CN111037068A - Welding process for improving deformation - Google Patents
Welding process for improving deformation Download PDFInfo
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- CN111037068A CN111037068A CN201911382185.6A CN201911382185A CN111037068A CN 111037068 A CN111037068 A CN 111037068A CN 201911382185 A CN201911382185 A CN 201911382185A CN 111037068 A CN111037068 A CN 111037068A
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- welding
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/235—Preliminary treatment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K33/00—Specially-profiled edge portions of workpieces for making soldering or welding connections; Filling the seams formed thereby
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/02—Seam welding; Backing means; Inserts
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- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Butt Welding And Welding Of Specific Article (AREA)
Abstract
The invention discloses a welding process for improving deformation, which relates to the technical field of welding, and adopts an assembly mode of first segmentation and then final assembly to weld segmented parts, but each segment of port must be reserved with allowance before assembly; changing the groove form, and changing the original welding line which is not provided with the groove into a V-shaped groove; backing welding, wherein the welding current of the backing welding is 90-100A, and the welding speed is 10-15 cm/min; the interval is 15-20 minutes or the temperature of the interlayer is less than 40 ℃; cover welding, wherein the welding current of the cover welding is 80-110A, and the welding speed is 9-13 cm/min; the assembly gap is 0-1mm, and the left gap and the right gap are symmetrical. Aiming at the problems of large welding stress, long welding time and poor welding quality in the prior art, the invention adopts an assembly mode of first segmentation and then final assembly and is matched with a welding process, thereby greatly reducing the welding stress, shortening the welding time and improving the welding quality.
Description
Technical Field
The invention relates to the technical field of welding, in particular to a welding process for improving deformation.
Background
In the welding process, how to control the deformation of the welded connection is a necessary research subject. At present, one of the most effective methods for controlling deformation is to use a rigid fixing method, which comprises the steps of fixing the pipe on the sample plate frame and then performing gas-filled welding. Although the results obtained in the test are improved to some extent compared with the previous ones. The total welding deformation shrinkage is controlled to be about 5m, the effect is close to the process requirement, but new problems (as follows) are generated:
1. the pipe fitting is fixed on a frame for welding, and the stress of the welded pipe fitting is increased although the welding deformation is correspondingly controlled.
2. When the rigid fixing method is adopted for welding, the welding difficulty is correspondingly increased, certain positions are difficult to weld, and the quality of welding seams is reduced.
3. The welding time is prolonged compared with the prior art, the welding time is 6 hours before, and the welding time is 7 hours now.
The post-weld results are not ideal in light of the new problems created by the above complaints. It appears that the rigid fixation method is not suitable for deformation control of the pipe.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a welding process for improving deformation, which has the advantages of ensuring the welding deformation, along with smaller welding stress, improving the welding quality and shortening the time consumption of a welding procedure.
In order to achieve the purpose, the invention provides the following technical scheme:
a welding process for improving deformation comprises the following steps,
the assembly mode of first segmenting and then assembling is adopted, the segmented components are welded firstly, and allowance must be left for each segment of port before assembly;
changing the groove form, and changing the original welding line which is not provided with the groove into a V-shaped groove;
backing welding, wherein the welding current of the backing welding is 90-100A, and the welding speed is 10-15 cm/min;
the interval is 15-20 minutes or the temperature of the interlayer is less than 40 ℃;
cover welding, wherein the welding current of the cover welding is 80-110A, and the welding speed is 9-13 cm/min;
the assembly gap is 0-1mm, and the left gap and the right gap are symmetrical.
