Structure homogenizing mechanism based large-heat-input gas electrical vertical welding gas shielded flux cored wire

Abstract

The invention discloses a tissue homogenizing mechanism based large-heat-input gas electrical vertical welding gas shielded flux cored wire. The tissue homogenizing mechanism based large-heat-input gas electrical vertical welding gas shielded flux cored wire comprises flux-cored wire skin and powder, wherein the flux-cored wire skin adopts a cold-rolled thin steel strip, the powder accounts for 15-25% of total mass of the flux-cored wire, and the powder consists of the following components in percentage by mass: 1-3% of one or two of titanium dioxide or rutile, 2-6% of feldspar, 1-4% of sodiumsilicate, 1-4% of lithium oxide, 4-10% of low-carbon ferromanganese iron, 4-8% of ferrosilicon, 1-5% of aluminium powder, 2-5% of ferro-molybdenum, 2-6% of nickel powder, 4-8% of rare-earth silicon,0.05-0.1% of boron powder, and the balance of reduced iron powder. The structure homogenizing mechanism based large-heat-input gas electrical vertical welding gas shielded flux cored wire can be applied to large-heat-input gas electrical vertical welding of 100 kJ/cm or more for a medium-thickness steel plate, meets large-heat-input gas electrical vertical welding of the steel-grade structural steel medium-thickness plate of 690 MPa or lower, and can reach maximum welding heat input of 300 kJ/cm.

Description

technical field [0001] The invention relates to a gas-shielded flux-cored welding wire, in particular to a high-heat input gas-electric vertical welding gas-shielded flux-cored wire based on a tissue homogenization mechanism, which can be applied to gas-electric vertical welding with a large heat input above 100kJ / cm. Background technique [0002] Gas electric vertical welding is a special vertical upward welding technology based on gas shielded metal welding, generally using CO 2 Gas protection, using water-cooled copper slider or slide plate and welding groove to form a cavity, molten welding metal fills the cavity and then cools to form. With the continuous development of the demand for various steel structures in the current large-scale manufacturing industry, the requirements for the quality and efficiency of steel structure welding are also getting higher and higher. For medium-thick steel plates of commonly used steel structures, through proper welding groove design ...

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Problems solved by technology

[0004] First, the extended high temperature residence time caused by high heat input welding causes a large amount of beneficial alloying elements to be burned, and the alloying effect of the weld is weakened;

[0005] Second, the extension of the high temperature residence time increases the tendency of the original columnar grains to grow. This irreversible process cannot be effectively refined in the subsequent cooling process, and the coarsening of the grains is likely to cause various embrittlements of the welded joints;

[0006] Third, after the cooling rate is reduced, high-temperature solid-state phase transformation is prone to occur, and pro-eutectoid massive ferrite or Widmanstatten structure with coarse grains is f

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