CN114720478A - Method for evaluating brazing metallurgical quality of honeycomb sealing structure - Google Patents
Method for evaluating brazing metallurgical quality of honeycomb sealing structure Download PDFInfo
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- 238000005219 brazing Methods 0.000 title claims abstract description 136
- 238000007789 sealing Methods 0.000 title claims abstract description 62
- 238000000034 method Methods 0.000 title claims abstract description 57
- 238000013441 quality evaluation Methods 0.000 claims abstract description 43
- 238000002360 preparation method Methods 0.000 claims abstract description 24
- 230000008569 process Effects 0.000 claims abstract description 7
- 238000012512 characterization method Methods 0.000 claims description 44
- 239000000463 material Substances 0.000 claims description 28
- 229910000679 solder Inorganic materials 0.000 claims description 28
- 230000009194 climbing Effects 0.000 claims description 27
- 238000011158 quantitative evaluation Methods 0.000 claims description 24
- 238000003892 spreading Methods 0.000 claims description 15
- 230000007480 spreading Effects 0.000 claims description 15
- 238000005498 polishing Methods 0.000 claims description 9
- 238000005530 etching Methods 0.000 claims description 7
- 239000002184 metal Substances 0.000 claims description 7
- 229910052751 metal Inorganic materials 0.000 claims description 7
- 238000005520 cutting process Methods 0.000 claims description 6
- 230000007547 defect Effects 0.000 claims description 5
- 239000000945 filler Substances 0.000 claims description 5
- 239000007788 liquid Substances 0.000 claims description 5
- 238000005070 sampling Methods 0.000 claims description 4
- 238000010276 construction Methods 0.000 claims 2
- 238000011156 evaluation Methods 0.000 description 10
- 238000001514 detection method Methods 0.000 description 6
- 238000005272 metallurgy Methods 0.000 description 5
- 229910000851 Alloy steel Inorganic materials 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000010935 stainless steel Substances 0.000 description 4
- 229910001220 stainless steel Inorganic materials 0.000 description 4
- 238000003466 welding Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 230000035515 penetration Effects 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
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- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000001917 fluorescence detection Methods 0.000 description 1
- 239000002737 fuel gas Substances 0.000 description 1
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- 230000003068 static effect Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/8803—Visual inspection
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
- G01N23/225—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material using electron or ion
- G01N23/2251—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material using electron or ion using incident electron beams, e.g. scanning electron microscopy [SEM]
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Abstract
The invention provides a method for evaluating the brazing metallurgical quality of a honeycomb sealing structure, wherein the honeycomb sealing structure comprises a core grid, a back plate and a brazing joint, the method for evaluating the brazing metallurgical quality of the honeycomb sealing structure comprises a sample preparation step and a quality evaluation step, in the sample preparation step, the honeycomb sealing structure to be evaluated is prepared into a sample, in the quality evaluation step, the brazing metallurgical quality of the sample is evaluated, in the quality evaluation step, quality indexes are quantitatively evaluated, and the quality indexes comprise quantitative representation of the sizes of holes in the brazing joint. The method for evaluating the brazing metallurgical quality of the honeycomb sealing structure can accurately evaluate whether the metallurgical quality of the brazing part is qualified or not, so that whether the brazing process meets the requirements or not is determined.
Description
Technical Field
The invention relates to a method for evaluating the brazing metallurgical quality of a honeycomb sealing structure, in particular to a method for evaluating the brazing metallurgical quality of a honeycomb sealing structure for a heavy-duty gas turbine.
Background
In order to effectively utilize fuel gas, reduce loss and improve the working efficiency of a combustion engine on a heavy-duty gas turbine, a honeycomb sealing structural member is often adopted between a static component and a rotating component. The honeycomb sealing structural member is mainly prepared from a honeycomb core grid and a back plate by a brazing method, and the brazing quality of the existing heavy-duty combustion engine honeycomb sealing member is usually detected by adopting a visual and leakage method. Visual inspection is primarily used to determine whether or not there are localized lack of penetration defects in the honeycomb. And if the incomplete penetration defect exists, injecting acetone or alcohol into the honeycomb holes for leakage detection, and observing the diffusion condition of the liquid at the bottom of the honeycomb core. The visual inspection and leakage are mainly performed on the outer surface of the brazing part, and whether the internal metallurgical quality of the brazing joint meets the requirements cannot be determined.
