Metal Science and Heat Treatment

doi: 10.1007/s11041-020-00479-3pmid: N/A

Shchegolev, A. V.; Kletsova, O. A.; Firsova, N. V.; Gryzunov, V. I.; Svechnikova, V. V.

doi: 10.1007/s11041-020-00457-9pmid: N/A

The structure and the hardness of steel 8Kh3SMF after isothermal quenching at 200 – 700°C with a step of 50°C and holds for 20 – 5000 sec are studied. An experimental isothermal diagram of decomposition of supercooled austenite is plotted. The kinetics of phase transformations in steel 8Kh3SMF is described with the help of the Austin–Rickett equation.

Liu, Tao; Chen, Dengfu; Long, Mujun; Liu, Peng; Duan, Huamei; Gui, Lintao; Fan, Helin; Chen, Huabiao

doi: 10.1007/s11041-020-00477-5pmid: N/A

The effects of titanium and nitrogen additions in 0.16% C – 1% Mn high-strength low-alloy steel and of the rate of crystallization cooling on precipitation of TiN nitride and of complex TiN-CaS particles are studied. The processes of formation and growth of TiN and TiN – CaS particles in the mushy zone are analyzed using a thermodynamic model of diffusion growth. The thermodynamic computations are checked experimentally. The steel is controlled for presence of coarse TiN inclusions.

Liu, Qingsuo; Wang, Fang; Zhang, Xin; Wang, Huibin; Li, Jinman

doi: 10.1007/s11041-020-00458-8pmid: N/A

The structure and mechanical properties of an ultrahigh-carbon steel modified with amorphous ferrosilicon with a low melting point are studied. The methods of x-ray diffraction, optical and scanning electron microscopy are used to study the effect of the amorphous modifier on the structure of eutectic ledeburite in the cast steel. Tests for tensile strength and impact toughness are conducted. It is shown that the mechanical properties increase as a result of the modification without subsequent heat treatment.

Zhang, Jiwang; Zhang, Yanbin; Wang, Huaqiang; Lu, Liantao

doi: 10.1007/s11041-020-00459-7pmid: N/A

An alloyed ferritic-pearlitic steel is studied after micro-shot peening with balls from a high-speed steel. The morphology and the roughness of the surface of the specimens are determined. Specimens with smooth and notched surfaces are subjected to multi-cycle fatigue tests. The fatigue resistance of the specimens with a smooth surface and with a notched surface increases by 22 and 27%, respectively, after the shot-peening. Observation of crack growth in specimens with small holes shows that micro-shot peening hinders crack propagation.

Sarkar, T.; Bose, P. K.; Sutradhar, G.

doi: 10.1007/s11041-020-00460-0pmid: N/A

Mechanical properties of copper-alloyed bainitic gray cast iron are studied after isothermal quenching for bainite at different temperatures and holds. The microstructure of the iron is determined by optical and scanning electron microscopy and x-ray diffraction. The hardness, the ultimate strength and the elongation of the cast iron are shown to be dependent on the content of the austenite and on the carbon content in the latter, which are determined by the temperature and duration of the isothermal hold.

Baydarov, S. Yu.; Kamynin, A. V.; Kraposhin, V. S.; Chernyshev, D. L.

doi: 10.1007/s11041-020-00461-zpmid: N/A

Main problems arising in installation of novel processes of production of permanent magnets based on the Fe – Cr – Co and Sm – Co systems are presented. The technological possibilities of production of permanent magnets from an alloy of the Fe – Cr – Co system by methods of MIM technology and powder metallurgy are described. Methods of MIM-technology with the use of domestic granulate are used to fabricate permanent magnets based on alloy 25Kh15KA (Fe – Co – Cr system) with residual induction Br = 1.12 T, maximum energy product (BH)max = 23.0 kJ/m3 and coercivity HcB = 39.7 kA/m.

Chermenskii, V. I.; Konchakovskii, I. V.; Ushakov, A. R.; Kharchuk, M. D.

doi: 10.1007/s11041-020-00462-ypmid: N/A

The effect of low-temperature thermocycling treatment of castable invar alloys on the microstructure and temperature coefficient of linear expansion (CLTE) is studied. The tooling used in the production of precision articles from carbon-filled plastic should possess a maximum CLTE, temperature stability of the structure, and invariability of the coefficient of thermal expansion under the impact of thermal cycles. It is shown that an optimum castable invar alloy with steadily low coefficient of thermal expansion should contain at least 32.7 wt.% nickel and about 0.8 wt.% additional carbon. The effect of the distribution of carbon in the alloy on its structural stability is discussed.

Lankin, A. M.; Lankin, M. V.; Lankin, I. M.

doi: 10.1007/s11041-020-00463-xpmid: N/A

A method for controlling the condition of permanent magnets based on solution of the problem of harmonic balance and full-scale and model tests is suggested. The method consists in determination of an unknown characteristic of a permanent magnet from the known form of current passing through an inductor system and from the form and amplitude of the line voltage in the inductor system. The method makes it possible to determine the magnetic characteristic of the permanent magnet with an error not exceeding 3%. The advantage of the method is the possibility of its application for nondestructive inspection of permanent magnets.

Belotserkovskii, M. A.; Grigorchik, A. N.; Kukareko, V. A.; Konstantinov, V. M.

doi: 10.1007/s11041-020-00464-wpmid: N/A

The structural and phase condition, microhardness and wear resistance of nitrided high-chromium wire steels 40Kh13, 40Kh17M, 02Kh17N11M2 and gasothermal coatings from these steels sprayed with the use of a high-enthalpy combustible gas are compared in the initial condition and after ion-plasma nitriding at 740 K. The phase composition and the microhardness of the nitrided wire materials used for the spraying are studied. The nitriding is shown to have a positive effect on the wear resistance and structure of the gasothermal coatings.