CN111853843A - Carbon steel flue/chimney lining stainless steel plate structure and air tightness detection method - Google Patents
Carbon steel flue/chimney lining stainless steel plate structure and air tightness detection method Download PDFInfo
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- CN111853843A CN111853843A CN202010862469.1A CN202010862469A CN111853843A CN 111853843 A CN111853843 A CN 111853843A CN 202010862469 A CN202010862469 A CN 202010862469A CN 111853843 A CN111853843 A CN 111853843A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J13/00—Fittings for chimneys or flues
- F23J13/02—Linings; Jackets; Casings
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
- G01M3/12—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point by observing elastic covers or coatings, e.g. soapy water
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Abstract
The invention discloses a carbon steel flue/chimney lining stainless steel plate structure and an air tightness detection method, wherein the stainless steel plate structure comprises the following components: the stainless steel plates are connected in a way of overlapping edges and welding along the circumferential direction and/or the axial direction of the inner wall of the carbon steel substrate; the edge of the upper stainless steel plate is welded on the lower stainless steel plate by adopting cover surface welding, and the welding seam is a continuous fillet welding seam; a plurality of plug welding holes are uniformly distributed on the stainless steel plate, and annular transition welding and cover surface full-weld welding are sequentially carried out in the plug welding holes on the carbon steel substrate. The air tightness detection method comprises the following steps: firstly, 2 vent holes are formed in a carbon steel substrate at the end part, close to two ends, of a carbon steel flue/chimney, and the positions of the vent holes need to avoid plug welding holes and transition welding positions of stainless steel plates; then welding a stainless steel plate lining, and continuously welding the outer ends of the stainless steel plates at the end parts close to the two ends of the carbon steel flue/chimney with the carbon steel substrate; after the welding of the lining is finished, appearance detection is carried out, and then an air tightness test is carried out by a compressed air method. The flue/chimney of the invention has high strength, good temperature resistance, reliable system operation and long service life.
Description
Technical Field
The invention relates to the technical field of corrosion prevention in the chemical industry, in particular to a carbon steel flue/chimney lining stainless steel plate structure and an air tightness detection method.
Background
The flue gas related to the chemical industry is often flue gas with strong corrosivity, taking limestone-gypsum wet desulphurization process as an example, the flue gas after desulphurization is saturated wet flue gas with weak acidity, and a carbon steel flue and a carbon steel chimney behind the carbon steel flue must be subjected to antiseptic treatment before being put into use. The conventional anticorrosion treatment methods at present generally comprise two methods, namely carbon steel lining glass flakes or carbon steel lining glue. The two anticorrosion treatment methods have basically consistent defects, namely, the two anticorrosion treatment methods cannot resist high temperature, and the anticorrosion treatment can be damaged when the temperature exceeds 100 ℃; secondly, easy damage, the maintenance cost is very high.
In addition, currently, 4 common nondestructive testing methods are mainly used for welding seams of stainless steel plate structures of carbon steel flue/chimney linings, namely Ultrasonic Testing (UT), magnetic powder testing (MT), X-Ray Testing (RT) and liquid Penetration Testing (PT). Wherein the ultrasonic wave is applied to a part with a thickness of more than 5mm and a regular shape; magnetic powder detection cannot detect austenitic stainless steel materials and welding seams welded by austenitic stainless steel welding rods; the X-ray detection mainly qualitatively detects the defects of the welding seam, and is not suitable for a stainless steel sheet lined in a carbon steel substrate; fluid penetration testing is not suitable for inspecting workpieces having multiple plug weld holes.
Disclosure of Invention
The invention aims to provide a stainless steel plate structure for the lining of a carbon steel flue/chimney, and the lining of the stainless steel plate structure is adopted to replace the conventional anticorrosive treatment modes of carbon steel lining glass flakes or carbon steel lining glue and the like, so that the flue/chimney has high strength, good temperature resistance, reliable system operation and long service life.
