Estimation of Temperature Conductivity Coefficient Impact upon Fatigue Damage of Material

V Bibik,A Galeeva

doi:10.1088/1757-899x/91/1/012033

Abstract

In the paper we consider the peculiarities of adhesive wear of cutting tools. Simulation of heat flows in the cutting zone showed that, as thermal conduction and heat conductivity of tool material grow, the heat flows from the front and back surfaces to tool holder will increase and so, the temperature of the contact areas of the tool will lower. When estimating the adhesive wear rate of cemented-carbide tool under the cutting rates corresponding to the cutting temperature of up to 900 °C, it is necessary to take the fatigue character of adhesive wear into consideration. The process of accumulation and development of fatigue damage is associated with micro- and macroplastic flowing of material, which is determined by the processes of initiation, motion, generation, and elimination of line defects - dislocations. Density of dislocations grows with increase of the loading cycles amount and increase of load amplitude. Growth of dislocations density leads to loosening of material, formation of micro- and macrocracks. The heat capacity of material grows as the loosening continues. In the given paper the authors prove theoretically that temperature conductivity coefficient which is associated with heat capacity of material, decreases as fatigue wear grows.

Highlights

One of the main factors affecting durability of cutting tools is temperature in the contact area [1, 2]
Simulation of heat flows in the cutting area showed that, as thermal conduction and heat conductivity of tool material grow, the heat flows from the front and back surfaces to tool holder will increase and so, the temperature of the contact areas of the tool will lower [3]
Analysis of cutting tool use under factory conditions showed that cemented-carbide tool is quite often used under the cutting rates which correspond to the temperatures of up to 900 С in the cutting area, i.e. under the cutting rates which are lower than the rate corresponding to the inflexion point of the curve showing the dependence of wear upon cutting rate [7]

Summary

Introduction

One of the main factors affecting durability of cutting tools is temperature in the contact area [1, 2]. Analysis of cutting tool use under factory conditions showed that cemented-carbide tool is quite often used under the cutting rates which correspond to the temperatures of up to 900 С in the cutting area, i.e. under the cutting rates which are lower than the rate corresponding to the inflexion point of the curve showing the dependence of wear upon cutting rate [7]. At this segment of the curve the durability of the tool increases as the cutting temperature grows Figure 2. Cyclic loading affecting the contact edges of the tool leads to formation of fatigue cracks resulting in separation of wear particles [7]

Results and Discussion

Conclusion