CN105044105A - Method for analyzing reliability of circuit conductor - Google Patents
Method for analyzing reliability of circuit conductor Download PDFInfo
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- CN105044105A CN105044105A CN201510310302.3A CN201510310302A CN105044105A CN 105044105 A CN105044105 A CN 105044105A CN 201510310302 A CN201510310302 A CN 201510310302A CN 105044105 A CN105044105 A CN 105044105A
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Abstract
The invention provides a method for analyzing the reliability of a circuit conductor. The method comprises the following steps: (1) taking samples of electric lines of circuits in use and copper-aluminium conductors of equipment connecting parts as well as metal conductors such as brass and aluminium alloys; (2) carrying out stereo microscopic analysis on the samples by using a stereo microscope; (3) carrying out metallographic structure microscopic analysis on the samples by using a metallographic microscope; and (4) carrying out electronic microcosmic and element content percentage analysis on the samples by using a scanning electron microscope and an energy spectrum coupling technique. According to the invention, microscopic and microcosmic analyzing methods of stereo, metallographic and scanning electron microscopes are used for testing stereo microscopy, metallographic structure, canning electron microscope microscopic features and element percentage content analysis of metal conductors in a running circuit, so as to determine whether a tested metal conductor has the problems of oxidization, corrosion and poor quality, thus providing scientific technical support for further determining whether a running circuit has the hidden danger of electrical fire.
Description
Technical field
The present invention relates to electric wiring and device security detection technique field, particularly relate to a kind of Analysis of Fire Hazard method of circuit conductor.
Background technology
Statistics according to China's electrical fire is divided, electrical fire 169861 is there is altogether according to 2003 to 2007 years, the ratio accounting for fire number is respectively 23%, 20.75,21.9%, 23.1%, 28.3%, the number proportion that electrically rises of fire accidents is respectively 28.36%, 30.90%, 31.09%, 37.83%, 45.33%, and the electrical fire of obvious China causes massive losses to China's economy and people's lives and properties.The number of times that electrical fire occurs and the loss caused occupy first of all kinds of fire, and the fire caused by electric wiring occupies first of electrical fire, electric wiring insulation ag(e)ing or with low quality or mechanical damage cause wire short-circuiting, electric leakage etc. to be the main causes causing electrical fire.Therefore, the technical method of the fire risk of research foundation inspection and detection electric wiring seems extremely important and necessary.The Microbeam Analysis Techniques of circuit conductor reliability detects the important content of of the technical method of the fire risk of electric wiring just.
Fine copper aluminium conductor resistance is determined by copper aluminium material matter inherent characteristic, but 100% fine copper aluminum is non-existent, all impurity can be contained to some extent in copper aluminium conductor material, in copper aluminium material material, the existence of impurity will increase the resistance value of conductor, and the more resistance values of the impurity contained are larger, impurity is to a certain extent many or say the degree that resistance value reaches certain, will abnormal heating during conductor energising, it is aging that heating can aggravate insulating layer of conductor, thus increase the fire risks such as short circuit.On the other hand, in use, because the effect of burn into oxidation, when there is oxide and salt in tissue, resistance value also can increase the qualified copper aluminium conductor of resistance value, and resistance value can increase with the serious of corrosion and oxidation.The excessive circuit that will cause of resistance generates heat, and heating will aggravate insulation ag(e)ing, thus causes the accident such as short circuit, electric leakage initiation fire.
Qualified electric wire is when by rated current, and the temperature that resistance heating produces is normal working temperature, does not have obvious harmful effect to the insulating property of electric wire.By certain super rated current within the short time that design allows, also obvious harmful effect can not be caused to the performance of wire cable insulating material, but long-time by super rated current, the temperature of circuit then will significantly raise, the chain rupture Sum decomposition of remarkable aggravation wire cable insulating material, and aggravate the corrosion of conductor.The conductor of electric wire causes because corroding the conductor inferior that impurity content is too high or impurity content own is too high, when by rated current or super rated current, all can aggravate heating and accelerate the thermal decomposition of wire cable insulating and release corrosive substance, corrosive substance can accelerate again the corrosion to conductor, this vicious cycle effect causes the electric conductivity of circuit constantly to worsen, after this deterioration acquires a certain degree, just likely cause some position heating of circuit, short circuit, electric leakage, the initiation electrical fire accident such as creepage.If by the rated current of several times or decades of times in the electric wire that there is impurity, namely during serious excess current (crossing load) state, will likely electric wire be directly made to have burnt on fire, the accidents such as initiation fire.
