Manual welding of pipes
Welding of Water Pipe Network
Purely practical article on this topic
Welding of Pipe Heating Systems
Purely practical article on this topic
Showing posts with label tube welding. Show all posts
Showing posts with label tube welding. Show all posts
10:49 PM
10:46 PM
Welding of Pipe Heating Systems
Purely practical article on this topic.
Welding of pipe heating systems
Assembly and welding of pipes of different lengths lashes up to 36 meters is on the metal racks with external chain of centralizers (Fig. a). The requirements for clearances and displacements of the edges depending on the used welding methods may be different. For example, if the process provides for jelly inside the pipe joints, the gaps can range from 0 to 1.5 mm. Conversely, if the process provides for a one-sided welding with subsequent control by a rentgenoprosvechivanii clearance must be strictly regulated in the case of welded joints in the assembly nonslewing position should be 3 5-4,0 mm. The welding joints with higher clearances than the welding joints with standard clearances by about 25-35%.
For example, the duration of the assembly and welding of pipe joints d820x9 mm. When the gap in the joint is equal to 1.5 mm, respectively, of 46 and 50 min. When the gap in the joint 3.5-4 mm during assembly and welding are, respectively, 30 and 80 min. Thus, at the expense of quality of welding, provided the necessary continuity of the weld metal and the formation of the back of the root layer.
The technology of welding pipe whip on the shelves
The first option. According to this variant (Fig. lb), the entire circumference of the ring interface is divided into five equal parts, two of which (№ 1 and 3) brewed in the ceiling and polupotolochnom positions.
The remaining sections of the joint brewed in an upright position, which contributes to the formation of the deposited weld metal and the higher productivity of welders. For the welding area number 5 the product is turned by 90 °.
The sequence of welding seam of the base layer is shown in Fig. 34, c. It is seen that the two welders welding is done by the "bottom up" and with the rotation of the product. Electrodes used for welding d4 mm mark SSSI or TMU-1355-21U.
The second option. Under the second option (Fig. c) joint is divided into four sections, which are brewed in pairs in an upright position, for which the product is turned on 180g This sequence of welding eliminates the welding in the overhead and bottom positions, which are characterized by a more unfavorable conditions for the formation of weld metal and the formation of defects such as sag, and menisci.
Welding seam of the base layer is made in the sequence shown in Fig. 34, the We see that the seams are imposed in the formation of metal-friendly provisions and permitted application of high-welding conditions. This contributes to better development of chemical and metallurgical processes and degassing of molten metal weld pool.
The sequence of jelly inside of pipes is shown in Fig. Overlay on the layers podvarochnyh seam produced, usually without transverse oscillation of the electrode. On the one hand, allows you to locate the thermal capacity of the arc at the fusion line edges and, thus, to be sure that the fusion joined pipe edges and on the other hand, increases in labor productivity.
See also:
Welding of Water Pipe Network
Welding of Pipe Heating Systems
Welding of pipe heating systems
general view of the assembly stand; 1 - Shelf 2 - pipe, 3-protective tent;
Assembly and welding of pipes of different lengths lashes up to 36 meters is on the metal racks with external chain of centralizers (Fig. a). The requirements for clearances and displacements of the edges depending on the used welding methods may be different. For example, if the process provides for jelly inside the pipe joints, the gaps can range from 0 to 1.5 mm. Conversely, if the process provides for a one-sided welding with subsequent control by a rentgenoprosvechivanii clearance must be strictly regulated in the case of welded joints in the assembly nonslewing position should be 3 5-4,0 mm. The welding joints with higher clearances than the welding joints with standard clearances by about 25-35%.
For example, the duration of the assembly and welding of pipe joints d820x9 mm. When the gap in the joint is equal to 1.5 mm, respectively, of 46 and 50 min. When the gap in the joint 3.5-4 mm during assembly and welding are, respectively, 30 and 80 min. Thus, at the expense of quality of welding, provided the necessary continuity of the weld metal and the formation of the back of the root layer.
The technology of welding pipe whip on the shelves
The first option. According to this variant (Fig. lb), the entire circumference of the ring interface is divided into five equal parts, two of which (№ 1 and 3) brewed in the ceiling and polupotolochnom positions.
