As the high-strength found an industrial use alloy structural improved steels, including such, as steel of 40X.  High-strength state is achieved by quenching on martensite, and the decrease of brittleness and the partial removal of residual cooling stress – by leave at a temperature 200-250  °C  with the duration 1,5-2 of hour. The task of increasing the impact toughness of high-strength structural steel with the retention of the high values of the hardness numbers and strength is immediate.

For the solution of this problem it is expedient to use the processing by the subsonic low-frequency pulsatory gas flow (gas-pulse processing) as the inexpensive, ecologically clean means of action on the structure, the stressed state and the mechanical properties of the metalware  1-6. Was carried out a study of the influence of gas-pulse working with the additional action of steel hollow balls on the structure and the properties of metallic materials for increasing its effectiveness with the aid of the standardly hardened models made from steel of 40Kh.

The length of the working part of the models was 55 mm, width –  4 mm, thickness –  2 mm.  Along the flat surface of model were placed hollow steel balls, in one case by the diameter 2,4 of mm, and in other –  3,2 mm. Then models were established on the output from the resonator of installation by plane with the balls towards the gas flow, and the working was accomplished      by the pulsatory air flow with the frequency 1130 of Hz and by the sound pressure 120 dB during 15 the minutes, that was being accompanied by the fluctuations of steel balls near the surface of models and by elastic interaction with it.

The general principle of gas-pulse working with the additional action of steel hollow balls is the following: near the surface of metalware place the hollow steel balls, which, varying in the gas flow with the frequency, compared with the pulsations of the pressure of flow itself, elastic interact with the surface of article, transferring to the latter its kinetic energy and causing propagation in it in addition to by flat, the spherical mechanical waves, which render additional influence on the microstructure and properties.

Vital difference from the shot peening is the absence in the case of gas-pulse working with the additional action of the steel hollow balls of the macroplastic deformation of the surface of article, which makes this technology of suitable for the application with respect to of thin-walled articles and articles with the high surface finish. The results of mechanical tests showed that the greatest impact toughness of the hardened steel models is observed in the case of applying the balls with a diameter 2,4 of mm, somewhat below – with the use of larger balls by a diameter 3,2 of mm and still it is somewhat below in the case of gas-pulse working without the use of balls.

Brittle failure was observed in the hardened model, which was not being undergone gas-pulse working with the dynamic effect. The value of hardness after gas-pulse working with the additional action by the being varied steel hollow balls with a diameter 2,4 of mm was reduced by 3 ones HRC, it whiches indicate the flow of tempering processes, more intensive than with the gas-pulse working of the hardened steel models without the use of additional action by balls.  Being based to given data it is possible to make output about a sufficient effectiveness of the use of the processing as the additions of the standard quenching of the machine parts and equipment from the alloy medium-carbon steel described above, heat-treated to the high-strength state.

2. Ivanov D.A., Zasukhin O.N. Gas-impulsive Treatment of Constructional Materials Without Pre-Heating // DVIGATELESTROYENIYE. – St. Petersburg, 2010, №2, p. 20-22.

3. Ivanov D.A., Zasukhin O.N. Controlled Gas Explosion Technology Combined with Thermal Treatment Improves Strength of Construction Materials // DVIGATELESTROYENIYE. – St. Petersburg, 2012, №3, p. 12-15.

4. Ivanov D.A., Zasukhin O.N. Working by the pulsatory gas flow of high-strength and spring steels // DVIGATELESTROYENIYE. – St. Petersburg, 2014, №3, p. 34-36.

5. Bulychyov A.V., Ivanov, D.A. Effect of gas-impulsive treatment on structure, properties and stress of metal products. // Technologiya Metallov (Technology of metals). – M., 2013, №11, p. 30-33.

6. Ivanov D.A., Zasukhin O.N. Use of pulsating subsonic gas flow for improvement of service properties of metal products // Technologiya Metallov (Technology of metals). – M., 2015, №1, p. 34-38.