Gas shielded welding method for low-carbon Q420q bridge steel

A gas-shielded welding and gas-shielded technology, applied in welding equipment, welding medium, welding equipment, etc., can solve problems affecting the popularization and application of new bridge steel, difficult construction environment, long project cycle, etc., achieve economical welding process and promote promotion , Excellent tensile properties

Inactive Publication Date: 2018-09-28
NORTHEASTERN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although pre-weld preheating and post-weld heat treatment can control the mechanical properties of welded joints, they also lead to problems such as difficult construction environment, high construction cost and long project period. How to obtain welded joints with excellent mechanical properties through reasonable welding process control Become one of the key technologies in the practical application of bridge steel
[0004

Method used

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  • Gas shielded welding method for low-carbon Q420q bridge steel
  • Gas shielded welding method for low-carbon Q420q bridge steel
  • Gas shielded welding method for low-carbon Q420q bridge steel

Examples

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[0036] Example 1

[0037] A gas shielded welding method for low-carbon Q420q bridge steel, the specific steps are as follows:

[0038] Step 1. Bevel:

[0039] A double-sided V-shaped symmetrical groove is opened on the Q420q bridge steel plate with a substrate combination of 14+14mm and a single-sided substrate size of 400×200×14mm. The groove angle is 60°, and the blunt edge is 1mm. 1mm gap;

[0040] Step 2, preprocessing:

[0041] Use 600 grit sandpaper to polish the V-shaped symmetrical groove and the steel plate within 5cm on both sides, and then clean it with acetone to remove rust and impurities to ensure the quality of the welded joint;

[0042] Step 3. Welding:

[0043] (1) At 20% CO 2 Under the protection of +80% Ar mixed gas, the bottom welding is performed. The bottom welding current is 200A, the welding voltage is 22V, the welding speed is 400mm / min, and the input energy is 6.6kJ / cm;

[0044] (2) After the bottom welding, in 20% CO 2 Filling welding is performed under the prot...

Example Embodiment

[0046] Example 2:

[0047] A gas shielded welding method for low-carbon Q420q bridge steel, the specific steps are as follows:

[0048] Step 1. Bevel:

[0049] Double-sided V-shaped symmetrical grooves are opened on the Q420q bridge steel plate with a substrate combination of 20+20mm and a single-sided substrate size of 400×200×20mm. The groove angle is 60° and the blunt edge is 2mm. Clearance 1.30mm;

[0050] Step 2, preprocessing:

[0051] Use 600 grit sandpaper to polish the V-shaped symmetrical groove and the steel plate within 5cm on both sides, and then clean it with acetone to remove rust and impurities to ensure the quality of the welded joint;

[0052] Step 3. Welding:

[0053] (1) At 20% CO 2 Under the protection of +80% Ar mixed gas, the bottom welding is performed. The welding current of the bottom welding is 230A, the welding voltage is 24V, the welding speed is 360mm / min, and the input energy is 9.2kJ / cm;

[0054] (2) After the bottom welding, in 20% CO 2 Filling welding is ...

Example Embodiment

[0057] Example 3:

[0058] A gas shielded welding method for low-carbon Q420q bridge steel, the specific steps are as follows:

[0059] Step 1. Bevel:

[0060] Double-sided V-shaped symmetrical grooves are opened on the Q420q bridge steel plate with a substrate combination of 40+40mm and a single-sided substrate size of 400×200×40mm. The groove angle is 55° and the blunt edge is 3mm. Gap 2mm;

[0061] Step 2, preprocessing:

[0062] Use 600 grit sandpaper to polish the V-shaped symmetrical groove and the steel plate within 5cm on both sides, and then clean it with acetone to remove rust and impurities to ensure the quality of the welded joint;

[0063] Step 3. Welding:

[0064] (1) At 20% CO 2 The bottom welding is performed under the protection of +80% Ar mixed gas, the welding current of the bottom welding is 280A, the welding voltage is 26V, the welding speed is 330mm / min, and the input energy is 13.23kJ / cm;

[0065] (2) After the bottom welding, in 20% CO 2 Filling welding is performe...

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Abstract

The invention discloses a gas shielded welding method for low-carbon Q420q bridge steel, and belongs to the technical field of welding of medium-thickness plates of the bridge steel. The method comprises the following steps that 1), double-face V-shaped symmetric grooves are formed a double-butt-joint base material of a low-carbon Q420q bridge steel base material; 2), grinding and cleaning are carried out on the V-shaped symmetric grooves and the two sides of the V-shaped symmetric grooves; and 3), backing welding and filling welding are carried out under the protection of the mixed gas with 20% of CO2 and 80% of Ar. According to the method, by adopting the welding process technologies, the welding process without preheating carried out before welding and without heat treatment carried outafter welding for the manufacturing process of the low-carbon Q420q bridge steel medium-thickness plate structure under the new national standard requirement is achieved, the simple, high-efficiencyand economical welding mode in the construction process of the medium-thickness plates of the bridge steel is achieved, and the method has important significance in promotion of popularization of thenovel low-carbon bridge steel of the grade.

Description

technical field [0001] The invention belongs to the technical field of bridge steel plate welding, and in particular relates to a gas shielded welding method for low-carbon Q420q bridge steel. Background technique [0002] The development of bridge construction technology and the increase in demand for road transportation make bridge engineering continue to develop in the direction of larger construction scale, shorter construction period, longer service period, easier post-maintenance and multi-purpose. Construction materials put forward higher requirements. As one of the main materials for bridge construction, high-strength bridge steel should have excellent comprehensive properties such as high strength, high toughness, and fatigue fracture resistance. The current national standard GBT 714-2015 "Structural Steel for Bridges" puts forward higher requirements for the chemical composition and low-temperature impact toughness of 420MPa-grade bridge steel. The impact energy ...

Claims

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Application Information

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IPC IPC(8): B23K9/16B23K9/235B23K33/00B23K35/38C22C38/04C22C38/02C22C38/06C22C38/26C22C38/28B23K103/04
CPCB23K9/16B23K9/235B23K33/004B23K35/383C22C38/001C22C38/02C22C38/04C22C38/06C22C38/26C22C38/28
Inventor 胡军张世超张彬齐祥羽董营高彩茹杜林秀
Owner NORTHEASTERN UNIV
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