CN111496352A - Welding method for sloping field pipeline - Google Patents

Abstract

The invention discloses a method for welding a sloping field pipeline, which solves the problems of complicated processing of asymmetric grooves, higher groove processing cost and relatively lower welding efficiency of a single welding torch. The method comprises the steps of pretreating the pipe orifice of the pipeline, wherein the welding process comprises root welding, filling welding and cover surface welding, and the method also comprises the step of changing the setting of the residence time of a welding wire at the upper edge and the lower edge along with the change of the welding position of the upper edge and the lower edge formed after the two bevel groups are assembled in the welding process. Compared with an asymmetric groove, the symmetrical UV composite groove is simple in field processing groove, lower in cost and more beneficial to pipe orifice management and assembly, and undercut and unmelted adverse effects caused by longitudinal welding are accurately controlled by adopting the process parameters of the residence time of the welding edges of the asymmetric upper groove and the asymmetric lower groove, so that the welding quality of a welding seam is ensured.

Description

Welding method for sloping field pipeline

Technical Field

The invention relates to the field of welding processes, in particular to a method for welding a sloping field pipeline.

Background

In recent years, oil and gas pipelines are developed to be large in caliber, long in distance, high in strength and high in pressure, the welding difficulty is increased, and the requirement on the welding quality is increased. It is difficult to meet the requirements of pipeline welding by manual arc welding and semi-automatic flux-cored welding. The automatic welding process is completed by mechanical and preset welding process parameters, the influence of human is very small, and the welding efficiency and the first-time qualified rate of welding are far higher than those of manual welding and semi-automatic welding.

At present, the construction of large-slope pipelines in mountain areas is carried out. The welding process mainly depends on manual electric arc welding and semi-automatic flux-cored wire welding, the labor intensity is high, the efficiency is low, and the qualification rate is far lower than that of the full-automatic welding process. At present, in the existing full-automatic welding process for large-gradient pipelines, in order to solve the problem that longitudinal welding seams are not easy to form, asymmetric grooves are adopted, and single-welding-torch automatic welding is adopted. The asymmetric groove machining is complicated, the groove machining cost is high, and the single welding torch welding efficiency is relatively low.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the asymmetric groove machining is complicated, the groove machining cost is high, the single welding torch welding efficiency is relatively low, and the invention provides the method for welding the sloping field pipeline, which solves the problems.

The invention is realized by the following technical scheme:

a method for welding sloping field pipelines comprises an internal welding system and comprises the following steps:

s1: pretreating the pipe orifice of the pipeline: the method comprises the steps of processing pipe orifices of two sections of pipelines to form a UV composite groove;

s2: and (3) welding: including adopting flexible intelligent pipeline internal welding system, two welding torch pipeline welding system to S1 the groove carries out root welding, filling welding and cosmetic welding, and welding process welding order is root welding, filling welding and cosmetic welding, wherein sets up the construction process in filling welding and cosmetic welding process, and the setting includes according to a set of welded groove the groove opening that the group formed after S1 is right sets up, still includes in the welding process to the upper edge that two groove groups formed after to and lower edge along with the change of welding position change the setting of welding wire at upper edge and lower edge dwell time, and the setting of welding wire at upper edge and lower edge dwell time includes in the in-process of filling welding and cosmetic welding, and the welding wire is at the setting of two welding torch pipeline welding system at upper edge and lower edge dwell time.

The two pipelines form a groove after being processed on the slope, the edge of the pipeline pipe opening far away from the zero-point elevation horizontal plane is the upper edge, and the edge of the pipeline pipe opening close to the zero-point elevation horizontal plane is the lower edge.

And (3) groove machining: the angle of the U-shaped outer opening A1 is 3-5 degrees, the angle of the V-shaped inner groove A2 is 37.5 degrees, the angle of the U-shaped opening R is 3.0-3.2mm, the thickness of the truncated edge H1 is 0.8-1.3mm, and the height of the V-shaped inner groove H2 is 1.4-1.9 (mm).

The preprocessing process of S1 is detailed as follows: firstly, positioning and assembling a pipe orifice by using a flexible intelligent pipeline internal welding system to form a welding seam;

the flexible intelligent pipeline internal welding system is used for detecting the butt gap distance and the misalignment distance after pairing, and the preset conditions are as follows: the flexible intelligent pipeline internal welding system controls the butt gap distance of the groove to be less than 0.5mm, and controls the staggered edge distance of the groove to be less than 1.5 mm;

after the flexible intelligent pipeline internal welding system is detected, repeatedly positioning and assembling the pipe orifice until the detection result meets the preset condition;

then, preheating the assembled welding line by a heating system, wherein the preheating temperature is 100-150 ℃;

sealing the pipe orifices on the two sides of the preheated pipeline;

and then carrying out root welding on the welding seam by adopting a flexible intelligent pipeline inner welding system, and after the root welding is finished, carrying out filling welding and cover surface welding on a welding bead formed after the welding seam is welded by an outer welding seam misalignment polishing operation by adopting a double-welding-torch pipeline welding system in sequence.

