• Journal of Welding and Joining
• /
• 제15권2호
• /
• pp.43-53
• /
• 1997

The complete joining method for dissimilar press punch materials and its real-time evaluation method is not available at present. Brazing method has been used for joining them, but it is known that the welded joint by the brazing has the lower bonding efficiency and reliability than the diffusion welding. The friction welding with a diffusion mechanism in bonding was applied in this study. This work was carried out to determine the proper friction welding conditions and to analyze mechanical properties of friction welded joints of sintered carbide tool materials (SKNM50 for the blade part of press punch) to alloy steel (SCM440 for the shank part of press punch) using aluminum (A6061 for the interlayer material) as an insert material between the sintered carbide tool materials and the alloy steel. In addition, acoustic emission test was carried out during friction welding to evaluate the weld quality.

• Tribology and Lubricants
• /
• 제29권2호
• /
• pp.98-104
• /
• 2013

Cu-matrix-sintered brake pads and heat-resistant low-alloy steel are commonly applied to basic brake systems in high-energy moving machines. We analyzed how the tribological characteristics are influenced by the inertial mass. A high inertial mass decreased the friction coefficient by about 15% compared to a low inertial mass under all velocity conditions. The wear rates of the friction materials increased with the inertial mass. Thus, the inertial mass influences the friction coefficient and wear rate of the friction materials and disk but not the friction stability.

• Tribology and Lubricants
• /
• 제14권1호
• /
• pp.45-53
• /
• 1998

Friction and wear test for two kinds of Cu-based sintered metallic friction material against cast iron disk was carried out by plate-on-disk type friction and wear tester to investigate the friction and wear characteristics of brake system in severe condition. In this experimental study, the counter specimen was cast iron which is being used generally in brakes of heavy duty equipments. Test friction materials were A type which was manufactured by foreign company and B type by domestic company. Friction coefficient and wear volume were measured and compared with each other. The experiment was performed under room temperature. The worn surface of cast iron disk and friction material were observed by scanning electron microscope. The temperature of surface of disk was measured continuously by the non-contacting thermometer. It was found that A type friction material had stable friction coefficient over the wide range of sliding condition, but B type friction material had unstable friction coefficient and lower value of 0.2 under the severe sliding condition.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 1995년도 특별강연 및 추계학술발표 개요집
• /
• pp.165-169
• /
• 1995

This paper deals with determining the proper friction welding condition and analyzing mechanical in of friction welded joints of sintered carbide tool materials (SKNM50 for the blade part of press punch) to alloy steel (SCM440 for the shank part of press punch), the alloy steel to aluminum(A6061 for the interlayer material between the blade part and the shank) and sintered carbide tool materials to aluminum. And also acoustic emission test will be carried out during fiction welding to evaluate the weld quality.

• 한국해양공학회지
• /
• 제10권1호
• /
• pp.36-46
• /
• 1996

This paper deals with determinig the proper friction welding condition and analyzing various mechanical properties of friction welded joints of sintered carbide tool materials(K20, P25, and SKDX5 for the blade part of drill or press punch) to alloy steel (SKH4, SCM440 for the shank part of drill or press punch), the alloy steel to aluminum(A6061 for the interlayer material between the blade part and the shank) and sintered carbide tool materials to alumminum. And also acoustic emission test will be carried out during fiction welding to evaluate the weld quality.

• 대한기계학회논문집A
• /
• 제20권1호
• /
• pp.44-52
• /
• 1996

Influence of frictional and mechanical properties was studied with the content(8-18 wt.%) and shapes(flake of irregular) of graphite that was used as lubricant components of copper-based sintered materials. The density, hardness and bending strength of friction materials with the shape of flake graphite were lower and decreased rapidly than that of irregular, as the content of graphite increases up to 18 wt.%. In friction test, wear rate was about 2.0-$2.5{\times}10^{-7}\textrm{cm}^3$/kgf.m and coefficient of friction was 0.30-0.37, independent on graphite content and shape. As the temperature of friction materials increased, wear rate decreased rapidly because oxides such as $Cu_2O$ and $SnO_2$ in the surface of friction material were formed.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 1994년도 추계학술대회강연 및 발표대회 강연및 발표논문 초록집
• /
• pp.12-13
• /
• 1994

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 1995년도 추계학술강연 및 발표대회 강연 및 발표논문 초록집
• /
• pp.15-15
• /
• 1995

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.975-985
• /
• 2011

Cu-Matrix sintered brake pads and low alloyed heat resistance steel are most applied to basic brake system for high energy moving machine. In this research, we analyzed tribological characteristics for influence of air velocity between disk and pad. At low brake pressure with air flow, friction stability was decreased due to no formation of tribofilm at disk surface. But there are no significant change of friction coefficient at all test conditions. Wear rate of friction materials were decreased with increasing of air flow velocity. In result, air flow velocity influenced friction stability, wear rate of friction materials and disk but not friction coefficient.

• Tribology and Lubricants
• /
• 제12권3호
• /
• pp.48-54
• /
• 1996

Examined in this paper, is the effect of B$_{4}$C addition on the frictional characteristics of Cu-Sn based sintered friction materials. For the specimens 1wt%, 2wt% and 4wt% of B$_{4}$C were added into the reference material. A pin-on-disk type friction tester was used to,measure the friction torque with respect to the surface temperature and sliding distance. Wear mechanism of each specimen is analyzed in the view point of the oxide film formation. The specimen containing 4wt% of B$_{4}$C showed stable friction and low wear since the oxide film was sustained up to higher surface temperature ranges.