The prior art CN103837549A discloses a technical solution for detecting a honeycomb article by using a fluorescence detection method, specifically, it comprises the following steps: (1) soaking the brazed parts with the honeycomb structures in a developing solution; (2) taking the level of the liquid in the bee lattices as the standard, and removing the developing solution from the bee lattice area of the part to be inspected; (3) after the developer is removed from the part cell area, slowly rotating the part along two axes of the surface of the cell area to be inspected, wherein the rotation angles of the rotating part from the horizontal plane are +90 degrees and-90 degrees respectively; (4) the bee space area was visually inspected. The technical scheme can accurately judge the brazing quality of the brazed honeycomb, guarantees the requirement of brazing quality detection of the honeycomb structure of the engine, and has the characteristics of quick operation and convenient application. However, the above method only detects the surface of the brazed portion, and cannot evaluate the metallurgical quality inside the joint.
The prior art CN106289855A discloses a metallographic detection method for the welding quality of a brazing metal honeycomb structure, which is not influenced by the shape and size of a sample during detection, can give a detection image, can visually and accurately judge the welding quality of the brazing metal honeycomb structure, and can analyze the influence factors of the welding quality according to the detection image, thereby providing a basis for process improvement and having practical application value. However, this method mainly analyzes the state of the brazed part and does not provide a clear quality evaluation criterion.
Disclosure of Invention
The invention mainly aims to provide a method for evaluating the brazing metallurgical quality of a honeycomb sealing structure, so as to solve the problems in the prior art.
In order to achieve the above object, according to one aspect of the present invention, there is provided a method of evaluating the brazing metallurgical quality of a honeycomb sealing structure including a core cell, a back plate and a brazed joint, the method of evaluating the brazing metallurgical quality of a honeycomb sealing structure including a sample preparation step of preparing the honeycomb sealing structure to be evaluated as a sample and a quality evaluation step of evaluating the brazing metallurgical quality of the sample, characterized in that in the quality evaluation step, a quality index including a quantitative representation of the size of holes in the brazed joint is quantitatively evaluated.
Preferably, the quantitative representation of the size of the holes comprises the total length of all holes in the braze joint.
Preferably, the quantitative evaluation is performed in combination with the climbing height of the brazing material between the core cells and/or the distance from the top of the core cells to the back plate when the quantitative evaluation is performed on the quantitative characterization of the size of the hole.
Preferably, the quality indicator further comprises a quantitative characterization of the braze size in the braze joint.
Preferably, the quantitative characterization of braze size includes a climb height of braze within a core cell of the honeycomb seal structure.
Preferably, the quantitative characterization of the brazing material size further comprises one or more of a spreading length of the brazing material in the core cells of the honeycomb sealing structure, a climbing height of the brazing material between the core cells, and a spreading total length of the brazing material of the adjacent core cells.
Preferably, the quantitative evaluation is performed in combination with a core grid bottom to back plate distance and/or a core grid top to back plate distance when the quantitative evaluation is performed using a quantitative characterization of braze size in the braze joint.
Preferably, the quality indicator further comprises a quantitative characterization of the location of holes in the brazed joint.
Preferably, the quantitative characterization of the position of the holes comprises the minimum distance of the holes from the top of the solder between the core cells and/or the minimum distance of the holes from the back plate.
Preferably, in performing the quantitative evaluation using a quantitative characterization of the location of holes in the braze joint, the quantitative evaluation is performed in combination with the core grid top to back plate distance and/or the core grid bottom to back plate distance.
Preferably, the quality indicator further comprises a quantitative characterization of the location of the core grid.
Preferably, the quantitative characterization of the location of the core cells comprises the core cell bottom to back plate distance and/or the core cell top to back plate distance.
Preferably, in the quality evaluation step, the quality indicator should meet one or more of the following conditions:
a≥0.7h；
a-b≥0.5h；
c＞0.1mm；
d＜0.1mm；
e is more than 0.15mm, and e is more than 6d and less than 50 percent of h;
f＞0.4mm；
k≥0.2h；
j＞d；
wherein a is the climbing height of the brazing solder between the core cells;
b is the total length of all holes in the brazed joint, and the length is less than the wall thickness t of the core grid or is not counted by a single hole of 0.08 mm;
c is the spreading length of the brazing solder in the core lattice, and when the brazing solder on the two sides of the brazing joint is asymmetrically spread, the average length value is taken;
d is the distance from the bottom of the core grid to the back plate, and when the distances from the bottoms of the adjacent core grids in the same brazing joint to the back plate are not equal, the average value of the distances is taken;
e is the climbing height of the brazing solder in the core lattice, and when the climbing heights of the brazing solder on the two sides of the brazing joint are asymmetric, the height average value is taken by the e;
f is the total spreading length of the brazing solder of the adjacent core grids, and when the total spreading length of the brazing solder is measured, the size of holes in the brazing solder is removed;
h is the distance from the top of each core lattice to the back plate, and when the distances from the tops of adjacent core lattices in the same brazing joint to the back plate are not equal, h is the average value of the distances;
k is the minimum distance of the holes from the top of the brazing filler metal between the core cells;
j is the minimum distance of the hole from the back plate.
