CN109434313B - Construction method of tower boiler wall-penetrating pipe - Google Patents
Construction method of tower boiler wall-penetrating pipe Download PDFInfo
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- CN109434313B CN109434313B CN201811255459.0A CN201811255459A CN109434313B CN 109434313 B CN109434313 B CN 109434313B CN 201811255459 A CN201811255459 A CN 201811255459A CN 109434313 B CN109434313 B CN 109434313B
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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
- B23K31/00—Processes relevant to this subclass, specially adapted for particular articles or purposes, but not covered by only one of the preceding main groups
- B23K31/02—Processes relevant to this subclass, specially adapted for particular articles or purposes, but not covered by only one of the preceding main groups relating to soldering or 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
- B23K37/00—Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
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Abstract
The invention relates to a boiler welding technology, in particular to a welding and heat treatment construction method of a tower boiler wall-penetrating pipe, which mainly comprises the following steps: firstly, vertically dividing a wall tube bundle into a first station, a second station, a closing station, a third station and a fourth station from left to right; secondly, respectively welding vertical wall pipes to the left side and the right side at the boundary of the first station and the second station, and simultaneously respectively welding vertical wall pipes to the left side and the right side at the boundary of the third station and the fourth station; then welding a transverse wall-penetrating pipe from bottom to top at the closing station; and then preheating the welding position of the through-wall tube bundle by using a flame heating mode, and finally carrying out heat treatment on the welding position of the through-wall tube bundle by using an electric heating mode. The invention greatly improves the construction efficiency, saves the construction cost and solves the problem of difficult welding and heat treatment of the wall-penetrating pipe in the tower boiler by improving the wall-penetrating welding procedure and the heat treatment thinking at the transition welding position.
Description
Technical Field
The invention relates to a boiler welding technology, in particular to a welding and heat treatment construction method of a tower type boiler wall-penetrating pipe.
Background
The tower boiler has a complex structure and a narrow space, and the research on the welding and heat treatment process of the through-wall pipe of the tower boiler at home and abroad is very little. The tower boiler wall-penetrating pipe has compact structure and small pipe row interval, and the wall-penetrating pipe penetrates through the wall surface and the sealing plate and is welded, and the sealing plate is a thin plate piece, so that the welding deformation of the sealing plate and the heat treatment after welding become a great technical problem. At present, the wall-penetrating pipe of the tower furnace has the disadvantages of complicated installation and welding procedures, low efficiency, difficult welding position and poor heat treatment effect, and can hardly achieve the expected effect.
Disclosure of Invention
In order to solve the problems, the invention provides a construction method of the wall-penetrating pipe of the tower boiler, which greatly improves the construction efficiency, saves the construction cost and solves the problem of difficult welding and heat treatment of the wall-penetrating pipe in the tower boiler by improving the wall-penetrating welding procedure and the heat treatment thought at the transition welding position. The technical scheme adopted by the invention is as follows:
the construction method of the tower boiler wall-penetrating pipe comprises the following steps:
s1, vertically dividing a wall tube bundle into a first station, a second station, a closing station, a third station and a fourth station from left to right, wherein the width of the closing station is the width of 4-8 wall tubes in transverse arrangement;
s2, respectively welding vertical wall penetrating pipes to the left side and the right side at the boundary of the first station and the second station, and simultaneously respectively welding vertical wall penetrating pipes to the left side and the right side at the boundary of the third station and the fourth station;
s3, welding a transverse wall tube from bottom to top at the closing station;
s4, preheating a welding position of the through-wall tube bundle in a flame heating mode, wherein the preheating temperature is 150-200 ℃;
s5, performing heat treatment on the welding position of the through-wall tube bundle in an electric heating mode, and respectively placing the two thermocouples on the through-wall tubes at different positions; and heating the wall penetrating pipes in the odd rows, and then heating the wall penetrating pipes in the even rows.
In step S5, the process parameters of the heat treatment are as follows: firstly heating up to 750-770 ℃ at a heating rate within 150 ℃/h, then preserving heat for 1-2 h, and then cooling down at a cooling rate within 150 ℃/h; the heating width takes the wall tube welding seam as the center, each side is at least 100mm, and the width of the heat preservation layer adopted by each side is 50-80 mm larger than the heating width of each side during heat preservation.
