Investigation of new steel with increased strength for low temperature applications

Abstract

Abstract The work established the patterns of a structural and phase transformations which occurs in the new steel of the 0,21C-1,0Mn-1,8Ni-0,3Cu-0,3Mo-0,03Ti-0,004B (%, mass) alloying system at different cooling rate. A thermokinetic diagram has been constructed. Laboratory samples of rolled products were manufactured and the mode of hardening of rolled sheets from a temperature of 860 ° C in water was tested to develop the industrial production of new steel using specialized equipment of the laboratory complex of LLC “EC Termodeform-MSTU”. The results of mechanical tests of rolled sheet samples after heat treatment showed that the steel under study in a hardened state has high strength characteristics in complex with increased impact strength at a test temperature of minus 70 °C: tensile strength σUTS = 1500 MPa, yield strength σ0.2 = 1150 MPa, relative elongation A5 = 12.5 %, hardness 429 HBW, impact strength KCV−70 = 50.3 J/cm2. This confirms its high quality and the possibility of using it for the production of heavily loaded mechanical engineering structures operated at low temperatures in the conditions of the Far North and the Arctic zone of the Russian Federation.