Wang Yi (Liaohe Petroleum Exploration Bureau Oilfield Construction Engineering Co., Ltd., Panjin 124012, Liaoning, China) 1 Prefabricated Prefabricated the top plate, bottom plate, and wall plate storage tank installation auxiliary materials and tanks according to the design requirements of the settling tank Interior and accessories. (The prefabrication process is omitted) 2 Pre-assembly inspection of the tank body welding: the tank foundation should meet the following requirements: â‘ the allowable deviation of the center elevation of the tank foundation is; 20mm. â‘¡ the surface of the foundation near the tank wall is arbitrary for every 10m arc length when there is a ring beam The height difference between the two points is not more than 6mm, and the height difference between any two points within the entire circumference is not more than 12mm; when there is no ring beam, the height difference between any two points within every 3m arc length is not more than 12mm. â‘¢ The surface of the tank foundation should be flat and dense without protrusions Uplift depressions and through cracks. The measurement method of the base surface of the tank can be implemented in accordance with the third point of Article 4.2.2 of the vertical cylindrical steel welded oil tank construction and acceptance specification: B128-90).
2.2 Group welding of tank bottom board Group welding of edge board: pay attention to the direction when assembling, make sure to leave a small plate at the dog hole, and avoid making holes in the bottom board. After the edge board is assembled, shrinkage joints should be left to prevent welding deformation. Generally, there are 2 tanks under 5000m3, and 4 tanks for 10000m3. The gap of the butt joints of the edge plate should be 10 = 12mm on the outside and 14 = 16mm on the inside if the edge plate does not have a groove. If the edge plate has a groove, it should be 8 = 12mm on the outside. 400mm long, inside welding 100 = 150mm long, the middle section is welded after the entire tank bottom is welded. After all the inside and outside welds of all edge boards are fully welded, shrink joints are welded. The inside and outside welds of the edge boards should be flush with the base metal. If the weld is slightly higher, it should be polished with a grinding wheel.
Welding of medium-width plates: If the middle-width plates are lapped, the amount of overlap should be 40mm. The overlapping parts of the triangle joints of the middle-width plates should be chamfered, the width is the width of the overlap, and the length is twice the width of the overlap. When welding, the short seam is followed by the long seam, and then the circumferential seam is used, and the section jump welding method is adopted. Generally can be divided into 4 sections of jump welding, the height of the weld is the thickness of the steel plate. For example, when the butt joint is adopted for the mid-width plate, the width of the width of the mid-width plate is allowed to be 1mm, and the length is not more than 2mm. The method of welding is the same as that of lap joint. To prevent welding deformation. When welding the bottom plate, the name of the welder 4 = 6 is appropriate, and mark the position of 0>, 90>, 180>, 270. around the tank.
2.3 Tank top panel welding 417 Before assembling the tank roof, the top wall panel should be welded first.
mark. Use a tape measure to put out the inner diameter of the can, draw a circle with a model, and check it. This also helps to align the corner seam of the last siding. For a prefabricated pillow at a point on the wall, the gap should not exceed 1m. Point a baffle between two adjacent pillows to ensure the ellipticity of the tank wall. On the outside of each pillow, one is about 100mm long! 57mm steel pipe, about 40 = 50mm from the inside of the tank wall, used to make wooden wedges to ensure the ellipse of the tank wall.
The vertical seam of the uppermost siding should be marked with an outer arc plate before welding to prevent the welding deformation. The finishing board is not paired. After all the welds are welded, the group is welded to ensure the verticality of the wall and the upper and lower mouths. The same circumference). After the welding seam is completed, check that the sag of the tank wall is straight, and the allowable deviation is not more than 3mm. The horizontal deviation of the upper mouth of the two adjacent wall plates should not be greater than 2mm. allow. The low-magnification metallurgical structure also found no fatigue cracks at the root of the small width under-weld.
