Microstructure and mechanical properties of heat-resistant 12% Cr ferritic-martensitic steel EK-181 after thermomechanical treatment

Abstract

The effect of high-temperature thermomechanical treatment (TMT) with the deformation in the austenitic region on the features of microstructure, phase transformations and mechanical properties of low-activation 12% Cr ferritic-martensitic steel EK-181 is investigated. It is established, that directly after thermomechanical treatment (without tempering) the sizes and density of V(CN) particles are comparable with those after a traditional heat treatment (air quenching and tempering at 720°C, 3 h), where these particles are formed only during tempering. It causes the increasing of the yield strength of the steel up to 1450 MPa at room temperature and up to 430 MPa at the test temperature T = 650°C. The potential of microstructure modification by this treatment aimed at improving heat resistance of steel is discussed.

Efficiency of Thermocycling Treatment Application for Hardening Casing Pipes from Steel 09G2S to Strength Group Q125

“…In this connection, in this paper the question of the expediency of using thermocyclic treatment for casing pipes from the economic point of view as compared with other types of treatments is considered. Table 1 shows the cost of casing pipes to obtain the strength group Q125 in accordance with API 5CT for various types of treatments used at the PSP pipe plant of LLP "KSP Steel" [6][7][8][9]. The use of traditional heat treatment for economically alloyed steel 09G2S, which consists in quenching with low temperature tempering, and in combination with mechanical action on the pipe body, does not make it possible to produce a strength group above N80 according to API 5CT, so the steels indicated in Table 1 differ high cost.…”