CN102831991A - Method for manufacturing epoxy-cast insulators - Google Patents
Method for manufacturing epoxy-cast insulators Download PDFInfo
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- CN102831991A CN102831991A CN2012102820010A CN201210282001A CN102831991A CN 102831991 A CN102831991 A CN 102831991A CN 2012102820010 A CN2012102820010 A CN 2012102820010A CN 201210282001 A CN201210282001 A CN 201210282001A CN 102831991 A CN102831991 A CN 102831991A
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Abstract
The invention relates to a method for manufacturing epoxy-cast insulators. The method includes steps of surface treatment for metal inserts, preparation of castable, moulding of the metal inserts, casting, solidification and demoulding. The step of surface treatment for the metal insert includes sand blasting for the inserts, cleaning of the inserts and gluing of the inserts. The cleaning of the inserts sequentially includes steps of (1), eroding the metal inserts in sodium hydroxide liquor at the temperature of 90+/-5 DEG C for 5 to 20 seconds; (2), washing the metal inserts by hot water at the temperature of 90+/-5 DEG C for 3 to 15 seconds; (3), washing the metal inserts by cold water at the temperature of 25+/-5 DEG C for 3 to 15 seconds; (4), washing the metal inserts by nitric acid at the temperature of 25+/-5 DEG C for 5 to 20 seconds; (5), washing the metal inserts by cold water at the temperature of 25+/-5 DEG C for 3 to 15 seconds; (6), washing the metal inserts by mixed acid of sulfuric acid at the temperature of 25+/-5 DEG C for 5 to 15 minutes; (7), washing the metal inserts by cold water at the temperature of 25+/-5 DEG C for 3 to 15 seconds; (8), washing the metal inserts by hot water at the temperature of 90+/-5 DEG C for 3 to 15 seconds; and (9), soaking the metal inserts in cold water and taking out the metal inserts before moulding for the inserts. The method has the advantages that binding force between the metal insert and a resin matrix is increased by about 50% as compared with the conventional surface treatment process, and bonding strength of the metal inserts and the resin matrix can reach 55MPa.
Description
Technical field
The present invention relates to a kind of epoxy casting insulator manufacturing approach.
Background technology
For high voltage switchgear; The height of its electric pressure depends primarily on each item electricity function index and the mechanical performance index of insulator; Electric pressure is high more, and is just harsher to the requirement of insulator, and the insulator mechanical performance index adopts the hydraulic pressure breakdown strength to weigh at present.For large-scale insulator; Like 1100kV GIS with disc insulator (diameter 934mm; Degree of depth 365mm, weight 140kg), require to have good mechanical performance satisfying under the prerequisite of its electric property; It is the designing requirement that the hydraulic pressure breakdown strength must reach regulation; And the height of hydraulic pressure breakdown strength is determined by the intensity and the toughness of insulator body, and under the certain condition of insulator design size, the curing in its epoxy casting production then is key one ring of decision insulator body intensity and toughness.
At present; The conventional manufacturing approach of epoxy casting insulator mainly comprises following technical process: pours, inserts dress mould, cast, curing and the demoulding are handled, prepared to insert surface such as mould preparation, center conductor; Wherein solidification process is the key link that influences pouring piece mechanical performance index height; That solidification process has generally is persistently overheating, be incubated and three Main Stage of lowering the temperature; The microstructure that the height of curing temperature and the length of curing time directly affect pouring piece forms and the contraction situation, and curing temperature is too high or persistently overheatingly comparatively fast all can cause pore even shrinkage cavity to produce, thereby influences the mechanical performance of pouring piece.
The epoxy resin casting workpiece curing that is adopted at present mainly contains two kinds: single hop solidifies and two sections curing, and its corresponding curing degree DSC curve is seen shown in Figure 1, single hop solidify with two sections solidify respectively the top and curve bottom in the corresponding diagram; Can know by curve shown in the figure; Single hop solidifies the general relatively low curing temperature of selecting, and improves curing degree for a long time through adding, therefore; The insulator curing degree that adopts single hop to solidify is generally on the low side; In its solidification process, glass transition temperature is low, and has tangible curing exothermic peak; Two sections curing very easily cause the too high situation of curing degree then because phase I and second stage temperature spread are excessive in second stage, and glass transition temperature is high in its solidification process, and flex point is not obvious.Adopt the insulator of above-mentioned two kinds of curings cast, its curing degree is crossed when hanging down, and insulator body is soft partially, pliable and tough, but its intensity is less than normal; Though and too high curing degree insulator strength is big, fragility is also big simultaneously, has increased the risk of cracking.