By adopting the technical scheme, allowance must be reserved for each section of port before assembly so as to ensure the deformation shrinkage of the sectional pipe after welding, so that the size of the pipe is kept at the design size of a drawing, and the deformation is reduced; the original welding seam without the groove is changed into the V-shaped groove, so that the backing welding current is reduced, the welding deformation is prevented from increasing, the back forming is promoted to be easier, the welding permeability is ensured, and the back forming is optimized; the heat conductivity of the copper alloy is 2-3 times higher than that of carbon steel, and the fluidity of a molten pool is good, so that the welding current can be properly reduced, the welding speed is improved, and the shrinkage of a welding seam is controlled by reducing the input of linear energy; the backing welding and the cover welding are carried out after a certain time interval, the time interval is generally 15-20 minutes, or the welding is carried out when the temperature between layers is less than 40 ℃, so that the heat of a welding line can be reduced, and the welding deformation is controlled.
The present invention in a preferred example may be further configured to: the backing welding adopts backing welding without welding wires.
By adopting the technical scheme, the weight of the molten pool metal is reduced, and the reverse side weld joint is prevented from being formed and thickened due to the large gravity of the molten pool metal.
The present invention in a preferred example may be further configured to: the cover welding adopts a spot welding wire adding method, and the wire adding amount is generally controlled to be 0.5-0.8mm higher than the surface of the base material.
By adopting the technical scheme, the metal amount on the surface of the welding seam can be controlled; meanwhile, the spot welding wire adding method can also effectively prevent the generation of defects such as air holes, interlayers and the like in the welding seam.
The present invention in a preferred example may be further configured to: the welding of each weld seam is required to be completed at one time.
By adopting the technical scheme, the welding deformation control is facilitated.
The present invention in a preferred example may be further configured to: and filling the larger part of the gap with a small current at the position where the assembly gap is larger than 1mm, wherein the filler is level with or recessed from the parent material.
By adopting the technical scheme, the backing welding is convenient to carry out.
The present invention in a preferred example may be further configured to: the width of the molten pool is 8-10 mm.
By adopting the technical scheme, the back forming can be more detailed, and the cover welding is favorably implemented.
The present invention in a preferred example may be further configured to: both backing welding and cover welding adopt a broken arc in-line method.
By adopting the technical scheme, the problems of welding penetration and welding flash caused by overheating of the welding line, welding deformation increase and the like are prevented, and the method is mainly adopted, so that the whole welding line can be heated more uniformly, and the welding line is formed more consistently.
In summary, the invention includes at least one of the following beneficial technical effects:
(1) through the assembly mode of first segmentation and then final assembly, the internal stress in the welding process can be effectively released, the time consumption of the welding process can be greatly reduced, and the processing efficiency is improved;
(2) the weight of molten pool metal is reduced by adopting backing welding without adding a welding wire in backing welding, and the reverse side welding seam is prevented from being formed and thickened due to the large gravity of the molten pool metal;
(3) the original welding seam without the groove is changed into the V-shaped groove, so that the backing welding current is reduced, the welding deformation is prevented from increasing, the back forming is promoted to be easier, the welding permeability is ensured, and the back forming is optimized.
Drawings
FIG. 1 is a schematic illustration of a segment-first-assembly mode;
fig. 2 is a schematic view of arc-breaking linear manual welding.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
According to the background art, the rigid fixation method is not suitable for controlling the deformation of the pipe. What is more effective method can be adopted, and at the moment, I think that the shipbuilding mode used in the shipbuilding industry, namely the method of assembling by sections and then assembling, and then I set up a set of new measures for controlling deformation and optimizing welding quality.
The invention discloses a welding process for improving deformation, which comprises the following steps:
referring to fig. 1, a sectional-first-assembly-then-final assembly mode is employed. Firstly, the segmented parts are welded, but 2-3m of allowance must be reserved at each segment of port before assembly, so that the deformation shrinkage of the segmented pipe after welding is ensured, the size of the pipe is kept at the design size of a drawing, and the problems of overlarge welding seam clearance, difficulty in assembling and the like in the final assembly process are avoided.
The groove form is changed, the original welding line without the groove is changed into a V-shaped groove, so that the backing welding current is reduced, the welding deformation is prevented from increasing, the back forming is promoted to be easier, the welding permeability is ensured, and the back forming is optimized.
