Method for improving high heat input welding performance of thick steel plates

Abstract

The invention discloses a method for improving the high heat input welding performance of thick steel plates. The method comprises the following steps of: 1) smelting and casting to obtain an ingot, wherein deoxidants are added in the deoxidation process of molten steel, the adding sequence of the deoxidants is Mn and Si, Al, Ti, and Ca, a Mg deoxidant is added in the casting process of the molten steel, and the initial oxygen potential during the deoxidation of Mg is accurately controlled by adding Fe2O3 powder into a casting ingot mould; and 2) rolling and cooling. In the method, microfine dispersive distribution and Mg-containing inclusions, which are formed by adding the deoxidants in the deoxidation process of the molten steel and adding the Fe2O3 powder into the casting ingot mould to accurately control the oxygen potential during the deoxidation of the Mg, can inhibit the growth of austenite grains in a welding heat affected zone, and promotes the growth of ferrite in the grains, so that the high heat input welding performance of the thick steel plates is greatly improved.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy and iron and steel materials, and in particular relates to a method for improving the large heat input welding performance of thick steel plates. Background technique [0002] For shipbuilding, construction and other fields, improving the high-energy-input welding performance of thick steel plates can improve welding efficiency, shorten manufacturing hours, and reduce manufacturing costs. For pressure vessels, oil and gas pipelines, and offshore platforms, improving the toughness of the welded heat-affected zone of thick steel plates has become an increasingly urgent requirement. [0003] After high input energy welding, the structure of the steel is destroyed, and the austenite grains grow obviously, forming a coarse-grained heat-affected zone, which reduces the toughness of the welded heat-affected zone. The structures that cause embrittlement in the coarse-grained heat-affected zone ar...

AI Technical Summary

Problems solved by technology

However, in the process of large input energy welding with welding input energy greater than 200kJ / cm, titanium oxide alone is still not enough to improve the toughness of the welding heat-affected zone

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