The state of the surface layers of quench-hardened steel after diamond grinding

This article describes the results of a study of the effect of grinding cylindrical specimens, with the end face of a diamond-impregnated wheel, on the state of the surface layer of a rolled steel. It was shown that finishing diamond grinding does not eliminate surface defects produced by previous machining operations.Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 5, No. 5, pp. 577–580, September–October, 1969.     

Precision dressing of diamond tools

The author of the paper proposes a dressing tool (an adhesively active roller dresser) and the related method for dressing diamond tools. Temperatures in the grinding zone are measured, and the temperature gradient in the diamond grit-workpiece contact zone is calculated.     

Phase composition of the surface layers of high-speed cutting steel after electrospark alloying and laser treatment

Due to the metallurgical processes occurring under the action of laser irradiation, which are accompanied by convectional mass transfer, phase formation, and the interaction of alloying elements with the base material and elements of the environment, tungsten carbide fully dissolves in the steel melt in the case where alloying was carried out with alloys based on this carbide. Moreover, the refractory component of tungsten-free electrode materials stayed completely unaltered. by partially losing a non-metal. These transformations occur under nonequilibrium conditions. To improve the tribotechnical properties and durability of a high-speed cutting steel upon cutting, it is reasonable to alloy its surface layer with elements and compounds which form stable oxides strongly bound to the base. Frantsevich Institute of Problems of Materials Technology, the Ukrainian Academy of Sciences, Kiev. Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 36, No. 1, pp. 83–86, January–February, 2000.     

Investigation of contact stresses and their influence on the physics of cutting of 45 steel by cutting tools of high-speed alloys

The influence of shear stresses on the physical processes proceeding on the surface of contact of a cutting tool with a chip removed has been investigated. The mechanisms of appearance of contact layers and the dependence of the lengths of the elastic and plastic parts of these layers on the normal and shear stresses in the contact zone have been considered. It was established that a natural “white” layer formed in the process of cutting plays a protective role and, as a consequence, decreases the rate of wear of the tool. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 6, pp. 184–187, November–December, 2005.     

Main characteristics of abrasive diamond layer in dressing tools

It is demonstrated that a dressing roller or stick as a single-layer abrasive diamond tool can be characterized, like a multilayer one, by two independent parameters—grit size (it suffices to indicate the upper sieve size only) and conditional concentration. The other characteristics (surface density of a powder batch, specific number of diamond grits) are unambiguously determined from these two parameters by means of theoretically substantiated and experimentally verified relationships. The limiting values of the diamond powder quantity on the surface of single-and multilayer tools have been established which differ from the data reported elsewhere.     

Carbon nanotube reinforced metal binder for diamond cutting tools

The potential of carbon nanotube reinforcement of metallic binders for the improvement of quality and efficiency of diamond cutting wheels is studied. The effect of multi-walled carbon nanotube (MWCNT) reinforcement on the mechanical properties i.e. hardness, Young modulus, strength and deformation behavior of copper and iron based binder for diamond cutting wheels is investigated experimentally and numerically. Computational micromechanical studies were carried out to clarify the mechanisms of the MWCNT material strengthening. It is demonstrated that the adding of MWCNTs leads to the decrease of grain size of the structural constituents of the binder, what in turn leads to the improved simultaneously hardness, Young modulus, plastic extension, bending strength and performances of the metallic binders. Comparing service properties of diamond end-cutting drill bits with and without MWCNT one observed the drastic increase of the cutting speed as a result of MWCNT reinforcement.     

The contribution of ion plasma sprayed coatings to performance of diamond dressing tools

The paper addresses the effect of ion plasma sprayed coatings on performance of diamond dressing tools under diamond abrasive machining conditions. The use of thick wear-resistant titanium nitride and carbide coatings with a compensating interlayer of a plastic metal (cobalt) is demonstrated to be a promising method for improving efficiency of dressing tools manufactured by electroplating and electroforming.     

Effect of surface layers on diffusion processes and the resulting stress state in solids

Generalized boundary conditions are formulated making it possible to take into account the influence of interfaces, grain boundaries and other discontinuities of the surface type on diffusion phenomena. Using these conditions, the authors find a solution of the problem of determining the concentration field and stress state during diffusion saturation of an elastic half-space through a thin surface coating. For a case when the mass transfer is effected through a local coating region, graphs of the concentration and stress distribution are constructed for various ratios of mass diffusivities of the surface coating and half-space materials.This paper was read at the VI All-Union Conference on diffusion-saturation treatments and surface coatings (Odessa, September 1966).     

Evolution of the working surface of diamond dressing sticks prior to its fracture

The paper addresses working surface wear of electroplated diamond dressing sticks at a stage prior to fracture during the dressing of abrasive wheels. The fracture is found to occur through drastic breakoff of diamond grits from the bond, the grit size and the nickel bond type being the main factors that dictate the fracture onset time. The authors provide a more precise definition of the relationship between the bond hydroabrasive wear parameters, kinematic characteristics of dressing, and physical-mechanical characteristics of the bond. The difference in the wear rate between diamond grits and the bond in a single-layer dressing tool is demonstrated to introduce large errors into the measurement of specific diamond consumption by weighing. A procedure is put forward which allows a variation in the mass wear ratio between diamond grits and a bond to improve the measurement accuracy.     

Thermal conditions and stress-strain state in the grain-matrix system of diamond tools

Numerical modeling of stationary and nonstationary fields of temperatures, strains and stresses in the diamond-matrix system is carried out. It is shown that the stress-strain state in the system greatly depends on thermal actions and the highest stress intensity in the system is in a transition layer between the grain and the matrix. We analyze the influence of physical properties of the matrix and transition layer, grain depth in the matrix, and the coefficient of heat transfer to environment on the temperature field and stress state in the system.     

Finite element analysis of bending occurring while cutting with high speed steel lathe cutting tools

The bending which occurs on a cutting tool during machining on a lathe affects tool life, surface roughness and dimension correctness. In this research, the bending which has been calculated by Castigliano theorem has been compared with the bending obtained by finite element method. Under the constant cutting conditions, material Ç1060 has been machined with high speed steel (HSS) lathe cutting tools having 60°, 75° and 90° of cutting edge angle. It was determined by using ANSYS finite elements program that the bending of the cutting tool generated by the forces, which varied between 1360 N and 1325 N and occurred during cutting, varied between 0.039958 and 0.04373 mm. According to the results, it has been observed that the bending that was calculated by Castigliano theorem and that varied between 0.03542 and 0.034505 mm was almost the same with the bending determined by finite elements method. In other words, it was seen that the calculated values approach to the analysed results up to 0.4% .