DSC curve by single hop curing and two sections curing among Fig. 1 can be known; The intensity of insulator has direct related with toughness and epoxy casting curing degree; For the large-scale insulator that requires higher hydraulic pressure breakdown strength; Its pouring technology must guarantee that insulator has higher intensity and toughness preferably; Adopt above-mentioned two kinds of epoxy resin casting workpiece curings to produce large-scale insulator and obviously can not reach its requirement to mechanical performance, that is to say that its solidification process need adopt a brand-new curing, this epoxy casting technology to insulator has proposed a new problem.
In addition; The adhesion of disc insulator center conductor metal insert and resin matrix also has certain influence to insulator hydraulic pressure breakdown strength; So in disc insulator cast production process; Before cast, must carry out surface treatment to metal inserts such as center conductors, to improve the adhesion of metal insert and resin matrix, the surface treatment method of the present routine that adopts is that metal insert is carried out sandblast and ultrasonic waves for cleaning; This processing method is simple, for large-scale disc insulator, can not satisfy its requirement to inserts and interlaminar resin adhesion.
Summary of the invention
The purpose of this invention is to provide a kind of epoxy casting insulator manufacturing approach that can improve adhesion between metal inserts such as center conductor and epoxy resin-base.
For realizing above-mentioned purpose; The present invention adopts following technical scheme: epoxy casting insulator manufacturing approach; Comprise the steps: metal insert surface treatment, preparation pours, metal insert dress mould, cast, curing and the demoulding; Wherein, the metal insert surface treatment step comprises that inserts sandblast, inserts clean and the inserts gluing, and wherein inserts cleans and undertaken by following sequential steps:
(1) 90 ± 5 ℃ of sodium hydroxide solution corrodes 5～20s;
(2) 90 ± 5 ℃ of hot water wash 3～15s;
(3) 25 ± 5 ℃ of cold wash 3～15s;
(4) 25 ± 5 ℃ of nitric acid are washed 5～20s;
(5) 25 ± 5 ℃ of cold wash 3～15s;
(6) 25 ± 5 ℃ of sulfuric acid based are mixed pickling 5～15min;
(7) 25 ± 5 ℃ of cold wash 3～15s;
(8) 90 ± 5 ℃ of hot water wash 3～15s;
(9) take out before cold water soak to the inserts dress mould.
Further, in the said step (6), sulfuric acid based is mixed pickle that pickling the uses mixed solution as the mixed solution of mixed solution, sulfuric acid and the chromic acid of sulfuric acid and nitric acid or sulfuric acid and nitric acid, chromic acid.
Further, after the demoulding, also have the destressing step, the destressing step is that the insulator after the demoulding is kept 4 ± 0.5h under 145 ± 3 ℃ of temperature.
Curing among the present invention is divided into three phases with solidification process and carries out (following abbreviate curing of the present invention as three sections curing), and its curing degree can come qualitative evaluation by DSC curve shown in Figure 1, among Fig. 1; Three sections solidify corresponding curve in the middle of being; The contrast of three curves can clearly be explained from Fig. 1, and the present invention makes in the solidification process persistently overheating mild through the reasonable control to Temperature Distribution in the solidification process and duration; And the duration is suitable; Glass transition temperature is moderate in the solidification process, and flex point is obvious, and does not have exothermic peak; Three sections curing have than single hop casting process to solidify and two sections curing degrees that curing is preferably, and following table is to adopting the intensity that three kinds of samples that curing is poured into a mould carry out and the data of toughness test:
Through the comparison to the test data in the above table and Fig. 2, Fig. 3 Electronic Speculum figure, the crystal grain that single hop solidifies is thick and inhomogeneous, and easy surrender causes intensity little, and elongation at break is big; The material of two sections curing is crisp partially, and easy embrittlement causes intensity little, and elongation at break is little; The disc insulator that uses three sections curing is for the disc insulator that uses single hop to solidify; Uniform crystal particles and tiny; Promoted the tight type and the uniformity of insulator tissue significantly, further made the insulator bulk strength obtain obvious lifting, solidified and two sections curing with respect to single hop; Adopt three sections pouring pieces that solidify acquisition when having higher intensity, also to have high toughness, comprehensive mechanical performance is good.Three sections curings make to be produced the large-scale disc insulator that meets instructions for use and becomes possibility; The specification that adopts method manufacturing of the present invention is the disc insulator of diameter 934mm, degree of depth 365mm, weight 140kg; Behind 10 thermal cycling tests of experience, the hydraulic pressure breakdown strength is up to 4.4MPa, in addition; The unit thickness breakdown strength of insulator can reach 35kV/mm, has guaranteed the electrical property of insulator.
