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Composite welding method for different-strength jointed connectors of Q370qE and Q690qE bridge structural steel

A q690qe, composite welding technology, applied in the field of steel bridge manufacturing, can solve the problems of great difficulty, large welding deformation, insufficient welding strength, etc., to achieve the advantages of control, reduce the cross-sectional area of ​​the weld, and ensure operability Effect

Active Publication Date: 2019-06-28
CHINA RAILWAY BAOJI BRIDGE GRP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the design of the bottom chord gusset plate and web, there are Q370qE and Q690qE different-strength high-strength steel butt joints. In the field of bridge manufacturing, there is no relevant experience in welding Q370qE and Q690qE different-strength joints for reference, and there is a difference in the tensile strength of the two high-strength steels. More than about 200Mpa, whether it is welding material matching or welding process selection, it is extremely difficult. The existing welding method adopts the conventional bridge steel welding method for welding, but the welding deformation is large and the welding strength is not enough

Method used

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  • Composite welding method for different-strength jointed connectors of Q370qE and Q690qE bridge structural steel
  • Composite welding method for different-strength jointed connectors of Q370qE and Q690qE bridge structural steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] The thickness of the welded steel plate is 32mm, and the materials are Q370qE and Q690qE respectively. Follow the steps below when welding:

[0056] (1) if figure 1 The schematic diagram of the opposite groove structure is shown, the groove is processed on both sides of the two steel plates, and the two sides of the groove are X-shaped as a whole; The groove forms an included angle of 60° as a whole, the large-angle groove angle on the other side is 40°, the large-angle groove between the two steel plates forms an included angle of 80° overall, and the blunt side is 2mm; the small-angle slope The ratio of the depth of the groove to the depth of the large-angle groove is 2:1, the depth of the small-angle groove is 20mm, and the depth of the large-angle groove is 10mm.

[0057] (2) Electromagnetic induction heating equipment is used to heat before welding, and the heating temperature is 70-80°C, such as figure 2 As shown, first use gas shielded welding to weld 3 backin...

Embodiment 2

[0090] The composite welding method of spliced ​​joints with different strengths for Q370qE and Q690qE bridge structural steels with a plate thickness of 50 mm, includes the following steps in sequence:

[0091] (1) Groove is processed on both sides at the joint of two steel plates made of Q370qE and Q690qE respectively. The mouth angle is 41 °, and the blunt edge is 2.5mm; the depth ratio of the small-angle groove and the large-angle groove is 2.5:1;

[0092] (2) First use gas shielded welding to weld 3 times on the side of the small-angle groove to form a bottom weld, and preheat the steel plate to 70-80°C before welding;

[0093] (3) After the bottoming weld is completed, the welding heat raises the temperature of the steel plate to 115-155°C, and the welding groove is fully welded by submerged arc automatic welding on the same side of the small-angle groove, and the welding heat input is controlled at 30-35KJ / cm, using multi-layer and multi-pass welding method for weldin...

Embodiment 3

[0125] The composite welding method of spliced ​​joints with different strengths for Q370qE and Q690qE bridge structural steels with a plate thickness of 50 mm, includes the following steps in sequence:

[0126] (1) Groove is processed on both sides at the joint of two steel plates made of Q370qE and Q690qE respectively. The double sides of the groove are X-shaped as a whole; The angle of the large-angle groove is 39°~41°, and the blunt edge is 2.5mm; the depth ratio of the small-angle groove to the depth of the large-angle groove is 2.5:1;

[0127] (2) First use gas shielded welding to weld 3 times on the side of the small-angle groove to form a bottom weld, and preheat the steel plate to 70-80°C before welding;

[0128] (3) After the bottoming weld is completed, the welding heat raises the temperature of the steel plate to 115-155°C, and the welding groove is fully welded by submerged arc automatic welding on the same side of the small-angle groove, and the welding heat inpu...

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Abstract

The invention discloses a composite welding method for different-strength jointed connectors of Q370qE and Q690qE bridge structural steel in the technical field of welding. According to the compositewelding method, firstly, chamfering is carried out on two faces at the position of a joint of two steel plates, the two faces of grooves are in an X shape on the whole, the small groove angle on one side is 29 degrees-31 degrees, the large groove angle on the other side is 39 degrees-41 degrees, and the truncated edge is 1.5 mm-2.5 mm; and the depth ratio of the small-angle groove to the large-angle groove is (2-2.5): 1; then, gas shielded welding is adopted to weld 2-4 lines on the side of the small-angle groove, bottoming welding lines are formed, welding grooves are welded fully through union melt welding on the same side of the small-angle groove, the steel plates are turned over, carbon arc gouging finishing is carried out on the side of the large-angle groove, union melt welding is adopted to weld the large-angle groove, and the groove is welded fully; and finally, heat preservation is carried out, and slow cooling is carried out until the normal temperature. The welding joints are excellent in mechanical performance, good in welding quality and cable of being used in bridge building.

Description

technical field [0001] The invention relates to a composite welding method of steel plates for bridges with different strengths, which belongs to the field of steel bridge manufacturing and is suitable for welding Q370qE and Q690qE high-strength bridge steel butt joints with different strengths. Background technique [0002] At present, domestic bridge steel is mainly made of Q345 steel and Q370 steel, and some steel truss beams with high stress have adopted Q420 steel and Q500 steel. Bridge steel is developing in the direction of high strength and high performance. The national key plan is to develop high-strength steel for bridges in my country, which is in line with the world's advanced level. For the first time, it launched ultra-low carbon bainite high-strength bridge steel Q690qE (tensile strength ≥ 810Mpa), and applied it in the Wuhan Jianghan Seventh Bridge Demonstration Project. [0003] Wuhan Jianghan Seventh Bridge is a heavy-duty highway bridge with a total lengt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K28/02B23K9/00
Inventor 黄鑫袁俊吴江波刘志刚杜伟李彦国张海涛穆长春薛喆彦杨洪涛
Owner CHINA RAILWAY BAOJI BRIDGE GRP
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