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 Improvement of Surface Properties of Inconel718 by HVOF Coating with WC-Metal Powder and by Laser Heat Treatment of the Coating

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Hui Gon Chun ◽  
Tong Yul Cho ◽  
Jae Hong Yoon ◽  
Gun Hwan Lee
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
Metal Powder ◽  
Surface Properties ◽  
Porous Coating ◽  
Wear Depth ◽  
Laser Heat Treatment ◽  
Hvof Coating ◽  
Laser Heat

High-velocity oxygen-fuel (HVOF) thermal spray coating with WC-metal powder was carried out by using optimal coating process on an Inconel718 surface for improvement of the surface properties, friction, wear, and corrosion resistance. Binder metals such as Cr and Ni were completely melted and WC was decomposed partially to W2C and graphite during the high temperature (up to 3500°C) thermal spraying. The melted metals were bonded with WC and other carbides and were formed as WC-metal coating. The graphite and excessively sprayed oxygen formed carbon oxide gases, and these gases formed porous coating by evolution of the gases. The surface properties were improved by HVOF coating and were improved further by CO2laser heat treatment (LH). Wear resistance of In718 surface was improved by coating and LH at 25°C and an elevated temperature of 450°C, resulting in reduction of wear trace traces, and was further improved by LH of the coating in reducing wear depth. Corrosion resistance due to coating in sea water was improved by LH. HVOF coating of WC-metal powder on a metal surface and a LH of the coating were highly recommended for the improvement of In718 surface properties, the friction behavior, and wear resistance.

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.

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.

Preform and Die Designs for Hot Forging Process of Linear Slide Block

2013 ◽  
Vol 419 ◽  
pp. 395-400 ◽  
Author(s):  
Cheng Hsien Yu ◽  
Jinn Jong Sheu
Keyword(s):  
Heat Treatment ◽  
Hot Forging ◽  
Laser Heat Treatment ◽  
Forging Process ◽  
Die Filling ◽  
Slide Block ◽  
Laser Heat ◽  
Wear And Corrosion ◽  
Linear Slide ◽  
Hot Forging Process

In this study, the preform and die designs of hot forging process were proposed for a long-flat slide block. This block is assembled to the linear slide for carrying the moving table. Three different billet geometry designs were proposed to obtain good die filling. The volume of the flash is limited to 30% with a flash thickness design in 3 mm. The forging die was designed with four ejectors to push up the forged part smoothly. The proposed billet geometries and die design were evaluated using CAE simulation. The simulation results indicated that the suitable perform design is able to achieve better material flow. The flash flow control is able to reduce the forming load and improve the die filling. The forging experiments were carried out to verify the proposed method, the experiment results showed good agreement with the CAE simulations. 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.

The Effects of HVOF Coating of WC-CrC-Ni Powder on In718 and of CO2 Laser Heat Treatment on the Coating

2009 ◽  
Vol 54 (3) ◽  
pp. 1100-1103 ◽  
Author(s):  
Tong-Yul Cho ◽  
Jae-Hong Yoon ◽  
Yun-Kon Joo ◽  
Shihong- Zhang ◽  
Wei Fang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Co2 Laser ◽  
Laser Heat Treatment ◽  
Hvof Coating ◽  
Laser Heat ◽  
Ni Powder

Improving the Properties of Magnetic Bearing Shaft Material by HVOF Coating of WC-Metal Powder and Laser Heat Treatment

2012 ◽  
Vol 560-561 ◽  
pp. 1052-1058 ◽  
Author(s):  
T.Y. Cho ◽  
Y.K. Joo ◽  
J. H. Yoon ◽  
H. G. Chun ◽  
S.H. Zhang
Keyword(s):  
Heat Treatment ◽  
Metal Powder ◽  
Laser Heating ◽  
Surface Hardness ◽  
Magnetic Bearing ◽  
Free Carbon ◽  
Laser Heat Treatment ◽  
Friction Coefficients ◽  
Hvof Coating ◽  
Laser Heat

Abstract. Micron-sized WC-metal (WC-0.6%C-21%Cr-6%Ni) powder was coated onto the substrate of magnetic bearing shaft material Inconel718 (substrate or In718) using JK3500 HVOF thermal sprayer for the improvement of the surface properties of the substrate. The optimal coating process for the highest surface hardness was obtained using the Taguchi experimental program. The coating was laser heat-treated (LH) by CO2(g) laser for further improvement of the properties. During the thermal spraying, a small portion of metal carbides of powder decomposed to W2C, metals and free carbon. The free carbon reacted with excessively sprayed oxygen, and formed carbon oxide gases, forming porous coating. By laser-heating, porosity decreased and the porous strips at the interface of coating and substrate (coat/sub) compacted. At the interface, the precipitated graphite concentration decreased and the metal elements diffused from both the coating and substrate increased, enhancing the functions as buffer zone and increasing adhesion of coating. The surface hardness of substrate increased by coating and further increased by laser-heating from 410±30 Hv to 983±101 Hv and 1425±94 Hv respectively. Porosity of coating decreased by laser-heating from 2.6±0.4% to 0.35±0.06%, and coating thickness shrank from 280㎛ to 200㎛. Friction coefficients of substrate decreased from 0.52±0.02 to 0.36±0.04 by coating, because the free carbon formed by decomposition of WC to W2C functioned as a solid lubricant. By increasing sliding surface temperature from 25°C to 450°C, the friction coefficients of substrate and coating were decreased from 0.52±0.02 to 0.31±0.02 and from 0.36±0.04 to 0.23±0.04 respectively, because of easy formation of free carbon and metal oxides which functioned as solid lubricants. Wear depth of surface was decreased by coating and by LH coating from 55µm to 32 µm and to 12 µm respectively. HVOF coating of WC-metal powder on In718 surface and laser heat-treatment of the coating are highly recommended for the improvement of the properties of magnetic bearing shaft.

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.

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