scholarly journals Advanced laser heat treatment with respect for the application for Tailored Heat Treated Blanks

2010 ◽  
Vol 5 ◽  
pp. 233-242 ◽  
Author(s):  
Marion Merklein ◽  
Hung Nguyen
Keyword(s):  
Heat Treatment ◽  
Laser Heat Treatment ◽  
Laser Heat ◽  
Heat Treated

Formability of Ultrafine-Grained AA6016 Sheets Processed by Accumulative Roll Bonding

2012 ◽  
Vol 504-506 ◽  
pp. 575-580 ◽  
Author(s):  
Tina Hausöl ◽  
Christian W. Schmidt ◽  
Verena Maier ◽  
Wolfgang Böhm ◽  
Hung Nguyen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Laser Heat Treatment ◽  
Bending Tests ◽  
Roll Bonding ◽  
Laser Heat ◽  
Heat Treated ◽  
Ultrafine Grained ◽  
Ultrafine Grained Microstructure ◽  
Bending Behaviour

Aluminium alloy AA6016 was accumulative roll bonded up to eight cycles in order to produce an ultrafine-grained microstructure. The formability of these sheets was investigated by means of bending tests. Furthermore the influence of a local laser heat treatment at the bending edge is observed. The strength of the UFG samples is increased by a factor of around two compared to the conventionally grained T4 condition which also results in up to 50 % higher punch forces needed for bending of ARB processed samples. An anisotropic bending behaviour is observed. By applying a tailored laser heat treatment along the bending edge prior to the bending tests a local recrystallization and recovery at the deformation zone of the samples is achieved. Thus, ductility is increased locally whereby bending to an angle of 80° is possible with lower forming forces compared to the non-heat treated specimens. The results are compared to previous studies on mechanical properties and formability investigations of ARB processed AA6016.

scholarly journals Nanostructuring Behavior of NiCrBSi and CoCrWC Thermal Spray Coatings Formed by Temperature-Controlled Laser Heat Treatment

2020 ◽  
Vol 58 (4) ◽  
pp. 247-256 ◽  
Author(s):  
Eun-Joon Chun
Keyword(s):  
Heat Treatment ◽  
Thermal Spray ◽  
Spray Coating ◽  
Thermal Spray Coating ◽  
Laser Heat Treatment ◽  
Real Time Control ◽  
Continuous Casting Mold ◽  
Time Control ◽  
Laser Heat ◽  
Heat Treated

.For surface hardening of a continuous casting mold component, a thermal spray coating of NiCrBSi (Metco-16C) and CoCrWC (Stellite-1) was performed followed by laser heat treatment of the coatings. To support selective modification of the thermal spray coating, a metallurgically determined surface temperature was maintained during the laser heat treatment, by real-time control of the laser power. In other words, nonhomogeneities in the macrosegregation of certain alloying elements, and voids in the as-sprayed state, could be improved. The main microstructural features of the Metco-16C coating laser-heat-treated at 1423 K were nanosized (100–150 nm) Cr5B3, M7C3, and M23C6 precipitates with a lamellar structure of Ni (FCC) and Ni3Si as the matrix phase. Those of the laser heat-treated Stellite- 1 coating at 1473 K were fine (30–250 nm) precipitates of WC, M7C3, and M23C6 based on a Co (FCC) matrix. The results show that laser heat treatment at 1423 K increased the hardness of the Mecto-16C coating to 1115 HV from the as-sprayed state (754 HV), while treatment at 1473 K increased the hardness of the Stellite-1 coating from 680 HV to 860 HV.

scholarly journals Correlation between Microstructure and Tribological Properties of Laser Surface Heat-Treated Stellite Coatings

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 433
Author(s):  
Chang-Kyoo Park ◽  
Jung-Hoon Lee ◽  
Nam-Hyun Kang ◽  
Eun-Joon Chun
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Tribological Properties ◽  
Superior Performance ◽  
Laser Heat Treatment ◽  
Continuous Casting Mold ◽  
Heat Treated Sample ◽  
Laser Heat ◽  
Heat Treated ◽  
Sprayed Coating

To manufacture superior-performance continuous casting mold components, high-velocity oxygen fuel spraying of a Stellite-1 coating was followed by its laser heat treatment at 1373–1473 K using a diode laser. The effects of the laser irradiation conditions on the macro- and microstructural variations along with the hardness and wear resistance within the Stellite-1 coating were evaluated. After the heat treatment, micro-voids within the sprayed coating decreased in number slightly with an increase in the heat treatment temperature. The hardness of the sprayed Stellite-1 coating increased from that of the as-sprayed coating (680 HV) after the laser heat treatment, with a hardness of 860 HV obtained at 1473 K. The cause of the increase in hardness could be the formation of nano-sized W- and Cr-based carbides such as WC, M7C3, and M23C6, as suggested by transmission electron microscopy analysis. The tribological properties of as-sprayed and laser heat-treated samples were investigated by a pin-on-disk tribometer. The laser heat treatment of Stellite-1 coating enhanced wear resistance. This resulted in a lower coefficient of friction and wear rate for the laser heat-treated sample than those for the as-sprayed sample.

