CN114603238A

CN114603238A - Novel welding process method for prefabricated welding joint of ocean engineering square tube structure

Info

Publication number: CN114603238A
Application number: CN202210348650.XA
Authority: CN
Inventors: 贾晓燕; 程尚华; 王世达; 王旭; 朱永强; 李晓明; 罗运良; 白晓科; 李梅豹; 孙爱丽
Original assignee: Penglai Jutal Offshore Engineering Heavy Industries Co ltd
Current assignee: Penglai Jutal Offshore Engineering Heavy Industries Co ltd
Priority date: 2022-04-01
Filing date: 2022-04-01
Publication date: 2022-06-10

Abstract

The invention discloses a novel welding process method for a prefabricated welding joint of an ocean engineering square tube structure, which comprises the following steps of: blanking the plate, and performing groove machining on the edge to be welded of the plate; assembling the welding joints of the plates to form a welding joint of a prefabricated square tube structure; adopting a metal powder-cored welding wire and carrying out back cover welding at the position of a welding joint by utilizing semi-automatic gas shielded welding; filling welding is carried out at the position of a welding joint by adopting a flux-cored wire and utilizing semi-automatic gas shielded welding; and adopting a flux-cored wire and performing cover surface welding at the position of the welding joint by utilizing semi-automatic gas shielded welding. The welding method can be used for welding the prefabricated welding nodes of the ocean engineering square tube structure, and is good in welding effect and simple and convenient to weld.

Description

Novel welding process method for prefabricated welding joint of ocean engineering square tube structure

Technical Field

The invention relates to the technical field of welding, in particular to a novel welding process method for a prefabricated welding joint of a square tube structure of ocean engineering.

Background

In ocean engineering and module projects, a large number of square tube rod pieces are assembled and welded, and therefore welding joints with high welding difficulty and high quality requirements are formed.

In the welding process, for the welding of the large-diameter square tube, double-sided welding is generally adopted, the first procedure is backing welding, and CO is adopted under normal conditions₂Gas shielded welding bottoming, submerged arc welding filling cover surface, back gouging. When this process is used, CO₂The gas shield welding bottoming can generate a lot of defects such as air holes, slag inclusion, incomplete welding and the like, back gouging is needed for obtaining qualified welding seams, the number and the depth of the defects directly influence the working capacity of the gouging, certain requirements are provided for the welding skill, the appearance of a groove after gouging is often irregular, the subsequent welding difficulty can be increased, and welding defects are easy to occur at the root part at ordinary times. Meanwhile, the air gouging machine has the advantages of high working noise, more smoke and dust, severe working environment and consumption of a large amount of carbon rods and electric energy. After the air gouging, the welding bead after the air gouging needs to be polished with large workload to weld the submerged arc welding, which consumes time and labor and has high cost.

For the prefabricated node assembled by a small-diameter circular tube and a square tube, a welding process of single-side welding and double-side forming is required. As analyzed from the prior art, with Shielded Metal Arc Welding (SMAW), quality is relatively guaranteed, but efficiency is low. The method is high in efficiency, but the root part is often not fused to cause repair, so that a plurality of ocean engineering enterprises refuse to use the surface tension transfer technology (STT) for backing welding.

In view of the above, it is necessary to provide a new technical solution to solve the above problems.

Disclosure of Invention

The invention aims to overcome at least one defect of the prior art, and provides a novel welding process method for a prefabricated structural joint of a marine engineering square tube, which can effectively solve the problems, does not need back gouging operation, and has the advantages of simple process, cost saving and good welding quality.

The invention provides a novel welding process method for a prefabricated welding joint of a square tube structure of ocean engineering, which comprises the following steps of:

s1, blanking the plate, and performing groove processing on the edge to be welded of the plate;

s2, performing welding joint pairing on the plate with the groove to form a prefabricated square tube structure welding joint, wherein the groove, the pairing gap and the truncated edge of the prefabricated square tube structure welding joint meet the preset pairing technical requirement;

s3, performing back cover welding on the finished prefabricated square tube by using a metal powder-cored welding wire and utilizing semi-automatic gas shielded welding at the welding joint position;

s4, filling and welding the prefabricated square tube with the bottom sealing welding at the welding joint by adopting a flux-cored wire and utilizing semi-automatic gas shielded welding;

and S5, adopting a flux-cored wire and performing cover surface welding on the prefabricated square tube subjected to filling welding at the welding joint position by utilizing semi-automatic gas shielded welding.

