Metal Science and Heat Treatment

doi: 10.1007/s11041-021-00599-4pmid: N/A

Kunitskaya, I. N.; Spektor, Ya. I.; Klimov, A. V.; Ol’shanetskii, V. E.

doi: 10.1007/s11041-021-00600-0pmid: N/A

Special features of the process of recrystallization of austenite under hot deformation and its effect on the physical and mechanical properties of rolled sections from bearing and structural steels under the conditions of thermal deformation treatment are studied.

Maisuradze, M. V.; Yudin, Yu. V.; Kuklina, A. A.

doi: 10.1007/s11041-021-00601-zpmid: N/A

Ametallographic study of advanced low-carbon martensitic steel with high resistance of the supercooled austenite to the transformations by pearlitic and bainitic mechanisms under continuous cooling is performed. The critical temperatures of the transformations occurring under heating and cooling are determined. The kinetics of the isothermal transformation of the austenite in the temperature range of 300 – 400°C is analyzed. The possibility of successful implementation of isothermal quenching of the steel after carburizing is demonstrated.

Lileev, A. S.; Reznikov, K. P.

doi: 10.1007/s11041-021-00602-ypmid: N/A

The causes of reversible variation of coercivity in alloys for permanent magnets as a result of cyclic heat treatments are analyzed including the effect of magnetostatic interaction between microvolumes on the processes of magnetization reversal and on the magnitude of the reversibility of the coercivity. A scheme of the processes occurring in alloys of the Sm – Co – Cu – Fe – Zr system is suggested, which makes it possible to explain logically the mechanism of the “damage – restoration” phenomenon.

Vasilenko, D. Yu.; Bratushev, D. Yu.; Shitov, A. V.; Popov, A. G.; Kolodkin, D. A.

doi: 10.1007/s11041-021-00603-xpmid: N/A

The effect of the chemical composition of the alloys on the magnetic properties of sintered Sm – Co – Fe – Cu – Zr magnets produced with mixing of alloy powders is studied. Elevation of (BH )max of Sm – Co – Fe – Cu – Zr magnets due to increase of the concentration of Fe to 20 wt.% requires observation of a strict proportion of the components and precision choice of the modes of heat treatment. Optimization of the chemical composition and use of step annealing with reduction of the temperature from 700 to 400°C has given sintered magnets with the following properties: Br = 11.7 – 11.9 kGs, HcB = 9 – 10 kOe, HcJ = 15 – 20 kOe, and (BH )max = 29 – 31 MGs · Oe.

Protasov, A. V.; Popov, A. G.; Gaviko, V. S.; Terent’ev, P. B.; Zhang, Tiangli

doi: 10.1007/s11041-021-00604-wpmid: N/A

The structure and magnetic hysteresis properties of nanocrystallized melt-spun ribbons with composition (Sm0.8Zr0.2)(Fe0.72Co0.24Ti0.04)z ( z = 10 – 12) are studied. It is shown that substitution of a part of iron in the composition of the alloy by cobalt raises substantially the Curie temperature but almost halves the coercivity. The decrease is connected with growth in the volume fraction of the α-(Fe, Co) soft magnetic phase and incompleteness of the process of ordering of the ThMn12-type phase during annealing at 875 – 900°C. In contrast to the rapidly hardened alloys not containing Co, hydrogenation of the of (Sm0.8Zr0.2)(Fe0.72Co0.24Ti0.04) RHA powders is not accompanied by absorption of hydrogen and growth of the magnetic hysteresis properties.

Sawicki, J.; Dybowski, K.; Zgórniak, P.

doi: 10.1007/s11041-021-00605-9pmid: N/A

Deformations of straight-sided splines (changes in the width of the hubs) of steels 16MnCr5, AMS6265 and 17CrNiMo7-6 are studied after different treatments, i.e., a hold at 1050°C without carburizing and with slow cooling to room temperature, vacuum carburizing with subsequent slow cooling to room temperature, and vacuum carburizing with subsequent oil quenching. The sizes of the deformations are shown to depend on the grade of the steel. The lowest deformations are obtained for steel 16MnCr5.

Chaus, A. S.; Kuracina, V.; Moravčík, R.; Hazlinger, M.; Kusý, M.

doi: 10.1007/s11041-021-00606-8pmid: N/A

The possibility of raising the wear resistance and prolonging the service of forging die inserts is analyzed with the aim to elevate the efficiency of the production process and to reduce the cost of forgings. Three sets of inserts fabricated from the same grade of die steel and subjected to the same heat treatment are studied. Additional nitriding (gas or ion plasma one) is applied to two sets for comparison. It is shown that the inserts subjected to ion nitriding have the highest wear resistance and endurance.

Smirnov, A. E.

doi: 10.1007/s11041-021-00607-7pmid: N/A

A process of hardening of steel 16Kh3NVFMB-Sh involving vacuum carburizing and subsequent hardening heat treatment is studied. It is shown that in order to obtain an optimum phase composition and, as a consequence, high operating properties, the steel should be subjected after carburizing to high tempering for formation of a fine ferrite-carbide structure. The treatment should be finished with quenching after the second heating, cold treatment and low tempering.

Vintaikin, B. E.; Boruta, V. S.; Litvinov, O. S.

doi: 10.1007/s11041-021-00608-6pmid: N/A

X-ray diffractometry with mathematical processing of the diffraction patterns by the Tikhonov method of regularization, which enhances the resolution, is used to study the phase state in Nd – Fe – Co – B – Zr-base alloys during the reverse reaction of HDDR process at different hydrogen pressures. The range of hydrogen pressures in which the reverse reaction (recombination) of the HDDR process develops fully is determined experimentally.