The improvement of 13MnNiMoNbR weld strength and low temperature toughness

摘要

For the thick steel plate 13MnNiMoNbR, submerged arc welding was carried out, three kinds of wires were used H08Mn2MoA, H10Mn2MoA, H10Mn2Ni2MoA and together with two kinds of fluxes which are SJ101, SJ102 .After welding ,normalizing plus tempering heat treatment was added.Using V-shaped notch Charpy impact test and the fracture morphology was observed for researching. The toughness of weld and heat affected zone was lower than 27J at -20 °C,cleavage fracture exited in main proportion. Experiments proved that because of the slow colling speed of weld after normalizing a large amount of the upper bainite produced. When normalizing temperature fell in the critical zone where the ferrite and austenite two-phase can exist together (critical normalizing),upper bainite in weld was eliminated , strength and low temperature (-20 °C) toughness correspond with national standard.