Preferably, in the step S1, the thickness of the plate is 10mm or 32mm, the groove is a T-shaped single-sided V-shaped groove, and the groove angle is 45 °; the range of the assembly gap is 2-4mm, and the size range of the truncated edge is 0-1 mm.

Preferably, when welding is carried out at the positions of 1G,2G and 4G, the welding gun is normally swung to carry out welding operation; and when welding is carried out at the 3G position, welding a welding gun close to the straight bevel side of the T-shaped single-side V-shaped groove.

Preferably, in the step S1, the thickness of the plate is 32mm, the groove is a T-shaped single-sided V-shaped groove, the angle of the groove is 45 °, and the root of the groove is in arc transition with a size of 6mm in radius; the range of the assembly gap is 2-4mm, and the size of the truncated edge is 2 mm.

Preferably, the welding gun is normally swung to perform the welding operation when welding at the 1G,2G, 3G and 4G positions.

Preferably, the filling welding in step S4 is the same as the flux-cored wire used for the cap welding in step S5.

Preferably, in the step S3, the thickness of the plate is not greater than 25mm, argon and carbon dioxide are used as shielding gas for bottom sealing welding, the diameter of a gas nozzle is 9mm, the dry elongation size range of the welding wire is 10-15 mm, the flow rate of the shielding gas is 15-20L/min, the welding current range at the 1G,2G and 4G positions is 125-145A, the welding current range at the 3G position is 105-125A, and the welding heat input range is 0.7 KJ/mm-1.1 KJ/mm.

Preferably, in the step S3, the thickness of the plate is greater than 25mm, the back cover welding shielding gas is argon and carbon dioxide, the diameter of the gas nozzle is 9mm, the dry extension size range of the welding wire is 10-15 mm, the flow rate of the shielding gas is 15-20L/min, the welding current ranges from 150 to 180A at positions 1G and 4G, the welding current ranges from 180 to 210A at positions 2G, the welding current ranges from 120 to 150A at positions 3G, and the welding heat input range is 0.7KJ/mm to 1.1 KJ/mm.

Preferably, in the step S4, the filling welding protection gas is carbon dioxide, the diameter of the gas nozzle is 20mm, the dry length dimension range of the welding wire is 15-20 mm, the flow rate of the protection gas is 15L/min-20L/min, the welding current range is 150-250A, the welding voltage range is 20-28V, the welding speed range is 160 mm/min-350 mm/min, and the welding heat input range is 0.9 KJ/mm-2.3 KJ/mm.

Preferably, in the step S5, the capping welding shielding gas is carbon dioxide, the diameter of the gas nozzle is 20mm, the dry length dimension of the welding wire is 15-20 mm, the flow rate of the shielding gas is 15L/min-20L/min, the welding current is 190-210A, the welding voltage is 20-25A, the welding speed is 160 mm/min-400 mm/min, and the welding heat input range is 1.0 KJ/mm-1.5 KJ/mm.

Compared with the prior art, the application has at least the following beneficial effects:

the invention adopts semi-automatic gas shielded welding process to weld the back cover welding, the filling welding and the cover surface welding, can weld prefabricated welding nodes of the ocean engineering square tube structure, and has good welding effect and simple and convenient welding operation. In addition, the invention can complete all welding steps of filling welding and cover surface welding by adopting a common gas shielded welding machine, has high applicability, only needs to replace welding wires once between the back cover welding step and the filling step, greatly simplifies the welding steps, avoids the problem of continuously replacing welding equipment and welding wires, reduces the labor intensity of welding, improves the welding efficiency, is more suitable for ocean engineering, and greatly reduces the welding cost of the square tube steel structure node.

Drawings

Some specific embodiments of the invention will be described in detail hereinafter by way of example and not by way of limitation with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. Attached with

In the figure:

FIG. 1 is a schematic view of a welding joint structure of the ocean engineering square tube structure of the present invention;

FIG. 2 is a schematic diagram of a groove structure of a mother material.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail and completely with reference to the following specific embodiments of the present application and the accompanying drawings. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Example 1

The square tube structure is composed of 4 plates, and a 45-degree groove is formed in one side of each plate at the joint of every two plates, so that the welded parts of the plates are combined into a T-shaped single-side V-shaped groove structure.

The novel welding process method for the prefabricated welding joint of the ocean engineering square tube structure comprises the following specific steps of:

1. selecting materials:

the plates of the prefabricated square tube test parent metal are made of EN 10025-3S 355NL materials, the total number of the plates is 4, the width of each plate is 450mm, the length of each plate is 1000mm, the wall thickness h is 10mm, the combined groove type between the test parent metals is a T-shaped single-side V-shaped groove, the groove angle alpha is 45 degrees, the groove gap L is 2-4mm, and the truncated edge a is 0-1 mm.

