THE ANALYSIS OF THE MECHANICAL PROPERTIES OF WELDING JOINTS OF HIGH-STRENGTH STEELS FOR OFFSHORE AND SHIP STRUCTURES

摘要

As the result of carried out research we proved the point, that in design and construction of ship and off-shore structures, it is possible to determine accurate values of end mechanical properties and microstructure of welded joints of category 420/690 steel thick plates. The strengthening meters we obtained in the course of work (cementite, solution, precipitation, ferrite grain size) together with end mechanical properties (R_m, R_e, A_5, Z, KV~0, KV~(20), KV~(40), KV~(60)) enable us to determine metallurgical agents (chemical composition, ν_(ch), t_0, t_h) which make it possible to meet acceptance requirements of high strength steel. The worked-out correlation equations of welded joints mechanical properties may be helpful in assessing the influence of welding technology (t_(8/5), T_(max), E) on meeting acceptance requirements. We proposed the equation which can be used for preliminary assessment of currently produced high strength steels weldability (C_(e31)) and correlation equations used to calculate maximum hardness of HAZ material (HV_(max)).