<title>Surface hardening using cw CO2 laser: laser heat treatment, modelation, and experimental work</title>

Laser surface hardening, is a process in which a shaped laser beam is scanned across the surface to produce a hard and wear-resistant surface on components. Compared with the conventional surface hardening process, the laser heat treatment offers a number of attractive characteristics such as minimal part distortion, self-quenching and the need for less finishing work. The challenge of laser hardening is the uneven surfaces found in molds such as those with sharp edges or holes. In these cases, due to the differences in the surrounding volume of the material, overheating problems often appear leading to unacceptable treatment results. The purpose of this paper is to present the new technology, “raio” developed by Talens System for laser hardening process. This technology is able to adapt to geometrical singularities of the components to be treated, ensuring the dimensions of the hardened area and hardness values are compliant with the requirements. The main features of the technology for laser hardening are validated on a set of samples of 1.2738 steel with representative discontinuities of molds. Mechanical and microstructural characterizations of the hardened cross sections confirm the advantages of the raio technology in regard to the quality compliance of the laser hardening process. Furthermore, raio offers the same advantages for other laser processes, like softening of critical area or laser cladding for repairing of damaged components.

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Influence of CO2 laser heat treatment on surface properties, electrochemical and tribological performance of HVOF sprayed WC–24%Cr3C2–6%Ni coating

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2009.09.025 ◽

2010 ◽

Vol 119 (3) ◽

pp. 458-464 ◽

Cited By ~ 34

Author(s):

Shi Hong Zhang ◽

Jae Hong Yoon ◽

Ming Xi Li ◽

Tong Yul Cho ◽

Yun Kon Joo ◽

...

Keyword(s):

Heat Treatment ◽

Surface Properties ◽

Co2 Laser ◽

Tribological Performance ◽

Laser Heat Treatment ◽

Laser Heat

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Effect of Laser Heat-Treatment and Laser Nitriding on the Microstructural Evolutions and Wear Behaviors of AISI P21 Mold Steel

Metals ◽

10.3390/met10111487 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1487

Author(s):

Won-Sang Shin ◽

Hyun Jong Yoo ◽

Jeoung Han Kim ◽

Jiyeon Choi ◽

Eun-Joon Chun ◽

...

Keyword(s):

Heat Treatment ◽

Wear Resistance ◽

Base Metal ◽

Surface Hardening ◽

Surface Hardness ◽

Laser Heat Treatment ◽

Laser Nitriding ◽

Laser Heat ◽

Heat Treated ◽

Pin On Disk

Laser heat-treatment and laser nitriding were conducted on an AISI P21 mold steel using a high-power diode laser with laser energy densities of 90 and 1125 J/mm2, respectively. No change in surface hardness was observed after laser heat-treatment. In contrast, a relatively larger surface hardness was measured after laser nitriding (i.e., 536 HV) compared with that of the base metal (i.e., 409 HV). The TEM and electron energy loss spectroscopy (EELS) analyses revealed that laser nitriding induced to develop AlN precipitates up to a depth of 15 μm from the surface, resulting in surface hardening. The laser-nitrided P21 exhibited a superior wear resistance compared with that of the base metal and laser heat-treated P21 in the pin-on-disk tribotests. After 100 m of a sliding distance of the pin-on-disk test, the total wear loss of the base metal was measured to be 0.74 mm3, and it decreased to 0.60 mm3 for the laser-nitrided P21. The base metal and laser heat-treated P21 showed similar wear behaviors. The larger wear resistance of the laser-nitrided P21 was attributed to the AlN precipitate-induced surface hardening.

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Optimization of the Case Depth of a Cylinder Made With 4340 Steel by a Control of the Laser Heat Treatment Parameters

Volume 1A: 38th Computers and Information in Engineering Conference ◽

10.1115/detc2018-85574 ◽

2018 ◽

Cited By ~ 2

Author(s):

Rachid Fakir ◽

Noureddine Barka ◽

Jean Brousseau

Keyword(s):

Heat Treatment ◽

Numerical Model ◽

Surface Temperature ◽

Laser Power ◽

Case Depth ◽

Maximum Temperature ◽

Laser Heat Treatment ◽

Laser Heat ◽

4340 Steel ◽

Cylindrical Workpiece

This paper presents a numerical model able to control the temperature distribution along a 4340 steel cylinder heat-treated with Nd: YAG laser. The numerical model developed using the numerical finite element method, was based on a study of surface temperature variation and the adjustment of this temperature by a control of the heat treatment laser power. The proposed analytical approach was built gradually by (i) the development of a numerical model of laser heat treatment of the cylindrical workpiece, (ii) an analysis of the results of simulations and experimental tests, (iii) development of a laser power adjustment approach, and (iv) proposal of a laser power control predictor using neural networks. This approach was made possible by highlighting the influence of the fixed (non-variable) parameters of the laser heat treatment on the case depth, and has shown that it is possible by controlling the laser parameters to homogenize the distribution of the maximum temperature reached on the surface for a uniform case depth. The feasibility and effectiveness of the proposed approach leads to a reliable and accurate model able to guarantee a uniform surface temperature and a regular case depth for a cylindrical workpiece of a length of 50-mm and with a diameter of between 16-mm and 22-mm.

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