• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.219-220
• /
• 2002

To establish a thermodynamic basis for degradation, a hypothesis was made on the potential correlation between entropy and degradation for wear of machinery components. This paper reports an experimental study of wear of model machinery component pairs, on an accelerated testing basis. Measured were wear, friction, temperatures, and entropy flow. Results show a strong correlation between the referenced wear and the production of entropy flow. The hypothesis linking wear to entropy led to formulations consistent with the Archard/Holm wear law.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.11
• /
• pp.1881-1888
• /
• 2003

This study show a numerical method to predict roll wear in the roll forming process. Archard's wear model was reformulated in an elemental form to predict volume of roll wear and then wear depth on the roll was calculated using the results of finite element analysis. Abrasive wear occurs at contact area in the roll forming process and the results of simulation are compared with experimental data in production line. The wear simulation approach with 3-D FEM program for roll forming process, SHAPE-RF is in good agreement with it in tendency.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1999.11a
• /
• pp.25-34
• /
• 1999

In this study, the sliding wear in spur gears, using Archard's wear model, is analyzed. Formulas of tooth sliding wear depth along the line of action are derived. The tooth profile is modified Id make a smooth transmission of the normal loads and the cylinder profile for reducing the pressure spike is suggested. The sliding wear rate is calculated with these profiling results. We expect these modification methods to contribute to the reduction of sliding wear in the root and the tip of tooth and tooth edge.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.6
• /
• pp.96-103
• /
• 2002

The objective of this study is to adjust the roll gap fur the dimension accuracy of bar in hot bar rolling process considering roll wear. In this study hot bar rolling processes fur round and oval passes have been investigated. In order to predict the roll wear, the wear model is reformulated as an incremental from and then wear depth of roll is calculated at each deformation step on contact area using the results of finite element analysis, such as relative sliding velocity and normal pressure at contact area. Archard's wear model was applied to predict the roll wear. To know the effects of thermal softening of DCI (Ductile Cast Iron) roll material according to operating conditions, high temperature micro hardness test is executed and a new wear model has been proposed by considering the thermal softening of DCI roll expressed in terms of the main tempering curve. The new technique developed in this study for adjusting roll gap can give more systematically and economically feasible means to improve the dimension accuracy of bar with full usefulness and generality.

• International Journal of Precision Engineering and Manufacturing
• /
• v.4 no.1
• /
• pp.56-62
• /
• 2003

The objective of this study is to adjust the roll gap for the dimension accuracy of bar in hot bar rolling process considering roll wear. In this study hot bar rolling processes for round and oval passes have been investigated. In order to predict the roll wear, the wear model is reformulated as an incremental form and then wear depth of roll is calculated at each deformation step on contact area using the results of finite element analysis, such as relative sliding velocity and normal pressure at contact area. Archard's wear model was applied to predict the roll wear. To know the effects of thermal softening of DCI (Ductile Cast Iron) roll material according to operating conditions, high temperature micro hardness test is executed and a new wear model has been proposed by considering the thermal softening of DCI roll expressed in terms of the main tempering curve. The new technique developed in this study for adjusting roll gap can give more systematically and economically feasible means to improve the dimension accuracy of bar with full usefulness and generality.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.1036-1041
• /
• 1997

The objective of this study is to adjust the roll gap for the dimension accuracy of bar in hot bar rolling process considering roll wear. In this study hot bar rolling processes for round and oval passes have been investigated. In order to predict the roll wear, the wear model is reformulated as an incremental form and then wear depth of roll is calculated at each deformation step on contact area using the results of finite element analysis, such as relative sliding velocity and normal pressure at contact area. Archard's wear model was applied to predict the roll wear. To know the effects of thermal softening of DCI (Ductile Cast Iron) roll material according to operating conditions, high temperature micro hardness test is executed and a new wear model has been proposed by considering the thermal softening of DCI roll expressed in terms of the main tempering curve. The new technique developed in this study for adjusting roll gap can give more systematically and economically feasible means to improve the dimension accuracy of bar with full usefulness and generality.

• Transactions of Materials Processing
• /
• v.12 no.4
• /
• pp.408-413
• /
• 2003

Dies may have to be replaced for a number of reasons, such as changes in dimensions due to die wear or plastic deformation, deterioration of the surface finish, break down of lubrication and cracking or breakage. In this paper, die cooling methods have been suggested to improve die service life considering die wear and plastic deformation in hot forging process. The yield strength of die decreases at higher temperatures and is dependent on hardness. Also, to evaluate die life due to wear, modified Archard's wear model has been proposed by considering the thermal softening of die expressed in terms of the main tempering curve. It was found that the use of die with cooling hole was more effective than that of direct cooling method to increase the die service life for spindle component.

• Transactions of Materials Processing
• /
• v.16 no.6
• /
• pp.479-487
• /
• 2007

Die life is generally estimated taking failure life and wear amount into consideration. In this study, the forging die life was investigated considering both of these two factors. The fatigue life prediction for the die was performed using the stress-life method, i.e. Goodman's and Gerber's equations. The Archard's wear model was used in the wear life simulation. These die life prediction techniques were applied to the die used in the forging process of the socket ball joint of a transportation system. A rigid-plastic finite element analysis for the die forging process of the socket ball was carried out and also the elastic stress analysis for the die set was performed in order to get basic data for the die fatigue life prediction. The wear volume of the die was measured using a 3-dimensional measurement apparatus. The simulation results were relatively in good agreement with the experimental measurements.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.10
• /
• pp.3031-3037
• /
• 1996

In cold forming processes, due to high working pressure action on the die surface, failure mechanics must be considered before die design. One of the main reasons of die failure in industrial application of metal forming technologies is wear. Die wear affects the tolerances of formed parts, metal flow and costs of process etc. The only way to control these failures into devlop methods which allow prediction of die wear and which are suited to be used in the design state in order to optimize the process. In this paper, the forming propcesses that involve cold forward extrusion and wire drawing were simulated by rigid plastic finite element method and its output were used for predicting die wear by Archard wear model. The simulation results were compared with the measured worn dies.

• Transactions of Materials Processing
• /
• v.24 no.4
• /
• pp.264-271
• /
• 2015

In the current study, a method was proposed to quantitatively predict the wear and fatigue life of a shearing die in order to determine an effective replacement period for the die. The shearing die model of a retainer manufacturing process was used for the proposed method of quantitative life prediction. The retainer is produced through shearing steps, such as piercing and notching. The shearing die of the retainer is carefully controlled because the dimensional accuracy of the retainer is critical. The fatigue life for the shearing die was predicted using ANSYS considering S-N curves of STD11 and Gerber’s equation. The wear life for the shearing die was predicted using DEFORM-3D considering the Archard’s wear model. Experimental shearing of the retainer was conducted to verify the effectiveness of the proposed method for predicting die life. The fatigue failure of the shearing die was macroscopically measured. The wear depth was measured using a 3D coordinate measuring machine. The results showed that the wear and fatigue life in the FE analysis agree well with the experimental results.