Mechanical properties of carbon chromium-manganese steels with a structure of unstable austenite

Abstract

1. The set of mechanical properties for steels with a structure of unstable austenite containing 0.6% C, O... 11% Cr, 8... 13% Mn is governed to a considerable degree by the level of structural stability in relation to formation of deformation martensite: formation of even a small amount of martensitic phases (several per cent) during extension or dynamic bend testing leads to embrittlement and a reduction in strength, ductility, and impact strength for the steel. 2. An increase in manganese content from 8 to 13% in steels of type 60Kh5 causes a reduction in Md temperature, an increase in deformation stability for austenite, and as a result of this an increase in the set of steel mechanical properties. An increase in chromium content to 6.5% in steels of type 60G10, which does not alter Md temperature, has little effect on the deformation stability of austenite and mechanical characteristics of steels, but a further increase in chromium content to 10.5% stabilizes austenite during plastic deformation. 3. An increase in test temperature for the steels studied to 150–200°C causes a reduction in the amount of martensitic phases formed during extension, as a result of which there is a sharp increase in ductility characteristics and the value of of with a reduction in the value of o0.2; with an increase in test temperature to 300°C the ductility properties of the steels decrease.