The present invention can reduce the defectives such as contraction line that pouring piece causes because of cure shrinkage in the initial employing of the phase I of three sections curing insulation 0.05MPa pressurization measure, and this has the meaning of outbalance for large-scale pouring piece.
Among the present invention; The process of surface treatment that adopts sandblast, cleaning to combine for metal inserts such as insulator center conductors with gluing; Because cleaning process adopts the cleaning step repeatedly of different solutions; Not only can remove insert surface layer materials such as center conductor, can also make simultaneously through the insert surface fluctuating homogeneous of blasting treatment and closely knit, thereby promote the adhesion between center conductor and the resin matrix; Use commercial blast to add the mode of ultrasonic waves for cleaning; The bond strength of resin and metal is merely about 25MPa; And the bond strength of metal insert of the present invention and interlaminar resin can reach about 55MPa; Its adhesion compare conventional process of surface treatment promoted about 50%, for the lifting of disc insulator hydraulic pressure destructive characteristics is laid a good foundation.
Among the present invention, after the demoulding, adopt 145 ± 3 ℃/4h stress removing, fully discharged the curing internal stress of disc insulator, and the time is appropriate, can not cause that fragility changes.
Description of drawings
Fig. 1 be single hop solidify, two sections solidify and three sections DSC curves contrasts of solidifying the insulator curing degree of the present invention;
Fig. 2 is the 4000 times of Electronic Speculum figure of disc insulator microstructure that form by the single hop curing behind the epoxy casting;
Fig. 3 is the 4000 times of Electronic Speculum figure of disc insulator microstructure that form according to three sections curings of the present invention behind the epoxy casting;
Fig. 4 is three sections curing temperature-time plots among the present invention;
Fig. 5 is the flow chart of epoxy casting insulator manufacturing approach embodiment 1 of the present invention.
Embodiment
The embodiment of epoxy casting insulator manufacturing approach provided by the invention is following
Embodiment 1: as shown in Figure 5, epoxy casting insulator manufacturing approach comprises the steps:
1, mould is prepared: mainly be made up of metal insert surface treatments such as mould processing, center conductor, inserts dress mould and mould preliminary drying;
2, preparation pours:, resin preliminary drying, curing agent preliminary drying and filler preliminary drying prepare burden after accomplishing, and then static batch mixing; This step is identical with corresponding conventional steps;
3, vacuum pouring: identical with the normal pouring mode;
4, solidify: curing schedule is three sections curing, and three sections curing are made up of the three phases of following order, see shown in Figure 4, the phase I: persistently overheating by normal temperature in 2h, and insulation 15h to 105 ℃, the preceding 6h employing 0.05MPa pressure heat-preserving among this insulation 15h; Get into second stage then: persistently overheating by 105 ℃ in 1h to 150 ℃, and insulation 15h; Then get into the phase III: persistently overheating by 150 ℃ in 1h to 155 ℃, and insulation 5h;
5, the demoulding;
6, stress removing: the destressing step is that the insulator after the demoulding is kept 4h under 145 ℃ of temperature.
Wherein, metal insert surface treatments such as the center conductor in the step 1 are cleaned by inserts sandblast, inserts successively and the inserts gluing is formed, and wherein the inserts cleaning step is undertaken by following sequential steps:
(1) 90 ℃ of sodium hydroxide solution corrodes 12s; Owing to formed the irregular loose structure of convex-concave on the metal insert surface after the blasting treatment; And there is oxide layer in insert surface; With sodium hydroxide solution this oxide layer is eaten away after the sandblast; The alkali lye of heat can enlarge the micropore on the insert surface, has guaranteed that endoporus outer oxide layer in insert surface hole can be etched thoroughly;
(2) 90 ℃ of hot water wash 9s; Employing can make the micropore of insert surface keep the not shrinkage cavity of original reaming state with the hot water of alkali lye uniform temp, is convenient to residual alkali lye and impurity flush away that hole endoporus outer surface is adhered to;
(3) 25 ℃ of cold wash 9s; Further clean the residue of insert surface, improve surface cleanliness;
(4) 25 ℃ of nitric acid are washed 12s; This step adopts nitric acid to carry out acid-base neutralization, removes the alkali erosion layer of insert surface;
(5) 25 ℃ of cold wash 9s; Raffinate and impurity that this step flush away insert surface is adhered to;
(6) 25 ℃ of sulfuric acid based are mixed pickling 9min; Pickle can adopt mixed solution or sulfuric acid and the nitric acid of mixed solution, sulfuric acid and the chromic acid of sulfuric acid and nitric acid, the mixed solution of chromic acid; This step is for the burr spike of eliminating insert surface etc., makes insert surface convex-concave uniformity, to improve the adhesion with resin;
(7) 25 ℃ of cold wash 9s; Remove residual acid solution and impurity that insert surface is adhered to;
(8) 90 ℃ of hot water wash 9s; Adopt hot water under the reaming state, to clean once more, thoroughly the residue of cleaning hole endoporus outer surface;
(9) take out before cold water soak to the inserts dress mould.If contact certain hour through the insert surface after the above-mentioned steps processing with air very easily oxidized; The oxide layer that produces can reduce the adhesion with resin; So before cast dress mould, inserts is soaked in the cold water with air-isolation; Prevent oxidized, when to be cast with inserts from water, take out the dress mould.