Preferably, the method for evaluating the brazing metallurgical quality of the honeycomb sealing structure is applied to the core grids with the following sizes:
the wall thickness t is 0.05mm-0.16 mm;
the core grid depth D is less than or equal to 7 mm;
the size L of the core grid is 0.8mm-3.2 mm.
Preferably, in the quality evaluation step, if any of the quality indexes does not meet, the corresponding brazed joint is determined to be defective.
Preferably, in the quality evaluation step, if more than 15% of the brazed joints in the test sample of the honeycomb sealing structure to be evaluated are failed, or the number of the brazed joints with j ≦ d defects exceeds 30% of the number of the failed brazed joints, the quality of the brazed metallurgy of the honeycomb sealing structure is determined to be failed.
Preferably, the sample is obtained by sampling a brazing sample prepared under the conditions of the same material, the same process and the same equipment as the actually used honeycomb sealing structure.
Preferably, the sample preparation step includes a cutting step in which the honeycomb seal structure is cut in a brazing seam vertical direction.
Preferably, the sample preparation step further includes an inlaying step of inlaying the sample of the honeycomb sealing structure obtained in the cutting step to expose a brazing seam section.
Preferably, the sample preparation step further includes a polishing step in which the sample of the honeycomb sealing structure obtained in the damascene step is ground and/or polished.
Preferably, the specimen preparation step further includes an etching step in which the specimen of the honeycomb seal structure processed in the polishing step is etched using an etching liquid.
Preferably, in the quality evaluation step, the sample is measured and evaluated using a metallographic microscope or a scanning electron microscope.
By applying the technical scheme of the invention, at least the following beneficial effects are obtained:
1. the method for evaluating the brazing metallurgical quality of the honeycomb sealing structure can accurately evaluate whether the metallurgical quality of the brazing part is qualified or not, so that whether the brazing process meets the requirements or not is determined.
2. The quality index with stronger adaptability is provided, and the method can be suitable for evaluating the metallurgical quality of different honeycomb core grid materials (including but not limited to high-temperature alloy and stainless steel), different back plate materials (including but not limited to high-temperature alloy and stainless steel), different brazing materials (including but not limited to nickel-based, copper-based and silver-based brazing filler metals) and honeycomb sealing element brazed joints with different structures.
3. The invention provides the size requirement of a better honeycomb core grid material, and when the size of the honeycomb core grid is in the size range limited by the invention, the quality evaluation accuracy and the reference value are better; however, other honeycomb core cell structures of similar dimensions may be similarly evaluated using the quality index of the present invention.
4. The invention provides a set of comprehensive quality evaluation indexes, when the brazing metallurgical quality needs to be evaluated quickly and simply, part of the indexes can be optimized for evaluation, and the flexibility is strong.
5. The invention also provides a preferable sample preparation scheme, which is matched with the quality evaluation method provided by the invention and can improve the quality evaluation effect.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are included to illustrate an exemplary embodiment of the invention and not to limit the invention. In the drawings:
FIG. 1 shows a schematic view of a honeycomb seal structure according to the present invention; and
FIG. 2 shows a brazed cross-sectional anatomical view of a honeycomb seal structure according to the present invention; and
figure 3 shows a brazed cross-sectional anatomical view of a honeycomb seal structure (including holes) according to the present invention.
Wherein the figures include the following reference numerals:
1. core grid, 2, backplate, 3, soldered joint, 4, hole.
Detailed Description
It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
The present invention is described in further detail below with reference to specific examples, which are not to be construed as limiting the scope of the invention as claimed.
Example 1
The embodiment provides a method for evaluating the brazing metallurgical quality of a honeycomb sealing structure, which comprises the following steps of firstly carrying out a sample preparation step before a quality evaluation step, wherein the sample preparation step specifically comprises the following steps:
the evaluation sample of the brazing metallurgical quality of the honeycomb sealing structure can be sampled on the finished product sample of the honeycomb sealing structure which is actually used; and the sample can be taken from the brazing sample prepared by the same material, the same process and the same equipment. The brazing sample piece is used for sampling, so that the damage to a finished product sample can be avoided, and the cost is saved.
The size of the sample is adjusted according to the actual product when sampling, and the sample can represent the main characteristics of the finished product.
The sample preparation step comprises a cutting step, a inlaying step, a polishing step and an etching step.