In the step S4, when the flame heating method is used, the distance between the flame core and the weld is at least 10mm, and the heating width is at least 100mm on each side of the weld of the wall tube.
In the above steps S1, S2 and S3, mirror surface welding is adopted, the mirror surface welding method adopts a mirror surface welding tool, the mirror surface welding tool includes a mirror surface, a pipe clamp head and a connecting pipe, the pipe clamp head is used for clamping the through-wall pipe, the mirror surface is installed at one end of the connecting pipe through a rotary joint, the pipe clamp head is screwed at the other end of the connecting pipe, and the connecting pipe is a serpentine pipe capable of being adjusted in a bending mode
The invention has the beneficial effects that:
firstly, improve wall pipe welding process, five stations are under construction simultaneously, have improved the efficiency of construction, have alleviateed the deformation of closing plate, have effectively solved tower boiler wall pipe welding difficult problem. Further optimize mirror surface and weld the technique, solved the narrow and small not good problem of welding in welding space.
And secondly, the wall penetrating pipes are subjected to heat treatment by adopting a staggered method, so that the heat treatment stability is greatly improved, and the interference of continuous heating on adjacent vertical wall penetrating pipes is avoided.
Drawings
FIG. 1 is a schematic diagram of a through-wall pipe welding station according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a mirror welding tool according to an embodiment of the present invention;
FIG. 3 is a schematic plan view of a wall tube bundle according to an embodiment of the present invention;
fig. 4 is a heat treatment process card after welding of the through-wall pipe according to the embodiment of the invention.
In the figure: 11 is a first station, 12 is a second station, 13 is a third station, 14 is a fourth station, 15 is a closing station, 21 is a mirror surface, 22 is a connecting pipe, 23 is a pipe chuck, 3 is a wall-penetrating pipe bundle, 4 is a heat collecting pipe and 5 is a primary low-temperature reheater.
Detailed Description
The invention is further explained below with reference to the drawings.
Referring to fig. 3, the ends of the wall-penetrating tube bundle 3 are sequentially connected to the primary low-temperature reheater corresponding to the heat collecting tubes 4 one by one. The invention relates to a construction method of a tower boiler wall-penetrating pipe, which comprises the following steps:
s1, a wall tube bundle 3 is vertically divided into a first station 11, a second station 12, a closing station 15, a third station 13 and a fourth station 14 from left to right, wherein the width of the closing station 15 is the width of 4-8 wall tubes in transverse arrangement;
s2, respectively welding vertical wall pipes to the left side and the right side at the boundary of the first station 11 and the second station 12, and simultaneously respectively welding vertical wall pipes to the left side and the right side at the boundary of the third station 13 and the fourth station 14;
s3, welding a transverse through-wall tube from bottom to top at the closing-up station 15, so that the welding deformation of the through-wall tube bundle 3 is greatly reduced;
s4, preheating a welding position of the through-wall tube bundle 3 in a flame heating mode, wherein the distance between a flame core and a welding line is at least 10mm, the heating width is at least 100mm by taking the welding line of the through-wall tube as the center and each side is at least 100mm, and the preheating temperature is 150-200 ℃;
s5, carrying out heat treatment on the welding position of the through-wall tube bundle 3 in an electric heating mode, and respectively placing two thermocouples on the through-wall tubes at different positions, namely, one welding position provided with the through-wall tube at the middle position is used for controlling the temperature, and the other welding position provided with the through-wall tube at the edge position is used for detecting; and heating the wall penetrating pipes in the odd rows, and then heating the wall penetrating pipes in the even rows. The technological parameters of the heat treatment are as follows: firstly heating up to 750-770 ℃ at a heating rate within 150 ℃/h, then preserving heat for 1-2 h, and then cooling down at a cooling rate within 150 ℃/h; the heating width takes the wall tube welding seam as the center, each side is at least 100mm, and the width of the heat preservation layer adopted by each side is 50-80 mm larger than the heating width of each side during heat preservation.
In the construction method of the tower boiler wall-penetrating pipe, the welding methods, namely the steps S1, S2 and S3, adopt a mirror surface welding method. The mirror surface welding method adopts a mirror surface welding tool, and combines with figure 2, the mirror surface welding tool comprises a mirror surface 21, a pipe clamp 23 and a connecting pipe 22, wherein the pipe clamp 23 is used for clamping the through-wall pipe, the mirror surface 21 is arranged at one end of the connecting pipe 22 through a rotary joint, the pipe clamp 23 is in threaded connection with the other end of the connecting pipe 22, and the connecting pipe 22 is a flexible and adjustable coiled pipe.
