阅读说明：本技术 大线能量焊接用钢焊接药芯焊丝及其制备方法与焊接方法 (Steel welding flux-cored wire for high heat input welding, preparation method and welding method thereof ) 是由 王存 于 2019-10-17 设计创作，主要内容包括：本发明属于焊接加工材料技术领域,具体涉及一种大线能量焊接用钢焊接药芯焊丝及其制备方法与焊接方法,所述药芯焊丝包括：药芯材料和用于包裹所述药芯材料的碳钢钢带外皮,所述药芯材料包括：C、Si、Mn、Ni、B、Ti、Nb、N,余量为Fe及不可避免的杂质；所述制备方法包括：混料、湿混及热处理、烘干及粉碎、焊丝成型；所述焊接方法包括采用CO<Sub>2</Sub>、Ar混合气体作为焊接保护气体。本发明所述药芯焊丝采用单质态的材料作为药芯材料的成分,在焊接操作之前,药芯材料的稳定更好,以使焊接的效果更稳定。(The invention belongs to the technical field of welding processing materials, and particularly relates to a steel welding flux-cored wire for high heat input welding, a preparation method and a welding method thereof, wherein the flux-cored wire comprises the following components: the flux-cored wire comprises a flux-cored material and a carbon steel strip sheath used for wrapping the flux-cored material, wherein the flux-cored material comprises: C. si, Mn, Ni, B, Ti, Nb, N, and the balance of Fe and inevitable impurities; the preparation method comprises the following steps: mixing, wet mixing and heat treatment, drying and crushing, and forming a welding wire; the welding method comprises using CO 2 And Ar mixed gas is used as welding protective gas. The flux-cored wire adopts the material in the elementary substance state as the component of the flux-cored material, and the flux-cored material is better stable before the welding operation, so that the welding effect is more stable.)

1. The utility model provides a steel welding flux cored wire for high heat input welding, flux cored wire includes the flux cored material and is used for wrapping up the carbon steel strip crust of flux cored material which characterized in that, the flux cored material includes: 0.02 to 0.12 wt% of C, 0 to 0.4 wt% of Si, 1.4 to 1.8 wt% of Mn, 1.8 to 2.6 wt% of Ni, not more than 0.01 wt% of B, not more than 0.01 wt% of Ti, not more than 0.1 wt% of Nb, not more than 0.01 wt% of N, and the balance of Fe and inevitable impurities.

2. The high heat input welding steel flux cored welding wire of claim 1, wherein the carbon steel strip sheath is an SPCC carbon steel strip with a thickness of 0.7mm and a width of 10.2 mm.

3. The steel welding flux-cored wire for high heat input welding according to claim 1, wherein the flux-cored material further comprises Co, and the content of Co is 0 to 0.2 wt%.

4. The steel welding flux-cored wire for high heat input welding according to claim 1, wherein the flux-cored material further comprises 1.2 to 2 wt% of Fe ₃O ₄。

5. The steel welding flux-cored wire for high heat input welding according to claim 1, wherein the flux-cored material further comprises 0.2 to 0.3 wt% of a rare earth element Ce.

6. The steel welding flux-cored wire for high heat input welding according to claim 1, wherein the flux-cored material further comprises 0.4 to 0.5 wt% of NaF.

7. A preparation method of a flux-cored wire comprises the following steps:

step 1, adding the components of the flux core material into a mixer according to the proportion in claim 1, uniformly mixing by using the mixer, and taking out, wherein the flux core material comprises 0.02-0.12 wt% of C, 0-0.4 wt% of Si, 1.4-1.8 wt% of Mn, 1.8-2.6 wt% of Ni, less than or equal to 0.01 wt% of B, less than or equal to 0.01 wt% of Ti, less than or equal to 0.1 wt% of Nb, less than or equal to 0.01 wt% of N, 0-0.2 wt% of Co, and 0-0.2 wt% of Fe ₃O ₄1.2 to 2 wt%, 0.4 to 0.5 wt% NaF, 1 to 1.5 wt% V, and the balance Fe and unavoidable impurities;

step 2, adopting water glass as a binder to wet-mix the uniformly mixed powder, placing the powder in a heat treatment furnace, preserving the heat at 800 ℃ for 8-10 hours, cooling the powder along with the furnace, and taking the powder out;

step 3, crushing the dried powder by using a planetary ball mill;