The invention also aims to provide a method for detecting the air tightness of the carbon steel flue/chimney lining stainless steel plate.
The lining of the carbon steel flue/chimney is formed by connecting a plurality of stainless steel plates along the circumferential direction and/or the axial direction of the inner wall of a carbon steel substrate of the carbon steel flue/chimney in a mode of overlapping edges and welding; the edge of the upper stainless steel plate is welded on the lower stainless steel plate by adopting cover surface welding, the welding seam is a continuous fillet welding seam, and the height of the welding seam is consistent with the thickness of the stainless steel plate;
the edge of the lower stainless steel plate is welded on the carbon steel substrate by transition welding; wherein, the welding seam covered by the upper stainless steel plate is a discontinuous fillet welding seam, and the height of the welding seam is consistent with the thickness of the stainless steel plate; the welding seam which is not covered by the upper stainless steel plate is a continuous fillet welding seam, and the height of the welding seam is consistent with the thickness of the stainless steel plate;
the stainless steel plate is uniformly distributed with a plurality of plug welding holes, the stainless steel plate is welded on a carbon steel substrate in the plug welding holes by annular transition welding and cover full-face welding in sequence, the height of a welding seam of the annular transition welding is 0.6-0.85 times of the thickness of the stainless steel plate, and the welding seam is a continuous fillet welding seam; the highest position of the welding line of the cover surface full welding is not more than 1.8mm outside the stainless steel plate.
Preferably, the overlapping width between the stainless steel plates is 20 mm.
Preferably, the distance between two adjacent plug welding holes is 300mm, and the diameter of each plug welding hole is phi 8-16 mm.
Preferably, the thickness H of the carbon steel substrate of the carbon steel flue/chimney is 6-20 mm, and the thickness of the stainless steel plate is 1.5-3 mm.
Preferably, when condensed water exists in the carbon steel flue/chimney, the flow direction of the condensed water in the carbon steel flue/chimney needs to be considered in the laying sequence of the stainless steel plates along the axial direction of the carbon steel flue/chimney, and the previous stainless steel plate is lapped on the next stainless steel plate along the flow direction of the condensed water.
Preferably, the stainless steel plate may be 316L, 2205, 2507, C276 or other stainless steel plate as required.
A method for detecting the air tightness of a carbon steel flue/chimney lining stainless steel plate comprises the following steps:
s1, before welding the stainless steel plate lining, 2 vent holes are formed in the carbon steel substrate at the end parts, close to the two ends, of the carbon steel flue/chimney, and the positions of the vent holes are required to be arranged in a mode of avoiding plug welding holes and transition welding positions of the stainless steel plate; the outer ends of the stainless steel plates at the end parts close to the two ends of the carbon steel flue/chimney need to be continuously welded with the carbon steel substrate;
and S2, after the welding of the carbon steel flue/chimney stainless steel plate lining is finished, firstly carrying out appearance detection on the lining, and then carrying out air tightness test on the lining by using a compressed air method.
Preferably, in step S2, the specific method for performing the airtightness test of the liner by the compressed air method is as follows:
(1) a first connecting pipe and a first ball valve are connected to the vent hole at one end of the carbon steel substrate to form an air outlet end; the vent hole at the other end is connected with a second connecting pipe and a second ball valve, and is finally connected to a compressed air source to form an air inlet end;
(2) compressed air is introduced between the sandwich layer of the stainless steel plate and the carbon steel substrate through the vent holes;
(3) the method comprises the steps of firstly opening the air outlet end ball valve, confirming that gas is sprayed out of the air outlet end ball valve, then closing the air outlet end ball valve, coating soapy water or diluted laundry detergent on all plug welding points and cover surface welding seams, judging whether bubbles emerge, and performing repair welding treatment on a stainless steel plate if yes until the stainless steel plate is qualified after no leakage is detected.
More preferably, the pressure of the compressed air is 0.01 to 0.07 MPa.
