ductile-brittle transition temperature

The transition temperature ( English: Nile ductility transition temperature) refers to a temperature between high and low position of a material in terms of its toughness properties. At the transition temperature results in further cooling to a sharp drop in impact energy consumed on a test specimen in the impact test.

Of importance, this is especially for standard steels with cubic crystal system raumzentriertem ( bcc ) are sprödbrechend below the transition temperature. This must be taken into account in the design of workpieces made ​​of this material in terms of the expected operating temperature.

The transition temperature is influenced by the chemical composition (in particular by the " steel pests " hydrogen and nitrogen), grain size, heat treatment condition, etc. Since there is a continuous transition, various definitions have been developed ( eg 27 J in the impact test and 50% Sprödbruchanteil in Battelle drop weight tear - test).

Historically, this issue was specifically addressed in the art, as warships of the Liberty class often lost on its northern route in the Arctic Ocean or even in the harbor without enemy action.