Effect of selective laser heat treatment on geometrical variation in boron steel components: An experimental investigation

2020 ◽  
Vol 235 (1-2) ◽  
pp. 54-64
Author(s):  
Vaishak Ramesh Sagar ◽  
Kristina Wärmefjord ◽  
Rikard Söderberg
Keyword(s):  
Heat Treatment ◽  
High Strength ◽  
Boron Steel ◽  
Laser Heat Treatment ◽  
Laser Heat ◽  
Heat Treated ◽  
Geometrical Variation ◽  
And Performance ◽  
Boron Steels ◽  
Heating Direction

Selective laser heat treatment is a well-known process for its ability to produce tailor heat treated blanks (THTB). Specifically, ultra high strength boron steels with tailored material properties can be produced. However, this process generates unwanted distortion and influences geometrical variation. This in turn can affect functionality, aesthetics, and performance of the final product. Understanding the effects on geometrical variation in the final product or the assembly will enable in designing and producing geometry assured products. In this paper, boron steel blanks were selectively laser heat treated with a specific heat treatment pattern and laser heating direction sequence. These heat treated blanks were then cold formed. Further on, spot welding simulation of the cold formed parts was performed to assess the effect on geometrical variation at the assembly level. The results show that the effect of selective laser heat treatment on geometrical variation at part level propagates further to the assembly level. It implies that the effect on geometrical variation should be minimized at part level, when the blanks are laser heat treated. Hence, the sources that influence geometrical variation at part level when employing selective laser heat treatment are presented and discussed. The motivation and possibilities to minimize the effects in the early design concept stages is provided.

Wear and Corrosion Resistances of Inconel718, HVOF Coating of WC-Metal Powder and Laser Heat-Treated Coating

2013 ◽  
Vol 419 ◽  
pp. 381-387
Author(s):  
Hui Gon Chun ◽  
Yun Kon Joo ◽  
Jae Hong Yoon ◽  
Tong Yul Cho ◽  
Wei Fang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Sea Water ◽  
Spray Coating ◽  
Porous Coating ◽  
Wear Depth ◽  
Laser Heat Treatment ◽  
Hvof Coating ◽  
Laser Heat ◽  
Wear And Corrosion ◽  
Heat Treated

For the Improvement of wear and corrosion resistances of Inconel718 (In718) surface, high velocity oxygen fuel (HVOF) thermal spray coating of micron-sized WC-Cr-C-Ni powder was coated onto Inconel718 surface and laser heat-treatment of the coating was carried out. Porous coating of porosity 2.2±0.4% was prepared by HVOF coating, and it was improved by laser heat-treatment, reducing the porosity to 0.35±0.08%. Micro-hardness of laser heat-treated coating increased more than four times compared to the surface of In718. Friction coefficient decreased by HVOF coating and laser heat-treatment. Wear resistance improved, decreasing the wear depth by the coating and laser heating. The interface between coating and In718 was compacted, and elements diffused from both coating and inconel718 substrate to interface, forming metal rich buffer zone (interface) and enhancing the adhesion of coating. Corrosion resistance improved by coating in sea water 3.5% NaCl solution and in 1M HCl acid, but it worsened in 1M NaOH base. For the improvement of wear and corrosion resistances of Inconel718, HVOF WC-metal power coating and laser heat-treatment are recommended.

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

Metals ◽  
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.

Optimization of Local Laser Heat Treatment Process Using a Simple FE-Model

2013 ◽  
Vol 762 ◽  
pp. 360-367
Author(s):  
Antti Järvenpää ◽  
T. Kiuru ◽  
Antti Määttä ◽  
Matias Jaskari ◽  
Kari Mäntyjärvi
Keyword(s):  
Heat Treatment ◽  
Finite Element ◽  
Process Parameters ◽  
Treatment Process ◽  
Maximum Temperature ◽  
Fe Model ◽  
Heat Treatment Process ◽  
Laser Heat Treatment ◽  
Laser Heat ◽  
Heat Treated

Local laser heat treatment is an efficient method to manufacture tailored heat-treated steel strips. It can be applied to soften narrow zones of the strip in order to improve its formability on desired areas. However, the properties achieved are dependent on several process parameters. An objective is to develop a predictive model to optimize the heat treatment parameters instead of using experimental trials. In the present study, a finite element model was applied to predict the maximum temperature and heating and cooling rates, as well as the heat distribution along the heat treated area. To develop the model and to test its feasibility, experiments were performed, in which process parameters were varied to study their effects on temperature distribution in a 6 mm thick abrasion resistant steel grade. Scanning of a laser beam was used to optimize the width and depth of the heat-affected zone.In practice, local laser heat treatment process parameters have to be optimized with care for successful results. The most important task is to minimize the temperature gradient between the surfaces and to keep the peak temperatures close to the austenitizing temperature. The results indicate that a simple model can be used to predict the outcome of the heat treatment, so that finite element modeling can be adopted as a suitable tool for design of local heat treatments, allowing more advanced treatments and applications with complex geometries.

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

2018 ◽  
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.

Sub-millisecond post exposure bake of chemically amplified resists by CO 2 laser heat treatment

2010 ◽  
Author(s):  
Byungki Jung ◽  
Jing Sha ◽  
Florencia Paredes ◽  
Christopher K. Ober ◽  
Michael O. Thompson ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Laser Heat Treatment ◽  
Post Exposure ◽  
Chemically Amplified ◽  
Laser Heat ◽  
Post Exposure Bake ◽  
Chemically Amplified Resists
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