INFLUENCE OF THE RATIO OF DYNAMIC AND STATIC STRESSES ON BRITTLE FRACTURE RESISTANCE OF LOW-ALLOYED STEEL WELDED JOINTS

摘要

Results of experimental studies of the influence of the ratio of static and dynamic stresses on limit stresses and second critical brittleness temperature of butt welded joints with a crack on 09G2 and 12GN2MFAYu steels under the conditions of room and low (to -80 °C) temperatures are analyzed. It is found that at the specified temperature the dynamic component of critical stress decreases linearly with increase of static stress. It is shown that decrease of limit stresses and increase of the second critical brittleness temperature take place at increase of the dynamic factor. Critical brittleness temperatures of welded joints of steel with higher mechanical properties are significantly lower. It is tound that ignoring the dynamic stresses leads to underestimated values of limit stress and overestimated values of second critical brittleness temperature. Presented analysis of research allows a more substantiated approach to assessment of brittle fracture resistance of structural elements made from the studied materials, and determination of their safety margins. 7 Ref., 1 Table, 7 Figures.