GOST 12119.3-98
GOST 12119.3−98 electrotechnical Steel. Methods for determining magnetic and electrical properties. Method of measuring coercive force in open magnetic circuit
GOST 12119.3−98
Group B39
INTERSTATE STANDARD
Electrotechnical steel
METHODS FOR DETERMINING MAGNETIC AND ELECTRICAL PROPERTIES
Method of measuring coercive force in open magnetic circuit
Electrical steel. Methods of test for magnetic and electrical properties.
Method for measurement of coercivity in broken magnetic circuit
ISS 77.040.20
AXTU 0909
Date of introduction 1999−07−01
Preface
1 DEVELOPED by the Russian Federation, the Interstate technical Committee for standardization MTK 120 «steel Products from ferrous metals and alloys"
INTRODUCED by Gosstandart of Russia
2 ADOPTED by the Interstate Council for standardization, Metrology and certification (minutes N 13 dated 28 may 1998)
The adoption voted:
The name of the state |
The name of the national authority for standardization |
| The Republic Of Azerbaijan | Azgosstandart |
| The Republic Of Armenia | Armastajad |
| The Republic Of Belarus | Gosstandart Of Belarus |
| Kyrgyz Republic | Kyrgyzstandart |
| Russian Federation | Gosstandart Of Russia |
| The Republic Of Tajikistan | Tajikistandart |
| Turkmenistan | The main state inspection of Turkmenistan |
| The Republic Of Uzbekistan | Standards |
| Ukraine | Gosstandart Of Ukraine |
3 Resolution of the State Committee of the Russian Federation for standardization and Metrology dated December 8, 1998 N 437 inter-state standard GOST 12119.3−98 introduced directly as state standard of the Russian Federation from July 1, 1999
4 REPLACE GOST 12119−80 in section 3
5 REISSUE
1 Scope
This standard specifies a method for determining the coercive force in open magnetic circuit with maximum magnetic field strength corresponding to the limit of static magnetic hysteresis loop.
2 Normative references
The present standard features references to the following standards:
GOST 8.377−80 State system for ensuring the uniformity of measurements. The soft magnetic materials. Methods of measurement in the determination of static magnetic characteristics
GOST 8711−93 Devices showing analog electrical measuring direct action and auxiliary parts to them. Part 2. Special requirements for ammeters and voltmeters
GOST 12119.0−98 electrotechnical Steel. Methods for determining magnetic and electrical properties. General requirements
GOST 23737−79 measure of electrical resistance. General specifications
3 General requirements
General requirements for methods of tests GOST 12119.0.
Terms used in this standard — GOST 12119.0.
4 Preparation of samples for testing
Samples for testing are made of strips or solid rods. The ratio of the length of the sample by the square root of the cross sectional area shall not be less than ten.
5 Used equipment
5.1 Install. Installation diagram is shown in figure 1.
Figure 1 — Scheme for measurements in an open magnetic circuit
Figure 1 — Scheme for measurements in an open magnetic circuit
5.1.1 Ammeter to measure DC current and subsequent determination of the magnetic field must have a range from 15 mA to 15 A, accuracy class not less than 0.2 according to GOST 8711.
Use a DC voltmeter with a resistor.
5.1.2 the Ballistic galvanometer And measurement of the magnetic flux must have the period of natural oscillations of at least 15; intermittent, close to critical; sensitivity of at least 100 cases/DHS; the category of the constancy of the zero position is not greater than one.
Use of ballistic galvanometer with a shunt, magneto or electronic integrating fluxmeter to measure magnetic flux of 0.1 to 10.0 MVB with an accuracy within ±1%; webartery with voltage dividers to expand the limits of measurement and (or) receiving of the samples is numerically equal to the amplitude of the magnetic induction in the sample.
5.1.3 Resistor for modulating the current in interval from 2 mA to 15 A with a resolution of 0.1%.
5.1.4 stores the resistance and
to adjust the sensitivity and the mode of the galvanometer should have a range from 0.1 Ohms to 10 ohms, accuracy class not less than 0.2 churchyard 23737.
5.1.5 the Solenoid winding I to the magnetization of the samples shall conform to the requirements of GOST 8.377.
5.1.6 Winding II to determine the coercive force should be made in the form of measuring a movable coil encompassing the sample. The number of turns of the coil must be such that the indication of the galvanometer and fluxmeter that corresponds to the maximum change of the magnetic flux in the sample was not less than 70% of the upper limit of measurement. The ratio of sample length to the length of the winding should be not less than three.
5.1.7 the power Source for magnetization of the sample should provide a constant output voltage not less than 20 V, the change of the magnetizing current is not more than 0.2% per minute, the ratio of the amplitude of the variable component of the output voltage to the DC component is not more than 0.05%. In magnetic field of more than 5 vehicles allowed increase in the ratio of 0.1%. You may use a DC regulator.
6 Preparation for measurements
The magnetizing current And a corresponding specified value of magnetic field intensity
, A/m, is calculated by the formula
where — a constant of solenoid, m
.
7 procedures for measuring
7.1 the Measurement of coercive force based on the pulse-induction method.
7.2 the Sample with the measuring coil placed in the Central part of the solenoid, put the switch in position 1, close the key
(see figure 1).
7.3 Install a resistor in the solenoid magnetizing current corresponding to the intensity of magnetic fields, sufficient for technical saturation of the sample material.
7.4 Smoothly reduce current to the value calculated by the formula (1) for the magnetic field intensity 20 A/m.
Switch off the current and set the maximum resistance of the resistor
.
7.5 Switch change (relative to initial) direction of the current and write down its value
. The field strength at this current value must be less than the coercive force.
Dropped from the sample coil and determine the indication of the galvanometer , del.
7.6 Repeat the operation at the 7.4, 7.5, gradually increasing magnetizing current. Define the positive deflection of the galvanometer relative to the source and negative
if the value of the current
.
7.7 the measurements of the coil must not leave the area of uniform field of the solenoid, then its initial and final position needs to be fixed, and the end position must be outside the field of the sample.
8 Rules for processing results of measurements
8.1 Coercivity , A/m, is calculated by the formula
where - a constant of solenoid, m
;
the value of the current that correspond to values of the indications of the galvanometer
, and a
, A.
8.2 the Error of measurement of the coercive force should not go beyond ±3%.
The text of the document is verified by:
the official publication of the
Electrotechnical steel.
Specifications. Methods of analysis:
SB. Standards. -
M.: IPK Publishing house of standards, 2003
