Control of Phase Composition of Complexly Alloyed High-Temperature Steels Under Vacuum Carburizing and Quenching

Смирнов, А. Е.

doi:10.1007/s11041-021-00607-7

Cited by 7 publications

(2 citation statements)

References 7 publications

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“…Additionally it is desirable to save fine austenite grains to prevent reducing of volumetric strength and toughness of steel during heating. Volumetric quenching, quenching after heating by high frequency currents and high-temperature thermomechanical surface treatment are usually used in manufacture of work rolls for multi-roll mills as a finishing heat treatment [11][12][13].…”

Section: Goal Settingmentioning

confidence: 99%

Device for two-way cooling of rolls of multi-roll mills during laser hardening

Chichenev¹,

Vasilyev²,

Karfidov³

et al. 2023

cisisr

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Development of the automotive industry, electronics, aviation and other modern branches of science and technology has led to the need to produce thin (up to 0.01 mm thick) and the thinnest (up to 0.001 mm) high-quality band from high-alloy steels, non-ferrous and noble metals, obtained on multi-roll cold rolling mills. One of the main requirements for work rolls is a high and uniform hardness of the surface of the barrel after hardening, which should increase the wear resistance of the working layer, reduce the degree of its damage and, thereby, ensure the high quality of the rolled strip. An effective way to improve the quality of rolls with a diameter of up to 20 mm is surface laser hardening. In laser hardening of rolling rolls, a technological scheme was used, according to which the roll made a screw movement at preset speed relative to a fixed laser beam, which led to formation of a continuous screw track (spiral) of the hardened material on the surface of the roll. The minimal rotational frequency, at which uniformity of the active layer is observed, has been experimentally established, while laser hardening of samples with doublesided water jet cooling turned out to be the most effective. The design of a sprayer device for cooling of rolls during laser processing is proposed, which provides a uniform active layer along the entire barrel length and significantly reduces buckling of rolls. The technology for the manufacture of rolls has been developed, which makes it possible to obtain work rolls for multi-roll mills with high operational resistance, and to improve the technical and economic indicators of production of precision band. Tests of the rolls made of Kh9VMFSh steel after laser hardening on the mill 300 showed reduction in wear by 1.5-2.0 times compared to the standard volume-hardened rolls and reduction in roll consumption from 0.22 to 0.11 kg / t.

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Section: Goal Settingmentioning

confidence: 99%

Device for two-way cooling of rolls of multi-roll mills during laser hardening

Chichenev¹,

Vasilyev²,

Karfidov³

et al. 2023

cisisr

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“…Finished heat treatment aimed of obtaining martensite structure with the required concentration of carbon and alloying elements is one of the main factors for acquiring the necessary operating parameters by work rolls. This heat treatment is usually presented by volumetric quenching, quenching after heating by high frequency current and hightemperature thermomechanical surface processing [13,14].…”

Section: Goal Settingmentioning

confidence: 99%

The effect of laser hardening on the operation resistance of rolls of multi-roll mills and the quality of the rolling strip

Chichenev,

Vasilyev,

Karfidov

et al. 2023

cisisr

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The results of experimental studies of the process of laser hardening of rolls of multi-roll mills during linear and spiral hardening of samples from Kh9VMFSh steel are presented. It was found that during linear laser treatment, the depth of the hardened layer significantly depends on the power of laser radiation and the speed of translational motion of samples; at the same time, it weakly depends on the diameter of the laser beam. Corresponding graphs, which are more convenient for practical use for selection of technological modes of laser processing, have been built. With spiral laser hardening, the surface of axisymmetric parts is subjected to cyclic heating, the number of cycles of which depends on the speed of translational motion and rotation speed. It is established that decrease of the temperature of the surface layers of the part heated by laser radiation practically does not occur due to thermal conductivity at a sufficiently high value of the rotation speed. It is shown that increase of the rotation speed of samples from 1,000 to 10,000 min-1 leads to increase of the depth of the hardened layer from 0.72 to 1.60 mm with a slight enlargement of hardness of the surface layers, while the depth of the hardened layer significantly depends on the speed of translational motion of the samples and their diameter; it should be taken into account when developing technological modes of laser hardening. Pilot-industrial tests of working rolls during rolling of the strip with 0.012×200 mm cross-section, made from L63 brass, showed that the surface purity of the rolled strip increased from the 7 th to the 8 th class of roughness, and the number of breaks decreased by 1.5-1.8 times. When rolling a strip of nickel NP-2 at a 20-roll mill 300, it was found that consumption of rolls that have been subjected to laser processing is 2 times less than consumption of volume-hardened rolls, while transverse thickness has decreased to ± 3 % (compared with ± 5 % during rolling in volume-hardened rolls).

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