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Through methods of modern materials science it is shown that plasma hardening of cast iron rolls of a rolling mill causes the formation of layers the structure of which is characterized by the regular change of mechanical characteristics, phase composition and defect substructure of the material and realized at different structure-scale levels: mac...
Context in source publication
Context 1
... process of plasma hardening of roll grooves is shown in Fig.1. It was realized with the technical characteristics: arc power -40 kW, arc current - 250 A, arc voltage -180 V, efficiency -180 m min - 1 , pressure of plasma producing gas -0.6 MPa, con- sumption of plasma producing gas -5 m 3 hour -1 , nozzle diameter -1.2 cm. ...
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Citations
... One of the ways to increase durability is the product working surface modification. There are various modification methods, including plasma techniques: thermohardening [10,11,12], ion-plasma diffusion implantation [13,14], ion-beam hardening treatment [15,16,17], which contribute to its hardness increase in varying degrees (by 15-50%). ...
The layered structure properties of an asymmetric combined gas discharge have been studied. The main physical parameters of the plasma in the zone of electron acceleration to high energies of tens and hundreds of electron-volts at various values of the supplied microwave power were determined based on the analysis of the discharge current-voltage characteristics. The effect of combined discharge plasma on the surface of products made of various materials and placed in the resonator chamber of a technological unit was experimentally investigated, and it is shown that it can lead to a significant increase in the strength of the processed products in terms of microhardness.
... The current stage of development of production in various sectors is characterized by tighter operating conditions of products from metal materials and alloys associated with the effect of high temperatures, the external power loads and corrosive environments. This requires continuous improvement of existing and development of new manufacturing technologies including technology of strengthening their surface layer [1,2], in particular, plasma technologies: thermal hardening [3][4][5], plasma ion diffusion [6,7], ion-beam hardening treatment [8][9][10][11]. ...
The work presents the study of technological considerations of the nanocomposite structure formation on complex profile surfaces under the influence of low-temperature plasma aimed at wear resistance increase of metal products, the research being conducted on the novel plant.
The paper proposes an approach to increasing the efficiency of plasma modification of the metal product surface layer based on the study of the effect of pressure in the working chamber of a technological unit on its course and outcomes. It was found that there is such influence, and it is manifested in a heat flow direction change and leads to the intensification of either heat conduction (with increasing pressure), or heat transfer and radiation from the surface (with decreasing pressure). In the first case this leads to the formation of the most compacted composite structure in the surface layer, and to the transition layer formation between the structure and the main material of the product. In the second case the compaction of the surface layer is minimal, no transition layer is formed. The pressure change effect mechanism associated with the violation of the dynamic equilibrium between adsorbed and desorbed particles on the product surface when changing the temperature regime has been identified. It is shown that after switching off the plasma, it is necessary to control the heat flow propagation, and that the course of the lag temperature curve can serve as an operational indicator of the control quality.