In the cutting step, the finished piece or the sample piece is cut in the perpendicular direction of the brazing seam using a slicer, a wire cutter, or the like.
In the embedding step, the sample is embedded by adopting a proper method, and the welding seam section is exposed.
In the polishing step, the brazing seams are ground according to 200#, 400#, 600#, 800#, 1200# metallographic abrasive paper, diamond polishing paste is adopted for polishing until no scratch is formed under a metallographic microscope, and the surfaces are washed by alcohol and dried.
In the etching step, the sample of the honeycomb seal structure processed in the polishing step is etched using an etching liquid.
After the sample preparation step, a quality evaluation step was performed.
In the quality evaluation step, a metallographic microscope or a scanning electron microscope is adopted to measure the size of the soldered joint.
The size range of the honeycomb core lattice applicable to the evaluation method of the intrinsic quality is as follows (see the attached figure 2 for details):
(1) the wall thickness t is 0.05mm-0.16 mm;
(2) the core grid depth D is not more than 7 mm;
(3) the size L of the core grid is 0.8mm-3.2 mm.
In the quality evaluation step, the quality index is quantitatively evaluated, and the quality index used is as follows (see fig. 2 and 3).
The symbols hereinafter have the following meanings:
a is the climbing height of the brazing material among the core grids;
b is the total length of all holes in the brazed joint, and the length is less than the wall thickness t of the core grid or is not counted by a single hole of 0.08 mm;
c is the spreading length of the brazing solder in the core lattice, and when the brazing solder on the two sides of the brazing joint is asymmetrically spread, the average length value is taken;
d is the distance from the bottom of the core grid to the back plate, and when the distances from the bottoms of the adjacent core grids in the same brazing joint to the back plate are not equal, the average value of the distances is taken;
e is the climbing height of the brazing solder in the core lattice, and when the climbing heights of the brazing solder on the two sides of the brazing joint are asymmetric, the height average value is taken by the e;
f is the total spreading length of the brazing solder of the adjacent core grids, and when the total spreading length of the brazing solder is measured, the size of holes in the brazing solder is removed;
h is the distance from the top of each core lattice to the back plate, and when the distances from the top of the adjacent core lattices to the back plate in the same brazing joint are not equal, h is taken as the average value of the distances;
k is the minimum distance of the holes from the top of the brazing filler metal between the core cells;
j is the minimum distance of the hole from the back plate.
(1) The quality indicator comprises a quantitative characterization of the size of holes in the braze joint, preferably the quantitative characterization of the size of holes comprises the total length of all holes in the braze joint, preferably the quantitative evaluation is performed in combination with the climbing height of the braze between core cells and/or the core cell top to back plate distance when the quantitative evaluation is performed using the quantitative characterization of the braze size in the braze joint, in particular:
a-b≥0.5h。
it should be noted that, although the index includes the distance h from the top of the core grid to the back plate and the climbing height a of the brazing material between the core grids to quantitatively evaluate the total length b of all holes in the brazing joint, it does not mean that the index necessarily depends on other parameters or variables such as the distance h from the top of the core grids to the back plate and/or the climbing height a of the brazing material between the core grids, and other fixed thresholds or quantitative relationships may be used instead of other parameters or variables, so that the quality index is independent of other parameters or variables such as the distance h from the top of the core grids to the back plate and the climbing height a of the brazing material between the core grids.
For example, it can be defined that a-b ≧ 3.5mm makes the quality index independent of the distance h from the top of the core cell to the backplate;
as another example, further, b ≦ 3mm may be defined so that the quality index is independent of the distance h from the top of the core cell to the back plate and the climbing height a of the brazing material between the core cells, and the quality index is quantitatively evaluated using only a fixed threshold of 3 mm.
Similarly, the dependency relationship of the following quality indicators is not limited to the embodiment, and the quality indicators can be used independently.
(2) The quality index further comprises a quantitative characterization of the braze size in the braze joint, preferably the quantitative characterization of the braze size comprises one or more of a climbing height of braze in a core cell of the honeycomb sealing structure, preferably the quantitative characterization of the braze size further comprises one or more of a spreading length of braze in a core cell of the honeycomb sealing structure, a climbing height of braze between core cells, a total spreading length of braze of adjacent core cells, preferably the quantitative evaluation is performed in combination with a core cell bottom to back plate distance and/or a core cell top to back plate distance when the quantitative evaluation is performed using the quantitative characterization of the braze size in the braze joint, in particular:
a≥0.7h，
c＞0.1mm，
e is more than 0.15mm, e is more than 6d and less than 50 percent of h,
f＞0.4mm。
(3) the quality index further comprises a quantitative characterization of the position of holes in the brazed joint, preferably the quantitative characterization of the position of holes comprises a minimum distance of a hole from the top of the solder between core cells and/or a minimum distance of a hole from the back plate, preferably the quantitative evaluation is performed in combination with a core cell top to back plate distance and/or a core cell bottom to back plate distance when the quantitative characterization of the position of holes in the brazed joint is used for the quantitative evaluation, in particular:
k≥0.2h，
j＞d。
(4) the quality indicator further comprises a quantitative characterization of the position of the core grid, preferably the quantitative characterization of the position of the core grid comprises a core grid bottom to back plate distance and/or a core grid top to back plate distance, in particular:
d＜0.1mm，
the indicator of the distance h from the top of the core grid to the back plate is included in the quality indicators and is not repeated here.