The remaining sections of the joint brewed in an upright position, which contributes to the formation of the deposited weld metal and the higher productivity of welders. For the welding area number 5 the product is turned by 90 °.
The sequence of welding seam of the base layer is shown in Fig. 34, c. It is seen that the two welders welding is done by the "bottom up" and with the rotation of the product. Electrodes used for welding d4 mm mark SSSI or TMU-1355-21U.
The second option. Under the second option (Fig. c) joint is divided into four sections, which are brewed in pairs in an upright position, for which the product is turned on 180g This sequence of welding eliminates the welding in the overhead and bottom positions, which are characterized by a more unfavorable conditions for the formation of weld metal and the formation of defects such as sag, and menisci.
Welding seam of the base layer is made in the sequence shown in Fig. 34, the We see that the seams are imposed in the formation of metal-friendly provisions and permitted application of high-welding conditions. This contributes to better development of chemical and metallurgical processes and degassing of molten metal weld pool.
The sequence of jelly inside of pipes is shown in Fig. Overlay on the layers podvarochnyh seam produced, usually without transverse oscillation of the electrode. On the one hand, allows you to locate the thermal capacity of the arc at the fusion line edges and, thus, to be sure that the fusion joined pipe edges and on the other hand, increases in labor productivity.
See also:
Welding of Water Pipe Network
Welding of Pipe Heating Systems
10:18 PM
Welding of Water Pipe Network
Purely practical article on this topic
Welding of water pipe network
A distinctive feature of the pipeline network is the presence of water in their construction of five specific types of compounds, namely "pipe + pipe", "tube + shift", "shift + flange", "removal of tube + sector", "shift + gate." The number of various compounds on assembly is determined by the degree of blocking of supplied equipment units. The most time consuming of them during installation of pipelines are compounds of the type "flange + shift" due to the fact that the welding of the joints requires additional installation and removal and partial disassembly of units being consolidated.
Welding of flanges to the pipe element is held at venues Pre-assembly of pipe units, which are located in the premises of the place of installation of power lines network. The technology of welding flanges with tube elements. In this first impose the outer seam, then the inner. Outer leg seam exceed the wall thickness of the pipe by 2-4 mm. The inner seam, which seam sealing is performed cathetus equal to the pipe wall thickness, and shall not exceed for economic reasons, regardless of 7 mm diameter pipes.
Welding technique, which determines to a large extent the quality of welds, the welder is selected on the basis of the conditions of formation of the deposited weld metal. The criterion for selection of welding equipment is in the gap junction. If the assembly is provided with no joints or gaps with minimal gaps, it is preferable to perform welding in position in the boat. This ensures adequate penetration without the edges of the molten weld metal flowing into the gap between the inner surface of the flange holes and the outer surface of the pipe. In cases where the gaps in some areas exceed 1.5 mm in the joint, weld in these areas is carried out with the transverse oscillations of the electrode, disposable to the axis of the tube blank at an angle of 25-30 °. This provides the greatest penetration of the base metal flange and its share in the deposited weld metal.
Welding of pipe flanges to the elements is performed on-site installation of network equipment and piping of water and is characterized by two features:
the need to disassemble the previously collected flanged connections for the imposition of the joints;
the presence of local damage pipe ends in a flattening and shortening of edges.
According to experimental data, about 70% of the joints have gaps between the pipe and an inner diameter of flange equal to 4.0-4.5 mm in the length of the perimeter of the circumference of the pipe from 100 to 250 mm. These areas are the joints welded corner joints, legs that exceed the standard rates on the value of the excess clearance in the joints. Capacity of pipe ends in their places of rough cuts made by the MMA welding electrodes with layer-stripping and verification of deposited weld metal.
After that the pump flanges removed, and the edge of the translation were available, subject to replacement surfacing.
The edges are restored by welding and the use of melted inserts, manufactured from wire 1.6-2.5 mm. The reconstruction of the edges are held in the following sequence. The pump is assembled with the bolt-on flange 2, 3, is installed into the place, then checked the build quality of transition 4 with a flange 3 and the fixed parts of the joint, requiring replacement of surfacing, and leveling.
