ◽

Laser Surface ◽

Processing Route ◽

Surface Microstructure ◽

High Power Laser ◽

Surface Processing ◽

Present Contribution ◽

Near Surface ◽

Rapid Processing ◽

Equilibrium Microstructure

Laser surface processing involves modification of surface microstructure and/or composition of the near surface region of a component using a high power laser beam. The advantages of laser surface processing over conventional equilibrium surface processing include rapid processing rate, retention of non-equilibrium microstructure, alloying in liquid state and development of processed zone with superior properties as compared to the same developed by equilibrium processing route. Microstructure plays an important role to control the final properties of the tailored component. In the present contribution, with a brief introduction to laser, and its application, the microstructures developed under optimum conditions by different laser surface processing will be discussed with the corresponding improvement in properties. Finally, a brief review of the future scope of research in laser surface processing will be presented.

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