Laser surface melt-hardening of gray and nodular irons

Grum, Janez; Šturm, Roman

doi:10.1016/s0169-4332(96)00648-4

Cited by 30 publications

(13 citation statements)

References 3 publications

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“…The measure for carbon solubility is the change in carbon concentration from the surface of a particular graphite nodule to the extreme point of diffusion path. Thus, during rapid cooling, hard ledeburite and/or martensite shells form surrounding graphite nodules [6,8]. Fig.…”

Section: Hardened Layermentioning

confidence: 99%

“…By choosing a suitable energy input, we can achieve rapid local heating rates up to the austenitic region or even the temperature of the surface layer melting which, after the cooling process is completed, enables us to obtain a modified layer of desired depth [4][5][6]. Rapid heat transfer into the remaining part of the cold mass can quite easily achieve the required surface layer cooling rates.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, in our case, the aim of laser surface remelting is to ensure a fine-grained microstructure with uniform microhardness, which cannot be achieved by other procedures for surface hardening pearlite-ferrite nodular irons. The properties of the modified layer depend on the microstructure prior to heat treatment and on the amount of energy input transferred to the surface layer of the specimen [1,3,6]. This study discusses the different effects of the laser remelting process on the microstructural changes in the surface layer as well as strain and residual stress developed in the nodular iron 500-7.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A new experimental technique for measuring strain and residual stresses during a laser remelting process

Grum

Šturm

2004

Journal of Materials Processing Technology

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Section: Hardened Layermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A new experimental technique for measuring strain and residual stresses during a laser remelting process

Grum

Šturm

2004

Journal of Materials Processing Technology

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“…For steels, the absorptivity increases when the wavelength is short. The Nd:YAG laser system with short wavelength at 1064 nm is suggested for surface hardening of steel [4]. In LSTH, As the gear teeth are not completely hardened, a relatively ductile core (35 to 45 HRC) combined with a hard surface (55 to 65 HRC) offer very remarkable gear properties, such as excellent wear resistance, toughness, and bending strength, and allows greater gear durability.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Laser Surface Transformation Hardening of 4340 Steel Spur Gears

Borki

Ouafi

Chebak

2019

JMMP

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This paper presents an experimental investigation of laser surface transformation hardening (LSTH) of 4340 steel spur gears using regression analysis. The experimental work is focused on the effects of various LSTH parameters on the hardness profile shape and the hardened depth variation. The investigations are based on a structured design of experiments and improved statistical analysis tools. The experimentations are carried out on AISI 4340 steel spur gears using a commercial 3 kW Nd:YAG laser system. Laser power, scanning speed, and rotation speed are used as process parameters to evaluate the variation of the hardened depth and to identify the possible relationship between the process parameters and the hardened zone physical and geometrical characteristics. Based on the experimental data and analysis of variance, the direct and interactive contributions of the process parameters on the variation of the hardness profile shape and the hardened depth are analyzed. The main effects and the interaction effects are also evaluated. The results reveal that all the process parameters are relevant. The cumulative contribution of the three parameters in the hardened depth variation represents more than 80% with a clear predominance of laser power. The contribution of the interactions between the parameters represents 12% to 16%. The resulting hardness values are relatively similar for all the experimental tests with about 60 HRC. The evaluation of the produced regression models for hardened depth prediction shows limited performance suggesting that the predictive modeling process can be improved.

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“…In addition to the hardness values HH, laser hardening quality can be also estimated through the depth of the four regions described previously, the melted region (dM), hardened region (dH), over-tempered region (dL) and total transformed region (dC). The hardness profile is a direct result of temperature distribution during and after heating and could greatly affect part distortion, martensite microstructure and compressive residual stresses resulting at the surface [8]. Many studies have featured the laser hardening process, the majority of which were experimental studies limited to examining the effect of process input parameters on the treated layer [5,6].…”

Section: Introductionmentioning

confidence: 99%

ANN Laser Hardening Quality Modeling Using Geometrical and Punctual Characterizing Approaches

2018

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Maximum hardness and hardened depth are the responses of interest in relation to the laser hardening process. These values define heat treatment quality and have a direct impact on mechanical performance. This paper aims to develop models capable of predicting the shape of the hardness profile depending on laser process parameters for controlling laser hardening quality (LHQ), or rather the response values. An experimental study was conducted to highlight hardened profile sensitivity to process input parameters such as laser power (P L), beam scanning speed (V S) and initial hardness in the core (H C). LHQ modeling was conducted by modeling attributes extracted from the hardness profile curve using two effective techniques based on the punctual and geometrical approaches. The process parameters with the most influence on the responses were laser power, beam scanning speed and initial hardness in the core. The obtained results demonstrate that the geometrical approach is more accurate and credible than the punctual approach according to performance assessment criteria.

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Laser surface melt-hardening of gray and nodular irons

Cited by 30 publications

References 3 publications

A new experimental technique for measuring strain and residual stresses during a laser remelting process

A new experimental technique for measuring strain and residual stresses during a laser remelting process

Experimental Investigation of Laser Surface Transformation Hardening of 4340 Steel Spur Gears

ANN Laser Hardening Quality Modeling Using Geometrical and Punctual Characterizing Approaches

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