Preferably, the second connecting pipe at the air inlet end is further connected with a pressure reducing valve and an air filter.
The invention has the following advantages and beneficial effects:
1. the carbon steel flue/chimney lining stainless steel plate structure adopts a brand new technical scheme, replaces the conventional anticorrosive treatment modes of carbon steel lining glass flakes or carbon steel lining glue and the like, and has the structural forms of plug welding and cover surface full welding, so that the carbon steel flue/chimney lining stainless steel plate structure has high strength, good temperature resistance, reliable system operation and long service life.
2. The method for detecting the air tightness of the carbon steel flue/chimney lining stainless steel plate can effectively ensure that the carbon steel flue/chimney is safely used at the working temperature and pressure.
3. The method for detecting the air tightness of the carbon steel flue/chimney lining stainless steel plate has the advantages of simple construction, visual display and strong operability.
4. The method for detecting the air tightness of the stainless steel plate of the carbon steel flue/chimney liner can detect all welding lines at one time, and is short in time consumption and low in detection cost.
Drawings
FIG. 1 is a diagram of a carbon steel flue/stack lining stainless steel panel layout according to an embodiment of the present invention;
FIG. 2 is a schematic illustration of a plug weld of stainless steel plates provided by an embodiment of the present invention;
FIG. 3 is a schematic view of a weld between stainless steel plates provided by an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a carbon steel substrate with open pores according to an embodiment of the present invention;
fig. 5 is a schematic view of a method for detecting airtightness after the stainless steel plate is welded according to an embodiment of the present invention.
In the figure: 1. a carbon steel substrate; 1-1, vent holes; 2. a stainless steel plate; 2-1, a first stainless steel plate; 2-2, a second stainless steel plate; 2-3, a third stainless steel plate; 3. plugging the welding hole; 4. annular transition welding; 5. fully welding the cover surface; 6. welding the cover surface; 7. transition welding; 8. a first steel pipe; 9. a first ball valve; 10. a second steel pipe; 11. a PU pipe; 12. a ball valve II; 13. a pressure reducing valve; 14. an air filter.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The embodiment of the invention provides a carbon steel flue/chimney lining stainless steel plate structure, wherein the lining of the carbon steel flue/chimney is formed by connecting a plurality of stainless steel plates 2 along the circumferential direction and/or the axial direction of the inner wall of a carbon steel substrate 1 of the carbon steel flue/chimney in a mode of overlapping and welding edges; the thickness H of the carbon steel substrate 1 of the carbon steel flue/chimney is 6-20 mm, the thickness of the stainless steel plate 2 is 1.5-3 mm, 2mm or 2.5mm is generally preferred, and the stainless steel plate 2 can be made of 316L, 2205, 2507 or C276 or other stainless steel plates according to needs. The lapping width between the stainless steel plates 2 is 20 mm; the edge of the upper stainless steel plate is welded on the lower stainless steel plate by adopting a cover surface welding 6, the welding seam is a continuous fillet welding seam, and the height of the welding seam is consistent with the thickness of the stainless steel plate;
the edge of the lower stainless steel plate is welded on the carbon steel substrate by transition welding 7; wherein, the welding seam covered by the upper stainless steel plate is a discontinuous fillet welding seam, and the height of the welding seam is consistent with the thickness of the stainless steel plate; the welding seam which is not covered by the upper stainless steel plate is a continuous fillet welding seam, and the height of the welding seam is consistent with the thickness of the stainless steel plate;
a plurality of plug welding holes 3 are uniformly distributed in the stainless steel plate 2, the distance between every two adjacent plug welding holes 3 is 300mm, and the diameter of each plug welding hole 3 is phi 8-16 mm; the stainless steel plate 2 is welded on the carbon steel substrate 1 in the plug welding hole 3 sequentially by adopting annular transition welding 4 and cover surface full-weld 5, the height of a welding seam of the annular transition welding 4 is 0.6-0.85 times of the thickness of the stainless steel plate, and the welding seam is a continuous fillet welding seam; the highest position of the welding line of the cover surface full welding 5 is not more than 1.8mm outside the stainless steel plate 2.
