Laser Surface Hardening

2021 ◽  
pp. 99-118
Author(s):  
L. Orazi ◽  
A. Rota ◽  
B. Reggiani

AbstractLaser surface hardening is rapidly growing in industrial applications due to its high flexibility, accuracy, cleanness and energy efficiency. However, the experimental process optimization can be a tricky task due to the number of involved parameters, thus suggesting for alternative approaches such as reliable numerical simulations. Conventional laser hardening models compute the achieved hardness on the basis of microstructure predictions due to carbon diffusion during the process heat thermal cycle. Nevertheless, this approach is very time consuming and not allows to simulate real complex products during laser treatments. To overcome this limitation, a novel simplified approach for laser surface hardening modelling is presented and discussed. The basic assumption consists in neglecting the austenite homogenization due to the short time and the insufficient carbon diffusion during the heating phase of the process. In the present work, this assumption is experimentally verified through nano-hardness measurements on C45 carbon steel samples both laser and oven treated by means of atomic force microscopy (AFM) technique.


2021 ◽  
Vol 1070 (1) ◽  
pp. 012107
Author(s):  
Ganesh Dongre ◽  
Avadhoot Rajurkar ◽  
Ramesh Gondil ◽  
Nandan Jaju

2002 ◽  
Vol 11 (3) ◽  
pp. 294-300 ◽  
Author(s):  
Jong-Hyun Hwang ◽  
Yun-Sig Lee ◽  
Dae-Young Kim ◽  
Joong-Geun Youn

2018 ◽  
Author(s):  
Sagar Sarkar ◽  
Ashish Kumar Nath

Laser surface hardening of most of the industrial components require depth of surface modification in the range of 100–150 micron. Conventional laser surface hardening uses laser as a heat source to modify a particular area of the surface without melting in an inert gas environment. However, the hardened profile in this case shows peak hardness value at a certain depth from the top surface. Also, hardening the top surface to get relatively much higher hardness near the top surface in case of thin sheets becomes difficult due to accumulation of heat below the surface of the specimen which in turn lowers the cooling rate. Hence, self-quenching becomes inadequate. In the present study, an in-house fabricated laser processing head with coaxial water nozzle has been used to flow a laminar water-jet during the laser surface hardening process to induce forced convection at the top surface. Thus, heat gets carried away by the water-jet from the top surface and by the water from the bottom surface as well. Results show that with judicious selection of process parameters, it is possible to get higher hardness (800 HV) to that of conventional laser surface hardening (500 HV) at the top surface using this process. Present process can be used for those cases where high hardness values are required near the top surface specially for thin sheets and thermally sensitive materials.


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