Welding process of super high strength and high toughness x120 pipeline steel girth weld

Abstract

The invention relates to a welding technology of super-high-strength high-toughness X120-level pipeline steel circumferential welds. The technology includes the following steps that (1), parent metal is prepared; (2), welding wires are prepared; (3), edge milling is performed; (4), rust and oil are removed; (5), protecting gas is adjusted; (6), pairing is performed; (7), a welding machine is started; (8), point fixing is performed; (9), preheating is performed; (10), root welding is performed; (11), slag crust and splash are eliminated; (12), interlayer temperature is controlled; (13), thermal welding is performed; (14), slag crust and splash are eliminated; (15), interlayer temperature is controlled; (16) the first time of filling welding is performed; (17) slag crust and splash are eliminated; (18), interlayer temperature is controlled; (19) the second time of filling welding is performed; (20) slag crust and splash are eliminated; (21), interlayer temperature is controlled; (22), cosmetic welding is performed; and (23) slag crust and splash are eliminated. By means of the welding technology of the super-high-strength high-toughness X120-level pipeline steel circumferential welds, it is guaranteed that the welding quality meets the using performance requirement, and meanwhile grain coarsening of a welding heat effect region and softening of a welding connector are obviously improved; the using quantity of welding materials can be reduced easily, the welding efficiency is improved, and the welding and manufacturing cost is reduced; and the beneficial effects that movability is good and adaptability is wide are achieved, and the welding technology can adapt to various complicated field construction conditions.

Description

technical field [0001] The invention belongs to the technical field of pipeline steel welding, and in particular relates to a welding process of an ultra-high-strength and high-toughness X120 grade pipeline steel circular weld seam. Background technique [0002] With the increasing demand for oil and natural gas worldwide, it is becoming more and more important to choose safer, economical and reliable pipeline steel to reduce the construction cost of long-distance oil and gas transmission pipelines, and to improve the stability, reliability and safety of the transportation process. more and more important. Compared with the X80 grade pipeline steel widely used in pipeline engineering, the strength of X120 pipeline steel has been increased by 40%, which has obvious effects on reducing the construction cost of pipelines and ensuring the safety of pipeline transportation. Therefore, in the near future, ultra-high strength and high toughness X120 grade pipeline steel will becom...

AI Technical Summary

Problems solved by technology

The shortcomings of this process are: two sets of welding equipment are used, one is a fusion welding system, and the other is a solid-phase connection friction stir welding system; and the field construction of the friction stir welding system is very operable and flexible. Restricted, thus limiting the feasibility of this process in actual field pipe laying construction operations; the cost of the entire process is too high

To make the X120 grade pipeline steel with a yield strength above 870MPa reach a plastic state, the strength, hardness and service life of the stirring head will face great challenges, so the consumption of the stirring head is very large, which is the current friction stir welding process. One of the bottlenecks that cannot be applied on a large scale in the field of steel welding

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