A low-hydrogen easy-welding basic flux-cored welding wire for structural steel prepared from steel slag

Abstract

The invention belongs to the technical field of welding materials, in particular to a low-hydrogen easy-to-weld basic flux-cored wire for structural steel prepared from steel slag. It is made of low-carbon cold-rolled steel strip wrapped core powder, which includes steel slag 22%‑28%, Mo40V40Al20 powder 7.5%‑9.0%, FeMn60Si34C0.02 powder 5.6%‑8.2%, FeTi80‑A powder 4.1%‑ 5.0%, CaF plated with Ni on the surface 2 Powder 7.8%‑9.6%, Nano TiO 2 4.2%-6.0%, 200 mesh nitrocellulose powder 3.1%-3.8%, feldspar 2.1%-3.0%, and the balance is FHT100·25 reduced iron powder. The invention has stable arc, small spatter, good post-weld forming, easy slag removal, suitable for all-position welding, low residual hydrogen content in deposited metal, uniform chemical composition and high mechanical properties, and is an innovation in the field of basic flux-cored welding wire. .

Description

technical field [0001] The invention belongs to the technical field of welding materials, and in particular relates to a low-hydrogen easy-welding basic flux-cored welding wire for structural steel prepared by using steel slag. Background technique [0002] Basic welding materials have the advantages of low hydrogen, high toughness, high crack resistance and excellent mechanical properties. Basic welding wire is generally the first choice for welding important structural parts. The core powder of the existing basic flux-cored welding wire for structural steel welding is composed of mineral powder and alloy powder. Due to the problems in the components, the mineral powder should be added with alkaline substances such as marble and magnesium oxide. When welding structural steel, the main problems are: ①The molten droplet transitions in coarse particles, and the splash is large during the welding process; ②The fluidity of the slag is too large, and it is difficult to realize al...

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Problems solved by technology

When welding structural steel, the main problems are: ①The molten droplet transitions in coarse particles, and the splash is large during the welding process; ②The fluidity of the slag is too large, and it is difficult to realize all-position welding; Make the weld narrow and poorly formed; ④ Difficult to remove slag; ⑤ In order to ensure the welding quality, the amount of marble added is usually reduced, but the alkalinity of the slag is reduced, and the crack resistance of the weld is poor; ⑥ In order to avoid hydrogen embrittlement, usually Fluorite (the main component is calcium fluoride) is added to remove hydrogen, but the arc atmosphere is deteriorated, and the welding arc is unstable; Poor mechanical properties

But there are the following deficiencies: ① Fluorite and sodium fluorosilicate are added to the flux core, which deteriorates the welding arc. Although the welding arc is stable as recorded in the manual, there is neither theoretical support nor data verification, and the flux cored wire belongs to Non-self-shielded welding wire, CO2 is required for welding 2 Gas protection, in addition to increasing the cost of use, is also easy to mix nitrogen in the air when the protective atmosphere is not good (on the one hand, nitrogen pores are generated, on the other hand, nitrogen enters the deposited metal, reducing its crack resistance), welding processability The degree of improvement is low; ②Al existing in steel slag 2 o 3 When welding with MnO, MnO·A1 will be generated 2 o 3 Spinel-type compounds, they are built on the iron oxide lattice on the surface of the weld metal, which will cause the slag and the weld metal to stick together firmly, making it more difficult to remove the slag; Added in the form of an intermediate alloy, resulting in poor uniformity of the chemical composition of the deposited metal, which is manifested in the highest yield strength of the deposited metal is only 670MPa, and the highest tensile strength is only 780MPa

But there are the following deficiencies: 1. The core powder is almost all industrial waste residue with high mineral content. Although 200 mesh cellulose powder and 80 mesh cellulose powder have been added, the arc combustion is still not sufficient and the stability is insufficient; 2. Although the cellulose Al in carbides and steel slag after powder combustion 2 o 3 Combined with MnO, the molten slag is partially loose, but the degree of improvement is limited, and there is still a phenomenon that the slag is difficult to remove; ③The hydrogen-removing component is not used in the core powder, which makes the deposited metal prone to "hydrogen embrittlement" and poor crack resistance

But there are the following deficiencies: 1. The basicity of steel slag is 1.18, which does not reach the 1.3 or more required by common basic welding rods (welding wires), and is not suitable for welding important components of structural steel; 2. SiO in steel slag 2 The content is small, the arc stability is poor during welding, and the welding processability is not good; ③ Al present in steel slag 2 o 3 When welding with MnO, MnO·A1 will be generated 2 o 3 Spinel-type compounds, which are built on the iron oxide lattice on the surface of the weld metal, although sawdust starch is added, the carbides after combustion and the Al in the steel slag 2 o 3 Combined with MnO, the slag is partially loose, but there is still a phenomenon that it is not easy to remove the slag; ④ Except for the ferromanganese slag containing 6% fluorite, other slags do not contain hydrogen removal components, resulting in "hydrogen embrittlement" in the deposited metal Phenomenon, poor crack resistance, low mechanical properties

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