Actual Problems in Machine Building 2016 No. 3

Актуальные проблемы в машиностроении. 2016. №3 Материаловедение в машиностроении ____________________________________________________________________ 397 INFLUENCE OF PRELIMINARY HEAT TREATMENT OF STRUCTURAL STEEL ON THE STRENGTHENING AT LASER-PLASMA PROCESSING Bagaev S.N. 1 , Academician, Director ILP SB RAS, e-mail: bagayev@laser.nsc.ru Grachev G.N. 1 , Head of the Laboratory, e-mail: grachev@laser.nsc.ru Smirnov A.L. 1 , Chief Designer, e-mail: asmir31@mail.ru Khomyakov M.N. 1 , Junior Researcher, e-mail: mnkhomy@gmail.com Tokarev A.O. 2 , D.Sc. (Engineering), Associate Professor, e-mail: aot51@ngs.ru Bataeva Z.B. 2 , Ph.D. (Engineering), Associate Professor, e-mail: bataevazb@ngs.ru Gerber A.J. 2 , Ph.D. student, e-mail: altair.93@bk.ru 1 Institute of Laser Physics of the SB RAS, 13/3 Akademika Lavrent'eva Prospekt, Novosibirsk, 600090, Russian Federation 2 Siberian State University of Water Transport, 33 Shhetinkina st., Novosibirsk, 630099, Russian Federation Abstract The presented results reflect the experiment on the impact of laser-plasma action on the structure and microhardness of the structural steel surface which includes various structure patterns, such as the ferrite-pearlite structure, the secondary sorbite and the martensitic structure. The polyfunctional CO 2 -laser oscillator - amplifier system was used as a means of technology equipment. As a material for study, the sheet structural low-alloyed steel 40ХН ГОСТ 4543-71 was selected in the different stages: as original steel and as the steel in the state of post-thermal treatment with the help of low and high secondary hardening. The obtained data show that laser-plasma treatment LPT allows to perform hardening of structural steel surface which achieves high (9,0 - 11,0 GPa) solidity reaching the depth of about 0,2 mm. It is possible to use the laser-plasma treatment as a method for local surface hardening in the manufacturing process or during the repairs of machine parts and tools at such different levels as a standard or annealed steel surface treatment which follows into mechanization treatment and also into full thermal treatment with various kinds of release for different degrees of solidity which is determined by the functioning of the treated parts. Keywords Laser plasma, structural steel, surface hardening, stages of technological process.