2. And (3) testing:

fully simulating the field to carry out all-position welding during welding, wherein the welding method selects consumable electrode gas shielded welding, an RMD backing welding technology is adopted, the welding machine selects a Miller Pipe Pro 300 model, and the backing welding material selects a metal powder core welding wire SC-70 ML.

For 4 welding seams of the prefabricated square tube, a welder can practice welding operation at 1G,2G, 3G and 4G positions, the back forming condition and the experience of the operation process of the welder are observed through multiple times of welding, welding parameters which are well formed at each position and are relatively easy to operate by the welder are selected, and the welding parameters at each position are recorded.

After the welding operation is finished, for a prefabricated square tube with the thickness of 10mm, 4 welding seams are formed in total, and one position is selected for each welding seam and is welded from the positions of 1G,2G, 3G and 4G.

The method comprises the following steps of firstly, carrying out back cover welding, wherein the back cover welding adopts a metal powder core welding wire with the welding wire mark SC-70ML of modern welding technology limited company to carry out semi-automatic gas shielded welding, and the back cover welding parameters are shown in table 1.

TABLE 1 is a table of parameters for back welding in EXAMPLE 1

And then filling welding is carried out, wherein the filling welding material is flux-cored wire with GFL-71Ni of the welding wire brand of Shengshan of Kunshan Jing group science and technology Limited company, and all welding passes are filled, and filling welding parameters are shown in table 2.

Table 2 shows the parameters of filler welding in example 1

And finally, performing cover surface welding, wherein the cover surface welding material is a flux-cored wire with a GFL-71Ni brand, produced by Kunzhan Jing group science and technology Limited company, and the cover surface welding parameters are shown in table 3.

Table 3 shows the weld parameters of the cover of example 1

Name (R)	Parameter(s)
		Type of shielding gas	CO₂
Diameter of gas nozzle	20mm
		Dry elongation of welding wire	15～20mm
Flow rate of shielding gas	15L/min～20L/min
		Welding current	190～210A
Welding voltage	20～25V
		Welding speed	160mm/min-400mm/min
Welding heat input	1.0KJ/mm～1.5KJ/mm

And after the welding is finished, NDT detection is carried out on the welded seam, and the root fusion condition is detected through a metallographic specimen.

The detection result shows that the welding seam fusion of the prefabricated square tube welding joint with the wall thickness of 10mm is good and has no defects.

Example 2

The embodiment is the same as the embodiment 1, except that the thickness h of the plate of the prefabricated square tube test base material is changed to 32mm, and the specific steps are as follows:

1. selecting materials:

the plates of the prefabricated square tube test parent metal are made of EN 10025-3S 355NL materials, the total number of the plates is 4, the width of each plate is 450mm, the length of each plate is 1000mm, the wall thickness h is 32mm, the combined groove type of the test parent metal is a T-shaped single-side V-shaped groove, the groove angle alpha is 45 degrees, the groove gap L is 2-4mm, and the truncated edge a is 0-1 mm.

2. And (3) testing:

For 4 welding seams of the prefabricated square tube, a welder can practice welding operation at 1G,2G, 3G and 4G positions, the back forming condition and the experience of the welder in the operation process are observed through multiple times of welding, welding parameters which are well formed at each position and are relatively easy to operate by the welder are selected, and the welding parameters at each position are recorded.

After the welding operation is finished, for the prefabricated square tube with the thickness of 32mm, 4 welding seams are available in total, one position is selected for each welding seam, welding is carried out from the positions of 1G,2G, 3G and 4G respectively, and the welding conditions are as follows:

the method comprises the following steps of firstly, carrying out back cover welding, wherein the back cover welding adopts a metal powder core welding wire with the welding wire mark SC-70ML of the modern welding technology company Limited to carry out semi-automatic gas shielded welding, and the back cover welding parameters are shown in a table 4.

Table 4 is a table of parameters for back welding in example 2

Then, filling welding is carried out, the filling welding material is selected from flux-cored wires with the GFL-71Ni brand of the welding wires from Shengshan of Kunshan Jing group science and technology Limited company, semi-automatic gas shielded welding is carried out, all welding passes are filled, and filling welding parameters are shown in table 5.

