• Journal of Welding and Joining
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• v.30 no.5
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• pp.40-45
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• 2012

Nowadays in Republic of Korea, whole amount of the thermite welding powder for rail joinning is dependent on import. However the demand of the thermite welding powder would be enlarge because some constructing high-speed train and city metro projects are currently in progress. In addition this is the main reason why we should develop the thermite welding powder, domestically. This study is focused on utilizing the recyclable materials like Al powders from cans and iron oxide scales from wire rods as the main components of the thermite welding powder. By minimizing Al content in weld zone by controlling the mixing ratio of the Al powder in the thermite welding powder, the excessive dissolution of the Si and Mn components came from the Al powders could be controled. The tensile strength of welding zone in welded rail was 740 MPa, with that the developed thermite welding powder.

• Journal of Powder Materials
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• v.30 no.4
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• pp.332-338
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• 2023

Thermite welding is an exceptional process that does not require additional energy supplies, resulting in welded joints that exhibit mechanical properties and conductivity equivalent to those of the parent materials. The global adoption of thermite welding is growing across various industries. However, in Korea, limited research is being conducted on the core technology of thermite welding. Currently, domestic production of thermite powder in Korea involves recycling copper oxide (CuO). Unfortunately, controlling the particle size of waste CuO poses challenges, leading to the unwanted formation of pores and cracks during thermite welding. In this study, we investigate the influence of powder particle size on thermite welding in the production of Cu-thermite powder using waste CuO. We conduct the ball milling process for 0.5-24 h using recycled CuO. The evolution of the powder shape and size is analyzed using particle size analysis and scanning electron microscopy (SEM). Furthermore, we examine the thermal reaction characteristics through differential scanning calorimetry. Additionally, the microstructures of the welded samples are observed using optical microscopy and SEM to evaluate the impact of powder particle size on weldability. Lastly, hardness measurements are performed to assess the strengths of the welded materials.

• Tribology and Lubricants
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• v.15 no.2
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• pp.178-183
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• 1999

This paper presents friction and wear related results of thermite and gas pressure welded rails under various environmental contact conditions. A welded rail which was fabricated by thermite welding and gas pressure one has been tested over full range of test conditions in a pin-on-disk wear testing machine. The results show that the friction coefficient and wear rates of a welded rail are heavily dependent on the contact pressures and sliding environments for two welding methods such as thermite and gas pressure weldings.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.345-353
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• 1999

This paper presents friction and wear related results of thermite and gas pressure welded rails under various environmental contact conditions. A welded rail which is manufactured by thermite welding and gas pressure one has been tested rail full range of test conditions in a pin-on-disk wear testing machine. The results show that the friction coefficient and wear rates of a welded rail are heavily dependent on the contact pressures and sliding environments for two welding methods such as thermite and gas pressure weldings.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.10a
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• pp.59-66
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• 1998

This paper presents friction and wear related results of thermite and gas pressure welded rails under various environmental contact conditions. A welded rail which is fabricated by thermite welding and gas pressure one has been tested over full range of test conditions in a pin-on-disk wear testing machine. The results show that the friction coefficient and wear rates of a welded rail are heavily dependent on the contact pressures and sliding environments for two welding methods such as thermite and gas pressure weldings.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.431-437
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• 2000

In this paper, thermite and gas pressure weldings have been used to join rails in-track and analyzed as functions of hardness and wear characteristics. The wear rate of thermite welded rail is low compared with that of gas pressure welded rail, which is tested in a pin-on-disk wear tester. The hardness of thermite welded materials is relatively high and narrowly distributed between three zones; welded part, thermally affected zone, and base matrix. Wear of a welded rail may be a major factor in railroad maintenance costs and failures at the rail-rail huh joint.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.10a
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• pp.234-243
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• 1998

In this paper, thermite and gas pressure weldings have been used to join rails in-track and analyzed as functions of hardness and wear characteristics. The wear rate of thermite welded rail is low compared with that of gas pressure welded rail, which is tested in a pin-on-disk wear tester. The hardness of thermite welded materials is relatively high and narrow distributed between three zones, welded part, thermally affected zone, and a base matrix. Wear of a welded rail may be a major factor in railroad maintenance costs and failures at the rail-rail butt joint.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.339-344
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• 1999

In this paper, the hardness and wear characteristics of the head hardened rail, which is made by thermite and gas pressure weldings have been presented. In general, the wear rate of the gas pressure welded rail is high and uniform compared with that of thermite welded rail. The results indicate that HH 370 welded rail shows stable in hardness and low wear rate compared with other two welded rails. The hardness of head hardened rails shows uniformly distributed along the welded zone, thermally affected zone and a base matrix.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2101-2106
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• 2011

It is reported that about more than 45% of damage shown in railroad rails include breakage of rail end which cross the center of Thermit welded zone. Thermite welding is always accompanied by numerous aluminum oxide and secondary inclusions, which may have a negative influence on the ductility and toughness of the weld metal. In this study the aluminum powder recycled by waste aluminum can was used for iron oxide generated after the process of welding rod and the remain aluminum was reduced by minimizing the quantity of aluminum. And complete dissolution was induced by using ferro Mn powder as the additive element. This study reviewed the applicability of heat treatment in the welded zone of rail using ceramic heating pad by carrying it out. This study could observe the improvement of the mechanical characteristics (UTS and elongation) and the changes of failure mechanism from brittleness to ductility. It could be found that improved strength and elongation result from pearilte fine structure.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.793-799
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• 2004

In track a third weakness point is joint part, turnout part, curve part. One of them joint part of rail have been known to the most weak point by loosen of joint bar and fish bolt due to impulse and vibration by wheel contact at times. In addition happen to deformation and failure at end of rail, failure and miniature of ballast gravel. Finally impact between wheel and rail become origin cause of a welded rail, noise and vibration. riding condition deterioration, besides track failure. In the present domestic, Thermite and Gas pressure weldings have been used to continuous welded rail(CWR), however stiffness and confidence in quality is lower than Flash butt welding method. FRW have the excellent capacity, however have a shortcoming large scale of machine and power equipment. Therefore we will introduce Mobile Flash Butt Welder can weld in track.