To make the desired shape space surfacing processed by grinding wheels. Validation of surfacing overlay welds is checked by putting on an available flange on the end of the transition. In cases where no such flanges, to test the geometry of deposition using flanged, welded to the pipe before the pump components, which assembled unit by crane lifted and set in position.
After checking the quality of welding and assembly of the flange welding is carried out with the transition of these elements outside seam.
The imposition of the internal weld is performed after disconnecting and removing the flange pump. From the general form of the inner seam, brewed with different gaps, it is clear that with the increase in the gap junction increases and the leg joint. In those areas where gaps exceeding 2.5 mm, welding is done with the use of additives in the form of the electrode or filler wire of 1.6-2.5 mm.
See also:
Welding of Water Pipe Network
Welding of Pipe Heating Systems
Welding of water pipe network
A distinctive feature of the pipeline network is the presence of water in their construction of five specific types of compounds, namely "pipe + pipe", "tube + shift", "shift + flange", "removal of tube + sector", "shift + gate." The number of various compounds on assembly is determined by the degree of blocking of supplied equipment units. The most time consuming of them during installation of pipelines are compounds of the type "flange + shift" due to the fact that the welding of the joints requires additional installation and removal and partial disassembly of units being consolidated.
Welding of flanges to the pipe element is held at venues Pre-assembly of pipe units, which are located in the premises of the place of installation of power lines network. The technology of welding flanges with tube elements. In this first impose the outer seam, then the inner. Outer leg seam exceed the wall thickness of the pipe by 2-4 mm. The inner seam, which seam sealing is performed cathetus equal to the pipe wall thickness, and shall not exceed for economic reasons, regardless of 7 mm diameter pipes.
Welding technique, which determines to a large extent the quality of welds, the welder is selected on the basis of the conditions of formation of the deposited weld metal. The criterion for selection of welding equipment is in the gap junction. If the assembly is provided with no joints or gaps with minimal gaps, it is preferable to perform welding in position in the boat. This ensures adequate penetration without the edges of the molten weld metal flowing into the gap between the inner surface of the flange holes and the outer surface of the pipe. In cases where the gaps in some areas exceed 1.5 mm in the joint, weld in these areas is carried out with the transverse oscillations of the electrode, disposable to the axis of the tube blank at an angle of 25-30 °. This provides the greatest penetration of the base metal flange and its share in the deposited weld metal.
Welding of pipe flanges to the elements is performed on-site installation of network equipment and piping of water and is characterized by two features:
the need to disassemble the previously collected flanged connections for the imposition of the joints;
the presence of local damage pipe ends in a flattening and shortening of edges.
According to experimental data, about 70% of the joints have gaps between the pipe and an inner diameter of flange equal to 4.0-4.5 mm in the length of the perimeter of the circumference of the pipe from 100 to 250 mm. These areas are the joints welded corner joints, legs that exceed the standard rates on the value of the excess clearance in the joints. Capacity of pipe ends in their places of rough cuts made by the MMA welding electrodes with layer-stripping and verification of deposited weld metal.
After that the pump flanges removed, and the edge of the translation were available, subject to replacement surfacing.
The edges are restored by welding and the use of melted inserts, manufactured from wire 1.6-2.5 mm. The reconstruction of the edges are held in the following sequence. The pump is assembled with the bolt-on flange 2, 3, is installed into the place, then checked the build quality of transition 4 with a flange 3 and the fixed parts of the joint, requiring replacement of surfacing, and leveling.
To make the desired shape space surfacing processed by grinding wheels. Validation of surfacing overlay welds is checked by putting on an available flange on the end of the transition. In cases where no such flanges, to test the geometry of deposition using flanged, welded to the pipe before the pump components, which assembled unit by crane lifted and set in position.
After checking the quality of welding and assembly of the flange welding is carried out with the transition of these elements outside seam.
The imposition of the internal weld is performed after disconnecting and removing the flange pump. From the general form of the inner seam, brewed with different gaps, it is clear that with the increase in the gap junction increases and the leg joint. In those areas where gaps exceeding 2.5 mm, welding is done with the use of additives in the form of the electrode or filler wire of 1.6-2.5 mm.
See also:
Welding of Water Pipe Network
Welding of Pipe Heating Systems