International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The features of structural changes in the cove zone on the tread of worn out railway wheels were investigated. The influence of laser processing in pulsed and continuous mode on the nature of the structure and properties of wheel steel was shown. The influence of laser treatment on the increase in the hardness and wear resistance of wheel steel has been established. It was shown possibility and necessity of local laser hardening of cove zone of railway wheels tread by coming out of bainite structure. A method for improving the wear resistance of the tread by local laser treatment has been proposed.

It was found that in the process of pulsed laser action, various phase and structural transformations occur in non -metallic inclusions, which take place under nonequilibrium conditions. It is shown that the melting of inclusions under laser action is corresponded with change of their structure and phase composition. Also it is shown that the nature of these transformations depends on the type of nonmetallic inclusion. It was found that nonequilibrium phase transformations contribute to a change in the structure, phase composition, properties and sizes of nonmetallic inclusions, as well as the inclusion-matrix interphase boundaries of steel. It is shown that changes in the structure and properties of non-metallic inclusions affect their behavior and the formation of defects in the laser-strengthened layer of steel
products.

Melting and crystallization of heterophase non-metallic inclusions “dispersed phases are in non-metallic matrix” was investigated. Mechanism of melting of the inclusions “dispersed phases are in non-metallic matrix” and inclusion-matrix boundaries under contact laser melting with steel matrix in the conditions of abnormal mass transfer connecting with formation of zones with high dislocation density and also with electron and electro-magnetic interaction between inclusion and steel matrix was proposed. That allows to create the possibilities for the influence on the inclusion-matrix boundaries and also on the chemical and phase composition of surface layer of non-metallic inclusions “dispersed phases are in non-metallic matrix”. Peculiarities of structure of non-metallic inclusions after speed crystallization were investigated. It was shown that under laser action the initial structure of inclusion-steel matrix boundaries transits into unstable equilibrium high-energy condition that cause development of the dissipation processes connecting with aspiration of system inclusionmatrix to the state with minimum of the free energy. In the result of the system inclusion-matrix transits to the state of unstable equilibrium which determines structure and properties of laser-quenched interphase boundary. Processes of melting, fusion and dissolution of nonmetallic inclusions “dispersed phases are in non-metallic matrix” and also of the melting of steel matrix play the great role in transformation of interphase inclusion-matrix boundaries under laser action.

Melting and crystallization of heterophase non-metallic inclusions ―eutectics‖ was investigated. Mechanism of melting of the eutectic inclusions and inclusion-matrix boundaries under contact laser melting with steel matrix in the conditions of abnormal mass transfer connecting with formation of zones with high dislocation density and also with electron and electro-magnetic interaction between inclusion and steel matrix was proposed. That allows to create the possibilities for the influence on the inclusion-matrix boundaries and also on the chemical and phase composition of surface layer of non-metallic inclusions. Peculiarities of structure of non-metallic inclusions after speed crystallization were investigated. It was shown that under laser action the initial composite colonial structure of inclusions transits into abnormal eutectic structure. Also it was shown that under laser action the initial structure of inclusion-steel matrix boundaries transits into unstable equilibrium high-energy condition that cause development of the dissipation processes connecting with aspiration of system inclusion-matrix to the state with minimum of the free energy. In the result of the system eutectic inclusion-matrix transits to the state of unstable equilibrium which determines structure and properties of laser-quenched interphase boundary. Processes of melting, fusion and dissolution of non-metallic inclusions ―eutectics‖ and also of the melting of steel matrix play the great role in transformation of interphase inclusion-matrix boundaries under laser action.

Melting and crystallization of heterophase non-metallic inclusions “phases are beside” was investigated. It was shown that under laser action the initial structure of inclusion-steel matrix boundaries transits into unstable equilibrium high-energy condition that cause development of the dissipation processes connecting with aspiration of system inclusion-matrix to the state with minimum of the free energy. In the result of the system heterophase inclusion-matrix transits to the state of unstable equilibrium which determines structure and properties of laser-quenched interphase boundary. Processes of melting, fusion and dissolution of non-metallic inclusions “phases are beside” and also of the melting of steel matrix play the great role in transformation of interphase inclusion-matrix boundaries under laser action.