Some illegal electric wire manufacturers; in order to obtain more interests; buy conductor inferior and insulation starting material; the conductor resistance of the electric wire produced is excessive and insulation course insulation resistance is less than normal; when causing by rated current and voltage, all can occur that abnormal heating destroys and cause short circuit or ignite insulation course or abnormal puncture short initiation fire accident.
The connecting portion of the electric wire in circuit causes the effects such as oxidation, corrosion due to self-contact resistance heating, the joint area that originally can well be energized can be made to occur that contact resistance is excessive, current lead-through is obstructed and is caused a large amount of heating in local, as long-time use, to dispel the heat and bad situation just may cause the generation of fire in addition.
PVC insulated line working temperature is generally no more than 70 DEG C, during overload operation, and electric current I will obviously increase, and the resistance value R of a permanent haulage line is certain, by Q=IUt=IR
2the known electric current I of t obviously increases and will heat Q be caused obviously to increase, simultaneously heat Q also by resistance and action time t impact, resistance is larger, action time t more long hair heat Q is more.Can find out that electric wire running temperature often rises from the document in aging test prediction insulating material life-span and will shorten 10% 10 DEG C of its serviceable lifes.This is due under heating status, while particularly high temperature action can make insulation course oxidation, decomposition, chain rupture, decompose hydrogen chloride and oxygen, acid-alkali salt etc. can make its conductor wrapped up constantly oxidized, corrosion resistance value is increased, conductor that is oxidized, corrosion can increase heating and react on insulation course when being energized, just in such vicious cycle, be that circuit constantly worsens, the probability of line short and electric leakage constantly rises, and the danger of breaking out of fire is also in continuous rising.Separately, soar in nonferrous metal price one road in recent years, and wire production cost thereupon straight line rises, in order to obtain stable even higher profit.The copper aluminium material material production electric wire inferior that part is cheap for sharp electric wire manufacturer of attempting brings into use.Copper aluminium material inferior mostly is coarse the melting down of old material and processes, or adds more inexpensive material to reduce wire cost in the original normal copper material used, or adopts copper-clad aluminum conductor (aluminum steel surface copper-clad paper tinsel or copper facing).Copper aluminium conductor resistance containing impurity can significantly increase, and current-carrying capacity can significantly reduce, and the wire thermal value when electric by same rated current with area also can obviously increase.Use the price of this electric wire of copper aluminium conductor manufacture of materials inferior obviously to reduce, thus ensure and improve the profit of electric wire factory, become to produce and cause a large amount of electric wires inferior to come into the market, thus leave disaster hidden-trouble.By conductor metallographic structure analysis, existence and the distribution situation of impurity can be found.
Substantially be all before coming into the market, carry out the quality monitoring of sampling observation formula in China to electric wire product, strong quality monitoring inspection is not all carried out to the particularly in-service electric wire after coming into the market.To use electric wire quality neither one science check and supervise technical method.
Summary of the invention
The object of the invention is to solve copper aluminum conductor in the electric wiring that above-mentioned prior art cannot detect or X alloy conductor and occur the defect of impurity or existence with low quality itself because of oxidation, corrosion, provide a kind of supervisory detection to come into the market and the analysis method for reliability of circuit conductor of electric wiring in use and the copper aluminum conductor of equipment and the security of the metallic conductor such as brass, aluminium conjunction.