step 4, sieving by adopting 100-mesh and 220-mesh sieves, wherein the particle size of the sieved powder is between 100 and 220 meshes;

step 5, placing the sieved powder into a powder stirring tank and stirring for 30 minutes;

step 6, detecting the water content of the stirred powder, and if the water content of the powder is less than or equal to 320ppm, performing step 7; if the water content in the powder is more than 320ppm, drying the powder by using a heat treatment furnace until the water content in the powder is less than or equal to 320ppm, and performing step 7;

step 7, mounting the carbon steel strip outer skin on a welding wire forming machine, then conveying the powder into a U-shaped carbon steel strip groove transversely arranged through a powder feeder at the speed of 5-8 r/min, and then rolling into a welding wire prototype;

step 8, drawing the welding wire prototype for the first time through drawing equipment, wherein the aperture of a drawing die for the first drawing is 3 mm;

step 9, changing the aperture of the drawing die to 1.6mm, drawing the welding wire subjected to the first drawing for the second time, and wiping off oil stains on the surface of the flux-cored welding wire subjected to the second drawing forming by adopting an acetone cleaning agent;

and step 10, putting the large linear energy welding wire with the diameter of 1.6mm into a heat treatment furnace, preserving the heat at 300 ℃ for 12 hours, and taking out to finish the manufacture.

8. The method for preparing the welding wire according to claim 7, wherein the step 10 further comprises the step of plating copper on the surface of the welding wire by using electroless plating, wherein the mass of the copper plating layer is 0.1% of the total mass of the welding wire.

9. The preparation method according to claim 7, wherein in the step 2, the water glass comprises 4-10 parts of silica sand, 3-6 parts of bentonite, 3-4 parts of sodium hydroxide, 2-5 parts of a collapsing agent, 3-4 parts of phenolic fiber, 4-8 parts of iron powder, 2-4 parts of phosphogypsum, 1-3 parts of gel, 1-3 parts of sodium sulfite and 20-35 parts of water by mass.

10. A method for welding by using flux-cored wire is characterized in that CO is adopted ₂Ar mixed gas is used as welding protective gas, Ar is used as cooling gas, and a water cooling block is used for being cushioned on the back surface of the welded workpiece, wherein CO is used as protective gas ₂The volume ratio of Ar to Ar is 4:6, and the conveying flow rate of gas is 20-30L/min; the transport flow rate of the cooling gas is 22 to 25L/min.

Technical Field

The invention belongs to the technical field of welding processing materials, and particularly relates to a steel welding flux-cored wire for high heat input welding, and a preparation method and a welding method thereof.

Background

In the construction process of ship manufacturing, large-scale steel structure welding, offshore oil platform welding and oil storage tank welding, the welding working hours account for about 40% of the total working hours, the welding cost accounts for about 17% of the manufacturing cost, the Japanese welding industry starts to apply a large-line energy welding technology from the beginning of the 90 s of the 20 th century, and the welding efficiency is improved by nearly 10 times compared with the traditional multi-pass welding mode. The welding wire produced in Japan can weld the thick plate seam with the thickness of less than 70mm in one-step forming mode, and the welding wire produced in China must be used for welding 10-40 times to complete the thick plate seam with the thickness of less than 70 mm. Therefore, the welding is carried out by using the welding wire made in China, and the time and the cost are long.

The flux-cored welding material with high heat input is a flux-cored welding material with heat input of 300KJ/cm or more, and in the field, the flux-cored welding material in Japan is the most advanced. In China, the development of the flux-cored alloy with high heat input (300-400 KJ/cm and above) is difficult. 5-9 ten thousand per ton of flux-cored alloy with large linear energy imported from Japan and with the energy of 100-200 KJ/cm; export to China is prohibited for more than 400 KJ/cm. At present, 100-300 KJ/cm of flux-cored alloy is imported from Japan, and 400KJ/cm and above are hardly used in China.

Under the condition of high heat input welding, the temperature of a welding joint is increased, the heating time is prolonged, the grain structure of a welding seam, a Heat Affected Zone (HAZ) and a fusion zone is coarsened, the mechanical property, particularly the impact toughness, of the material is deteriorated, and the use safety of the material is threatened. In order to solve the problem, a great amount of Acicular Ferrite (AF) is formed by induction by using fine inclusions in weld metal as nucleation starting points to refine weld metal structures and improve the comprehensive mechanical properties of welds.

