Peculiarities of welding T-joints made from high-strength martensitic-bainitic steel

摘要

Mechanical properties of high-strength alloyed steel 12KhGN2MFDRA and peculiarities of formation of welded joints in making fillet welds are investigated. It is shown that steel acquires high values of mechanical properties, such as σ{sub}0.2≥980 MPa; σ{sub}B≥1078 MPa; δ{sub}5≥10% and KCV{sup}(-50)≥29 J/cm{sup}2 after quenching in combination with tempering. It is established that in T-joint welding within the range of 6...15 mm thicknesses the rate of cooling (w{sub}(6/5)) of HAZ metal of web and flange is varied from 1,8 to 60℃/s. Within this interval of cooling rates the structure of HAZ metal is mainly formed in martensitic and bainitic regions with hardness HV 303...375.