Method to analyse coated electrodes

FIELD: electrical engineering.

SUBSTANCE: reliability of repeated arc firing is estimated, in analysing coated electrodes, proceeding from actual conductivity magnitude defined in contact between flowed end face of interconnected electrode under analysis and metal plate. Obtained magnitudes of actual conductivity allow estimating reliability of repeated firing. Higher the conductivity, higher reliability of repeated firing.

EFFECT: higher accuracy of estimation.

1 dwg, 2 tbl

 

The invention relates to the field of welding, in particular for arc welding with coated electrodes, and can be used when creating new covered electrodes.

The known method of expert assessment of the nature of re-ignition of the arc when the circuit electrode on the product (Bulat AV quality Assessment of electrodes/ Welding production. 2000, No. 11. - P.45-49). The method consists in the following. Pre-selected benchmark to compare the nature of the re-ignition of the arc. Several authoritative experts compare the nature of the re-ignition of the test electrode and the reference. Qualitative comparative assessment proposed the following: better than standard level benchmark worse than benchmark worse than benchmark. The following evaluation criteria when compared with the standard: better than benchmark and benchmark - ignition instant after complete cooling of the electrode without destroying bulocki formed on the end face of the electrode; worse than standard ignition instant after a short break (10-30 s) in the arc without destroying bulocki; much worse than standard ignition delayed after a short break (10-30 s) in the arc and the complete destruction of volacci.

The disadvantages of this method are: despite the entered criteria of the nature of the re-ignition of the arc assessment is qualities is authorized and subjective; since the known method is not quantitative criteria (assessment only in points), it does not allow full use of mathematical methods for selecting a coating composition of the electrodes.

The closest way to the same destination to the claimed invention on the totality of symptoms is the way to determine the reliability of re-ignition of the arc (Belov, Y.M., Satchels A.A. ABOUT choosing ways to improve the re-ignition of the arc // Electrode production on the threshold of the new Millennium. Collection of materials of scientific-technical seminar. May 2000. - P.106-110), adopted by the authors for the prototype, which consists in the fact that the estimate produced by the conductivity of the electrode coating, determined by calculation depending on the components of the coating. Known in the technical literature data re-ignition of the arc is largely determined by the content in coating of titanium dioxide and iron powder. The more coverage of these components, the more reliable re-ignition. This is related to the fact that when a high content of titanium dioxide and iron powder conductivity of the coating increases. The electrodes with the content of titanium dioxide is about 10% and iron powder (about 10-15% arc will not be re-lit without destroying the sleeve on the end face of the electrode.

Weeks is the action known way, taken as a prototype, is the low accuracy of estimation of reliability of re-ignition of the arc, as it does not take into account the influence of all of the components in the coating of the electrodes, and ignores the fact that the reliability of re-ignition is determined by the conductivity of the coating and not the liquid melt and solidified at the end of the electrode and the inner surface of the sleeve oxide film or a slag crust. In addition, the conductivity is estimated by calculation according to the technical literature data (in General, these data on the electrical conductivity of the slag melts), which is not enough for effective evaluation.

The task to be solved by the invention, is to improve the accuracy of estimating the reliability of re-ignition of the arc, depending on the composition of the coating components and manufacturing techniques electrodes.

The problem is solved due to the fact that in the known method of estimating the reliability of re-ignition of the arc when welding with coated electrodes, the reliability is determined by the value of electrical conductivity between the melted during welding an end face of the electrode and the product is installed in contact, at the same time, the higher the conductivity, the higher the reliability.

The invention consists in the following. The electrode after welding has stopped, and full cooling is (or without cooling) establish a special tripod, close to the product and determine the conductivity of the contact between the welded metal and the melted end of the electrode, and the largest found conductivity make a conclusion about the reliability of re-ignition. The higher the conductivity, the higher the reliability of re-ignition. Specific conductivity includes conductivity sleeve cover electrode and solidified slag on the inner wall of the sleeve. If the sleeve is not formed, is determined by the conductivity of the oxide film and solidified slag located on the charred end of the electrode.

The difference of the proposed method from the prototype method is that the reliability is determined by the value of electrical conductivity between the melted during welding an end face of the electrode and the product is installed in contact, at the same time, the higher the conductivity, the higher the reliability. This allows to take into account the influence of all components included in the coating composition of the electrode. To determine the actual conductivity at the end of the electrode that provides a sufficiently high accuracy evaluation of the re-ignition of the arc.

The proposed method is illustrated by a drawing, which shows a diagram of the research facility.

Implementation of the proposed method of assessment re-ignition of the arc can be shown by following the respective example.

The investigated electrode 1 after melting pinched vertically on a tripod, with melted edge rested against the metal plate 2 (see drawing). On the other end of the electrode 1 hook clamp with wire, and was supplied "+" source, and a metal plate "-" from the power source (rectifier national Department of standardization 1M). In the circuit consisted of two R1shunt resistance 39 kω each, one parallel circuit of the electrode 1, the other consistently. In a parallel circuit resistance was ammeter And 50 μa with RAthe internal resistance of 2 kω.

After electrical circuitry has been completely assembled, the included power supply with rectifier, and was energised. The voltage gradually increased from zero. At a certain value of the voltage needle of the microammeter started to deviate. By adjusting the power supply needle of the microammeter recorded within 10-20 μa and recorded the readings of the voltmeter on the power supply and microammeter. Thus measured, all the studied electrodes. We then conducted the calculation of the conductance 1/Rxto contact "face melted electrode metal plate".

Were investigated electrodes of production of JSC "Uralhimmontazh" Perm type e-46 brand Mr-3 GOST 9466-75, GOST 9467-75, THE 36.23.25-007-90 and the electrodes of production FOR SIBES" Tyumen licensed ESAB (ISO 2560: E43 3R11) type uh-46A brand OK-46 GOST 9466-75, GOST 9467-75 and experimental electrodes ELUR with the following composition table 1. The calculated value of the electric conductivity of the melted end of the experimental electrodes are given in table 2.

Table 1
The coating composition of the experimental electrodes, wt.%
No. e YesSiMnMicaFeTiGraphiteMarble
11015329
218151015
322122112
46122212

<>
Table 2
Calculated values of the electric conductivity of the melted end of the experimental electrodes
Electrode1/Rx, 1/Mω1/Rxcp, 1/Mω
12345
Mr-30,006380,022190,027370,028510,024140,10859
OK-460,051330,025654,464290,029320,039114,60970
No. 10,413560,205970,187160,275030,285631,36736
No. 20,015390,08217 0,034210,137120,102770,37166
No. 30,017960,068450,082170,205970,025650,40020
No. 40,413560,257730,235520,286530,344231,53758

The proposed method determines the actual conductivity of the contact face of the electrode and products, allows to take into account the influence of all components included in the coating composition of the electrode, therefore, provides a sufficiently high accuracy of estimation of reliability of re-ignition of the arc, depending on the composition of the coating components and manufacturing techniques electrodes.

The method of study covered electrodes, including the assessment of the reliability of the re-ignition of the arc during welding, characterized in that the reliability of re-ignition of the arc is done according to the actual value of the conductivity, which is determined by the contact between the melted end of the investigated electrode and the metal plate, collected in El is stricescu chain.



 

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12 cl, 3 dwg, 1 tbl, 1 ex

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