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High-efficient submerged welding method for low-temperature steel

A technology of submerged arc welding and low-temperature steel, which is applied in the field of submerged arc welding flux-cored wire, welding process and welding joints, and flux. Efficiency improvement, low tendency of cold cracking, and low content of diffusible hydrogen

Inactive Publication Date: 2016-08-03
HAINING RUIAO METAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

High current welding can significantly improve the welding efficiency, but at the same time it will deteriorate the low temperature impact toughness of the seam metal
On the premise of ensuring the quality of welded joints, the existing flux-cored welding wire and submerged arc flux can only withstand submerged arc welding with a welding heat input of 50kJ / cm, that is, current ≤ 700A, voltage ≤ 34A, and the efficiency is not high
[0005] At the same time, due to the moisture-absorbing characteristics of flux-cored wire, it often leads to a high content of diffusible hydrogen in the weld metal, which damages the safety of high-strength welded joints.
Therefore, it is usually necessary to heat the welding wire at 350°C and heat it for 3 hours before welding, and the procedure is cumbersome.
[0006] In view of the impact energy requirements of low temperature steel welding joints at -40°C, there is no submerged arc welding flux-cored wire, flux and process that can adapt to high current 800-1300A

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Flux cored wire composition contains 0.08%C, 0.15%Si, 1.62%Mn, 0.86%Ni, 10%CaF 2 ,0.95%CaCO 3 , 0.008%P, 0.003%S. The diameter of the welding wire is 3.2mm, the filling rate of the powder is 20%, the particle size of the powder is about 300 mesh, and the area ratio of the iron sheet on the cross section is 60%.

[0035] The flux is sintered flux, the basicity is 1.65, and the specific composition includes 28% CaF 2 , 16%Al 2 O 3 , 11%SiO 2 and 1.5%TiO 2 , It needs to be dried at 250 ℃ for more than 2 hours before welding.

[0036] The test base metal is 20mm thick, the tensile strength is 652MPa, and the impact energy at -40°C is 156J.

[0037] The welding process parameters are as follows:

[0038] (1) The welding groove is Y-shaped, the angle is 25°, the blunt edge is 2mm, and the gap is 1.0mm;

[0039] (2) The welding current is 1100A, the voltage is 42V, and the wire feeding rate is 7m / min.

[0040] After welding inspection, no defects were found, and the qu...

Embodiment 2

[0045] Flux cored wire composition contains 0.09%C, 0.06%Si, 1.96%Mn, 0.56%Ni, 14%CaF 2 ,1.15%CaCO 3 , 0.15%Mo, 0.009%P, 0.004%S. The diameter of the welding wire is 4.0mm, the filling rate of the powder is 24%, the particle size of the powder is about 200 mesh, and the area ratio of the iron sheet on the cross section is 55%.

[0046] The flux is sintered flux, the basicity is 1.85, and the specific composition includes 32% CaF 2 , 6%Al 2 O 3 , 12%SiO 2 , 0.8%BaO and 1.5%TiO 2 , It needs to be dried at 250 ℃ for more than 2 hours before welding.

[0047] The test base metal is 40mm thick, the tensile strength is 732MPa, and the impact energy at -40°C is 156J.

[0048] The welding process parameters are as follows:

[0049] (1) Double V-shaped welding groove, the angle is 35°, the blunt edge is 3mm, and the gap is 1.0mm;

[0050] (2) The welding current is 1300A, the voltage is 46V, and the wire feeding rate is 7.5m / min.

[0051] After welding inspection, no defects ...

Embodiment 3

[0056] Flux cored wire composition contains 0.05%C, 0.20%Si, 1.60%Mn, 0.90%Ni, 5%CaF 2 ,0.6%CaCO 3 , 0.15%Cr, 0.006%P, 0.003%S. The diameter of the welding wire is 4.0mm, the filling rate of the powder is 14%, the particle size of the powder is about 250 mesh, and the area ratio of the iron sheet on the cross section is 75%.

[0057] The flux is sintered flux, the basicity is 1.75, and the specific composition includes 35% CaF 2 , 7%Al 2 O 3 , 10%SiO 2 , 2.0%BaO and 2.0%TiO 2 , It needs to be dried at 250 ℃ for more than 2 hours before welding.

[0058] The test base metal is 30mm thick, the tensile strength is 682MPa, and the impact energy at -40°C is 216J.

[0059] The welding process parameters are as follows:

[0060] (1) Double V-shaped welding groove, the angle is 30°, the blunt edge is 2mm, and the gap is 1.0mm;

[0061] (2) The welding current is 800A, the voltage is 36V, and the wire feeding rate is 7.8m / min.

[0062] After welding inspection, no defects wer...

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Abstract

The invention discloses a high-efficient submerged welding method for low-temperature steel. The welding technology comprises a flux cored wire, solder and a method. Medical powder filling rate of the flux cored wire is 12 to 25%; and the flux core wire contains the following components according to weight by percentage: 0.05 to0.12% of C, no more than 0.2% of Si, 1.6 to 2.0% of Mn, 0.50 to 0.90% of Ni, 2.5 to 15% of CaF2, 0.3 to 1.2% of CaCO3. CaF2-Al2O3-SiO2 submerged solder with alkalinity of 1.5 to 2.0 is employed; welding current is 700 to 1300A; wire feeding speed is no less than 6m / min; and efficiency can be improved by 50% compared with the prior art. The high-efficient submerged welding method for low-temperature steel can be widely applied to welding in fields of ships and maritime work.

Description

technical field [0001] The invention relates to a high-efficiency submerged arc welding method for low-temperature steel, in particular to a submerged arc welding flux-cored welding wire, flux, welding process and welding joint that require low-temperature impact toughness at -40°C. Background technique [0002] In recent years, the vigorous development of shipbuilding, marine engineering and other industries has brought about the rapid development and demand of low-temperature steel. In order to ensure structural safety, classification society regulations and other technical regulations usually require that the -40°C impact energy of the welded structure is above 47J, which requires the base metal steel plate and welding materials to meet the -40°C impact energy requirements. [0003] Welding man-hours account for about 25-35% of the manufacturing man-hours of large-scale welded structures such as ships. Therefore, improving welding efficiency is very important for improvin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/368B23K35/30B23K35/12B23K9/18
Inventor 张焕鑫
Owner HAINING RUIAO METAL TECH CO LTD
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