• Journal of the Korean Society for Heat Treatment
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• v.30 no.4
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• pp.164-168
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• 2017

Intense electron beam was irradiated on the CrAlN thin films deposited in SKD61 under different incident energies and then the effect of electron beam irradiation on the enhancement of surface hardness and wear resistance was investigated. Surface hardness and wear resistance of the CrAlN films is increased proportionally with the electron beam energy. While the surface hardness of as deposited CrAlN film is Hv ($0.1g{\cdot}f$) 450, the hardness oflectron irradiated (600 eV) film is Hv ($0.1g{\cdot}f$) 2050. The width of wear track of the untreated SKD61 is $X\_{\mu}m$, while the track-width of the electron irradiated CrAlN (600 eV) film is $787{\mu}m$, respectively. From the observed results, it is supposed that the optimal electron beam irradiation can be one of the useful surface treatment technologies for the enhancement of surface hardness and wear resistance of CrAlN/SKD61, simultaneously.

• Journal of Welding and Joining
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• v.33 no.3
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• pp.54-61
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• 2015

In this study, effect of laser power on hardness and microstructure of SKD61 Hot Die steel of which surface was melted and hardened with Yb:YAG disk laser was investigated. Beam speed was fixed at 70 mm/sec and distance between them was 0.8 mm about Laser surface melting. The only thing that was changed laser power. Laser powers were 2.0, 2.4 and 2.8 kW. No defect was found under all conditions. As the laser power increased, the penetration depth were deepened and the bead width was also widened. There was no hardness deviation of fusion zone at same laser power and it was higher than that of heat affected zone. In addition, the more laser power increased, the more hardness in fusion zone decreased. Fusion zone was macroscopically dendrite structure. However, core matric in dendrite was lath martensite of 100 nm size. There were $M_{23}C_6$ of 500 nm and the VC and $Mo_2C$ of a nano meters on boundary of dendrite.

• Journal of the Korean institute of surface engineering
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• v.43 no.6
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• pp.278-282
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• 2010

In this research, the friction and wear characteristic behaviors of coating materials of TiAlN and CrAlN were investigated. The wear test was conducted in air and un-lubricated state using the reciprocating friction wear tester. Temperature were 50 and $120^{\circ}C$, and load were 3, 7, and 11 kgf for tests. By comparing the coefficient of friction and observing the wear microstructure, the friction and wear characteristic behaviors of TiAlN and CrAlN coating layers on SKD61 were investigated. The coefficient of friction of CrAlN coating was lower than that of TiAlN at all conditions. Therefore, CrAlN was suggested to be more advantageous coating than TiAlN for the extrusion mold of aluminum.

• Journal of Power System Engineering
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• v.18 no.5
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• pp.94-99
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• 2014

In this study, AISI M2 powder was selected primarily through various literature in order to improve the hardness and wear resistance. Among the laser metal deposition parameters, laser power was studied to improve the deposition efficiency in the laser metal deposition using a diode pumped disk laser. SKD61 hot work steel plate and AISI M2 powder were used as a substrate and powder for laser metal deposition, respectively. Fixed parameters are CTWD, focal position, travel speed, powder feed rate, etc. Experiments for the laser metal deposition were carried out by changing laser power. Through optical micrographs analysis of cross-section in LMD track, effect of the major parameters were predicted by track pitch. As the track pitch increased, so the reheated zone width, the overlap width and the minimum thickness was decreased. The hardness was decreased in the HAZ area, the hardness in the reheated HAZ area was decreased significantly and regularly in particular.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.50-56
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• 2015

