Abstract

The main controlled thermophysical parameters of plasma modification are the maximum heating temperature T and cooling rate W of the surface layer. The parameters T and W during the plasma modification are not the parameters of direct control, but are complex ones, the value of which being influenced by a large number of factors – the power of the plasma jet (determined by the current strength I and the voltage in the jet U), the pressure and flow rate of the plasma-forming gas (Pg, Qg), processing speed (plasmatron movement v), pressure and flow rate of cooling water (Рw, Qw), processing distance h, thermophysical characteristics of the processed material, shape and dimensions of the processed product. The effective use of direct action plasmatrons is known; while indirect plasmatrons are used more widely. Of the varieties of indirect plasmatrons, the most preferable is the use of plasmatrons with a sectioned interelectrode insert (SII). The use of the plasmatrons with SII makes it possible to implement the technology of plasma nanostructuring either in a narrow range of mode parameters (microfusion); or when machining a tool with a cutting edge of a special (serrated) shape – for example, threading or thread rolling. Consequently, for a wider practical use of the plasma nanostructuring technology, it is necessary to improve the basic design of the plasmatron in order to implement the conditions for nanostructuring (simultaneous achieving high heating temperatures close to the melting temperature of the instrumental material and a cooling rate of about 106...107°С/sec), for range of mode parameters and for a wide range of hardened tools. The established computational and experimental regularities make it possible to choose the optimal combinations of the design parameters of the plasmatron and the parameters of the processing mode for the implementation of the process of plasma nanostructuring of the metalworking tool. The work is performed individually for each specific combination: plasmatron – processed material (steel, alloy) – shape and size of the tool

Highlights

  • Встановлені закономірності впливу конструктивних параметрів плазмотронів з секціонованою міжелектродною вставкою на ефективність процесів плазмового модифікування

  • The parameters T and W during the plasma modification are not the parameters of direct control, but are complex ones, the value of which being influenced by a large number of factors – the power of the plasma jet, the pressure and flow rate of the plasma-forming gas (Pg, Qg), processing speed, pressure and flow rate of cooling water (Рw, Qw), processing distance h, thermophysical characteristics of the processed material, shape and dimensions of the processed product

  • Of the varieties of indirect plasmatrons, the most preferable is the use of plasmatrons with a sectioned interelectrode insert (SII)

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Summary

ВІСНИК ПРИАЗОВСЬКОГО ДЕРЖАВНОГО ТЕХНІЧНОГО УНІВЕРСИТЕТУ

Вип. 40 p-ISSN: 2225-6733; e-ISSN: 2519-271X erogeneous diffusive nucleation and their use to form new type microstructures and eliminate chemical nonuniformities in bulk industrial product made of alloy structural steels». Vіsnik Priazovs’kogo derzhavnogo tehnіchnogo unіversitetu – Reporter of the Priazovskyi State Technical University, 2002, no. Design features of the plasmatron for surface nanostructuring of the metal cutting tool. The use of the plasmatrons with SII makes it possible to implement the technology of plasma nanostructuring either in a narrow range of mode parameters (microfusion); or when machining a tool with a cutting edge of a special (serrated) shape – for example, threading or thread rolling. Залежно від співвідношення параметрів Т і W області оптимальної реалізації процесів плазмового модифікування показані на рисунку 1. 1 – Області оптимальної реалізації процесів плазмового поверхневого модифікування: 1 – плазмовий відпуск; 2 – плазмове гартування; 3 – плазмове мікрооплавлення; 4 – плазмова наноструктуризація; 5 – плазмова аморфизация Рис. 1 – Області оптимальної реалізації процесів плазмового поверхневого модифікування: 1 – плазмовий відпуск; 2 – плазмове гартування; 3 – плазмове мікрооплавлення; 4 – плазмова наноструктуризація; 5 – плазмова аморфизация

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