After the heat treatment is finished and the self-inspection is qualified, a detection department is entrusted in time to carry out physicochemical and nondestructive detection according to the regulation and specification requirements, and the welding line of the through-wall pipe which is unqualified in detection is processed according to the following requirements:
a) and (3) the weld joint hardness value is higher than a specified value due to insufficient postweld heat treatment temperature or time, or the weld joint with insufficient postweld heat treatment is judged by on-site metallographic examination, and the postweld heat treatment is carried out again.
b) After-welding heat treatment, the constant temperature exceeds the standard, or after-welding heat treatment time is too long, so that the hardness value is lower than the specified value, or metallographic detection judges that the welding seam metal is overheated, and the welding joint needs to be cut off and re-welded.
The present invention, in combination with the following several embodiments, does greatly improve the construction efficiency and the weld strength.
Example one
S1, a wall tube bundle 3 is vertically divided into a first station 11, a second station 12, a closing station 15, a third station 13 and a fourth station 14 from left to right, wherein the width of the closing station 15 is the width of 6 wall tubes which are transversely arranged;
s2, respectively welding vertical wall pipes to the left side and the right side at the boundary of the first station 11 and the second station 12, and simultaneously respectively welding vertical wall pipes to the left side and the right side at the boundary of the third station 13 and the fourth station 14;
s3, welding a transverse wall tube from bottom to top at the closing station 15;
s4, preheating a welding position of the through-wall tube bundle 3 in a flame heating mode, wherein the distance between a flame core and a welding line is 10mm, the heating width is 100mm on each side by taking the welding line of the through-wall tube as a center, and the preheating temperature is 200 ℃;
s5, performing heat treatment on the welding position of the through-wall tube bundle 3 in an electric heating mode, and respectively placing two thermocouples on the through-wall tubes at different positions; and heating the wall penetrating pipes in the odd rows, and then heating the wall penetrating pipes in the even rows. The technological parameters of the heat treatment are as follows: firstly heating at a heating speed of 150 ℃/h to 750 ℃, then preserving heat for 2h, and then cooling at a cooling speed of 150 ℃/h; the heating width takes the wall tube welding seam as the center and each side is 100mm, and the width of the heat insulation layer adopted by each side is 50mm larger than the heating width of each side during heat insulation.
In the embodiment, 99% of the weld surfaces have no cracks or abnormalities and meet the detection standard.
Example two
S1, a wall tube bundle 3 is vertically divided into a first station 11, a second station 12, a closing station 15, a third station 13 and a fourth station 14 from left to right, wherein the width of the closing station 15 is the width of 8 wall tubes which are transversely arranged;
s2, respectively welding vertical wall pipes to the left side and the right side at the boundary of the first station 11 and the second station 12, and simultaneously respectively welding vertical wall pipes to the left side and the right side at the boundary of the third station 13 and the fourth station 14;
s3, welding a transverse wall tube from bottom to top at the closing station 15;
s4, preheating a welding position of the through-wall tube bundle 3 in a flame heating mode, wherein the distance between a flame core and a welding line is 15mm, the heating width is 120mm on each side by taking the welding line of the through-wall tube as a center, and the preheating temperature is 150 ℃;
s5, performing heat treatment on the welding position of the through-wall tube bundle 3 in an electric heating mode, and respectively placing two thermocouples on the through-wall tubes at different positions; and heating the wall penetrating pipes in the odd rows, and then heating the wall penetrating pipes in the even rows. The technological parameters of the heat treatment are as follows: firstly heating at a heating speed of 120 ℃/h, keeping the temperature for 1h after the temperature reaches 770 ℃, and then cooling at a cooling speed of 130 ℃/h; the heating width takes the wall tube welding seam as the center and each side is 120mm, and the width of the heat insulation layer adopted by each side is 80mm larger than the heating width of each side during heat insulation.
98.7% of the welding surface of this embodiment has no crack, no anomaly, relatively speaking, the welding seam crackle mainly concentrates on 15 regions of binding off station, has the crackle in total 4 wall tube welding seams, and the crack arc length all is between 3~6mm, and the crack deepest point is 0.11 mm.