An analysis method for reliability for circuit conductor, comprises the following steps:
(1) electric wiring of in use circuit and the copper aluminum conductor at equipment connection position and brass, aluminium alloy conductor is got as test analysis sample;
(2), Stereo microscope is used to carry out microscopic analysis to institute's sample thief;
(3), metaloscope is used institute's sample thief to be carried out to the microscopic analysis of metallographic structure;
(4), scanning electron microscope and power spectrum coupling technique is used to carry out electron microscopic and constituent content percentage analysis to institute's sample thief;
(5) the body formula of comprehensive conductor sample, metallographic structure, the percentage analysis of electron microscopic characteristic sum constituent content, judge whether metal conductor measured exists oxidation, corrosion and feature inferior, and whether quality of conducting electricity occurs downtrending or poor.
The present invention is extracted in by extracting suitable position on circuit in use the conductor sample running electric wire, the microscopic observation of body formula is carried out to the conductive surface of electric wire sample, metallographic structure analysis is carried out to conductor, can find that conductive surface uses aging because of long-time or melt adhesion or charing by the insulation course that heat effect causes, the defects such as conductive surface is corroded, also can find that conductor top layer or inside metallographic are because the long period is by thermal oxide preferably, corrode the metallurgical structure caused obviously grow up or comprise the features such as impurity, thus scientifically can analyze the situation judging whether circuit exists undesirable element or conductor and cancerated.By body formula, metallographic, micro-and the elemental composition percentage analysis method of scanning electron microscope and power spectrum, the body formula of testing running the metallic conductor in circuit is micro-, metallographic structure, scanning electron microscope microscopic features, and the elemental composition number percent of conductor, judge whether metal conductor measured exists aging to analyze, oxidation, corrosion characteristics or itself with low quality be a kind of scientific and effective method, for inferring whether conduction quality occurs downtrending, whether conductor quality is inferior, and for judging that the electric disaster hidden-trouble that whether exists running circuit provides scientific and technical foundation further.
Embodiment
For making the object, technical solutions and advantages of the present invention clearly, below technical scheme in the present invention be clearly and completely described, obviously, described embodiment is the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
In the qualification work of electrical fire material evidence with in analyzing with circuit marginal testing, technician can from the copper aluminum conductor of censorship or sampling observation and copper, the surperficial body formula of the conductor material of aluminium alloy is micro-, inside metallographic Electronic Speculum microcosmic and element percentage content, copper aluminum conductor or brass are found, aluminium alloy conductor is because of oxidation or corrosive attack or produce the oxide of faking and occurring, inorganic salt particle, the serious superelevation of impurity element degree, what have is exactly with the low-quality goods of the very large iron of resistance value for the copper of electric conductivity excellence, and because being subject to the features such as circuit abnormality heating functioin inside metallographic abnormal growth.The impure many toughness of copper aluminium conductor will be deteriorated in theory, and fragility becomes large, and electric conductivity is deteriorated, and resistance becomes large.Become with resistance and just can aggravate greatly copper aluminum conductor and brass, aluminium alloy conductor heating, cause accelerating the failure of insulation material layer to cause short circuit, electric leakage, cause electrical fire generation.Can, the technical data such as inside metallographic, section Electronic Speculum microcosmic and element percentage content micro-according to the surface of copper aluminum conductor and brass, aluminium alloy conductor, just can judge copper aluminum conductor and brass, aluminium alloy conductor oxidation, corrode, and the basic condition of the too high poorly conductive caused of impurity content.
Experimental technique:
That one, chooses Water demand is using electric wire copper aluminum conductor or the X alloy conductor sample of circuit;
Two, use that body formula is micro-, the technical data such as the body formula microscopic features at the electric wire copper aluminum conductor or X alloy conductor sample that use circuit, metallographic structure feature, electron-microscope scanning microscopic feature and element percentage content that metallographic examination, scanning electron microscope, spectroscopic technique test analysis have been chosen;
Three, according to body formula microscopic features, metallographic structure feature, the technical data such as electron-microscope scanning microscopic feature and element percentage content of metallic conductor, metal guide physical efficiency electric conductivity and the security of insulating material insulating property and disaster hidden-trouble analysis is carried out.
1, sample:
Choose copper aluminum conductor and the metallic conductor such as brass, the aluminium alloy sample at the position such as electric wiring and equipment connection of in use circuit.