In the quality evaluation step, if any one of the quality indexes does not meet, the corresponding brazing joint is judged to be unqualified.
In the quality evaluation step, if more than 15% of the brazed joints in the sample of the honeycomb sealing structure to be evaluated are unqualified, or the number of the brazed joints with j not more than d defects exceeds 30% of the number of the unqualified brazed joints, the brazing metallurgical quality of the honeycomb sealing structure is judged to be unqualified.
Example 2
This example proposes a method for evaluating the quality of braze metallurgy of a honeycomb seal structure, which is preceded by a sample preparation step, which is the same as in example 1.
After the sample preparation step, a quality evaluation step was performed.
In the quality evaluation step, a metallographic microscope or a scanning electron microscope is adopted to measure the size of the soldered joint.
The size range of the honeycomb core lattice applicable to the evaluation method of the intrinsic quality is as follows (see the attached figure 2 for details):
(1) the wall thickness t is 0.05mm-0.16 mm;
(2) the core grid depth D is not more than 7 mm;
(3) the size L of the core grid is 0.8mm-3.2 mm.
In the quality evaluation step, the quality index is quantitatively evaluated, and the quality index used is as follows (see fig. 2 and 3).
The symbols hereinafter have the following meanings:
a is the climbing height of the brazing solder between the core grids;
b is the total length of all holes in the brazed joint, and the length is less than the wall thickness t of the core grid or is not counted by a single hole of 0.08 mm;
d is the distance from the bottom of the core grid to the back plate, and when the distances from the bottoms of the adjacent core grids in the same brazing joint to the back plate are not equal, the average value of the distances is taken;
e is the climbing height of the brazing solder in the core lattice, and when the climbing heights of the brazing solder on the two sides of the brazing joint are asymmetric, the height average value is taken by the e;
h is the distance from the top of the core lattice to the back plate, and when the distances from the tops of the adjacent core lattices in the same brazing joint to the back plate are not equal, h is the average value of the distances.
(1) The quality indicator comprises a quantitative characterization of the size of holes in the braze joint, preferably the quantitative characterization of the size of holes comprises the total length of all holes in the braze joint, preferably the quantitative evaluation is performed in combination with the climbing height of the braze between core cells and/or the core cell top to back plate distance when the quantitative evaluation is performed using the quantitative characterization of the braze size in the braze joint, in particular:
a-b≥0.5h。
(2) the quality indicator further comprises a quantitative characterization of the braze size in the braze joint, preferably the quantitative characterization of the braze size comprises a climbing height of braze in a core cell of the honeycomb seal structure, preferably the quantitative evaluation is performed in combination with a core cell bottom to back plate distance and/or a core cell top to back plate distance when the quantitative evaluation is performed using the quantitative characterization of the braze size in the braze joint, in particular:
e is more than 0.15mm, and e is more than 6d and less than 50 percent of h.
It should be noted that the dependency relationship of the quality indicators is not limited to the embodiment, and the quality indicators can be used independently, for example, the quality indicators are determined by a fixed threshold, rather than by a proportional relationship between the quality indicators and each other.
In addition, the two quality indexes are selected to evaluate the brazing metallurgical quality, and it is also feasible to select the quality indexes in a combined manner or use a single quality index for evaluation according to the actual test requirements.
In the quality evaluation step, if any of the quality indexes does not meet, the corresponding brazed joint is judged to be unqualified.
In the quality evaluation step, if more than 15% of the brazed joints in the sample of the honeycomb seal structure to be evaluated are failed, it is determined that the honeycomb seal structure is failed in the brazing metallurgical quality.
Example 3
This example proposes a method for evaluating the quality of braze metallurgy of a honeycomb seal structure, which is preceded by a sample preparation step, which is the same as in example 1.
After the sample preparation step, a quality evaluation step was performed.