In this study, AISI M2 powder was selected primarily through various pieces of literature in order to improve the hardness and wear resistance. Among the laser metal deposition parameters, laser power was studied to improve the deposition efficiency in the laser metal deposition using a diode-pumped disk laser. An SKD61 hot work steel plate and AISI M2 powder were used as a substrate and powder for laser metal deposition, respectively. Experiments for the laser metal deposition were carried out by changing the laser power and track layer. The quality of the track surface and cross-section after applying the single-layer method was better than that obtained from applying the multi-layer method. As the laser power increased, the track thickness was increased, and the surface roughness deviation was decreased. In laser power condition of 1.6kW, the maximum hardness of the deposition track was 790Hv. This value was 40% better than the hardness of the SKD61 after heat treatment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.26-30
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• 1996

This paper presents the performance of CBN tools in the machining of hardened die-materials, SKD11 and SKD61 steel with HRC 50, by high-speed face milling. Generally, grinding or EDM is being used in machining of hardened materials but the cost is very high. If those can be replaced by cutting, it will be a greatly economical advantage. CBN tool has been recognized as an effective tool in turning, but it has not been in milling. So wear and surface roughness mode of CBN tool for hardened SKD11 and SKD61 steel were investigated by high-speed face milling in this study Also the relation between cutting force and wear mode of CBN tools was investigated.

• Journal of the Korean institute of surface engineering
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• v.47 no.6
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• pp.282-286
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• 2014

Wear characteristic of the nitrided SKD61 which is a typical mold material using for the extrusion of Al6061 alloy was investigated. The surface of SKD61 was nitrided by salt bath and plasma processes. The thickness of surface nitride layer was about $8.9{\mu}m{\sim}21.3{\mu}m$. Reciprocating friction wear test conducted using pin on disk type indicated the plasma treatment followed salt bath has a lower friction coefficient and a smaller adhesive wear with Al6061 alloy. That was identified by the $Fe_4N$ which has a better wear resistance than FeN mainly formed by plasma nitriding.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.170-170
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• 2015

아크이온플레이팅(AIP)을 이용하여 SKD61강에 TiN 및 TiAlN을 증착함으로써 내산화성 및 아연증기와의 반응을 억제할 수 있었으며, 도금두께 제어를 위한 에어나이프의 수명개선 및 생산성향상에 매우 중요한 요인으로 판단되었다.

• Journal of Korea Foundry Society
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• v.29 no.4
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• pp.169-175
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• 2009

Effect of iron and manganese contents on die soldering reaction has been studied in Al-9wt.%Si-0.3wt.%Mg alloy. Ternary ${\alpha}_{hcp}-Al_8Fe_2Si$ and ${\alpha}_{bcc}-Al_8Fe_2Si$ intermetallic compounds formed by interaction diffusion between Al-Si-Mg system alloy melt and SKD61 die steel surface. Thickness of soldering reaction layer in die steel surface decreased as Fe and Mn contents of the melts increased : When Fe content of Al-9wt.%Si-0.3wt.%Mg melts at constant 0.5wt%Mn content was 0.15wt.%, 0.45wt.% and 0.6wt.%, thickness of soldered layer of each alloy was $64.5{\mu}m,\;57.3{\mu}m$ and $46.9{\mu}m$ respectively. For Mn content of the alloy melts at constant 0.45wt.%Fe content was 0.30wt.%, 0.50wt.% and 0.70wt.%, thickness of soldered layer of each alloy was $66.1{\mu}m,\;57.3{\mu}m$ and $48.3{\mu}m$ respectively.

• Journal of the Korean institute of surface engineering
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• v.42 no.6
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• pp.272-275
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• 2009

The purpose of this study is to show the friction and wear characteristic behaviors of TiN and CrN coated SKD61 which is applied to Al 6xxx extrusion mold material. The friction and wear characteristic behaviors of both coating layers were investigated by the reciprocating friction wear tester under atmospheric pressure and un-lubricated state. The processing parameters in this study were temperature (50 and $120^{\circ}C$) and load (3, 5, and 11 kgf). This study was carried out while comparing the coefficient of friction and microstructure of TiN and CrN coating layers on SKD61. The coefficient of friction of CrN became lower than that of TiN at all conditions. Therefore, CrN was suggested to be more advantageous than TiN for extrusion mold.