Thermal expansion control of composite coatings on 42CrMo by laser cladding

Qi, Kang; Yang, Yong; Hu, Guofang; Lu, Xin; Li, Jindong

doi:10.1016/j.surfcoat.2020.125983

Cited by 51 publications

(14 citation statements)

References 27 publications

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“…During solidification in the laser cladding, the growing grains met. When the molten pool cooled, under the comprehensive action of the temperature gradient, structural fluctuations, and structural changes, local internal stress then formed in the cladding layer, which led to the formation of a small number of dislocation lines in the NV E690 cladding layer [ 21 ].…”

Section: Results and Analysismentioning

confidence: 99%

Dislocation Mechanism and Grain Refinement of Surface Modification of NV E690 Cladding Layer Induced by Laser Shock Peening

et al. 2022

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To investigate the relationship between the dislocation configuration and the grain refinement in the NV E690 cladding layer caused by laser shock peening, NV E690 high-strength steel powder was used to repair prefabricated pits in samples of 690 high-strength steel by laser cladding, where the laser shock peening of the cladding layer was performed by laser shock at different power densities. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to observe the microstructures of these samples before and after the laser shock process. The results showed that the metallurgical bonding between the cladding layer and the substrate after laser cladding repair was good. When the laser power density was 4.77 GW/cm2, multiple edge dislocations, dislocation dipoles, and extended dislocations were distributed over the cladding layer. When the laser power density was 7.96 GW/cm2, a geometrically necessary dislocation divided the large original grain into two subgrains with different orientations. When the laser power density was 11.15 GW/cm2, geometric dislocations divided the entire large grain into fine grains. The grain refinement model of the NV E690 cladding layer, when treated by laser shock peening, can describe the grain refinement process induced by the dislocation movement of this cladding layer.

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Section: Results and Analysismentioning

confidence: 99%

Dislocation Mechanism and Grain Refinement of Surface Modification of NV E690 Cladding Layer Induced by Laser Shock Peening

et al. 2022

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“…Different rates of heat being received by different materials, each with different thermal expansion coefficients therefore introduces a very significant risk when it comes to the LC deposition. Due to its highest expansion coefficient value from the three materials and as the layer constrained by both its upper and lower interfaces, 5 the nickel-based alloy interlayer is therefore experiencing the highest level of thermal stresses. Therefore, the LC process must be done with extra care in the deposition procedure, in order to correctly align the thermal expansion magnitudes 5 to those which best satisfy the stress predictions at bonding regions.…”

Section: Discussionmentioning

confidence: 99%

“…Crack formations and flaking are consequences of thermal stresses, which surpass the coating adhesion bonding strength to the substrate. 5 A degree of expansion results from the increase in temperature of a rotor subject to braking conditions. When a rotor is non-homogeneous (as in the case of coatings), thermal expansion differences mean high thermal stresses are developed at the materials interface.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, challenges, such as crack formations and flaking of coated layers, have demonstrated to occur during braking events. 3 Among other coating technologies, laser cladding (LC; also known as laser metal deposition) by using metal powder welding consumables offers metallurgical bonding of the coating to the substrate, high purity of coating, very low porosity level 5 and quite small thermal deformations of the substrate. It has been proven through pin-on-disc wear testing comparisons with a grey cast iron (GCI) disc that an LC Ni/carbide coating mass wear is halved, specific wear loss is quartered while there was no 'substantial increase' in wear from the pin neither.…”

Section: Introductionmentioning

confidence: 99%

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Simulation of thermal and mechanical performance of laser cladded disc brake rotors

Athanassiou

Olofsson

Wahlström

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part J:

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Disc brakes wear during braking events and release airborne particulates. These particle emissions are currently one of the highest contributors to non-exhaust particle emissions and introduce health hazards as well as environmental contamination. To reduce this problem, wear and corrosion-resistant disc coatings have been implemented on grey cast iron brake disc rotors by using various deposition techniques such as thermal spraying and overlay welding. High thermal gradients during braking introduce risks of flaking off and cracking of thermally sprayed coatings with adhesive bonding to the substrate. Overlay welding by laser cladding offers metallurgical bonding of the coating to the substrate and other benefits that motivate laser cladding as a candidate for the coating of the grey cast iron brake discs. This study aims to investigate the effect of laser cladding on the thermal and thermo-structural performance of the coated grey cast iron brake discs. Therefore, thermal and thermo-stress analysis with COMSOL Multiphysics 5.6 software is performed on braking events of grey cast iron brake discs as non-coated – reference and laser cladding coated with stainless steel welding consumables. The Results demonstrated that surface temperatures were more localised, overall higher in the laser cladded coating with over three times the stresses attained of reference grey cast iron discs. The output of the simulations has been compared by tests found in the literature. Laser cladding presented higher reliability and braking performance, nonetheless requiring the evaluation of its thermal impact on other system components.

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“…Laser melting is one of the methods of laser surface strengthening. It has the characteristics of fast heating and cooling and can improve the mechanical properties of materials by changing their surface properties without changing their composition [2][3][4][5]. For example, Li et al studied the quality and mechanical properties of Ti6Al4V selected-area laser melting and forming [6].…”

Section: Introductionmentioning

confidence: 99%

A Study on the Dynamic Evolution Mechanism of the Steady Magnetic Field on the Internal Flow Behavior of a Laser Melting Pool

Xie

Wang

et al. 2023

Metals

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A 2D model of laser melting consisting of heat transfer, hydrodynamic flow, surface tension, and a free surface motion was established. A physical field simulation of the laser melting process was performed, and the effect of steady magnetic field parameters on the internal flow and temperature fields of the melt pool was analyzed and validated by experiments. The results show that the steady magnetic field can suppress the melt pool flow rate, but slightly influences its temperature field, and with an increase in the magnetic field strength, the ripples on the melting surface decrease with increasing magnetic flux density. Compared with the molten pool depth experiment results, the simulation molten pool depth was 792 μm, representing a difference in value of 13.5%. The surface ripples of the molten pool fluctuated greatly in the absence of a magnetic field, while the surface ripples were suppressed when the magnetic flux density was 2T. This is consistent with the simulation results, thus effectively demonstrating the simulation model’s accuracy.

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Thermal expansion control of composite coatings on 42CrMo by laser cladding

Cited by 51 publications

References 27 publications

Dislocation Mechanism and Grain Refinement of Surface Modification of NV E690 Cladding Layer Induced by Laser Shock Peening

Dislocation Mechanism and Grain Refinement of Surface Modification of NV E690 Cladding Layer Induced by Laser Shock Peening

Simulation of thermal and mechanical performance of laser cladded disc brake rotors

A Study on the Dynamic Evolution Mechanism of the Steady Magnetic Field on the Internal Flow Behavior of a Laser Melting Pool

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