No defects such as surface cracks were found in the crane beam inspection, which also relied on the good toughness of the base material; 16Mnq material was selected at that time, the base material was normalized, and the grain size was 8 when the material was re-inspected. value. 7.9 / cm2, -403 aging (cold pull 56) impact value. 5.3 / cm2 (the above value is the steel test value at that time, not the standard value of steel mechanical properties), it should be considered that this batch of materials has good impact toughness after being selected. There are always many unfavorable factors in manufacturing to reduce the fatigue performance of structural parts, so improving the impact toughness of the base material is a very important method to effectively prevent the growth rate of fatigue cracks and prevent fatigue damage. The data shows that "the value has a linear function relationship with the impact toughness of the V-notch, and the value obtained on the basis of the design assumption can be converted into a V-shaped defect! Summary Because of the limited conditions, there is no connection between the upper flange and the web. The work stress measurement of T-shaped welds has insufficient points in the analysis of the problem. We believe that for Article 6.3.10 of the G 81-91 Building Steel Structure Welding Code, the flange plate and the web of the crane beam for extra heavy work are required The connected T-shaped welds should be penetrated to ensure their safe operation. However, the article mentions that it is not appropriate to use the allowable sum of individual strip defects as not less than 100mm as the judgment standard, which results in a large number of repairs, but It does not necessarily guarantee the fatigue strength of the component.
During practical work, the most influencing factor of this type of T-shaped joint is the generation of solidified thermal cracks during the welding and filling process; in order to prevent the generation of solidified thermal cracks, strict welding process measures and corresponding non-destructive testing methods must be available The impact value of the mouth is used to select the material used for I. orie Ke blishing guarantee (certify the welding quality of the 9-shaped joint i. ed.http: // horizontal deviation should not be greater than 6mm, the gap of the pairing should be implemented according to the drawing requirements; when the thickness of the board is less than 10mm, the amount of wrong edges should not be greater than the board 1/10 of the thickness, when the thickness of the board is greater than 10mm, it should not be greater than 1.5mm. After passing the inspection, pull the perimeter of the upper and lower mouths and close them. The difference between the upper and lower mouths should not be greater than 5mm. Preparation work before assembly welding of the tank top plate // Put the auxiliary materials for tank start into the tank first.
0. Assembly welding of hemming angle steel: the butt joint of hemming angle steel should be grooved to ensure penetration, and the no-arc position of about 300mm at each end of the hemming angle steel should be cut off, after the entire hemming angle steel is installed, then Weld according to drawing requirements. After the welding of the edging angle steel group, when the diameter of the tank is less than or equal to 12.5m, the radius tolerance is 13mm; when the diameter is 12.5-45m, the radius tolerance is 19mm. 3. Umbrella assembly: umbrella frame The horizontal difference of any two points of the upper channel steel should not be greater than 12mm. The vertical deviation of the umbrella stand column should not be greater than 0.14 of the column height, and not greater than 10mm. The umbrella stand should be properly pre-raised to ensure After the tank is lifted, it meets the blueprint requirements.
d. Draw the equal parts according to the number of tank top plates on the figure eight iron, and place a baffle at the middle of each equal part to prevent the top plate from slipping during assembly.
/, Pairing: When assembling the tank top plate, the lower part is paired according to the divided size, and the upper overlap is 40-60mm. After pairing 4-5 pieces in one direction, continue pairing in the corresponding other direction to prevent the umbrella frame from being overweight in one direction. After the entire tank roof is assembled, spot welding is carried out after checking for defects. During spot welding, spot welding is performed from the middle of the weld seam to both sides, and the overlapping part of the two adjacent top plates connected to the edging angle steel needs to be subjected to corner cutting. The entire peripheral seam is spot welded on the figure eight iron after finding a circle, and the allowable deviation of the overlap of the top plate is 5mm. 0. Welding: The tank top plate is welded by the section jump welding method, and the height of the weld seam is the thickness of the top plate. The connection between the periphery of the top plate and the figure eight iron is finally welded. The height of the weld is 3/4 of the top plate and no more than 4mm. The ribs and connections of the two adjacent top plates use lap joints, and the lap width is twice the width of the ribs, and they are fully welded through. The height of the weld is the thickness of the rib. The lap welding of two adjacent roof plates in the tank adopts intermittent welding. The welding specifications are generally from 100mm to 200mm. After the roof plate is welded and formed, the tank top plate is checked and the gap is not more than 15mm. Group welding of tank wall plates (1) Group welding Pre-preparation work: place the swell position according to the specific position of the top plate, and tighten it with a jack to make the swell close to the tank wall. According to the position of the expansion hook, a square hole with a length of about 1m and a width of about 800mm is opened on the top plate. Weld the cut plate to the top plate on the side, and hang the side column into the tank from the square hole with a crane. Generally, the center distance of the side column is 600-700mm (determined according to the size of the gourd and the actual situation on site). After the side column is placed, spot weld two clips on each side of the base, and spot weld two posts in the two 45. directions inside the side column. When the tank reaches the corresponding height, the side column is pulled up to swing the rope, and the lifting baffle is welded on the expanded wall plate.