2, body formula is analyzed:
Find in the embodiment using Stereo microscope to analyze acquired sample: obvious adhesion phenomenon has occurred for the insulation course of the sample had and wire, insulation course can not completely from conductor peel off, some sample part insulation course outside surfaces are substantially intact, inside surface and conductor generation focal adhesion, conductive surface has metallic luster, and oxidative phenomena is slight; There is obvious crack performance in the insulation course outside surface of part wire samples, inside surface and conductor generation focal adhesion, and obvious oxidation has appearred in conductive surface, and surface loses metallic luster; Some conductive surface also has insulating packing obviously to reunite, and the existing oxidation of conductive surface and evidence of corrosion feature, also should exist resistance and increase, during by larger current, may produce the fire risk of abnormal heating igniting flammable items.And cracking has appearred in electric wire insulation layer, illustrate that the physical and mechanical properties of the insulation course of wire samples and insulating property obviously decline, had the danger of breakdown initiation fire to exist.There are certain quality problems in these Problems existing all interpret sample place circuit, these problems probably become the key factor causing electrical fire.
3, metallographic microanalysis:
(1) carry out finding in the embodiment of metallographic examination to choosing conductor sample: the metallographic structure of sample segment in the sample chosen, or abnormal growth or containing impurity or occur cavity etc. defect; Sample segment fibr tissue disappears, and illustrates that occurring overcurrent for a long time or repeatedly exceeding stream fever phenomenon in use once appearred in circuit; The fibr tissue of segment conductor disappears, its metallographic structure obviously grow up for etc. tissue of pulling crystal, illustrate that overheated manifesting once appearred in circuit, namely this circuit have overload experience; There is impurity agglomeration in sample segment metallographic structure, this may increase the resistance value of electric wire, this to wire electric conductivity should be have dysgenic.There is a cavity in sample segment, this has harmful effect to the conduction of wire and mechanical property; Sample segment fibr tissue disappears, and metallographic structure is abnormal becomes large, illustrates that place circuit once occurred that the long period surpassed rated current.
(2) grafting sample is analyzed: can find out that from metallographic examination arcing can make to produce between the conductor of unlike material to ooze mutually, pass through metallographic examination, also the material situation of conductor roughly can be found out from metallographic structure feature, the metallographic structure of one of them wiring board socket sheet metal, its tissue signature is close to the metallographic structure of iron and steel, this situation illustrates that the ability and intelligence quality of this socket exists serious quality problems, owing to too much causing containing ferro element, copper content reduces, cause its poor electric conductivity, easily abnormal heating is there is during energising, there is the danger of initiation fire in wiring board in this wise.
4, sem energy spectrum analysis:
(1) choose in body formula and find out that insulation course and conductor have the sample of adhesion, or metallographic examination contain impurity, cavity, pore conductor sample carry out scanning electron microscope and power spectrum combination analysis.
Find in the analysis embodiment of selected sample by using scanning electron microscope: obvious cotton-shaped bur has appearred in part wire samples surface, for insulation course and wire there occurs aging adhesion, analysis result is consistent with the analysis of body formula, just there is white crystals particle in the more clear conductive line surfaces had of scanning electron microscope display, should be insulation course to come off, the inorganic filler of reuniting, illustrate that problem has appearred in this wire insulation quality, too many or the filler skewness in major ingredient of possible filler, there is etch pit or spot in part conductive line surfaces, illustrate that the electric conductivity of conductor has certain decline.
(2) by using power spectrum to find in the analysis embodiment of the conductor sample chosen: had wire samples to occur iron and aluminium element, wherein the degree of aluminium element is up to 13%, illustrates that this wire samples contains more aluminium impurity and a certain amount of iron contamination.The inserted sheet of wiring board sample and wire is had all to occur ferro element number in addition, the iron content of inserted sheet is up to 64%, the main body that this inserted sheet is described has been ferrous material, ferro element on wire should be when there is arcing, enter wire from inserted sheet, this socket can think a low-quality goods, use such socket wine to there is poorly conductive, it is overheated to there will be during use, and Long-Time Service can exist serious disaster hidden-trouble.