The heat conductivity of the copper alloy is 2-3 times higher than that of carbon steel, and the fluidity of a molten pool is good, so that the welding current can be properly reduced, the welding speed is improved, and the shrinkage of a welding seam is controlled by reducing the input of linear energy.
The welding process parameters are given in the following table:
the backing welding and the cover welding are carried out after a certain time interval, the time interval is generally 15-20 minutes, or the welding is carried out when the temperature between layers is less than 40 ℃, so that the heat of a welding line can be reduced, and the welding deformation is controlled.
In the assembling process, the phenomenon that the assembling clearance is overlarge and is generally controlled to be 0-1mm and the left and the right parts are symmetrical is avoided as much as possible, and the angular deformation caused by uneven welding heat input in the welding process is prevented. If the part with the assembly gap larger than 1mm exists, the welding wire can be added to the part with the large gap for fast filling by using small current, and welding is carried out after cooling.
The backing welding of each welding seam is completed once, and the same is true of the cover surface. If the whole pipe fitting is welded with the upper half circle first and then welded with the lower half circle after turning over, the control of welding deformation is very unfavorable.
In addition to the above control of the welding deformation, the present invention also takes the following measures to control the inner and outer margins of the weld.
1. The method adopts backing without wire welding to reduce the weight of molten pool metal and prevent the reverse side weld seam from being formed and thickened due to the large gravity of the molten pool metal.
2. During cover surface welding, a spot welding wire adding method is utilized, the metal amount on the surface of a welding seam can be controlled, and the wire adding amount is generally controlled to be 0.5-0.8mm higher than the surface of a base material. Meanwhile, the spot welding wire adding method can also effectively prevent the generation of defects such as air holes, interlayers and the like in the welding seam.
3. If the gap is larger than 1m, the larger part of the gap is filled up with small current. The filling speed is high, the filling amount is not large, and the filling quantity can be flat or concave with the base material, so that backing welding can be performed easily. After filling, the defect of excessive reverse forming caused by large gap can be prevented.
4. The welding current is not easy to be too large so as to reduce the surface area of the molten pool and control the width of the molten pool, and for common pipe diameters, such as phi 159x2.5 is less than or equal to 10m, and phi 89x2 is less than or equal to 8m, the reverse surface forming is more detailed, and the surface covering is easier.
5. As shown in FIG. 2, the surface is laid by a broken arc-in-line method. The method can prevent the problems of weld penetration and weld beading, welding deformation increase and the like caused by overheating of the weld joint, and mainly can ensure that the whole weld joint is uniformly heated and the weld joint is formed uniformly.
Through the improvement of the process measures, the effect is obvious (see the following table)
| Comparison before and after process improvement | Welding deformation/mm | Welding time per | Argon gas consumption/bottle | Height/mm of internal and external remainders | The welding seam is beautiful | Inherent defects in the weld | Difficulty of welding |
| Before the process is improved | ＞10 | 6 hours | 5 | 2-3 | Is poor | Much more | Difficulty in |
| After the process is improved | ＜3 | 4 hours | 3 | ＜1 | Good taste | Chinese character shao (a Chinese character of 'shao') | Is easy to use |
From a comparison of the above data, we can see that the advantages of the improved process are significant. Practice proves that the assembly mode of first division and then total assembly is greatly improved, and welding deformation and stress release of the segmented components are completed. The method brings advantages for the following welding deformation control, and the number of welding seams generating deformation factors is obviously reduced. And other process improvement measures are matched, so that the generation of welding deformation is greatly reduced, the product meets the process specification, meanwhile, the welding difficulty is reduced, the production efficiency is improved, the production cost is saved, and the quality of a welding seam is ensured.
The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.