Preferably, when condensed water exists in the carbon steel flue/chimney, the flow direction of the condensed water in the carbon steel flue/chimney needs to be considered in the laying sequence of the stainless steel plates along the axial direction of the carbon steel flue/chimney, and the previous stainless steel plate is lapped on the next stainless steel plate along the flow direction of the condensed water.
As shown in figure 1, the hole punching distance of the stainless steel plate 2 is 300x300mm, the diameter of the plug welding hole 3 is phi 8-16 mm, the material of the stainless steel plate 2 can adopt 316L, 2205, 2507, C276 and the like according to actual needs, the processed stainless steel plate 2 is sequentially laid and welded on the carbon steel substrate 1, and welding rods (cover surface welding) between the stainless steel plates 2 and welding rods between the carbon steel substrate 1 and the stainless steel plate 2 need to strictly adopt welding rods corresponding to the material of the stainless steel plate 2.
The specific scheme is as follows: firstly, laying a first stainless steel plate 2-1, plug-welding the first stainless steel plate 2-1 onto a carbon steel substrate 1 of a carbon steel flue/chimney according to the drawing 2, specifically, firstly, performing annular transition welding 4 in a plug welding hole 3, wherein the height of a welding seam is 0.6-0.85 times of the thickness of the stainless steel plate and is a continuous fillet welding seam, and then performing cover full welding 5 on the plug welding hole, wherein the highest position of the welding seam is not more than 1.8mm of the outside of the stainless steel plate; after the first stainless steel plate 2-1 is laid, the second stainless steel plate 2-2 is the same as the first stainless steel plate 2-1 in plug welding of the carbon steel substrate 1, the second stainless steel plate 2-2 is welded on the first stainless steel plate 2-1 in a cover surface welding 6 mode, the covering width is 20mm (see figure 3), specifically, a welding seam between the edge of the first stainless steel plate 2-1 and the carbon steel substrate 1 is a transition welding 7, the welding seam is a discontinuous angle welding seam, and the height of the welding seam is consistent with the thickness of the stainless steel plate; the part uncovered by the second stainless steel plate is a continuous fillet weld, and the height of the weld is consistent with the thickness of the stainless steel plate. The cover surface welding 6 between the second stainless steel plate 2-2 and the first stainless steel plate 2-1 is a continuous fillet welding, and the height of the welding seam is consistent with the thickness of the stainless steel plate. And sequentially paving a third stainless steel plate, a fourth stainless steel plate and a fifth stainless steel plate according to the mode. If condensed water (such as a desulfurization system) is generated in the carbon steel flue/chimney, the order of laying should take into consideration the flow direction of the condensed water in the carbon steel flue/chimney, and taking fig. 1 as an example, the third stainless steel plate 2-3 is covered on the first stainless steel plate 2-1, and the flow direction of the condensed water should be from the third stainless steel plate 2-3 to the first stainless steel plate 2-1.
The carbon steel flue/chimney lining stainless steel plate structure replaces the conventional anticorrosive treatment modes of carbon steel lining glass flakes or carbon steel lining glue and the like, and has the advantages of high strength, good temperature resistance, reliable system operation and long service life.
A method for detecting the air tightness of a carbon steel flue/chimney lining stainless steel plate comprises the following steps:
s1, before welding the lining of the stainless steel plate 2, as shown in FIG. 4, 2M 8 vent holes 1-1 need to be formed in the carbon steel substrate 1 at the end parts, close to the two ends, of the carbon steel flue/chimney, and the positions of the vent holes 1-1 need to be arranged in a way of avoiding the positions of the plug welding holes 3 and the stainless steel plate transition welding 7; welding stainless steel plates according to the welding requirements of the figures 1-3, wherein the outer ends of the stainless steel plates 2 at the end parts close to the two ends of the carbon steel flue/chimney need to be continuously welded with the carbon steel substrate 1;
and S2, after the welding of the carbon steel flue/chimney stainless steel plate lining is finished, firstly carrying out appearance detection on the lining, and then carrying out air tightness test on the lining by using a compressed air method.