The residence time of the torch of the dual torch pipe welding system is greater at the upper edge than at the lower edge on average during welding.

Furthermore, the double-welding-torch pipeline welding system needs to have the functions of arc horizontal, vertical and width tracking and trolley welding position tracking, and according to the welding position, the upper groove welding retention time is increased, namely the upper edge retention time is increased, the lower groove welding retention time is reduced, and the arc length is reduced so as to eliminate the undercut of the upper groove and prevent the lower crevasse from being melted.

The invention has the following advantages and beneficial effects:

compared with an asymmetric groove, the groove is simple to machine on site, has lower cost and is more beneficial to pipe orifice management and assembly.

The double-welding-torch pipeline welding system adopted by the invention is simple to operate and high in intelligent degree, the welding process is completed by software and a preset welding process expert system, and the welding process does not need human intervention, so that the labor intensity of a welder is reduced, and the primary qualified rate of a welding seam can be ensured. The welding efficiency is far higher than that of single-welding-torch automatic welding.

According to the invention, by adopting the process parameters of the residence time of the welding edge of the upper groove and the lower groove which are asymmetric, the undercut and unmelted adverse effects caused by longitudinal welding are accurately controlled, and the welding quality of the welding seam is ensured.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

fig. 1 is a diagram of a specific operation process of the present invention.

FIG. 2 is a schematic diagram of groove preparation according to the present invention.

Fig. 3 is a schematic view of a weld pass sequence of the present invention.

Detailed Description

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any inventive changes, are within the scope of the present invention.

The method comprises the following steps of welding mountainous pipelines, wherein the materials are X70, the specification is 1219 × 18.4.4, groove processing is carried out on a pipe orifice by using a groove machine to form a symmetrical UV compound groove, positioning and assembling are carried out on the pipe orifice by using a flexible intelligent pipeline inner welding system, preheating is carried out on the well pipe orifice by using medium-frequency heating or electric heating, root welding of a welding seam is completed by using the flexible intelligent pipeline inner welding system, and hot welding, filling and cover surface welding of the welding seam are completed by using a double-welding-torch pipeline welding system, and the concrete operation steps are as follows:

before groove processing, the pipe orifices on the inner surface and the outer surface of the steel pipe and the pipe orifices on the two sides are cleaned within the range of 150mm, and phosphorus, abrasion, rust, slag, grease, paint and other harmful substances influencing the welding quality are avoided. The pipe orifice and two sides are mechanically cleaned within 20mm to show metallic luster.

Before groove machining, the welding seams of the inner and outer pipes are polished, so that the welding seams of the inner and outer pipes within 150mm of the pipe end are polished to be flush with the female pipe.

The storage of the welding wire should be performed according to the requirements of the manufacturer's product specification, and any damaged or deteriorated welding wire is not applied to welding.

After the package is removed, the wet and rusty welding wire is not used for welding.

And (3) performing groove machining on the pipe orifice of the pipeline to be welded by using a groove machine to form a symmetrical UV composite groove. The machined groove was used within 24 hours. Groove preparation is shown in fig. 2, and the dimensions are as follows:

groove form	UV composite groove	Wall thickness T (mm)	18.4
				U-shaped opening angle A1	4°	Blunt thickness H1(mm)	1.0±0.2
U type R (mm)	3.0	V-groove angle A2	37.5°
				V groove height H2(mm)	1.7±0.2	Paired opening gap W (mm)	6.1

And polishing and derusting the inner wall and the outer wall of the pipe orifice before the pipe orifice is assembled.

Positioning and assembling pipe orifice by using flexible intelligent pipeline internal welding system

After assembly, the butt gap G is required to be less than or equal to 0.5mm, the misalignment O is required to be less than or equal to 1.5mm, the misalignment is preferably uniformly distributed along the circumference of the steel pipe, and the misalignment is not required to be placed at an overhead welding position as much as possible.

And preheating the assembled welding line by using electric heating or inductive heating. The preheating temperature is 100-150 ℃, and the preheating range is that the welding bead and the two sides of the welding seam are not less than 75mm respectively.

Before welding, the pipe orifices on two sides of the pipeline are sealed to prevent the air in the pipe from flowing too fast.