In the quality evaluation step, a metallographic microscope or a scanning electron microscope is adopted to measure the size of the soldered joint.
The size range of the honeycomb core lattice applicable to the evaluation method of the intrinsic quality is as follows (see the attached figure 2 for details):
(1) the wall thickness t is 0.05mm-0.16 mm;
(2) the core grid depth D is not more than 7 mm;
(3) the size L of the core grid is 0.8mm-3.2 mm.
In the quality evaluation step, the quality index is quantitatively evaluated, and the quality index used is as follows (see fig. 2 and 3).
The symbols hereinafter have the following meanings:
a is the climbing height of the brazing material among the core grids;
b is the total length of all holes in the brazed joint, and the length is less than the wall thickness t of the core grid or is not counted by a single hole of 0.08 mm;
h is the distance from the top of the core lattice to the back plate, and when the distances from the tops of the adjacent core lattices in the same brazing joint to the back plate are not equal, h is the average value of the distances.
The quality indicator comprises a quantitative characterization of the size of holes in the braze joint, preferably the quantitative characterization of the size of holes comprises the total length of all holes in the braze joint, preferably the quantitative evaluation is performed in combination with the climbing height of the braze between core cells and/or the core cell top to back plate distance when the quantitative evaluation is performed using the quantitative characterization of the braze size in the braze joint, in particular:
a-b≥0.5h。
it should be noted that the dependency relationship of the quality indicators is not limited to the embodiment, and the quality indicators can be used independently, for example, the quality indicators are determined by a fixed threshold, rather than by a proportional relationship between the quality indicators and each other.
In addition, the quality index is selected to evaluate the brazing metallurgy quality in the embodiment, and it is also feasible to select the quality index in a combined manner or use other single quality indexes to evaluate according to the actual test requirements.
In the quality evaluation step, if any of the quality indexes does not meet, the corresponding brazed joint is judged to be unqualified.
In the quality evaluation step, if more than 15% of the brazed joints in the sample of the honeycomb seal structure to be evaluated are failed, it is determined that the honeycomb seal structure is failed in the brazing metallurgical quality.
Example 4
This example proposes a method for evaluating the quality of braze metallurgy of a honeycomb seal structure, which is preceded by a sample preparation step, which is the same as in example 1.
After the sample preparation step, a quality evaluation step was performed.
In the quality evaluation step, a metallographic microscope or a scanning electron microscope is adopted to measure the size of the soldered joint.
The size range of the honeycomb core lattice applicable to the evaluation method of the intrinsic quality is as follows (see the attached figure 2 for details):
(1) the wall thickness t is 0.05mm-0.16 mm;
(2) the core grid depth D is not more than 7 mm;
(3) the size L of the core grid is 0.8mm-3.2 mm.
In the quality evaluation step, the quality index is quantitatively evaluated, and the quality index used is as follows (see fig. 2 and 3).
The symbols hereinafter have the following meanings:
b is the total length of all holes in the brazed joint, and the length is less than the wall thickness t of the core grid or is not counted by a single hole of 0.08 mm.
The quality indicator comprises a quantitative characterization of the size of the holes in the brazed joint, preferably the quantitative characterization of the size of the holes comprises the total length of all holes in the brazed joint, in particular:
b≤1mm。
in the quality evaluation step, if the quality indexes are not met, the corresponding brazing joint is judged to be unqualified.
In the quality evaluation step, if more than 15% of the brazed joints in the sample of the honeycomb seal structure to be evaluated are failed, it is determined that the honeycomb seal structure is failed in the brazing metallurgical quality.
Example 5
In this example, the sample was evaluated by the evaluation method in example 1.
A section of honeycomb brazing sample piece with the core lattice geometric parameters of 0.08mm wall thickness, 1.6mm core lattice size and 7mm depth is cut and corroded, and the sizes of all key parameters are measured according to the requirements in the attached figures 2-3 as follows:
a＝6.8mm；
b＝0.1mm，a-b＝6.7mm；
c＝0.3mm；
d＝0.05mm；
e＝0.5mm；
f＝0.7mm；
h＝7.1mm；
k＝2.4mm；
the measured size is confirmed to completely meet the requirements of the invention.
Through a tensile test, the honeycomb sealing element can bear the ultimate shear force of 224.7MPa to 248 MPa. When the honeycomb seal is installed at the second stage, the third stage and the fourth stage stator blade roots of the heavy-duty gas turbine, when the depth of the honeycomb is 0.8mm-7mm, based on the hot fluid-solid coupling simulation, the shearing force of the honeycomb core grids under the comprehensive action of pneumatic load and hot load does not exceed the limit value.