This baffle generally uses steel plates over 14mm. There are two pieces of each gourd, welded at about 500mm from each side of the expanding hook, and the gourds are tightened so that the tightness of each gourd is basically the same.
2) The butt welding of the vertical joints of the second-layer siding: According to the requirements of the drawings, the second siding is grouped, and the outer arc plates are marked on the joints of the well-aligned joints. The number of outer arc plates of each vertical seam is determined by the plate thickness and plate width. If the width of the board exceeds 2m or the thickness of the board is less than 6mm, 3 arc boards are used. If the width of the board is less than 2m or the thickness of the board is greater than 6mm, two arc boards are used. After the completion of the group butt joint heat expansion and contraction). Use a hoist at the upper and lower ends to tighten the wall plate and then weld the standing seam. After the standing seam is welded, loosen the gourd at the end, and then lift the can. After the tank reaches the specified height, it is generally 30mm higher than the wall plate) Use a wooden wedge to tighten the bottom opening, and use a baffle to align the top opening. The hoist is tightened at the end, and then the ring seams are grouped, and the ring seams can be welded side by side. The gap of the ring seams is generally about 2mm. When the thickness of the upper siding is less than 8mm, the amount of wrong edge is not more than 1.5mm; when the thickness of the upper siding is not less than 8mm, the amount of wrong edge should not be more than 2/10 of the thickness of the board, and not more than 3mm. The welding sequence of the ring seam is : Fill the outside first, then the inside cover, then the outside cover. If the thickness of the board is not greater than 10mm when welding in the girth seam, a back bar should be punched at each side of the 500mm on each side of the T-shaped seam, because the welding stress at the T-shaped seam is concentrated and it is most easily deformed. After the girth welding is completed, the welding seam is cooled and then expanded.
After welding, the allowable deviation of the verticality of the wall panel should not be greater than 0.34. The angular deformation of the weld seam and the 1m long arc sample inspection, when the thickness of the panel is not greater than 12mm, the angular deformation is not greater than 10mm; When it is more than 12mm, the angular deformation is not more than 8mm. The local uneven deformation of the tank wall is not more than 13mm. After the paired welding of each layer of wall panels: the group of each layer of wall panels is the same as the second layer. The last wall panel leaves the closing panel unaligned. After the auxiliary materials in the tank are poured out and the materials in the tank are poured in, the group welding is performed. The back seam of the group welding is played with several back bars to prevent the tank wall panel. Deformed.
After the ring seam welding of the last board is completed, lift the can by 20mm, clean the pillow under the can and the bottom plate under the can wall, and then put the can down.
Group butt welding at the connection between the last wall plate and the tank bottom plate: the last corner weld seam is aligned with the vertical and ellipticity of the tank wall using a gourd or jack to align the position, spot welding and welding, Welding height is performed as required.