EXAMPLE III
S1, a wall tube bundle 3 is vertically divided into a first station 11, a second station 12, a closing station 15, a third station 13 and a fourth station 14 from left to right, wherein the width of the closing station 15 is the width of 4 wall tubes which are transversely arranged;
s2, respectively welding vertical wall pipes to the left side and the right side at the boundary of the first station 11 and the second station 12, and simultaneously respectively welding vertical wall pipes to the left side and the right side at the boundary of the third station 13 and the fourth station 14;
s3, welding a transverse wall tube from bottom to top at the closing station 15;
s4, preheating a welding position of the through-wall tube bundle 3 in a flame heating mode, wherein the distance between a flame core and a welding line is 10mm, the heating width is 120mm on each side by taking the welding line of the through-wall tube as a center, and the preheating temperature is 180 ℃;
s5, performing heat treatment on the welding position of the through-wall tube bundle 3 in an electric heating mode, and respectively placing two thermocouples on the through-wall tubes at different positions; and heating the wall penetrating pipes in the odd rows, and then heating the wall penetrating pipes in the even rows. The technological parameters of the heat treatment are as follows: firstly heating up to 762 ℃ within 130 ℃/h, then preserving heat for 1.5h, and then cooling down at a cooling speed of 130 ℃/h; the heating width takes the wall tube welding seam as the center and each side is 150mm, and the width of the heat insulation layer adopted by each side is 60mm larger than the heating width of each side during heat insulation.
In the embodiment, 99.2% of the welding surface has no cracks and no abnormity, and compared with the second embodiment, the arc length of the welding seam crack of the second embodiment is obviously smaller and is 2-4 mm, and the crack width is small and is not easy to identify by naked eyes.
Example four
S1, a wall tube bundle 3 is vertically divided into a first station 11, a second station 12, a closing station 15, a third station 13 and a fourth station 14 from left to right, wherein the width of the closing station 15 is the width of 6 wall tubes which are transversely arranged;
s2, respectively welding vertical wall pipes to the left side and the right side at the boundary of the first station 11 and the second station 12, and simultaneously respectively welding vertical wall pipes to the left side and the right side at the boundary of the third station 13 and the fourth station 14;
s3, welding a transverse wall tube from bottom to top at the closing station 15;
s4, preheating the welding position of the through-wall tube bundle 3 in a flame heating mode, wherein the distance between a flame core and a welding line is at least 10mm, the heating width is at least 100mm by taking the welding line of the through-wall tube as the center and each side is at least 160 ℃;
s5, performing heat treatment on the welding position of the through-wall tube bundle 3 in an electric heating mode, and respectively placing two thermocouples on the through-wall tubes at different positions; and heating the wall penetrating pipes in the odd rows, and then heating the wall penetrating pipes in the even rows. The technological parameters of the heat treatment are as follows: firstly heating up to 758 ℃, keeping the temperature for 1-2 h, and then cooling down at a cooling speed of 120 ℃/h; the heating width takes the wall tube welding seam as the center and each side is 150mm, and the width of the heat insulation layer adopted by each side is 60mm larger than the heating width of each side during heat insulation.
99.6% of the welding surface of the embodiment has no cracks and no abnormity, and compared with the third embodiment, the arc length of the cracks of the welding seam of the third embodiment is obviously smaller and is 2-4 mm, the width of the cracks is small, and the cracks are not easy to identify by naked eyes, and the welding effect of the third embodiment is relatively best.
Comparative example
The welding wall pipes are sequentially arranged in a row from the middle to two sides, and after welding, the flatness of the sealing plate is measured to find that the sealing plate is transversely provided with a radian bulge with the height of 5 mm. After all the welding is finished and the pipe stands for 12 hours, cracks are obviously seen on the welding seam of the through-wall pipe at the middle part. And standing for 12 hours after the crack defects are repaired, and performing heat treatment on the welding seams in sequence line by line, wherein the heat treatment process parameters are the same as those of the first embodiment. After the heat treatment, the detection of defective welds in the self-test phase was as high as 15.2%. And after the repair, the inspection department is entrusted to carry out physicochemical and nondestructive inspection, and the result shows that the weld joint defect is still 6.8 percent.