Example 6
In this example, the sample was evaluated by the evaluation method in example 1.
A section of honeycomb brazing sample piece with the core lattice geometric parameters of 0.05mm wall thickness, 3.2mm core lattice size and 7mm depth is cut and corroded, and the sizes of all key parameters are measured according to the requirements in the attached figures 2-3 as follows:
a＝6.7mm；
b＝0.2mm，a-b＝6.5mm；
c＝0.6mm；
d＝0.07mm；
e＝0.8mm；
f＝1.3mm；
h＝7.2mm；
k＝3.3mm；
the measured size is confirmed to completely meet the requirements of the invention.
Through a tensile test, the honeycomb sealing element can bear the limit shear force of 248.5MPa to 269.2 MPa. When the honeycomb seal is installed at the second-stage and fourth-stage stator blade roots of the heavy-duty gas turbine, and the honeycomb depth is 0.8mm-7mm, based on the thermo-fluid-solid coupling simulation, the shearing force of the honeycomb core lattice under the combined action of pneumatic load and thermal load does not exceed the limit value.
From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:
1. the method for evaluating the brazing metallurgical quality of the honeycomb sealing structure can accurately evaluate whether the metallurgical quality of the brazing part is qualified or not, so that whether the brazing process meets the requirements or not is determined.
2. The quality index with stronger adaptability is provided, and the method can be suitable for evaluating the metallurgical quality of different honeycomb core grid materials (including but not limited to high-temperature alloy and stainless steel), different back plate materials (including but not limited to high-temperature alloy and stainless steel), different brazing materials (including but not limited to nickel-based, copper-based and silver-based brazing filler metals) and honeycomb sealing element brazed joints with different structures.
3. The invention provides the size requirement of a better honeycomb core grid material, and when the size of the honeycomb core grid is in the size range limited by the invention, the quality evaluation accuracy and the reference value are better; however, other honeycomb core cell structures of similar dimensions may be similarly evaluated using the quality index of the present invention.
4. The invention provides a set of comprehensive quality evaluation indexes, when the brazing metallurgical quality needs to be evaluated quickly and simply, part of the indexes can be optimized for evaluation, and the flexibility is strong.
5. The invention also provides a preferable sample preparation scheme, which is matched with the quality evaluation method provided by the invention and can improve the quality evaluation effect.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (22)
1. The method for evaluating the brazing metallurgical quality of the honeycomb sealing structure comprises a sample preparation step and a quality evaluation step, wherein the honeycomb sealing structure to be evaluated is prepared into a sample, and the brazing metallurgical quality of the sample is evaluated in the quality evaluation step.
2. The method of evaluating the braze metallurgical quality of a honeycomb seal construction of claim 1, wherein said quantitative characterization of the size of the holes comprises the total length of all holes in said braze joint.
3. The method for evaluating the brazing metallurgical quality of the honeycomb sealing structure according to claim 1, wherein the quantitative evaluation is carried out in combination with the climbing height of the brazing material among the core cells and/or the distance from the top of the core cells to the back plate when the quantitative evaluation is carried out on the quantitative characterization of the size of the holes.
4. The method of evaluating braze metallurgical quality of a honeycomb seal structure according to claim 1, wherein said quality index further comprises a quantitative characterization of braze size in said braze joint.
5. The method of evaluating braze metallurgical quality of a honeycomb sealing structure according to claim 4, wherein said quantitative characterization of braze size comprises a climb height of braze within a core grid of said honeycomb sealing structure.
6. The method for evaluating the brazing metallurgical quality of the honeycomb sealing structure according to claim 5, wherein the quantitative characterization of the brazing material size further comprises one or more of the spreading length of the brazing material in the core grids of the honeycomb sealing structure, the climbing height of the brazing material between the core grids and the spreading total length of the brazing material of the adjacent core grids.
7. The method for evaluating the brazing metallurgical quality of the honeycomb sealing structure according to claim 4, wherein the quantitative evaluation is carried out in combination with a core grid bottom to back plate distance and/or a core grid top to back plate distance when the quantitative evaluation is carried out by using quantitative characterization of the size of the brazing material in the brazing joint.
8. The method of evaluating the braze metallurgical quality of a honeycomb seal structure according to claim 1, wherein said quality index further comprises a quantitative characterization of the location of holes in said braze joint.
9. The method of evaluating braze metallurgical quality of a honeycomb seal structure according to claim 8, wherein said quantitative characterization of the location of the holes comprises a minimum distance of a hole from a top of the braze between the cells and/or a minimum distance of a hole from the backing plate.