After welding the bottom wall panel, the following requirements should be met: /. The horizontal allowable deviation of the two adjacent wall panels should not be greater than 2mm. The horizontal allowable deviation of any two points on the entire circumference should not be greater than 6mm. The allowable deviation should not be greater than 3mm. 3. At the height of the bottom wall plate 1m, the radius of any point on the inner surface is allowed to deviate. When the diameter of the tank is not greater than 12.5m, the allowable deviation of the radius is 13mm; when the diameter of the tank is greater than 12. 5m, The allowable deviation of the radius is 19mm. Check the geometry and size of the tank body: A. After the welding of the tank bottom plate is completed, the depth of the local uneven deformation should not be greater than 24 of the deformation length, and should not be greater than 50mm. B. The welding of the tank top plate is completed After the local concave and convex deformation, the top plate curvature model should be used to check, the gap should not be greater than 15mm. C, after assembly of the tank wall plate, the geometry and size should meet the following requirements: /, the allowable deviation of the tank wall height should not exceed the design The allowable deviation of the height sag should not be greater than 0.44 of the height of the tank wall, and should not be greater than 50mm. 3. Local uneven deformation of the tank wall, when the thickness of the wall plate is less than or equal to 25mm, the amount of deformation is not more than 13mm. D. Bottom wall plate Inner surface radius Allowable deviation, when the diameter of the tank is smaller than or equal to 13mm; when the diameter of the tank is larger than 12.5m, the allowable deviation of the radius is 19mm. The welding traces of the fixtures on the wall of the tank should be eliminated, and the welding scars should be polished and smooth.
After welding each tank wall panel, X-ray flaw detection should be carried out. The number of flaws and the standard set of 20 sets of standing seams should be set according to the thickness of the board to ensure that the welding is accurate (strict. The right cylinder is executed Rules for the construction and acceptance of shaped steel oil receiving tanks (12890)), 6.2.4 and 6.2.9.
Non-destructive testing of the corner seam between the tank bottom and the tank wall: A. All welds at the tank bottom are tested for leaks using the vacuum box method.
B. Magnetic particle inspection is used at the T-shaped seam of the tank bottom.
C. Butt welds of the arcuate edge plate at the bottom of the tank. When the thickness of the plate is greater than or equal to 10 mm, X-ray inspection should be performed within 300 mm of the outer end of each butt weld; when the thickness of the plate is 69 mm, each welder applies a weld At least one sample should be checked according to the above method, and the implementation standard is the provisions in Article 6.2.9 of the Specification for Construction and Acceptance of Vertical Cylindrical Steel Welded Oil Tanks (B12890).
D. The fillet weld between the bottom wall plate and the arc-shaped edge plate is used for penetration testing.
Pour out the side pillars, bulge, gourd, umbrella frame, etc. of the tank from the left tail plate. ! Installation of the central column in the tank installation process: After the bottom plate of the tank is welded, the bottom plate, the reinforcing plate and the central column of the central column are welded to the center of the tank. The ribs of the reinforcing plate are assembled and welded after the oil collecting tank is assembled. Two hooks are welded symmetrically at the corresponding positions above the oil collecting tank. Two hoists are installed to lift the oil collecting tank and the cross oil tank during the tank lifting process.
When the tank reaches the corresponding height, install the cross oil groove, oil collection groove and annular oil groove in the tank.
A. Annular oil tank: After laying the line on the tank wall, spot weld the prefabricated annular oil tank to the tank wall. If the side column hinders the installation, the side column can be left out until the tank is raised to the position of the annular oil tank beyond the side When the column is used, spot weld the annular oil groove on the tank wall. The whole annular oil groove is spot welded and then welded to prevent deformation. Weld a support at a distance of 2m between the vertical plate of the annular oil tank and the tank wall to prevent the deformation of the vertical plate of the annular oil tank during welding. After welding, remove the support.
B. Cross oil groove: When the cross oil groove is installed, the center should be slightly lower than the edge. The reinforcing plate of the cross oil groove uses a butt joint, and a pad is added at the joint. The length is 2 times the width of the rib, and it is completely welded through.
C. Oil collecting tank: After welding the bottom plate of the tank, place the prefabricated oil collecting tank in the center of the tank. Before aligning the cross oil groove, hoist the oil collection groove to the corresponding position. There should be a gap of about 50mm between the oil collecting groove, the bottom plate and the center column, so that the oil collecting groove can rise and fall with the tank. After the tank body is completed, the gap is sealed with a steel plate by overlapping, and three baffles are spot-welded at the position of the central column under the bottom plate of the oil collecting tank to prevent the oil collecting tank from sliding down. After each layer of the wall, the original baffle will be cut off under the bottom of the oil sump.
Installation of the oil collecting tank: After the annular oil tank and the cross oil tank in the tank are installed, install the water collecting tank at the position required by the drawings and weld them firmly.
