Effect of modifying tungsten additions on formation of primary structure of R6M5-type high-speed steel

The effect of modifying additions of powder and compact (in the form of chips) tungsten on the formation of the primary structure of the R6M5-type tungsten-molybdenum high-speed steel has been investigated. The results of metallographic and electron microprobe analyses of base and modified steels have been discussed. It has been shown that the modification of the R6M5 steel with tungsten brings about considerable qualitative and quantitative changes in the microstructure of the matrix and carbide component of eutectic origin.     

Wear resistance of high-speed cutting powder steels with molybdenum disulfide additives

The effect of molybdenum disulphide additives on the tribological properties of high-speed powder steels produced by hot isostatic pressing has been investigated. The firction coefficients are determined at sliding velocities from 0.5 to 2.0 m/s and under loads from 1 to 15 Mpa, and the wear resistance of the experimental steel is determined. It is shown that the molybdenum disulphide additives reduce the friction coefficient and promote the wear resistance of the steel.     

Precipitation of Secondary Carbides in M2 High-Speed Steel Modified with Titanium diboride

The precipitation of the secondary carbides in high-speed steel of AISI M2 type modified with titanium diboride has been investigated for both the cast and the heat-treated states. The primary focus was on the effect of austenitizing temperatures on the secondary carbide precipitation during tempering. Some differences in origin of the secondary carbides, as well as in their shape and size distribution, were found in the tempered microstructure for the different austenitizing temperatures. After austenitization at 1180 °C and triple tempering at 560 °C, the secondary carbide particles of a spherical shape up to 200 nm in size were identified by selected area electron diffraction as M₂₃C₆. After austenitization at 1220 °C, two types of the secondary carbides were found in the tempered microstructure, M₂₃C₆ with a size up to 200 nm and M₆C with a size up to 400 nm. In both the cases, the carbide particles were slightly angular. After austenitization at 1260 °C, only M₆C secondary carbides were revealed in the tempered microstructure, which occurred as the angular particles up to 350 nm in size. In addition, considerably finer M₂₃C₆ carbide particles with a size of 10-40 nm were found to precipitate in the tempered microstructure.     

Influence of cutting conditions of cast-metal cutting tools on their wear and durability: Analysis of cutting conditions of tools

The conditions of operation of metal-cutting tools in various applications and of various standard dimensions are analyzed. Long-standing statistical observations at a number of industrial facilities have revealed the dominating mechanisms of wear and the main causes of failure of the tools have been established in response to the conditions of their operation and design features. A range of tools has been selected for comparative durability tests in industrial conditions.