Preferably, in step S2, the specific method for performing the airtightness test of the liner by the compressed air method is as follows:
(1) as shown in fig. 5, a steel pipe I8 (with a movable joint) of phi 8 and a ball valve I9 of phi 8 are sequentially connected to an M8 vent hole 1-1 at one end of the carbon steel substrate to form an air outlet end; the M8 vent hole 1-1 at the other end is sequentially connected with a phi 8 steel pipe II 10 (with a movable joint), a PU pipe 11, a ball valve II 12, a pressure reducing valve 13 and an air filter 14, and finally connected to a compressed air source to form an air inlet end;
(2) compressed air is introduced into the interlayer between the stainless steel plate 2 and the carbon steel substrate 1 through the vent holes 1-1, the pressure of the compressed air is 0.01-0.07 MPa, the pressure can be adjusted according to actual conditions, the welding line can be burst open when the pressure is too high, and the detection effect can be influenced when the pressure is too low.
(3) Firstly opening the first air outlet end ball valve 9, confirming that air is sprayed out of the first air outlet end ball valve 9, proving that the whole interlayer is communicated, then closing the first air outlet end ball valve 9, coating soap water or diluted laundry detergent on all plug welding points and cover surface welding seams, judging whether bubbles emerge, and performing repair welding treatment on a stainless steel plate if yes until the stainless steel plate is qualified after no leakage is detected.
The method for detecting the air tightness of the carbon steel flue/chimney lining stainless steel plate can effectively ensure that the carbon steel flue/chimney is safely used at the working temperature and pressure.
The method for detecting the air tightness of the carbon steel flue/chimney lining stainless steel plate has the advantages of simple construction, visual display and strong operability.
The method for detecting the air tightness of the stainless steel plate of the carbon steel flue/chimney liner can detect all welding lines at one time, and is short in time consumption and low in detection cost.
The details, features and advantages of a carbon steel flue/stack lining stainless steel plate structure and a method for detecting air tightness, etc. of the present invention will be specifically described below by way of examples, however, all the descriptions are for illustrative purposes only and should not be construed as forming any limitation on the present invention. Furthermore, any single feature described or implicit in an embodiment herein, or any single feature shown or implicit in each figure, may nevertheless be combined or subtracted between any of these features (or their equivalents) to arrive at still further embodiments of the invention that may not be directly mentioned herein. In addition, for the sake of simplicity, the same or similar features may be indicated in only one place in the same drawing.
Example (b):
when the amount of the treated flue gas is 900000m3H, tail smoke chimney of limestone-gypsum wet desulphurization system with temperature of 150 ℃, diameter D of carbon steel chimney phi 4000mm (inner wall), total height 110m, wall thickness 12mm, processing in 5 sections, each section L being 22m, lining 2205 stainless steel plate, taking any section of chimney as an example:
1. before welding the lining of the chimney, according to the figure 4, 2M 8 vent holes 1-1 are pre-opened on a carbon steel substrate 1 of which the end parts close to two ends of the side wall of the chimney are 500mm respectively, and the vent holes 1-1 are arranged to avoid the positions of plug welding holes 3 and stainless steel plate transition welding holes 7;
2. the size of the single 2205 stainless steel plate 2 is 2mm (thickness) x 1470mm (width) x12586mm (length), 15 blocks are needed, the spacing of the plug welding holes 3 is 300x300mm, and the punching diameter is phi 12 mm. And (3) paving a first stainless steel plate, wherein the outer end of the stainless steel plate is 115mm away from the outer end of the carbon steel substrate 1, plug welding is carried out on the stainless steel plate according to the schematic diagram of fig. 2, a welding rod adopts Nicrofer S5923-FM59, the inner part of the plug welding hole 3 is subjected to annular transition welding 4, the height of a welding seam is 1.3mm, the welding seam is a continuous fillet welding seam, then the plug welding hole is subjected to cover surface full welding 5, and the highest position of the welding seam is not more than 1.8mm of the outer part of. The diameter of the chimney is 4000mm, the unfolding length is 12566mm, and a stainless steel plate is just paved for one circle (the length of the stainless steel plate is 12586mm, and 20mm of lap joint is covered and welded);