Installation of process piping such as water collection system and oil-water distribution system in the tank: After the tank body is completely completed, install it after completing the vacuum leak test of the bottom plate. During installation, ensure that the upper level of the process piping support is level.
4 Installation of tank accessories Tank roof platform and railing installation: After the tank roof is welded, install the tank roof platform railing according to the drawings. The upright post of the railing can be left when it meets the open edge post of the tank top plate, and then be installed after the opening position is sealed.
Installation of accessories such as tank top light-transmitting holes and breathing valve: After welding the tank top plate, install other accessories such as light-transmitting holes. Pay attention to the opening position during installation, not at the top rib. Use anti-deformation measures during welding, and install the breathing valve disk ladder after the center roof is installed: the general disk ladder is best to use the sub-assembly method. When the tank is high enough to install 2 tripods, assemble a section of the ladder, when the tank is high enough to install the third tripod, assemble the second section of the ladder, and so on to the end.
Spray water pipe installation: When the tank reaches the corresponding height, install the spray water pipe according to the drawings. Install a short flange at the riser of the sprinkler. After the tank body is completed, the square tube is prefabricated below, and the upper part can be connected with bolts. When installing the riser, pay attention to the verticality of the riser. When the spray water pipe interferes with the tray ladder, the spray water pipe at the tray ladder can be slightly modified, based on the principle of convenience for the people on and off the tray ladder.
Foam generator and piping installation: After the top plate is welded together, the foam generator can be installed. The foam generator is installed according to the requirements of the drawings. Installed to the flange, the riser installation is the same as the spray water pipe riser.
Wind resistance assembly welding: Assemble the wind resistance when the tank reaches the corresponding height. There is no need to cut off the arc-free ends at both ends of the wind resistance, and the two ends should be grooved to ensure the welding quality. After the wind resistance is fully assembled, expand the inside of the tank to the corresponding position for expansion, and then weld according to the drawings to prevent welding deformation.
Tank valve group, manhole and cleaning hole. The following items should be paid attention to during installation: the deviation of the center position of the opening joint should not be greater than 10mm, and the allowable deviation of the external elongation of the joint is 5mm. The radius of curvature of the opening reinforcing plate is consistent with the curvature of the tank.
The sealing surface of the flange of the opening take-over flange shall be flat and free from weld burrs or scratches.
The sealing surface of the flange should be perpendicular to the axis of the connecting pipe, and the inclination should not be greater than 18 and 3mm of the outer diameter of the flange. The bolt holes of the flange should be installed across the middle.
Attention should be paid to the opening of the tank wall: the reinforced weld is more than 200mm away from the standing seam and more than 100mm away from the ring seam. For reinforcement, open the signal hole directly below.
Anti-deformation measures should be taken when welding, and the welding meat is full.
The opening of the board. After the reinforcement plate and the opening joint are assembled and welded with the corresponding tank wall plate and passed the inspection, the whole stress relief heat treatment shall be carried out.
5 After the various inspections of the tank are completed and qualified, the tank can be sealed for settlement. When settling, the light-transmitting holes on the tank should be opened to discharge air and facilitate observation of the water level. The following points should be achieved when the water is settled: 5.1 All accessories and other welding components with the tank body should be completed.
All welds on the tank must not be painted.
Use fresh water. When the tank wall is ordinary carbon steel or 16M, it should be filled with water to the design maximum water level and keep 48> tank wall without leakage, no deformation is qualified.
The test of the strength and tightness of the tank roof: it is conducted when the water level is 1m away from the highest water level. When the test pressure is reached, the tank roof is observed to be deformed and the weld seam is not leaked.
The stability test of the tank roof is carried out after filling to the highest water level. When the test pressure is reached, no abnormal deformation of the tank top is qualified. After the test, it is open to the atmosphere.
Pay attention to the water filling speed when filling the water. Generally, fill the water to 4m first, and park 24>. After there is no unacceptable settlement, continue to wait for the accessories at a speed of 24h per 2m water. The installation requirements for the accessories of the exhalation valve are the same as the ectoricMblishing water of the transparent hole, every morning and evening! Watch it once. d.http: //
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