Water-Jet Assisted Laser Surface Hardening of Medium Carbon Steel Using Fiber Laser

2018 ◽  
Author(s):  
Sagar Sarkar ◽  
Ashish Kumar Nath
Keyword(s):  
Surface Hardening ◽  
High Hardness ◽  
Medium Carbon Steel ◽  
Water Jet ◽  
Laser Surface ◽  
Peak Hardness ◽  
Bottom Surface ◽  
Thin Sheets ◽  
Laser Surface Hardening ◽  
Conventional Laser

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.

Non-conventional laser surface hardening for axisymmetric components

2014 ◽  
Author(s):  
Erica Liverani ◽  
Nadine Battiato ◽  
Alessandro Ascari ◽  
Alessandro Fortunato
Keyword(s):  
Surface Hardening ◽  
Laser Surface ◽  
Laser Surface Hardening ◽  
Conventional Laser

A complete residual stress model for laser surface hardening of complex medium carbon steel components

2016 ◽  
Vol 302 ◽  
pp. 100-106 ◽  
Author(s):  
Erica Liverani ◽  
Adrian H.A. Lutey ◽  
Alessandro Ascari ◽  
Alessandro Fortunato ◽  
Luca Tomesani
Keyword(s):  
Residual Stress ◽  
Carbon Steel ◽  
Surface Hardening ◽  
Medium Carbon Steel ◽  
Laser Surface ◽  
Complex Medium ◽  
Stress Model ◽  
Medium Carbon ◽  
Laser Surface Hardening

scholarly journals LASER SURFACE HARDENING OF AISI 1055 STEEL IN WATER SUBMERGED CONDITION

2019 ◽  
Vol 27 (01) ◽  
pp. 1950087
Author(s):  
NIROJ MAHARJAN ◽  
WEI ZHOU ◽  
YU ZHOU ◽  
NAIEN WU
Keyword(s):  
Surface Hardening ◽  
Water Movement ◽  
Laser Energy ◽  
Surface Hardness ◽  
Surface Oxidation ◽  
Water Layer ◽  
Laser Surface ◽  
Laser Hardening ◽  
Laser Surface Hardening ◽  
Conventional Laser

Underwater laser hardening might produce better surface mechanical properties than conventional laser hardening in air due to additional cooling effect by water. However, it has not been studied in detail. This study investigates the effect of water layer on laser surface hardening of AISI 1055 steel. It is found that laser surface hardening is feasible with water layer up to 3[Formula: see text]mm above the steel surface. A higher surface hardness is achieved during underwater processing. This is attributed to fast cooling by water which facilitates complete martensitic transformation. Nevertheless, the hardened area is smaller than that in conventional laser hardening in air due to attenuation of laser energy. Above 3[Formula: see text]mm, the laser beam is severely attenuated due to formation of vapor plume. Furthermore, it is found that surface oxidation cannot be prevented completely even during underwater treatment, and the water movement results in random distribution of metal slag on the surface.

scholarly journals Comparison of Wear Performance of Austempered and Quench-Tempered Gray Cast Irons Enhanced by Laser Hardening Treatment

2020 ◽  
Vol 10 (9) ◽  
pp. 3049
Author(s):  
Bingxu Wang ◽  
Gary C. Barber ◽  
Rui Wang ◽  
Yuming Pan
Keyword(s):  
Heat Treatment ◽  
Cast Iron ◽  
Surface Hardening ◽  
Gray Cast Iron ◽  
High Hardness ◽  
Laser Surface ◽  
Gray Cast ◽  
Wear Loss ◽  
Laser Surface Hardening ◽  
Hardening Treatment

The current research studied the effects of laser surface hardening treatment on the phase transformation and wear properties of gray cast irons heat treated by austempering or quench-tempering, respectively. Three austempering temperatures of 232 °C, 288 °C, and 343 °C with a constant holding duration of 120 min and three tempering temperatures of 316 °C, 399 °C, and 482 °C with a constant holding duration of 60 min were utilized to prepare austempered and quench-tempered gray cast iron specimens with equivalent macro-hardness values. A ball-on-flat reciprocating wear test configuration was used to investigate the wear resistance of austempered and quench-tempered gray cast iron specimens before and after applying laser surface-hardening treatment. The phase transformation, hardness, mass loss, and worn surfaces were evaluated. There were four zones in the matrix of the laser-hardened austempered gray cast iron. Zone 1 contained ledeburite without the presence of graphite flakes. Zone 2 contained martensite and had a high hardness, which was greater than 67 HRC. Zone 4 was the substrate containing the acicular ferrite and carbon-saturated austenite with a hardness of 41–27 HRC. In Zone 3, the substrate was tempered by the low thermal radiation. For the laser-hardened quench-tempered gray cast iron specimens, three zones were observed beneath the laser-hardened surface. Zone 1 also contained ledeburite, and Zone 2 was full martensite. Zone 3 was the substrate containing the tempered martensite. The tempered martensite became coarse with increasing tempering temperature due to the decomposition of the as-quenched martensite and precipitation of cementite particles. In the wear tests, the gray cast iron specimens without heat treatment had the highest wear loss. The wear performance was improved by applying quench-tempering heat treatment and further enhanced by applying austempering heat treatment. Austempered gray cast iron specimens had lower mass loss than the quench-tempered gray cast iron specimens, which was attributed to the high fracture toughness of acicular ferrite and stable austenite. After utilizing the laser surface hardening treatment, both austempered and quench-tempered gray cast iron specimens had decreased wear loss due to the high surface protection provided by the ledeburitic and martensitic structures with high hardness. In the worn surfaces, it was found that cracks were the dominant wear mechanism. The results of this work have significant value in the future applications of gray cast iron engineering components and provide valuable references for future studies on laser-hardened gray cast iron.

scholarly journals Experimental investigation on a novel approach for laser surface hardening modelling

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
L. Orazi ◽  
A. Rota ◽  
B. Reggiani
Keyword(s):  
Surface Hardening ◽  
Carbon Diffusion ◽  
Industrial Applications ◽  
Laser Surface ◽  
Simplified Approach ◽  
Laser Surface Hardening ◽  
Novel Approach ◽  
Laser Treatments ◽  
High Flexibility ◽  
Short Time

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.

scholarly journals Laser surface hardening of SS316L

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