Laser transformation hardening of a tool steel: Simulation-based parameter optimization and experimental results

Tobar, M.J.; Álvarez, Carlos Luis Molpeceres; Amado, J.M.; Ramil, A.; Saavedra, E.; Yáñez, A.

doi:10.1016/j.surfcoat.2005.11.067

Cited by 43 publications

(22 citation statements)

References 7 publications

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“…Rapid cooling of the austenite, which is formed only within a thin layer during laser hardening due to the self-sealing of the material when the laser beam is moved away, makes it difficult for carbon to diffuse outside its lattice [26] [27]. When the carbon is trapped in the network and cooled, the face-centered cubic crystal structure of austenite is transformed into a hybrid quadratic structure, called martensite [5]. The martensitic volume fraction, f, which is formed on a period T, is given by Equation (11) …”

Section: Metallurgical Modelingmentioning

confidence: 99%

See 1 more Smart Citation

Hardness Profile Prediction for a 4340 Steel Spline Shaft Heat Treated by Laser Using a 3D Modeling and Experimental Validation

Hadhri¹,

Ouafi²,

Barka³

2016

MSCE

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Laser surface transformation hardening becomes one of the most effective processes used to improve wear and fatigue resistance of mechanical parts. In this process, the material physicochemical properties and the heating system parameters have significant effects on the characteristics of the hardened surface. To appropriately exploit the benefits presented by the laser surface hardening, it is necessary to develop a comprehensive strategy to control the process variables in order to produce desired hardened surface attributes without being forced to use the traditional and fastidious trial and error procedures. The paper presents a study of hardness profile predictive modeling and experimental validation for spline shafts using a 3D model. The proposed approach is based on thermal and metallurgical simulations, experimental investigations and statistical analysis to build the prediction model. The simulation of the hardening process is carried out using 3D finite element model on commercial software. The model is used to estimate the temperature distribution and the hardness profile attributes for various hardening parameters, such as laser power, shaft rotation speed and scanning speed. The experimental calibration and validation of the model are performed on a 3 kW Nd:Yag laser system using a structured experimental design and confirmed statistical analysis tools. The results reveal that the model can provide not only a consistent and accurate prediction of temperature distribution and hardness profile characteristics under variable hardening parameters and conditions but also a comprehensive and quantitative analysis of process parameters effects. The modelling results show a great concordance between predicted and measured values for the dimensions of hardened zones.

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Section: Metallurgical Modelingmentioning

confidence: 99%

“…Subsequent removal of this energy results in self-quenching caused by the conduction of heat into the relatively cool bulk of the material. This produces a rapidly cooled surface layer and causes a transformation of the austenite into martensite [1]- [5].…”

Section: Introductionmentioning

confidence: 99%

Hardness Profile Prediction for a 4340 Steel Spline Shaft Heat Treated by Laser Using a 3D Modeling and Experimental Validation

Hadhri¹,

Ouafi²,

Barka³

2016

MSCE

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“…Due to the complex nature of underpinned physics and many controlling parameters of laser techniques, conducting experiments of those processes cost a lot of time and efforts. Regarding the fact, simulation and modelling of laser surface modification processes offer the best way of optimising the process and predicting residual stress [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical modelling of laser surface glazing for H13 tool steel

et al. 2018

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A two-dimensional thermomechanical finite element (FE) model of laser surface glazing (LSG) has been developed for H13 tool steel. The direct coupling technique of ANSYS 17.2 (APDL) has been utilised to solve the transient thermomechanical process. A H13 tool steel cylindrical cross-section has been modelled for laser power 200 W and 300 W at constant 0.2 mm beam width and 0.15 ms residence time. The model can predict temperature distribution, stress-strain increments in elastic and plastic region with time and space. The crack formation tendency also can be assumed by analysing the von Mises stress in the heat-concentrated zone. Isotropic and kinematic hardening models have been applied separately to predict the after-yield phenomena. At 200 W laser power, the peak surface temperature achieved is 1520 K which is below the melting point (1727 K) of H13 tool steel. For laser power 300 W, the peak surface temperature is 2523 K. Tensile residual stresses on surface have been found after cooling, which are in agreement with literature. Isotropic model shows higher residual stress that increases with laser power. Conversely, kinematic model gives lower residual stress which decreases with laser power. Therefore, both plasticity models could work in LSG for H13 tool steel.

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“…Also the reduction of the tempering effect that appears when several hardening tracks are placed next to each other is a main challenge [8,12,13]. The enabler to enhance all of these factors is the temperature field [14] that is caused by the intensity distribution of the laser as well as the feed rate, spot size and temperature regulation. A lot of research has been done to predict the outcome of these parameters by simulation [12,[15][16][17].…”

Section: Introductionmentioning

confidence: 99%

“…Mioković et al [19] researched the effect of the austenitisation process as well as the martensitic kinetics. Tobar et al [14] implemented an even more complex model of the metallurgical effect in laser hardening. Leung et al [20] described the effect of an optimized intensity distribution caused by a diffractive optical kinoform.…”

Section: Introductionmentioning

confidence: 99%

Optimization of the Laser Hardening Process by Adapting the Intensity Distribution to Generate a Top-hat Temperature Distribution Using Freeform Optics

2017

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Laser hardening is a surface hardening process which enables high quality results due to the controllability of the energy input. The hardened area is determined by the heat distribution caused by the intensity profile of the laser beam. However, commonly used top-hat laser beams do not provide an ideal temperature profile. Therefore, in this paper the beam profile, and thus the temperature profile, is optimized using freeform optics. The intensity distribution is modified to generate a top-hat temperature profile on the surface. The results of laser hardening with the optimized distribution are thereupon compared with results using a top-hat intensity distribution.

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Laser transformation hardening of a tool steel: Simulation-based parameter optimization and experimental results

Cited by 43 publications

References 7 publications

Hardness Profile Prediction for a 4340 Steel Spline Shaft Heat Treated by Laser Using a 3D Modeling and Experimental Validation

Hardness Profile Prediction for a 4340 Steel Spline Shaft Heat Treated by Laser Using a 3D Modeling and Experimental Validation

Thermomechanical modelling of laser surface glazing for H13 tool steel

Optimization of the Laser Hardening Process by Adapting the Intensity Distribution to Generate a Top-hat Temperature Distribution Using Freeform Optics

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