Electron beam welding joint, steel material for electron beam welding, and manufacturing method thereof

Abstract

A steel for electron-beam welding joint includes as a composition, by mass%, at least C: 0.02% to 0.10%, Si: 0.05% to 0.30%, Mn: 1.5% to 2.5%, Al: more than 0.004% to 0.05% or less, Ti: 0.005% to 0.015%, N: 0.0020% to 0.0060%, P: limited to 0.015% or less, S: limited to 0.010% or less, O: limited to 0.0035% or less, and a balance consisting of iron and unavoidable impurities, wherein an index value CeEBB is 0.42% to 0.65%, a number of inclusion particles having an equivalent circle diameter of 1.0 µm or more is 20 pieces / mm 2 or less at a thickness center portion, and a number of nitride particles containing Ti of 10% or more and having an equivalent circle diameter of 0.05 µm or more and less than 0.5 µm is 1 × 10 3 pieces / mm 2 or more at the thickness center portion.

Description

technical field [0001] The present invention relates to a steel material for electron beam welding which is welded by irradiating electron beams to a welded part sandwiching a plate-shaped or foil-shaped insert metal on the groove surface, and to a manufacturing method thereof, and further relates to a method for manufacturing the steel material through the groove surface of the steel material. Electron beam welded joints formed by irradiating electron beams to the welded parts embedded in the metal. [0002] This application claims priority based on Japanese Patent Application No. 2010-260531 for which it applied in Japan on November 22, 2010, and uses the content here. Background technique [0003] In recent years, in response to CO, which is one of the causes of global environmental warming, 2 With the reduction of gas and the depletion of fossil fuels such as oil in the future, we are actively trying to use renewable natural energy. Wind power is also considered to be ...

AI Technical Summary

Problems solved by technology

Regarding δc, since the size of the test piece affects the fracture toughness obtained by the CTOD (Crack Tip Opening Displacement: crack tip opening displacement) test, it can be obtained even in a small test such as the conventional V-notch Charpy impact test. Good results, in the CTOD test for welded joints of large steel structures, it may not be possible to obtain a good fracture toughness value δc of 0.5mm or more at 0°C

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