3. according to the schematic diagram of fig. 3, a second stainless steel plate, a third stainless steel plate … … and a 15 th stainless steel plate are laid in sequence, the outer end of the 15 th stainless steel plate is 115mm away from the outer end of the carbon steel substrate (the effective laying length of the 15 stainless steel plates is 1470+1450x 14-21770 mm, the length of a chimney is 22m, the rest 115mm at two ends are blank, and the stainless steel plates are supplemented after the two segments of chimneys are butted);
4. the airtightness of the weld seam of the stainless steel lined plate structure was measured in accordance with the method shown in FIG. 5. The outer end of the stainless steel plate close to the end parts of the two ends of the section of the chimney needs to be continuously welded with the carbon steel substrate, after the end, appearance inspection is carried out, and then air tightness detection is started. The M8 vent hole at one end of the carbon steel substrate is connected with a phi 8 steel pipe (with a movable joint) and a phi 8 ball valve; the M8 vent hole at the other end is connected with a phi 8 steel pipe (with a movable joint), a PU pipe, a ball valve, a pressure reducing valve and an air filter, and finally connected with a compressed air source. Introducing 0.02MPa compressed air into an interlayer between the stainless steel plate lining and the carbon steel substrate through the vent holes, firstly opening the air outlet end ball valve, confirming that gas is sprayed out of the ball valve, then closing the air outlet end ball valve, coating soapy water or diluted laundry detergent on all plug welding point and cover surface welding joints, judging whether bubbles are emitted, and performing repair welding treatment if yes until the inspection that no leakage exists is qualified.
Finally, it should be noted that: the above examples are only used to illustrate the technical solution of the present invention, but not to limit the same, for example, the diameter, length and thickness of the carbon steel flue/chimney, the material, size and opening size of the stainless steel plate, the pressure of the compressed air, etc. can be adjusted and varied according to the actual situation; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: it is to be understood that modifications may be made to the technical solutions described in the foregoing embodiments, or some or all of the technical features may be equivalently replaced, and the modifications or the replacements may not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A structure of a carbon steel flue/chimney lining stainless steel plate is characterized in that the lining of the carbon steel flue/chimney is formed by connecting a plurality of stainless steel plates in a mode of edge lap joint and welding along the circumferential direction and/or the axial direction of the inner wall of a carbon steel substrate of the carbon steel flue/chimney; the edge of the upper stainless steel plate is welded on the lower stainless steel plate by adopting cover surface welding, the welding seam is a continuous fillet welding seam, and the height of the welding seam is consistent with the thickness of the stainless steel plate;
the edge of the lower stainless steel plate is welded on the carbon steel substrate by transition welding; wherein, the welding seam covered by the upper stainless steel plate is a discontinuous fillet welding seam, and the height of the welding seam is consistent with the thickness of the stainless steel plate; the welding seam which is not covered by the upper stainless steel plate is a continuous fillet welding seam, and the height of the welding seam is consistent with the thickness of the stainless steel plate;
the stainless steel plate is uniformly distributed with a plurality of plug welding holes, the stainless steel plate is welded on a carbon steel substrate in the plug welding holes by annular transition welding and cover full-face welding in sequence, the height of a welding seam of the annular transition welding is 0.6-0.85 times of the thickness of the stainless steel plate, and the welding seam is a continuous fillet welding seam; the highest position of the welding line of the cover surface full welding is not more than 1.8mm outside the stainless steel plate.
