Keyword: «equal-channel angular pressing»

The changes of microstructure and resistance of steel 09G2S to brittle fracture after the "cold" (at room temperature) equal channel angular pressing (ECAP) were investigated. It is shown that getting of the nano and submicrocrystalline microstructures has provided a technically significant improvement in the mechanical and operational properties of the steel (strength, toughness), including at fall of tests temperature to –40 °C. The qualitative analysis of features of crack formation processes in nanostructured metal under dynamic loading was conducted. It was revealed that the high values of impact toughness are due to the implementation of energy–intensive micromechanisms of fracture – ductile dimpled fracture and dispersed quasi- cleavage, intensive branching of micro- and macrocracks, what caused the slowing of their velocity and the formation of a developed relief.

The paper considers the production of a layered steel composite by pressure welding (forge welding) and its strengthening by equal-channel angular pressing (ECAP). The layered steel composite material was obtained by forge welding of plates of low-alloy steel 09G2S and alloyed carbon steel 40H. In addition, plates of 09G2S were subjected to forge welding. ECAP resulted in an increase in the strength of the layered steels. ECA pressing was carried out on a bulk blank obtained by forge welding of 8 steel plates (09G2S + 09G2S) and (09G2S + 40H). Data on the microstructure and proportionality limit in uniaxial compression tests before and after ECAP are presented. As a result of the ECAP effect, the proportionality limit of the 09G2S layered steel increased by 1.7 times compared to the 09G2S matrix material, and the layered steel composite by 1.8 times.