The present invention adopts body formula, metallographic, scanning electron microscope microtechnic and power spectrum element percentage can qualitative analysis preferably and confirmatory sample conductor and insulation course reliability containing quantitative analysis, has good corresponding relation between several technical method.By the summary checking identified actual Fire material evidence, confirm to use that body formula is micro-, metallography microscope, scanning electron microscope micro-analysis and power spectrum element percentage content analysis, the performance present situation of metallic conductor and insulating material sample and the trend of hydraulic performance decline can be analyzed by quantitative and semi-quantitative preferably.Above four kinds of methods combining are got up to analyze the technical data of metallic conductor in four, just can evaluate better and judge metallic conductor electrical safety, just can find that in the poor wire connection local pyrexia in electric appliance circuits, electric appliance circuits, conductor material inferior reduces the heating of conductive capability increase circuit, accelerated oxidation corrosion causes resistance to increase the danger causing the initiation fires such as heating further.If the present invention is also to use scanning electron microscope to carry out the tests such as homogeneity to dielectric filler material, at auxiliary use thermal infrared imager, on-the-spot abnormal heating mensuration is carried out to circuit, determine and choose test sample, just can analyze and judge the disaster hidden-trouble of electric wiring better, thus science and objective technique evaluation are made to the security of electric wiring.
Last it is noted that above embodiment is only in order to illustrate technical scheme of the present invention, be not intended to limit; Although with reference to previous embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that: it still can be modified to the technical scheme described in foregoing embodiments, or carries out equivalent replacement to wherein portion of techniques feature; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the spirit and scope of various embodiments of the present invention technical scheme.
Claims (1)
1. an analysis method for reliability for circuit conductor, is characterized in that, comprises the following steps:
(1) electric wiring of in use circuit and the copper aluminum conductor at equipment connection position and brass, aluminium alloy conductor is got as test analysis sample;
(2), Stereo microscope is used to carry out microscopic analysis to institute's sample thief;
(3), metaloscope is used institute's sample thief to be carried out to the microscopic analysis of metallographic structure;
(4), scanning electron microscope and power spectrum coupling technique is used to carry out electron microscopic and constituent content percentage analysis to institute's sample thief;
(5) the body formula of comprehensive conductor sample, metallographic structure, the percentage analysis of electron microscopic characteristic sum constituent content, judge whether metal conductor measured exists oxidation, corrosion and feature inferior, and whether quality of conducting electricity occurs downtrending or poor.
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| CN201510310302.3A CN105044105A (en) | 2015-06-08 | 2015-06-08 | Method for analyzing reliability of circuit conductor |
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| CN201510310302.3A CN105044105A (en) | 2015-06-08 | 2015-06-08 | Method for analyzing reliability of circuit conductor |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111665267A (en) * | 2020-06-16 | 2020-09-15 | 沈阳兴华航空电器有限责任公司 | Visual detection method for compression joint quality of pit-pressing type contact |
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| CN101726442A (en) * | 2008-10-24 | 2010-06-09 | 中国科学院金属研究所 | In situ evaluation system and method of reliability of thin-film materials on flexible electronic substrate |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111665267A (en) * | 2020-06-16 | 2020-09-15 | 沈阳兴华航空电器有限责任公司 | Visual detection method for compression joint quality of pit-pressing type contact |
| CN111665267B (en) * | 2020-06-16 | 2023-06-13 | 沈阳兴华航空电器有限责任公司 | Visual detection method for crimping quality of pit-press type contact |
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Address after: 610036 Sichuan Fire Research Institute, Ministry of Public Security, No. 69 Jinke South Road, Jinniu District, Chengdu City, Sichuan Province Applicant after: Sichuan Institute of Fire Protection, Ministry of Emergency Management Address before: 610036 Sichuan Fire Research Institute, Ministry of Public Security, No. 69 Jinke South Road, Jinniu District, Chengdu City, Sichuan Province Applicant before: Sichuan Fire Fighting Inst., Ministry of Public Safety |
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Application publication date: 20151111 |
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