Shielding gas for high-power TIG welding

A high-power, shielding gas technology, applied in the direction of welding medium, welding equipment, welding equipment, etc., can solve the problems of small ratio of weld penetration depth to fusion width, large heating area of ​​welding plate, and high heat production, etc., to improve depth effect of aspect ratio

Inactive Publication Date: 2013-09-11
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The following disadvantages exist under high-power TIG welding conditions: (1) High-power heat generation is more, the heating area of ​​the welding plate is larger, and improper protection of the welding plate is prone to oxidation, which not only greatly deteriorates the mechanical properties and corrosion resistance of the weld , and also affect the appearance of the weld; (2) The high current aggravates the burning of the tungsten electrode; (3) There is a problem that the ratio of the penetration depth to the fusion width of the general TIG welding seam is small

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] This welding process is especially aimed at the butt welding workpiece of AISI304 stainless steel with a thickness of 4mm, without opening the bevel.

[0014] DC positive connection of welding power supply (that is, the workpiece is connected to the positive pole of the power supply, and the torch electrode is connected to the negative pole of the power supply), the current is 330-360A, the voltage is 14-15V, the welding speed is 400-700mm / min, and the protective gas composition is 2-3% (volume percentage) Hydrogen, 8-10% (volume percentage) helium and the remaining volume of argon, the protective gas flow rate is 11-16L / min.

[0015] The weld width obtained at last is 6.0mm, and the weld has been tested to meet the standards of ASTM A262 and AS3992-1998. Under this condition, the weld seam is well protected, and the tungsten electrode is basically not burned.

Embodiment 2

[0017] This welding process is especially aimed at high-power TIG root welding for multi-pass welding of AISI304 stainless steel with a thickness of 20mm.

[0018] When using the TIG welding method for bottom welding, the welding power supply is directly connected to the positive pole of the power supply (that is, the workpiece is connected to the positive pole of the power supply, and the torch electrode is connected to the negative pole of the power supply), the current is 220-300A, the voltage is 15-16V, and the protective gas is composed of 4-5% hydrogen, 5 ~6% helium (volume percentage) and the remaining volume of argon, the protective gas flow rate is 11~16L / min.

[0019] The minimum effective thickness of the final bottoming bead is 4.7mm, and the width of the heat-affected zone (HAZ) is about 3mm. Under this condition, the weld seam is well protected, and the tungsten electrode is basically not burned.

Embodiment 3

[0021] This welding process is especially aimed at welding the butt weld of AISI304 stainless steel plate with a thickness of 12mm by high-power TIG welding method.

[0022] DC positive connection of welding power supply (that is, the workpiece is connected to the positive pole of the power supply, and the torch electrode is connected to the negative pole of the power supply), the current is 600-720A, the voltage is 14-16V, the welding speed is 225-375mm / min, and the protective gas is composed of 2-3% hydrogen, 8- 10% helium (volume percent) and the remaining volume argon.

[0023] The weld width obtained at last is about 12mm, and the weld has been tested to meet the standards of ASTM A262 and AS3992-1998. Under this condition, the weld seam is well protected, and the tungsten electrode is basically not burned.

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PUM

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Abstract

The invention discloses a shielding gas for high-power TIG welding. The shielding gas for high-power TIG welding is composed of, by volume, 1% to 5% of hydrogen, 2% to 10% of helium, and the balance argon. The shielding gas is applicable to metal welding, particularly austenitic stainless steel welding, by a high-power TIG. According to the shielding gas for high-power TIG welding, oxidation conditions of the surface of a welded joint and oxidation conditions of areas nearby the welded joint can be improved, the depth-to-width ratio of TIG welding can be improved, and burning losses of tungsten electrodes can be reduced.

Description

technical field [0001] The present invention relates to a shielding gas for high-power TIG welding technology, more specifically, welding austenitic stainless steel. Background technique [0002] As we all know, non-melting electrode gas shielded welding (TIG welding) is a welding method widely used in modern industrial production, and it is a representative of high-quality welding methods. However, this method still has obvious limitations. The welding penetration is shallow, the ratio of the depth to width of the molten pool (depth-to-width ratio) is only about 0.2, the deposition efficiency is low, and the welding efficiency is low. Generally, it is limited to welding plates below 3mm. , when the thick plate needs to open the groove for multi-pass welding. If multi-pass welding is used, the welding deformation and heat-affected zone will increase, which will usually affect the quality of welded joints. [0003] In order to adapt to the current trend of large-scale, high...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/38B23K9/167
Inventor 罗震赵春凤李会军李洋冯梦楠
Owner TIANJIN UNIV
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