Table 5 shows the parameters of filler welding in example 2

Name (R)	Parameter(s)
		Type of shielding gas	CO₂
Diameter of gas nozzle	20mm
		Dry elongation of welding wire	15～20mm
Flow rate of shielding gas	15L/min～20L/min
		Welding current	150～250A
Welding voltage	20～28V
		Welding speed	160mm/min-350mm/min
Welding heat input	0.9KJ/mm～2.3KJ/mm

And finally, performing cover surface welding, wherein the cover surface welding material is a flux-cored wire with the GFL-71Ni brand of the welding wire from Shengshan of Kunshan Jing group science and technology Limited company, and the cover surface welding parameters are shown in Table 6.

TABLE 6 shows parameters for the surface welding of example 2

The detection result shows that for the welding of the prefabricated square tube test base metal with the wall thickness of 32mm, the welding quality of the 2G position and the 4G position is stable, the root can be completely fused, no defect occurs in 1G, however, in the 3G position, a groove is formed on the bevel edge side, the depth of the groove is smaller than 0.5mm through measurement, the groove reaches the qualified standard according to the process standard requirement, but in the welding of an actual workpiece, whether the groove is qualified or not cannot be judged by using a metallographic picture, the groove can only be detected through UT, and for a welding seam which just can meet the standard requirement, in the actual judgment of UT detection personnel, certain judgment difficulty is provided, misjudgment is easily caused, the levels of welders are different, and the condition that the welding quality of the 3G position cannot meet the process requirement is easily caused.

When the prefabricated square tube with the wall thickness of 32mm is welded on a single-side V-shaped groove type welding seam, the welding difficulty of the 3G position is the largest, the welding quality is the least stable, the welding quality is 1G second, the welding quality of the 2G position and the 4G position is the most stable, and the 2G position, the 4G position and the corresponding parameters of the positions are preferably selected for welding by adopting the technology.

Example 3

The embodiment of the invention is the same as the embodiment 2, and the difference is that part of the groove structure is changed, specifically, the radian with the radius of 6mm is machined at the root part of the groove, and the specific steps are as follows:

1. selecting materials:

the plate of the prefabricated square tube test parent metal is made of EN 10025-3S 355NL material, 4 blocks in total, the width of the plate is 450mm, the length of the plate is 1000mm, the wall thickness h is 32mm, the combined groove type of the test parent metal is a T-shaped single-side V-shaped groove, the groove angle alpha is 45 degrees, the radian of the machining radius R at the root of the groove is 6mm, the groove gap L is 2-4mm, and the blunt edge a is 2 mm.

2. And (3) testing:

For a prefabricated square tube with the thickness of 32mm, 4 welding seams are totally formed, one position is selected for each welding seam, welding is performed from the positions of 1G,2G, 3G and 4G respectively, and the welding process parameters are as follows:

the method comprises the following steps of firstly, carrying out back cover welding, wherein the back cover welding adopts a metal powder core welding wire with the welding wire mark SC-70ML of the modern welding technology company Limited to carry out semi-automatic gas shielded welding, and the back cover welding parameters are shown in a table 7.

Table 7 shows parameters of back welding in example 3

And then filling welding is carried out, wherein the filling welding material is flux-cored wire with GFL-71Ni of Gangshan of Kunshan Jing group science and technology Limited company, and semi-automatic gas shielded welding is carried out to fill all welding passes, and filling welding parameters are shown in Table 8.

Table 8 shows the parameters of filler welding in example 3

Then, cap welding is carried out, the cap welding material is selected from flux-cored wires with the GFL-71Ni brand of the welding wires from Shengshan of Kunshan Jing group science and technology Limited company, and semi-automatic gas shielded welding is carried out, and the cap welding parameters are shown in Table 9.

TABLE 9 shows parameters for cap welding in EXAMPLE 3

Name (R)	Parameter(s)
		Type of shielding gas	CO₂
Diameter of gas nozzle	20mm
		Dry elongation of welding wire	15～20mm
Flow rate of shielding gas	15L/min～20L/min
		Welding current	190～210A
Welding voltage	20～25V
		Speed of welding	160mm/min-400mm/min
Welding heat input	1.0KJ/mm～1.5KJ/mm

And after the welding is finished, NDT detection is carried out on the welded seam, and the root fusion condition is detected through a metallographic specimen. According to metallographic result detection, after the radian of 6mm is machined at the root of the T-shaped single-side V-shaped groove, the welding wire rod can be extended to reach a reasonable position, so that the splashing amount of 4G position welding and the groove of a 3G position are directly reduced, and the welding defect of the 3G position can be effectively compensated.

