Metal Science and Heat Treatment

Kremnev, L.; Sapronov, I.

doi: 10.1007/s11041-014-9672-6pmid: N/A

The distribution of alloying components in local regions of the martensitic matrix of high-speed steels R6M5K5 and R6M5K5-MP produced by the conventional process and by the method of powder metallurgy is studied. It is shown that the alloying components are segregated in the martensite, and the segregation is related to the content of retained austenite after hardening and to the microhardness and heat resistance of the steels after final heat treatment.

Chaus, A.; Porubski, J.

doi: 10.1007/s11041-014-9673-5pmid: N/A

The effect of heat treatment on the change in the primary structure of a cast high-speed steel of type R6M5 modified with tungsten additives in the form of powder and chips is studied. The results of metallographic and microscopic x-ray spectrum analyses of the steels are discussed. Primary attention is devoted to the effect of the austenization temperature on the variation of the chemical and phase compositions and to the morphology and distribution of eutectic carbides after a complete heat treatment.

Petrova, L.; Shestopalova, L.; Aleksandrov, V.

doi: 10.1007/s11041-014-9674-4pmid: N/A

The process of thermochemical treatment of steel 40Kh13 involving successive stages of oxidizing and oxynitriding is considered. The three-layer modified coating obtained consists of a zone of internal nitriding and a surface nitride zone of a powder-like ε-phase, which are separated by a nanosize oxide film. The hardness of the surface after such treatment, the wear resistance of the steel under conditions of abrasive and hydroabrasive wear, and the corrosion resistance in an abrasive environment of an oil-well formation fluid are determined. The process considered is shown to be more advantageous than the traditional nitriding.

Rodionov, I.

doi: 10.1007/s11041-014-9675-3pmid: N/A

The structure of the surface of steam-heat-deposited oxide coatings on medical implants from biologically inert titanium alloy VT6 is studied by the methods of microprocessor profilometry, light microscopy, and computer processing of microimages. The capacity of the coatings for integrative interaction with bone tissue is determined.

Olshanetskii, V.; Stepanova, L.; Greshta, V.; Pavlenko, D.; Tkach, D.

doi: 10.1007/s11041-014-9676-2pmid: N/A

The laws of the influence of plastic strain accumulated in titanium VT1-0 in the process of helical extrusion on its plasticity are studied. The values of total and uniform elongation and the parameter of an elementary cell of titanium after different numbers of cycles of helical extrusion are determined.

Greben’kov, S.; Shatsov, A.; Ryaposov, I.

doi: 10.1007/s11041-014-9677-1pmid: N/A

The characteristics of hardening of low-carbon martensitic steels alloyed with strong carbide-forming elements and having a lath and lath-globular structure are investigated. The structure of the steels is studied and the strength, ductility and toughness characteristics are determined. The true strain-stress curves are plotted. The hardening parameters are computed for the stages of uniform and lumped deformation. The experimental data match well the Ludwig – Hollomon equation.

Song, Y.; Chen, G.; Wang, J.; Liu, J.; Yu, X.; Hua, J.; Bai, X.; Zhang, T.; Zhang, J.; Tang, W.

doi: 10.1007/s11041-014-9678-0pmid: N/A

The microstructures, surfaces and types of fracture of welded joints of dissimilar steels T92/HR3C are studied after short-term tests at 500 – 650°C. A pioneer equation is obtained for describing the long-term strength of welded joints with the help of data of short-term tensile tests. The values of the long-term strength computed by the equation agree well with experimental data.

Trayno, A.; Rusakov, A.; Lutsenko, A.; Slavov, V.; Mishnev, P.

doi: 10.1007/s11041-014-9679-zpmid: N/A

Physical simulation of a process of production of tube strip steels of strength category X80 for large-diameter oil and gas transportation tubes is performed. Mechanical properties of the steels are determined. Two processes (basic and alternative ones) are suggested for making strips of strength category X80.

Vutova, K.; Donchev, V.; Vassileva, V.; Mladenov, G.

doi: 10.1007/s11041-014-9680-6pmid: N/A

An amended quasi-stationary model of heat transfer in a metallic ingot hardening in a water-cooled crucible after electron-beam melting and refining of the metal is suggested. The processes of heat transfer and heat flows through different interfaces are considered for aluminum and tantalum under the assumption of three mechanisms of heat transfer. The model allows for the temperature dependences of the thermal conductivity and specific heat capacity. Experimental results are used for estimating the distribution of energy in beam heating of the metal and the losses of heat to radiation and evaporation from the upper surface of the ingot. Data on the shape of the hardening front, on the geometry of the molten zone, on the heat flow at various treatment parameters (electron beam power, casting rate, etc.) are obtained and discussed.

Kraposhin, V.; Plokhikh, A.; Talis, A.; Kostina, M.; Muradyan, S.

doi: 10.1007/s11041-014-9681-5pmid: N/A

The geometric mechanism of cooperative transformation of σ-phase into bcc-ferrite observed in some austenitic stainless steels is considered. This mechanism is used to explain the elevation of the hardenability of steels upon the introduction of alloying elements.