Wear Of Tool Materials Research Articles

Surface formation under the conditions of electroerosion grinding with variable polarity of electrodes

The contact zone is the area of mutual penetration of the cutting edges into the processedmaterial and the protrusions of the materials in the gaps between the grains. The parameters of thestate of the zone include its size and shape, the ratio of cut and uncut parts of metal in each area ofthe zone, the physical processes of formation, including: chipping, heat generation, plasticdeformation of the material, tool material wear and damage, physical and chemical effects oncooling lubricants.The formation of the processed surface in the conditions of electroerosive diamond grindingwith variable polarity of electrodes in the cutting zone is investigated in the article. A physicalmodel of diamond tool wear has been developed considering the erosion processes affecting thewheel connection. The construction takes into account dimensional wear, processes of chipping andpulling out single abrasive grains from the bond, under the action of the components of cuttingforces, considering the probability of grain contact with metal, the size of wear sites and the actualdepth of microcutting.The obtained ratios allow us to directly determine the probability of contact of the cut chipsfrom the body, formed by the cutting edge of the grain, with the bond surface of the grinding wheel.When solving the problem of the probability of contacting the set of chips formed by the set ofedges of the grains lying in the working layer of the tool, it is also necessary to use the probabilityof the density distribution along the depth.The type of the obtained ratios directly shows that a significant part of the chips formed bythe cutting edges in contact with the rough surface of the workpiece are short and do not come intocontact with the ligament until separation from the body of the workpiece, even without shrinkage.The obtained relations can be used in solving the corresponding problems of grinding theperiphery of the circle, for example, round external grinding. With a clearer description of theprocess, it is necessary to directly apply the nonstationary representation, taking into accountadditional nonstationary ones, introduced by the trajectories of the cutting edges as a function of theangle of rotation of the circle and the part in the process of their interaction.

Особенности изнашивания инструментальных материалов при механической обработке резанием заготовок из полимерных композиционных материалов

Tool materials used for polymeric composite blank machining, kinds of tool material wear arising at machining these blanks, and also the impact of technological parameters upon tool wear are considered. The obtained results allow estimating the potentialities of physical models at polymeric composite blanks cutting.

THE IMPORTANCE OF PRIMARY CARBIDES FOR THE TRIBOLOGICAL PROPERTIES OF FERROUS ALLOYS

Among the materials used for the mill rolls, one of the main groups are materials with eutectoid primary carbides in their microstructure. The volume fraction and morphology of these carbides influent in a significant way on the tribological properties of tool materials. In the paper, the role of the primary carbides morphology on the fatigue wear of mill rolls after exploitation was presented. The role of the primary carbides morphology in the sliding wear of tool materials was also investigated. The evaluation of the sliding wear mechanism and its degree was performed by the investigation of the mill rolls surface roughness after exploitation. Whereas, the role of ledeburite cementite morphology in wear mechanism changes ware investigated by the laboratory tests. Tests were performed with the use of different loads, time, and temperature during the trials. The microcutting of counter sample material by the primary carbides from the tested samples was observed.

Milling research and tool selection design of SiC14Cu4Mg0.5Si based on Aluminium matrix 2A14

The selection of milling tools for SiC14Cu4Mg0.5Si based on Aluminium matrix 2A14 was analyzed, and the factors that affect the efficiency of the milling were discussed. The SiC14Cu4Mg0.5Si was designed for use on the moon landing vehicle or missile wings, but the hardness of aluminium-silicon carbide composite material was very high, much higher than the general hardness of cemented carbide, which will bring many difficulties in the aluminium-silicon carbide composite material processing. The chemical compositions of SiC14Cu4Mg0.5Si were analyzed. A new selected indexable cutter was designed to mill SiC14Cu4Mg0.5Si. The structure design of milling cutter was different from the conventional milling cutter, breaking the previous limitations to a certain extent, pioneering the idea. The tool material wear was detected by experiments. The mechanical and physical properties of SiC14Cu4Mg0.5Si were also tested. SiC14Cu4Mg0.5Si exhibited different surface quality characteristics under different milling tools.

Friction surfacing of a cold work tool steel—Microstructure and sliding wear behavior

Friction surfacing is a solid-state joining process, during which process temperatures below melting, a high cooling rate, and a high degree of deformation lead to a very fine microstructure and exceptional mechanical properties of the coating material. In the presented study, the friction surfacing process was used to apply self-mating layers onto cold work tool steels, which e.g. are used for deep-drawing dies in the automotive industry. Such dies are subject to wear during operation and the repair of the dies by arc-welding includes many process steps besides the final hard surfacing. By the use of friction surfacing, hard tool steel coatings can be generated in one process step before the final machining operation. A martensitic microstructure and high hardness up to 900 HV10 can be reached within the coatings. Boundary lubricated reciprocating sliding wear tests (ball-on-flat) were conducted on cast and hardened material as well as the coatings. The results showed that over a wide range of loading the coated samples perform as well as the original die material, showing tribochemical reactions and very small wear volumes. After more than 500,000 sliding passes, both the coatings' and the original tool material's wear is dominated by surface fatigue.

Effect of residual elements on the machinability of leaded free machining steels

The machinability of a material can be defined in terms of the wear rate of the cutting tool used to machine the material. The lower the tool wear rate or the greater the tool life the better the machinability. The wear processes of cutting tools are complicated, but recent work has shown that cutting tool wear rates during machining can be directly related to tool material wear rates when rubbing in a modified crossed cylinder wear experiment (Mills & Akhtar 1975). The wear of cutting tools can be simulated by simple experiments. Here I present results on the effect of total residual levels in leaded low carbon free machining steels on the tool life of M2 high speed steel. The results will be discussed in terms of a simple wear model.

A method for studying the behavior of cutting fluids in wear of tool materials : L. V. Colwell. ASME, Transactions, v. 80, no. 5, July 1958, p. 1054–1058

A method for studying the behavior of cutting fluids in wear of tool materials : L. V. Colwell. ASME, Transactions, v. 80, no. 5, July 1958, p. 1054–1058

A Method for Studying the Behavior of Cutting Fluids in Wear of Tool Materials

Abstract Refinements of design and instrumentation in a new friction and wear machine result in some new types of information which show promise of extending knowledge of the mechanisms of friction, lubrication, and wear. Provision has been made for varying normal load linearly with time and oscillating it between preset values. There is continuous recording of both the normal load and the friction reaction. Continuous recording at oscillating normal loads has discriminated sharply between lubricant additives. Close control of test conditions in wear studies has made it possible to identify high residual compressive stresses produced in finish grinding of cutting tools.