10. The method of evaluating the braze metallurgical quality of a honeycomb seal structure according to claim 8, wherein said quantitative evaluation is performed in combination with core grid top to back plate distance and/or core grid bottom to back plate distance when said quantitative evaluation is performed using quantitative characterization of the location of holes in said braze joints.
11. The method of evaluating the braze metallurgical quality of a honeycomb seal construction of claim 1, wherein said quality index further comprises a quantitative characterization of the location of said core cells.
12. The method of evaluating braze metallurgical quality of a honeycomb seal structure according to claim 11, wherein the quantitative characterization of the location of the core cells comprises a core cell bottom to back plate distance and/or a core cell top to back plate distance.
13. Method for evaluating the braze metallurgical quality of a honeycomb sealing structure according to any one of claims 1-12, wherein in the quality evaluation step the quality index is adapted to one or more of the following conditions:
a≥0.7h；
a-b≥0.5h；
c＞0.1mm；
d＜0.1mm；
e is more than 0.15mm, and e is more than 6d and less than 50 percent of h;
f＞0.4mm；
k≥0.2h；
j＞d；
wherein a is the climbing height of the brazing solder between the core cells;
b is the total length of all holes in the brazed joint, and the length is less than the wall thickness t of the core grid or is not counted by a single hole of 0.08 mm;
c is the spreading length of the brazing solder in the core lattice, and when the brazing solder on the two sides of the brazing joint is asymmetrically spread, the average length value is taken;
d is the distance from the bottom of the core grid to the back plate, and when the distances from the bottoms of the adjacent core grids in the same brazing joint to the back plate are not equal, the average value of the distances is taken;
e is the climbing height of the brazing solder in the core lattice, and when the climbing heights of the brazing solder on the two sides of the brazing joint are asymmetric, the height average value is taken by the e;
f is the total spreading length of the brazing solder of the adjacent core grids, and when the total spreading length of the brazing solder is measured, the size of holes in the brazing solder is removed;
h is the distance from the top of each core lattice to the back plate, and when the distances from the tops of adjacent core lattices in the same brazing joint to the back plate are not equal, h is the average value of the distances;
k is the minimum distance of the holes from the top of the brazing filler metal between the core cells;
j is the minimum distance of the hole from the back plate.
14. The method for evaluating the braze metallurgical quality of a honeycomb sealing structure according to claim 13, wherein the method for evaluating the braze metallurgical quality of a honeycomb sealing structure is applied to the core grids with the following sizes:
the wall thickness t is 0.05mm-0.16 mm;
the core grid depth D is less than or equal to 7 mm;
the size L of the core grid is 0.8mm-3.2 mm.
15. The method for evaluating the brazing metallurgical quality of the honeycomb sealing structure according to claim 14, wherein in the quality evaluating step, if any one of the quality indexes is not met, the corresponding brazing joint is judged to be unqualified.
16. The method for evaluating the brazing metallurgical quality of the honeycomb sealing structure according to claim 15, wherein in the quality evaluating step, if more than 15% of the brazed joints in the test sample of the honeycomb sealing structure to be evaluated are failed, or the number of the brazed joints having j ≦ d defects exceeds 30% of the number of the failed brazed joints, the brazing metallurgical quality of the honeycomb sealing structure is judged to be failed.
17. The method for evaluating the brazing metallurgical quality of the honeycomb sealing structure according to any one of claims 1 to 12, wherein the sample is obtained by sampling a brazing sample prepared under the conditions of the same material, the same process and the same equipment as the honeycomb sealing structure actually used.
18. A method of evaluating the brazing metallurgical quality of a honeycomb sealing structure according to any one of claims 1 to 12, wherein said sample preparation step includes a cutting step in which said honeycomb sealing structure is cut in a brazing seam perpendicular direction.
19. The method of evaluating the brazing metallurgical quality of a honeycomb sealing structure according to claim 18, wherein the sample preparation step further comprises an inlaying step in which the sample of the honeycomb sealing structure obtained in the cutting step is inlaid to expose a brazing seam section.
20. The method of evaluating braze metallurgical quality of a honeycomb sealing structure according to claim 19, wherein said sample preparation step further comprises a polishing step in which the sample of honeycomb sealing structure obtained in said inlaying step is ground and/or polished.
21. The method of evaluating the braze metallurgical quality of a honeycomb sealing structure according to claim 20, wherein said specimen preparation step further comprises an etching step in which a specimen of said honeycomb sealing structure treated in said polishing step is etched using an etching liquid.
22. The method for evaluating the brazing metallurgical quality of the honeycomb sealing structure according to any one of claims 1 to 12, wherein in the quality evaluation step, the sample is measured and evaluated using a metallographic microscope or a scanning electron microscope.
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