Melting and crystallization of heterophase non-metallic inclusions “high-melting phase surrounding with low-melting cover” was investigated. It was shown that under laser action the initial structure of inclusion-steel matrix boundaries transits into unstable equilibrium high-energy condition that cause development of the dissipation processes connecting with aspiration of system inclusionmatrix to the state with minimum of free energy. In the result of the system heterophase inclusion-matrix transits to the state of unstable equilibrium which determines structure and properties of laser-quenched interphase boundary. Processes of melting, fusion and dissolution of non-metallic inclusions “high-melting phase surrounding with low-melting cover” and also of the melting of steel matrix play the great role in transformation of interphase inclusion-matrix boundaries under laser action.

Melting and crystallization of eutectic non-metallic inclusions was investigated. It was shown that under laser action the initial structure of eutectic inclusion-steel matrix boundaries transits into unstable equilibrium high-energy condition that cause development of the dissipation processes connecting with aspiration of system inclusion-matrix to the state with minimum of free energy. In the result of the system eutectic inclusion-matrix transits to the state of unstable equilibrium which determines structure and properties of laser-quenched interphase boundary. Processes of melting, fusion and dissolution of eutectic non-metallic inclusions and also of the melting of steel matrix play the great role in transformation of inclusion-matrix boundaries under laser action.

Melting and crystallization of heterophase non-metallic inclusions “high-melting phase surrounding with low-melting cover” was investigated. It was shown that under laser action the initial structure of inclusion-steel matrix boundaries transits into unstable equilibrium high-energy condition that cause development of the dissipation processes connecting with aspiration of system inclusionmatrix to the state with minimum of free energy. In the result of the system heterophase inclusion-matrix transits to the state of unstable equilibrium which determines structure and properties of laser-quenched interphase boundary. Processes of melting, fusion and dissolution of non-metallic inclusions “high-melting phase surrounding with low-melting cover” and also of the melting of steel matrix play the great role in transformation of interphase inclusion-matrix boundaries under laser action.

Melting and crystallization of heterophase non-metallic inclusions “high-melting phase surrounding with low-melting cover” was investigated. It was shown that under laser action the initial structure of inclusion-steel matrix boundaries transits into unstable equilibrium high-energy condition that cause development of the dissipation processes connecting with aspiration of system inclusionmatrix to the state with minimum of free energy. In the result of the system heterophase inclusion-matrix transits to the state of unstable equilibrium which determines structure and properties of laser-quenched interphase boundary. Processes of melting, fusion and dissolution of non-metallic inclusions “high-melting phase surrounding with low-melting cover” and also of the melting of steel matrix play the great role in transformation of interphase inclusion-matrix boundaries under laser action.

Melting and crystallization of non-metallic inclusions in contact with steel matrix during laser treatment was investigated. It was shown that laser action is the method of local change of inclusion structure in the surface fused layers and also of the properties of non-metallic inclusion surface. Peculiarities of steel matrix saturation with elements of non-metallic inclusions during different regimes of laser action were investigated. It was shown the role of that process in the formation of local structure of steel matrix near non-metallic inclusions. That allows to realize possibility of transformation of the non-metallic inclusions how sources of inside local alloying of steel matrix. It was fixed that in local areas of steel matrix the liquation strengthened zones were formed. They represent different types of composite layers: gradiental zones with cascade and “spot” distribution of elements and nanohardness, dispersal zones with different types of microphases and nanophases, “tunnel” zones, and also zones with combine structure. It was shown the role of non-metallic inclusions in development of micro heterogeneous strengthening of steels under laser treatment.