Scientific journal
Scientific Review. Technical science
ISSN 2500-0799
ПИ №ФС77-57440

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MECHANICAL AND HEAT TREATMENT OF THE STRUCTURAL LOW-CARBON STEEL 09G2S

Smirnov A.I. 1 Pertsev A.S. 2 Panov D.O. 2 Simonov Y.N. 2
1 Novosibirsk State Technical University Novosibirsk
2 Perm national research polytechnic university
We investigated the laws of formation of the structure and properties of structural steel 09G2S at different stages of mechanical and heat treatment. Round billets of steel 09G2S were subjected to pretreatment - toughening before cold radial forging. We used methods of metallographic analysis, transmission electron microscopy, carried out tests on the uniaxial tension and impact toughness KCU and the KCT. The results showed that the cold forging of round billets causes dispersion the elements of the structure and subgrain structure of the investigated steel as a result of the fragmentation structure by cold plastic deformation. The structurally free ferrite, which was observed in the structure of the investigated steel after toughening, is practically absent in the structure of steel 09G2S. Heating the steel 09G2S after deformation to 500 °C and 600 °C causes a behavior of recrystallization processes, and microstructure becomes homogeneous in the wall section of round billets and there are no areas of excessive ferrite. The average size of subgrains of α- phase is 555 nm after cold plastic deformation with a deformation ratio of 55% and annealing at 500 °C. With increasing deformation ratio the cold plastic deformation by radial forging causes an increase in the strength characteristics σ0,2 and σB of structural steel 09G2S after toughening by 50 % and 30 %, respectively. The elongation is reduced by almost 2 times, impact toughness remains at a high level. After annealing of deformed structural steel 09G2S at 600 ˚C the characteristics of the mechanical properties σ0,2, σB, KCU and the KCT are equal the characteristics of the mechanical properties of structural steel 09G2S after toughening, and the ductility significantly reduces - δ by 42%, and ψ by 10%.