Embodiment 2: the epoxy casting insulator manufacturing approach of present embodiment and the difference of embodiment 1 are: the cleaning step of metal insert is undertaken by following sequential steps in the step 1:
(1) 95 ℃ of sodium hydroxide solution corrodes 5s;
(2) 95 ℃ of hot water wash 3s;
(3) 30 ℃ of cold wash 3s;
(4) 30 ℃ of nitric acid are washed 5s;
(5) 30 ℃ of cold wash 3s;
(6) 30 ℃ of sulfuric acid based are mixed pickling 5min; Pickle can adopt mixed solution or sulfuric acid and the nitric acid of mixed solution, sulfuric acid and the chromic acid of sulfuric acid and nitric acid, the mixed solution of chromic acid;
(7) 30 ℃ of cold wash 3s;
(8) 95 ℃ of hot water wash 3s;
(9) take out before cold water soak to the inserts dress mould.
In addition, in the step 4, solidify and form the phase I by the three phases of following order: persistently overheating by normal temperature in 1.5h to 102 ℃, and insulation 15.5h, the preceding 6h among this insulation 15.5h is the 0.05MPa pressure heat-preserving; Get into second stage then: persistently overheating by 102 ℃ in 0.5h to 147 ℃, and insulation 15.5h; Then get into the phase III: persistently overheating by 147 ℃ in 0.5h to 152 ℃, and insulation 5.5h.
In the step 6, the destressing step is that the pouring piece after the demoulding is kept 4.5h under 142 ℃ of temperature.
Embodiment 3: the epoxy casting insulator manufacturing approach of present embodiment and the difference of embodiment 1 are: the cleaning step of metal insert is undertaken by following sequential steps in the step 1:
(1) 85 ℃ of sodium hydroxide solution corrodes 20s;
(2) 85 ℃ of hot water wash 15s;
(3) 20 ℃ of cold wash 15s;
(4) 20 ℃ of nitric acid are washed 20s;
(5) 20 ℃ of cold wash 15s;
(6) 20 ℃ of sulfuric acid based are mixed pickling 15min; Pickle can adopt mixed solution or sulfuric acid and the nitric acid of mixed solution, sulfuric acid and the chromic acid of sulfuric acid and nitric acid, the mixed solution of chromic acid;
(7) 20 ℃ of cold wash 15s;
(8) 85 ℃ of hot water wash 15s;
(9) take out before cold water soak to the inserts dress mould.
In addition, in the step 4, solidify and form the phase I by the three phases of following order: persistently overheating by normal temperature in 2.5h to 108 ℃, and insulation 14.5h, the preceding 6h among this insulation 14.5h is the 0.05MPa pressure heat-preserving; Get into second stage then: persistently overheating by 108 ℃ in 1.5h to 153 ℃, and insulation 14.5h; Then get into the phase III: persistently overheating by 153 ℃ in 1.5h to 158 ℃, and insulation 4.5h.
In the step 6, the destressing step is that the pouring piece after the demoulding is kept 3.5h under 148 ℃ of temperature.
Epoxy casting insulator manufacturing approach of the present invention; Metal insert surface treatment methods such as center conductor wherein are specially adapted to the production of large-scale disc insulator; The disc insulator that adopts the inventive method to produce; The bond strength of its center conductor metal inserts and interlaminar resin can reach about 55MPa, its adhesion compare conventional process of surface treatment promoted about 50%, for the lifting of disc insulator hydraulic pressure destructive characteristics is laid a good foundation.
