Wide-gap square butt joint welding technology and welding structure

Abstract

The invention relates to a wide-gap square butt joint welding technology and welding structure. A copper liner is adopted to replace a ceramic liner, and the problem that ceramic is molten and stirred to generate slag inclusion is avoided. In the backing weld process, the copper liner is cooled, a weld joint is fast cooled and formed, meanwhile, a weld connector is prevented from generating an overheated structure, the segregation degree is effectively reduced, and the mechanical performance of the weld connector is improved. A solid welding wire is used for backing weld, and weld cracks are not prone to being generated. A contrast test shows that when a gap is 12 mm, the ceramic liner is adopted for single-face CO2 welding, the formed surface of the weld joint on the back face is wide, backing thickness is increased, the weld joint is overheated, reinforcement height is large, forming deteriorates, the liner is prone to falling off, and impact toughness is reduced severely; through the wide-gap square butt joint welding technology, the weld joint is formed attractively and is golden, a backing weld channel on a macro-test sample is small and even in grain, and a welding technology test displays that all indexes of the mechanical performance of the whole weld connector meet the requirement of EH36 steel plates.

Description

technical field [0001] The invention relates to the field of welding technology, in particular to a wide-gap flat butt welding process and welding structure, and is especially suitable for single-sided flat butt automatic welding when the closing seam of steel structures such as ships, bridges, and tanks is greater than 10 mm. Background technique [0002] At present, ceramic liner CO is mostly used for large closing welding of hull sections 2 For welding, the gap is required to be 5-8mm. For the closing welding of ultra-wide welds (also known as wide gaps) with a gap greater than 10mm, the "long meat" process must be used, that is, surfacing welding on the groove. After surfacing welding, the groove should be trimmed to The standard gap is 5 ~ 8mm, and then the ceramic liner CO is used 2 Welding, its efficiency is less than 50% of the normal; if the ceramic liner CO is directly used 2 Due to the influence of the ceramic liner, the bottom weld will produce serious segregat...

AI Technical Summary

Problems solved by technology

[0002] At present, ceramic liner CO is mostly used for large closing welding of hull sections 2 For welding, the gap is required to be 5-8mm. For the closing welding of ultra-wide welds (also known as wide gaps) with a gap greater than 10mm, the "long meat" process must be used, that is, surfacing welding on the groove. After surfacing welding, the groove should be trimmed to The standard gap is 5 ~ 8mm, and then the ceramic liner CO is used 2 Welding, its efficiency is less than 50% of the normal; if the ceramic liner CO is directly used 2 Due to the influence of the ceramic liner, the bottom weld will produce serious segregation and inclusions, which will seriously affect the mechanical properties of the welded joint, and even produce macroscopic cracks.

Alternatively, the ceramic liner CO 2 The welding wire used in welding is flux-cored wire, which is also prone to weld cracks.

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