Weldability of Fe-36% Ni Alloy (Report II) : Effect of Chemical Composition on Reheated Hot Cracking in Weld Metal(Materials, Metallurgy & Weldability)

概要

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Studies are made on chemical compositions of Fe-36% Ni alloy for membrane-type LNG tanks to prevent ductilitydip crack in weld metal. Cross-bead type hot cracking test are conducted for 24 different composition alloy samples. The relationship between chemical composition and total crack length is studied by regression analysis. Materials having good properties against the ductility-dip crack are produced on practical produetion line and are used for practical fabrication of model tanks. Conclusions thus obtained are as follows: 1) S, O, N and Al are the elements promoting ductility-dip crack, while P shows a slight trend of promoting the crack. Si and Mn function as the elements inhibiting the crack formation. 2) By using the basic elements and impurity elements contained in the alloys, an estimating equation for the total crack length in Cross-bead cracking test is obtained. 3) Materials having good properties against the crack are produced on practical production line and are used for practical fabrication of model tanks. Obtained results are favorable.
大阪大学の論文