Claims (7)
1. A welding process for improving deformation is characterized by comprising the following steps,
the assembly mode of first segmenting and then assembling is adopted, the segmented components are welded firstly, and allowance must be left for each segment of port before assembly;
changing the groove form, and changing the original welding line which is not provided with the groove into a V-shaped groove;
backing welding, wherein the welding current of the backing welding is 90-100A, and the welding speed is 10-15 cm/min;
the interval is 15-20 minutes or the temperature of the interlayer is less than 40 ℃;
cover welding, wherein the welding current of the cover welding is 80-110A, and the welding speed is 9-13 cm/min;
the assembly gap is 0-1mm, and the left gap and the right gap are symmetrical.
2. A deformation-improved welding process as set forth in claim 1, characterized in that the backing welding is performed without a welding wire.
3. A welding process with improved deformation as claimed in claim 1, wherein the welding of cover surface adopts spot welding and wire feeding method, and the wire feeding amount is controlled to be 0.5-0.8mm higher than the surface of the base material.
4. A deformation modified welding process as claimed in claim 1, wherein each weld is required to be welded at one pass.
5. A welding process for improving deformation according to claim 1, wherein the assembly gap is larger than 1mm, the larger gap is filled with small current, and the filler is flush with or recessed from the base material.
6. A deformation modified welding process as claimed in claim 1, in which the weld pool width is 8-10 mm.
7. A welding process for improving deformation as set forth in claim 1, wherein the backing welding and the cover welding are performed by arc-breaking linear welding.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911382185.6A CN111037068A (en) | 2019-12-27 | 2019-12-27 | Welding process for improving deformation |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911382185.6A CN111037068A (en) | 2019-12-27 | 2019-12-27 | Welding process for improving deformation |
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| CN111037068A true CN111037068A (en) | 2020-04-21 |
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| CN201911382185.6A Pending CN111037068A (en) | 2019-12-27 | 2019-12-27 | Welding process for improving deformation |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101628357A (en) * | 2009-08-05 | 2010-01-20 | 南通明德重工有限公司 | Welding process for butt joint of two pipes |
| CN101637864A (en) * | 2009-08-25 | 2010-02-03 | 江苏沪宁钢机股份有限公司 | Manufacturing method of integral linear arched pipe |
| CN101862884A (en) * | 2010-06-08 | 2010-10-20 | 西安石油大学 | Pipe-pipe site butt welding method of continuous pipes |
| CN104907673A (en) * | 2015-06-30 | 2015-09-16 | 湖北省建工工业设备安装有限公司 | Installation method of outdoor carbon steel oxygen transferring pipeline |
| CN105983755A (en) * | 2015-01-28 | 2016-10-05 | 胜利油田金岛工程安装有限责任公司 | Surfacing welding method for enclosed connection of long-distance pipeline without mending |
| CN109514047A (en) * | 2019-01-03 | 2019-03-26 | 上海江南船舶管业有限公司 | The welding procedure of thick-walled pipe |
-
2019
- 2019-12-27 CN CN201911382185.6A patent/CN111037068A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101628357A (en) * | 2009-08-05 | 2010-01-20 | 南通明德重工有限公司 | Welding process for butt joint of two pipes |
| CN101637864A (en) * | 2009-08-25 | 2010-02-03 | 江苏沪宁钢机股份有限公司 | Manufacturing method of integral linear arched pipe |
| CN101862884A (en) * | 2010-06-08 | 2010-10-20 | 西安石油大学 | Pipe-pipe site butt welding method of continuous pipes |
| CN105983755A (en) * | 2015-01-28 | 2016-10-05 | 胜利油田金岛工程安装有限责任公司 | Surfacing welding method for enclosed connection of long-distance pipeline without mending |
| CN104907673A (en) * | 2015-06-30 | 2015-09-16 | 湖北省建工工业设备安装有限公司 | Installation method of outdoor carbon steel oxygen transferring pipeline |
| CN109514047A (en) * | 2019-01-03 | 2019-03-26 | 上海江南船舶管业有限公司 | The welding procedure of thick-walled pipe |
Non-Patent Citations (1)
| Title |
|---|
| 尹显奇: "《钢结构制作安装工艺手册》", 31 May 2006, 中国计划出版社 * |
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Application publication date: 20200421 |
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