Research on durability of turning tools made of low-alloy high-speed steels

Abstract

This paper presents the results of investigations of temperature field distribution in the cutting edge and yield strength of tool material for low-alloy high-speed steels. Investigations of temperature distribution in cutting edges were made during C60 steel turning using a semi-natural constantan thermo-element. The obtained results show that the decrease in addition alloy content does not influence the change in thermal-physical properties of lowalloy high-speed steels. Investigations of the durability of cutting edges confirm that to define working conditions of the tool made of high-speed steel, resistance against hardness loss with increasing temperature at temperatures higher and lower than tempering temperature is the most significant. The results of durability investigations of cutters made of HS3-1-2 steel with various kinds of surface treatment confirm the reasons for cutting edge wear of tools made of high-speed steel and ways of the increasing their durability.

Influence of Heat Treatment on Content of the Carbide Phases in the Microstructure of High-Speed Steel

“…To ensure applicable quality requirements during production of tools made of HSSs, it is very important that their cutting ability is not lower than comparable tools made of classic high-speed steels [2].…”

“…However, in the case of smaller carbon content in steel, ferrite can be formed or even part melting of the grain boundaries can occur. HSSs should be used in a state of high hardness, which involves the determination of the optimum temperatures of austenitising and tempering [2,[7][8][9]. Austenitising temperature of a tool steel set in the process of tool manufacture should produce a grain size determined by the Snyder-Graff of no less than 10, a bending strength of 2500-3000 MPa and a hardness of about 63 HRC.…”

Grindability of Selected Grades of Low-Alloy High-Speed Steel

“…Loss of tool life under cutting is caused by wheel burns on the surface of the tool point, which are formed during tool sharpening. High grinding temperatures facilitate the formation of an increased amount of retained austenite on the surface layer of high-speed steel [7]. This reduces tool life under cutting.…”

Technology of Heat Treating-Straightening of Long Shafts With Low Rigidity

“…It is known that the fullest dimensional characteristic of stability of a material in time is the value of the maximum stress that does not undergo relaxation over a long time, that is referred to as the conventional relaxation limit. That value is recommended to be used as the basic characteristic of material stability in the machine building industry [3,5,9].…”