For example, the chinese patent application No. CN201811391453.6 discloses a flux-cored wire for high heat input welding, a method for manufacturing the same, and an application thereof, wherein the flux-cored wire comprises a sheath and a flux core filled in the sheath, and the flux core accounts for 13.0 to 13.5% by mass of the flux-cored wire; the flux core comprises the following components in percentage by mass: TiO 2 ₂5.0～5.6％，SiO ₂0.3～0.6％，Al ₂O ₃0.15-0.25% of NaF, 0.2-0.3% of Mg-Al alloy, 0.4-0.5% of Si, 2.0-2.5% of Mn, 0.04-0.11% of Ti, 0.009-0.01% of B and the balance of Fe; the preparation method adopts a steel belt method, the flux core is sealed in the outer skin through O-shaped butt joint, and the flux-cored wire is obtained after forming and reducing; the flux-cored wire is used for welding steel plates with the yield strength not less than 400 MPa.

Disclosure of Invention

The invention aims to provide a steel welding flux-cored wire for high heat input welding, a preparation method and a welding method thereof aiming at the defects in the prior art.

The invention adopts the following technical scheme:

a steel welding flux-cored wire for high heat input welding, the flux-cored wire comprising a flux-cored material and a carbon steel strip sheath for wrapping the flux-cored material, the flux-cored material comprising: 0.02 to 0.12 wt% of C, 0 to 0.4 wt% of Si, 1.4 to 1.8 wt% of Mn, 1.8 to 2.6 wt% of Ni, not more than 0.01 wt% of B, not more than 0.01 wt% of Ti, not more than 0.1 wt% of Nb, not more than 0.01 wt% of N, and the balance of Fe and inevitable impurities.

Further, the carbon steel strip outer skin is an SPCC carbon steel strip with the thickness of 0.7mm and the width of 10.2 mm.

Further, the flux core material also comprises Co, and the content of Co is 0-0.2 wt%.

Further, the flux core material also comprises 1.2-2 wt% of Fe ₃O ₄。

Further, the flux core material also comprises 0.2-0.3 wt% of rare earth elements.

Further, the flux core material also comprises 0.4-0.5 wt% of NaF.

Further, the flux core material also comprises 1-1.5 wt% of V.

The invention also provides a preparation method of the flux-cored wire, which comprises the following steps:

step 1, adding all components of a flux-cored material into a mixer, uniformly mixing by using the mixer, and taking out, wherein the flux-cored material comprises 0.02-0.12 wt% of C, 0-0.4 wt% of Si, 1.4-1.8 wt% of Mn, 1.8-2.6 wt% of Ni, less than or equal to 0.01 wt% of B, less than or equal to 0.01 wt% of Ti, less than or equal to 0.1 wt% of Nb, less than or equal to 0.01 wt% of N, 0-0.2 wt% of Co, and Fe ₃O ₄1.2 to 2 wt%, 0.4 to 0.5 wt% NaF, 1 to 1.5 wt% V, and the balance Fe and unavoidable impurities;

step 2, adopting water glass as a binder to wet-mix the uniformly mixed powder, placing the powder in a heat treatment furnace, preserving the heat at 800 ℃ for 8-10 hours, cooling the powder along with the furnace, and taking the powder out;

step 3, crushing the dried powder by using a planetary ball mill;

step 4, sieving by adopting 100-mesh and 220-mesh sieves, wherein the particle size of the sieved powder is 100-220 meshes;

step 5, placing the sieved powder into a powder stirring tank and stirring for 30 minutes;

step 6, detecting the water content of the stirred powder, and if the water content of the powder is less than or equal to 320ppm, performing step 7; if the water content in the powder is more than 320ppm, drying the powder by using a heat treatment furnace until the water content in the powder is less than or equal to 320ppm, and performing step 7;

step 7, mounting the carbon steel strip outer skin on a welding wire forming machine, conveying the powder into a U-shaped carbon steel strip groove transversely arranged through a powder feeder at the speed of 5-8 r/min, and then rolling into a welding wire prototype;

step 8, drawing the welding wire prototype for the first time through drawing equipment, wherein the aperture of a drawing die for the first drawing is 3 mm;

step 9, changing the aperture of the drawing die to 1.6mm, drawing the welding wire subjected to the first drawing for the second time, and wiping off oil stains on the surface of the flux-cored welding wire subjected to the second drawing forming by adopting an acetone cleaning agent;

and step 10, putting the large linear energy welding wire with the diameter of 1.6mm into a heat treatment furnace, preserving the heat at 300 ℃ for 12 hours, and taking out to finish the manufacture.