The flexible intelligent pipeline internal welding system is used for completing root welding of a welding line, and the root welding technological parameters are as follows:

and (3) installing a trolley track of the double-welding-torch automatic welding system, and adjusting the distance from the welding seam side of the track to the welding seam to be 140 mm.

And (4) polishing the staggered edge of the external welding line by using an angle grinder to cut the groove without damaging.

Arcing or arc-stopping requirements: the arc striking or arc closing positions of adjacent welding beads are staggered by more than 30 mm.

And selecting a HW welding bead of a remote controller of the double-welding-torch automatic welding system to complete the hot welding of the welding seam, wherein the welding is stopped only by pressing a key to start the arc, the welding process does not need to be operated, and the hot welding process parameters are as follows.

And selecting a welding pass of a remote controller F1 of the automatic welding system with double welding torches to finish the filling-welding of the welding seam, wherein the welding only needs to be stopped by pressing a key to start arc, the welding process does not need to be operated, and the filling-welding process parameters are as follows.

And selecting a remote controller F2 welding pass of the double-welding-torch automatic welding system to finish the second filling welding of the welding seam, wherein the welding process only needs to stop starting by pressing a key, the welding process needs to adjust the wire feeding amount to fill and level the welding seam, and the second filling welding process parameters are as follows.

And C1 welding beads of a remote controller of the double-welding-torch automatic welding system are selected to complete the cover welding of the welding seams, the welding process only needs to be stopped by pressing a key to start arc, the welding gun needs to be horizontal, the welding gun swings wide to keep the edges of the welding seams fused, the walking speed is finely adjusted to keep the extra height of the welding seams, and the technological parameters of the cover welding are as follows.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (5)

1. A method for welding sloping field pipelines comprises a flexible intelligent pipeline internal welding system and a double-welding-torch pipeline welding system, and is characterized by comprising the following steps:

s1: pretreating the pipe orifice of the pipeline: the method comprises the steps of processing pipe orifices of two sections of pipelines to form a UV composite groove;

s2: and (3) welding: including adopting flexible intelligent pipeline internal welding system, two welding torch pipeline welding system to S1 the groove carries out root welding, filling welding and cosmetic welding, and welding process welding order is root welding, filling welding and cosmetic welding, wherein sets up the construction process in filling welding and cosmetic welding process, and the setting includes according to a set of welded groove the groove opening that the group formed after S1 is right sets up, still includes in the welding process to the upper edge that two groove groups formed after to and lower edge along with the change of welding position change the setting of welding wire at upper edge and lower edge dwell time, and the setting of welding wire at upper edge and lower edge dwell time includes in the in-process of filling welding and cosmetic welding, and the welding wire is at the setting of two welding torch pipeline welding system at upper edge and lower edge dwell time.

2. The method for welding sloping field pipes according to claim 1, wherein the two pipes are processed on the sloping field and then assembled into a weld, wherein the edge of the pipe orifice far away from the zero-altitude level is the upper edge, and the edge of the pipe orifice near the zero-altitude level is the lower edge.

3. The method for welding sloping field pipes according to claim 2, wherein the groove machining: the angle of the U-shaped outer opening A1 is 3-5 degrees, the angle of the V-shaped inner groove A2 is 37.5 degrees, the angle of the U-shaped opening R is 3.0-3.2mm, the thickness of the truncated edge H1 is 0.8-1.3mm, and the height of the V-shaped inner groove H2 is 1.4-1.9 (mm).

4. The welding method for sloping field pipes as claimed in claim 3, wherein the preprocessing process of S1 is detailed as follows: firstly, positioning and assembling a pipe orifice by using a flexible intelligent pipeline internal welding system to form a welding seam;

the flexible intelligent pipeline internal welding system is used for detecting the butt gap distance and the misalignment distance after pairing, and the preset conditions are as follows: the flexible intelligent pipeline internal welding system controls the butt gap distance of the groove to be less than 0.5mm, and controls the staggered edge distance of the groove to be less than 1.5 mm;

after the flexible intelligent pipeline internal welding system is detected, repeatedly positioning and assembling the pipe orifice until the detection result meets the preset condition;

then, preheating the assembled welding line by a heating system, wherein the preheating temperature is 100-150 ℃;

sealing the pipe orifices on the two sides of the preheated pipeline;

and then carrying out root welding on the welding seam by adopting a flexible intelligent pipeline inner welding system, and after the root welding is finished, carrying out filling welding and cover surface welding on a welding bead formed after the welding seam is welded by an outer welding seam misalignment polishing operation by adopting a double-welding-torch pipeline welding system in sequence.

5. The method of claim 4 wherein the residence time of the torch of the dual torch pipe welding system at the upper edge is greater than the residence time at the lower edge on average during welding.

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