Glass-magnesium grain cored wire and production technology of steel for high heat input welding

Abstract

The invention discloses a glass-magnesium grain cored wire and a production technology of a steel for high heat input welding. The cored wire comprises an outer layer and a core, wherein the outer layer is low-carbon steel, and the thickness is 0.5-1.0mm; the core is slow release deactivation magnesium grains, and comprises a slow release agent and deactivation magnesium grains, wherein the slow release agent is glass chips, and is 5-90% of the content of the core; the deactivation magnesium grains are 10-95% of the content of the core. The cored wire is used for preparing steel for the high heat input welding. According to the glass-magnesium grain cored wire disclosed by the invention, a slow release deactivation magnesium grain cored wire using glass as the slow release agent is fed to liquid steel, so that the absorption rate of Mg is stable; the effect and the utilization rate of the Mg are high; inclusions are disperse and rich, and the inclusions containing the Mg reach 80% or above. The glass-magnesium grain cored wire has the characteristics of being simple to control, and low in production cost, and the steel for the high heat input welding can be industrially produced in a large-scaled manner.

Description

technical field [0001] The invention belongs to the technical field of low-alloy steel manufacturing, and in particular relates to a glass-magnesium particle cored wire and its application and a production process of steel for high-energy-input welding. Background technique [0002] Steel plates are widely used in infrastructure and large structures such as buildings, bridges, pressure vessels, storage tanks, pipelines and ships. The development trend of large-scale and high-rise building components requires that the thickness of the steel plate be increased, and at the same time have higher comprehensive properties, including higher mechanical properties, efficient processing properties, and excellent corrosion resistance and fatigue damage resistance. [0003] However, as the strength of the steel plate increases, its impact toughness and weldability decrease significantly, and the susceptibility to weld cracks increases. In order to improve the welding efficiency of engi...

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Problems solved by technology

[0005] Magnesium metal is a relatively active element with a boiling point of 1107°C. Due to the high temperature of molten steel in the steelmaking process, its vapor pressure is as high as 2.0×10 6 Pa, so the addition of magnesium in molten steel is prone to evaporation loss and oxidation loss. Improper addition will cause strong oxidation reaction and strong splash in molten steel, which is easy to cause safety problems, and it is also difficult to accurately control Mg in steel

European patent EP1052303A2 "Low-alloy high-strength steel with excellent low-temperature toughness when welded with large input energy" introduced the method of using Ti-Mg composite to obtain fine oxide particles in the test steel, but this test method is only suitable for laboratory vacuum smelting furnace smelting

Chinese patent CN103938065A "A Method for Compositely Adding Magnesium and Titanium to Steel for Large Energy Input Welding" adopts the method of feeding Mg-Y-Ni alloy wire in the tundish to increase the Mg concentration in the molten steel, and the inevitable bandage will occur when adding Mg Injecting other elements, it is difficult to achieve separate adjustment of Mg content

Chinese patent CN 101724774A "method of adding magnesium in the process of welding thick steel plate with large heat input", and Chinese patent CN102191356A "inclusion control method of thick steel plate for large heat input welding" introduced the method of evenly paving Ni-Mg at the bottom of the mold The alloy method obtains a stable Mg yield in steel, but this method is suitable for smelting in a small-scale vacuum smelting furnace, and cannot realize the large-scale industrial production of converter-continuous casting, and it is difficult to bring in other elements when adding Mg. Realize the adjustment of Mg content and timing of adding Mg

Chinese patent CN203048979U "a solid metal magnesium alloy cored wire for steelmaking desulfurization", although its method is used for steelmaking desulfurization, not for the microalloying of steel for large heat input welding, its solid metal magnesium alloy cladding The core part of the core wire is a magnesium alloy, and other metal elements will also be brought in when the molten steel is fed, and the independent control of Mg cannot be fully realized

And it contains Mg93.6%, when this cored wire is fed to molten steel, it cannot achieve flame retardancy

When the cored wire is fed into the molten steel, the cored wire is melted by the molten steel, and the red hot cored end will continue to oxidize strongly, burning the entire cored wire all the time, and cannot be used for actual production

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