2. A carbon steel flue/stack liner stainless steel panel construction as claimed in claim 1 wherein the overlap width between the stainless steel panels is 20 mm.
3. The carbon steel flue/chimney lining stainless steel plate structure of claim 1, wherein the distance between two adjacent plug welding holes is 300mm, and the diameter of the plug welding hole is phi 8-16 mm.
4. The structure of the carbon steel flue/chimney lining stainless steel plate of claim 1, wherein the carbon steel substrate thickness H of the carbon steel flue/chimney is 6-20 mm, and the thickness of the stainless steel plate is 1.5-3 mm.
5. A carbon steel flue/chimney liner stainless steel plate structure according to claim 1, wherein when condensate water exists in the carbon steel flue/chimney, the stainless steel plates are laid along the axial direction of the carbon steel flue/chimney in a sequence that takes into account the flow direction of the condensate water in the carbon steel flue/chimney, and the former stainless steel plate overlaps the next stainless steel plate along the flow direction of the condensate water.
6. The structure of a stainless steel lining of a carbon steel flue/chimney as claimed in claim 1, wherein the stainless steel plate is 316L, 2205, 2507 or C276.
7. A method for detecting the air tightness of a carbon steel flue/chimney lining stainless steel plate comprises the following steps:
s1, before welding the stainless steel plate lining, 2 vent holes are formed in the carbon steel substrate at the end parts, close to the two ends, of the carbon steel flue/chimney, and the positions of the vent holes are required to be arranged in a mode of avoiding plug welding holes and transition welding positions of the stainless steel plate; the outer ends of the stainless steel plates at the end parts close to the two ends of the carbon steel flue/chimney need to be continuously welded with the carbon steel substrate;
and S2, after the welding of the carbon steel flue/chimney stainless steel plate lining is finished, firstly carrying out appearance detection on the lining, and then carrying out air tightness test on the lining by using a compressed air method.
8. The method for detecting the airtightness of a stainless steel plate for a carbon steel flue/chimney liner according to claim 7, wherein in step S2, the specific method for performing the airtightness test of the liner by a compressed air method is as follows:
(1) a first connecting pipe and a first ball valve are connected to the vent hole at one end of the carbon steel substrate to form an air outlet end; the vent hole at the other end is connected with a second connecting pipe and a second ball valve, and is finally connected to a compressed air source to form an air inlet end;
(2) compressed air is introduced between the sandwich layer of the stainless steel plate and the carbon steel substrate through the vent holes;
(3) the method comprises the steps of firstly opening the air outlet end ball valve, confirming that gas is sprayed out of the air outlet end ball valve, then closing the air outlet end ball valve, coating soapy water or diluted laundry detergent on all plug welding points and cover surface welding seams, judging whether bubbles emerge, and performing repair welding treatment on a stainless steel plate if yes until the stainless steel plate is qualified after no leakage is detected.
9. The method for detecting the air tightness of the carbon steel flue/chimney lining stainless steel plate according to claim 8, wherein the pressure of the compressed air is 0.01-0.07 MPa.
10. The method for detecting the air tightness of the stainless steel plate of the carbon steel flue/chimney liner according to claim 8, wherein a pressure reducing valve and an air filter are further connected to the second connecting pipe at the air inlet end.
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|---|---|---|---|---|
| CN114055679A (en) * | 2021-10-27 | 2022-02-18 | 东风延锋汽车饰件系统有限公司 | Method for dredging micropores of nickel shell of IMG female die vacuum composite die |
| CN114055679B (en) * | 2021-10-27 | 2023-12-05 | 东风延锋汽车饰件系统有限公司 | Method for dredging micropores of nickel shell of IMG female die vacuum compound die |
| CN114059833A (en) * | 2021-11-01 | 2022-02-18 | 云南建投第二安装工程有限公司 | Construction method for lining stainless steel of pulp tower of pulp mill |
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