Further, step 6 comprises the step of sieving the powder with the water content less than or equal to 320ppm again, wherein the particle size of the sieved powder is 100-220 meshes.

Further, step 7 includes a step of detecting a wire empty in the wire blank.

Further, the step 10 includes a step of plating copper on the surface of the welding wire by using electroless plating, wherein the mass of the copper plating layer is 0.1% of the total mass of the welding wire.

Further, in step 10, before the copper plating on the surface of the welding wire, the method further comprises the step of performing appearance treatment on the welding wire, and performing electrolytic alkali washing on the welding wire; after the alkali washing is finished, carrying out water washing on the welding wire; carrying out electrolytic pickling after the water cleaning is finished, and carrying out water cleaning again after the electrolytic pickling is finished; and drying the welding wire after the water cleaning is finished.

Further, step 10 includes the step of sizing the wire.

Further, the step 10 includes a step of packaging the completed welding wire, wherein the packaged welding wire is provided with a silica gel moisture absorbing material.

Further, in the step 2, the water glass is composed of 4-10 parts of silica sand, 3-6 parts of bentonite, 3-4 parts of sodium hydroxide, 2-5 parts of a collapsing agent, 3-4 parts of phenolic fiber, 4-8 parts of iron powder, 2-4 parts of phosphogypsum, 1-3 parts of gel, 1-3 parts of sodium sulfite and 20-35 parts of water, and the components are calculated according to mass.

Further, in step 9, the acetone cleaning agent comprises 40 to 50 parts by mass of acetone, 10 to 20 parts by mass of diethylenetriamine, 10 to 15 parts by mass of ethanol, and 10 to 20 parts by mass of butyl acetate.

The invention also provides a method for welding by using the flux-cored wire, which adopts CO ₂Ar mixed gas is used as welding protective gas, Ar is used as cooling gas, and a water cooling block is used for being cushioned on the back surface of the welded workpiece, wherein CO is used as protective gas ₂And Ar in a volume ratio of 4:6, of gasThe conveying flow is 20-30L/min; the transport flow rate of the cooling gas is 22 to 25L/min.

Further, welding is performed at a welding voltage of 32 to 36V, a welding current of 300 to 350A and a welding speed of 0.35 to 0.45 mm/s.

Further, the extending length of the flux-cored wire is 20 mm.

The invention has the beneficial effects that:

1. according to the preparation method of the flux-cored wire, the flux-cored material is better stable before welding operation by mainly adopting the material in a simple substance state as the component of the flux-cored material, so that the welding effect is more stable.

2. The flux-cored wire disclosed by the invention can play a role in refining grains by adding the rare earth element, so that the impact toughness is improved.

3. The flux-cored wire is a Ti-B series high-heat input flux-cored wire component, the weld metal of the flux-cored wire contains a large amount of fine and dispersed inclusions, and a large amount of AF acicular ferrite which is distributed in a crossed manner is induced by the inclusions, and the fine structure can strongly prevent crack propagation and improve the low-temperature impact toughness of the weld deposited metal.

4. According to the preparation method of the flux-cored wire, the condition of generating diffusible hydrogen can be reduced by adding NaF.

5. The preparation method of the flux-cored wire effectively reduces the water content in the flux-cored wire through a mode of multiple heat treatments.

6. According to the preparation method of the flux-cored wire, the step of plating copper on the surface of the welding wire is adopted, so that the formed welding wire is rust-proof and corrosion-proof; the conductivity of the welding wire is effectively increased; reduce the friction with the welding gun and lead the wire feeding to be smooth.

7. According to the preparation method of the flux-cored wire, the apparent quality of the formed welding wire is better through the step of performing apparent treatment on the welding wire.

Drawings

FIG. 1 is a metallographic structure diagram of a weld of a flux cored material with V added in example 7 of the present invention;

FIG. 2 is a metallographic structure diagram of a weld of a flux-cored material without V in example 7 of the present invention.

Detailed Description

In order that the above objects, features and advantages of the present invention may be more clearly understood, the present invention is described in further detail below with reference to specific embodiments, it should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.