Experimental Study on the Impact Toughness of Thick Plate Butt Weld of Steel Structure at Low Temperature

摘要

Within industry developing rapidly, buildings become higher and larger,rnand offshore structures like drilling platforms increase continuously,rnwhich means the steel thick plate is used more and more widely.rnThickness increase leads to the amount of weld increase, which meansrnmore heat-affect makes the performance of weld and the adjacent steelrnmaterial deteriorate, and the sensitivity of weld defects is also relativelyrnmore significant. These factors cause the weld toughness performancernof steel thick plate to get worse, especially in the low-temperaturernenvironment. Therefore, it is very necessary to study the impactrntoughness of weld of steel thick plate. This paper does an experimentalrnstudy on the impact toughness of butt weld of 150mm thick plate at lowrntemperature, including weld metal and heat-affect zone. The resultsrnshow that the impact toughness of them reduces with the temperaturernreducing, and that of heat-affect zone also reduces with the positionrnchanging from the surface to the center along the thickness direction,rnvariation of which is the same as steel thick plate itself, but valuernrelatively decreases. The paper also gives a regression analysis withrnBoltzmann equation, obtaining the ductile-brittle transition temperaturernof weld metal and heat affected zone under different conditions and itsrnvariation. Test conclusions indicate that butt weld of thick plate of steelrnstructure has clear brittle features, which must be paid sufficientrnattention to.