Claims (4)
1. The construction method of the tower boiler wall-penetrating pipe is characterized by comprising the following steps:
s1, a wall tube bundle (3) is vertically divided into a first station (11), a second station (12), a closing station (15), a third station (13) and a fourth station (14) from left to right, wherein the width of the closing station (15) is 4-8 in the transverse arrangement of the wall tubes;
s2, respectively welding vertical through-wall pipes to the left side and the right side at the boundary of the first station (11) and the second station (12), and simultaneously respectively welding vertical through-wall pipes to the left side and the right side at the boundary of the third station (13) and the fourth station (14);
s3, welding a transverse wall-penetrating pipe at the closing station (15) from bottom to top;
s4, preheating the welding position of the through-wall tube bundle (3) in a flame heating mode, wherein the preheating temperature is 150-200 ℃;
s5, performing heat treatment on the welding position of the through-wall tube bundle (3) in an electric heating mode, and respectively placing two thermocouples on the through-wall tubes at different positions; and heating the wall penetrating pipes in the odd rows, and then heating the wall penetrating pipes in the even rows.
2. The construction method of the tower boiler through-wall pipe according to claim 1, characterized in that: in step S5, the process parameters of the heat treatment are as follows: firstly heating up to 750-770 ℃ at a heating rate within 150 ℃/h, then preserving heat for 1-2 h, and then cooling down at a cooling rate within 150 ℃/h; the heating width takes the wall tube welding seam as the center, each side is at least 100mm, and the width of the heat preservation layer adopted by each side is 50-80 mm larger than the heating width of each side during heat preservation.
3. The construction method of the tower boiler through-wall pipe according to claim 1, characterized in that: in the step S4, when the flame heating method is used, the distance between the flame core and the weld is at least 10mm, and the heating width is at least 100mm on each side of the weld of the wall tube.
4. The construction method of the tower boiler through-wall pipe according to claim 1, characterized in that: in the above steps S2 and S3, a mirror surface welding method is adopted, the mirror surface welding method adopts a mirror surface welding tool, the mirror surface welding tool includes a mirror surface (21), a pipe clamp (23) for clamping on the wall-through pipe, and a connecting pipe (22), the mirror surface (21) is installed at one end of the connecting pipe (22) through a rotary joint, the pipe clamp (23) is screwed at the other end of the connecting pipe (22), and the connecting pipe (22) is a serpentine pipe capable of being adjusted in a bending manner.
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| WO2020082322A1 (en) * | 2018-10-26 | 2020-04-30 | 中国电建集团山东电力建设第一工程有限公司 | Construction method for in-wall pipe in tower boiler |
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| EP0819909A3 (en) * | 1996-07-15 | 1999-06-09 | Rosink Apparate- und Anlagenbau GmbH | Tube bundle for boiler or heat exchanger and process for making same |
| CN101004258A (en) * | 2006-01-18 | 2007-07-25 | 天津市津鲁源电力工程技术服务有限公司 | Solid flexible seal method for boilers in power plants |
| CN201611110U (en) * | 2009-11-30 | 2010-10-20 | 上海锅炉厂有限公司 | Seal structure for water-cooling screen passing through hearth front wall |
| CN201593781U (en) * | 2009-12-28 | 2010-09-29 | 抚顺石油机械有限责任公司 | Water-cooling support device of residual heat boiler |
| DE102011013094A1 (en) * | 2011-03-04 | 2012-09-06 | Rwe Technology Gmbh | Process for the heat treatment of welds on power plant and plant components |
| CN105665889A (en) * | 2014-11-19 | 2016-06-15 | 重庆尚科机械制造有限公司 | Welding process for large-size pipes |
| CN105986077A (en) * | 2015-01-31 | 2016-10-05 | 重庆麦卡瑞机械制造有限公司 | Heat treatment operation method |
| CN205049521U (en) * | 2015-10-22 | 2016-02-24 | 湖南汇丰工程检测有限公司 | Boiler wall pipe |
| CN105817744B (en) * | 2016-04-06 | 2017-11-17 | 大唐淮北发电厂 | A kind of narrow location pipe plugging mirror surface welding method |
| US10773346B2 (en) * | 2016-06-10 | 2020-09-15 | General Electric Technology Gmbh | System and method for assembling a heat exchanger |
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