For ease of description, spatially relative terms, such as "over", "above", "on", "upper surface", "over", and the like, may be used herein to describe one element or feature's spatial relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above" may encompass both an orientation of "above" and "below. The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise, and it should be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A novel welding process method for prefabricated welding nodes of ocean engineering square tube structures is characterized by comprising the following steps:

s1, blanking a plate, and performing groove processing on the edge to be welded of the plate;

s3, performing back cover welding on the finished prefabricated square tube by using a metal powder core welding wire and utilizing semi-automatic gas shielded welding to form a pair group at the position of a welding joint;

and S5, adopting a flux-cored wire and performing cap welding on the prefabricated square tube subjected to filling welding at the welding joint position by using semi-automatic gas shielded welding.

2. The new welding process method for the prefabricated welding joint of the ocean engineering square tube structure according to claim 1, wherein in the step S1, the thickness of the plate is 10mm or 32mm, the groove is a T-shaped single-side V-shaped groove, and the angle of the groove is 45 degrees; the range of the assembly gap is 2-4mm, and the size range of the truncated edge is 0-1 mm.

3. The new welding process method for the prefabricated welding joint of the ocean engineering square tube structure according to the claim 2, wherein when welding is carried out at the positions of 1G,2G and 4G, a welding gun is normally swung to carry out welding operation; and when welding is carried out at the 3G position, welding a welding gun close to the straight bevel side of the T-shaped single-side V-shaped groove.

4. The new welding process method for the prefabricated welding nodes of the ocean engineering square tube structure according to claim 1, wherein in the step S1, the thickness of the plate is 32mm, the groove is a T-shaped single-side V-shaped groove, the angle of the groove is 45 degrees, and the root of the groove is in arc transition with the size of 6mm in radius; the range of the assembly gap is 2-4mm, and the size of the truncated edge is 2 mm.

5. The new welding process method for the prefabricated welding joint of the ocean engineering square tube structure according to claim 4, wherein a welding gun is normally swung to perform welding operation when welding at 1G,2G, 3G and 4G positions.

6. The new welding process method for the prefabricated welded joint of the ocean engineering square tube structure as claimed in claim 1, wherein the filling welding in the step S4 is the same as the flux cored wire model used for the facing welding in the step S5.

7. The new welding process method for the prefabricated welding joint of the ocean engineering square tube structure according to claim 1, wherein in the step S3, the thickness of the plate is not more than 25mm, argon and carbon dioxide are used as shielding gases for welding in the back cover welding process, the diameter of a gas nozzle is 9mm, the dry length dimension range of a welding wire is 10-15 mm, the flow rate of the shielding gases is 15L/min-20L/min, the welding current range of 1G,2G and 4G positions is 125-145A, the welding current range of 3G positions is 105-125A, and the welding heat input range is 0.7 KJ/mm-1.1 KJ/mm.

8. The new welding process method for the prefabricated welding joint of the ocean engineering square tube structure according to claim 1, wherein in the step S3, the thickness of the plate is more than 25mm, the back cover welding shielding gas is argon and carbon dioxide, the diameter of a gas nozzle is 9mm, the dry length of the welding wire ranges from 10mm to 15mm, the flow rate of the shielding gas ranges from 15L/min to 20L/min, the welding current ranges from 150A to 180A at 1G and 4G positions, the welding current ranges from 180A to 210A at 2G positions, the welding current ranges from 120A to 150A at 3G positions, and the welding heat input range is 0.7KJ/mm to 1.1 KJ/mm.

9. The new welding process method for prefabricated welding joints of ocean engineering square tube structures according to claim 1, wherein in step S4, the filling welding shielding gas is carbon dioxide, the diameter of a gas nozzle is 20mm, the dry extension size of a welding wire is 15-20 mm, the flow rate of the shielding gas is 15-20L/min, the welding current is 150-250A, the welding voltage is 20-28V, the welding speed is 160-350 mm/min, and the welding heat input range is 0.9 KJ/mm-2.3 KJ/mm.

10. The new welding process method for the prefabricated welding joint of the ocean engineering square tube structure according to claim 1, wherein in the step S5, the cover welding shielding gas is carbon dioxide, the diameter of a gas nozzle is 20mm, the length of the welding wire is 15-20 mm, the flow rate of the shielding gas is 15L/min-20L/min, the welding current is 190-210A, the welding voltage is 20-25A, the welding speed is 160 mm/min-400 mm/min, and the welding heat input range is 1.0 KJ/mm-1.5 KJ/mm.