Claims (3)
1. epoxy casting insulator manufacturing approach; It is characterized in that: comprise the steps: metal insert surface treatment, preparation pours, metal insert dress mould, cast, curing and the demoulding; Wherein, The metal insert surface treatment step comprises that inserts sandblast, inserts clean and the inserts gluing, and wherein inserts cleans and undertaken by following sequential steps:
(1) 90 ± 5 ℃ of sodium hydroxide solution corrodes 5～20s;
(2) 90 ± 5 ℃ of hot water wash 3～15s;
(3) 25 ± 5 ℃ of cold wash 3～15s;
(4) 25 ± 5 ℃ of nitric acid are washed 5～20s;
(5) 25 ± 5 ℃ of cold wash 3～15s;
(6) 25 ± 5 ℃ of sulfuric acid based are mixed pickling 5～15min;
(7) 25 ± 5 ℃ of cold wash 3～15s;
(8) 90 ± 5 ℃ of hot water wash 3～15s;
(9) take out before cold water soak to the inserts dress mould.
2. epoxy casting insulator manufacturing approach according to claim 1; It is characterized in that: in the said step (6), sulfuric acid based is mixed pickle that pickling the uses mixed solution as the mixed solution of mixed solution, sulfuric acid and the chromic acid of sulfuric acid and nitric acid or sulfuric acid and nitric acid, chromic acid.
3. epoxy casting insulator manufacturing approach according to claim 1 and 2 is characterized in that: after the demoulding, also have the destressing step, the destressing step is that the insulator after the demoulding is kept 4 ± 0.5h under 145 ± 3 ℃ of temperature.
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| CN201210282001.0A CN102831991B (en) | 2012-08-09 | 2012-08-09 | Method for manufacturing epoxy-cast insulators |
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| CN102831991B CN102831991B (en) | 2014-12-10 |
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| CN1604237A (en) * | 2004-10-22 | 2005-04-06 | 西安交通大学 | vacuum insulator coating capable of increasing flashover voltage and method of preparation thereof |
| CN101252034A (en) * | 2008-04-03 | 2008-08-27 | 醴陵泓嘉机械实业有限公司 | Column support type hollow combined insulator and production process thereof |
| CN101540225A (en) * | 2009-03-24 | 2009-09-23 | 西安交通大学 | Method for preparing silicon rubber insulator super-hydrophobicity surface |
| CN101840757A (en) * | 2010-05-21 | 2010-09-22 | 扬州东宇电气有限公司 | Manufacturing method for environment-friendly type insulator shell |
| CN101859616A (en) * | 2009-04-09 | 2010-10-13 | 何愈 | Method for improving mechanical strength of insulation resin products |
| CN102074323A (en) * | 2009-11-23 | 2011-05-25 | 常熟风范电力设备股份有限公司 | Novel insulating cross arm and manufacturing process thereof |
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2012
- 2012-08-09 CN CN201210282001.0A patent/CN102831991B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1604237A (en) * | 2004-10-22 | 2005-04-06 | 西安交通大学 | vacuum insulator coating capable of increasing flashover voltage and method of preparation thereof |
| CN101252034A (en) * | 2008-04-03 | 2008-08-27 | 醴陵泓嘉机械实业有限公司 | Column support type hollow combined insulator and production process thereof |
| CN101540225A (en) * | 2009-03-24 | 2009-09-23 | 西安交通大学 | Method for preparing silicon rubber insulator super-hydrophobicity surface |
| CN101859616A (en) * | 2009-04-09 | 2010-10-13 | 何愈 | Method for improving mechanical strength of insulation resin products |
| CN102074323A (en) * | 2009-11-23 | 2011-05-25 | 常熟风范电力设备股份有限公司 | Novel insulating cross arm and manufacturing process thereof |
| CN101840757A (en) * | 2010-05-21 | 2010-09-22 | 扬州东宇电气有限公司 | Manufacturing method for environment-friendly type insulator shell |
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Address after: South East of Pingdingshan city in Henan province 467001 No. 22 Applicant after: Pinggao Electric Co., Ltd., Henan Applicant after: Pinggao Group Co., Ltd. Applicant after: State Grid Corporation of China Address before: South East of Pingdingshan city in Henan province 467001 No. 23 Applicant before: Pinggao Electric Co., Ltd., Henan Applicant before: Pinggao Group Co., Ltd. Applicant before: State Grid Corporation of China |
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