Attached ferromagnetic coercimeter
The invention relates to the field of magnetic measurements of the coercive force of local areas of the product. Proposed attached ferromagnetic coercimeter containing U-shaped core with magnetizing and demagnetizing windings of the indicator element in the form of ferromagnetic cumulative counter and compares the device. The indicator element is designed in the form of two ferromagnetic cumulative counters with accumulation factors, changing in opposite directions of the elements mounted on the side bars of the U-shaped core, the outputs of which are connected with the input of the comparing device, and magnetizing, she demagnetizing coil is installed on the middle rod. The measured value is determined by the frequency difference between the ferromagnetic cumulative counters in comparing the device, which improves the measurement accuracy and sensitivity. 1 Il.
The invention relates to magnetic measurements, and can be used to measure the coercive force of local areas of the product.
Known side ferromagnetic coercimeter consisting of terrasond and attached to the solenoid . This device poses the te layer-by-layer quality control of heat treatment. The measurement process includes a pre-magnetization and smooth demagnetization. For measure the coercive force is accepted, the degaussing current, in which the useful signal in the measuring winding terrasond equal to zero.
The disadvantage of this side of the ferromagnetic coercimeter is that the indicator winding terrasond electromotive force is not zero in the absence of an external constant magnetic field, which leads to additional error.
Known side ferromagnetic coercimeter containing terrasond on the U-shaped core is used as the indicator element, the magnetizing and demagnetizing winding located on the jumpers core terrasond . U-shaped core terrasond and product form a closed magnetic circuit. On the rods core terrasond are winding through which the terminals periodically with a frequency doubled brought to saturation. On the jumpers placed the measuring winding - she magnetizing, which highlighted the useful signal by using a flat schema.
The disadvantage attached ferromagnetic coercimeter is that the value electoratewise force, reduces the measurement accuracy.
The prototype of the invention is attached ferromagnetic coercimeter  containing U-shaped core with magnetizing and demagnetizing winding, the indicator element in the form of at least one ferromagnetic cumulative counter and compares the device.
When the product is not magnetized, the frequency of the output signal of the indicator element takes a value of f1that after magnetization reaches a value of f2. Using a degaussing current adjusted value of the output frequency f2to the initial value f1at the output of the comparing device, the frequency is zero, the current razmahivanie if this is taken as a measure of the coercive force.
The disadvantage of the prototype is the lack of settings on the signal interference caused by the gap between the ends of the U-shaped core and products, which reduces the accuracy and sensitivity of measurements.
The present invention allows to obtain a new technical effect of improving the measurement accuracy and sensitivity.
This technical effect is achieved by the fact that the indicator element ferromagnetic cumulative counter consists of two ferromagnetic cumulative counters with the cylinder which are connected with the input of the comparing device, and magnetizing, she demagnetizing coil is installed on the middle rod.
The drawing shows a schematic side ferromagnetic coercimeter.
Attached ferromagnetic coercimeter contains a U-shaped core 1 placed thereon magnetizing and demagnetizing winding 2 and indicator elements 3 and 4, in the form of two ferromagnetic cumulative counters, with accumulation factors of opposite signs, located on the side rods of the core 1. The outputs of the indicator elements is connected to the input of the comparing device 5, and U-shaped core 1 and article 6 form a closed magnetic circuit.
Attached ferromagnetic coercimeter works as follows.
The gap between the ends of the core 1 and 6 product significantly affects the accuracy of the measurement and depends on the uniformity touch the ends of the U-shaped core 1 with the surface of the test object 6.
The magnetizing winding 2 is de-energized and the degaussing current is equal to zero, the indicator elements 3 and 4 have some originally established, the values of the coefficients of accumulation1and K2with indicator elements 3 and 4 are removed signals whose frequency is equal compliance and articles 6 different the value of f1and f2not equal among themselves. By setting the gap between the core 1 and article 6 achieve equality of these frequencies and as a result, the output signal of the comparison circuit is equal to zero
Article 6 of the part is subjected to application of short pulse current flowing through the magnetizing winding 2. At this time, the power supply and signal recording cumulative counters indicator elements 3 and 4 are disabled.
After magnetizing the residual induction of the product 6 creates a flux in the closed magnetic circuit through the core 1, the coefficients of accumulation of indicator elements 3 and 4 take the values of
K’1=K1-n and K’2=K2+n
where n is an integer.
Depending on the direction of the magnetic flux in the magnetic circuit core 1 and article 6 (which depends on the direction of the magnetizing field and the operation of the device is not affected) the integer n characterizing the change accumulation, has the sign + or -. The frequency of the output signal of the indicator elements 3 and 4 become respectively equal to
Thus, the frequency of the output signal of the indicator element 3 becomes larger by the value off, and the frequency of the recording.
The frequency difference indicator elements 3 and 4 from the output comparing device 5 is proportional to the magnitude of the residual induction of the tested part 6:
Since the coefficients of accumulation of indicator elements 3 and 4 are changed in opposite directions, the frequency differencef becomes twice that improves the sensitivity compared to the prototype.
For measuring the coercive force of the product 6 in the magnetizing winding 2 serves a current of reverse polarity.
If you increase the DC demagnetization in magnetic circuit core 1 and article 6 creates a magnetic flux in opposite directions. The coefficients of accumulation of indicator elements 3 and 4 are changed, closer to the original meaning. Accordingly, the frequency at the output of the comparison circuit.
The degaussing current value at which the frequency of the output signal of the comparison circuit takes the value of zero is taken as a measure of the coercive force.
The use of the invention allows the quality control of ferromagnetic products by two parameters: the magnetic induction and the coercive force. This increases the accuracy of reading of Semenov 3 and 4 in opposite directions makes it possible to increase the sensitivity of the measured parameters, accordingly, to increase the limits of measurement of the magnetic induction and the coercive force of the product 6.
Sources of information
1. The journal of nondestructive testing", 1972, No. 6, S. 21.
2. USSR author's certificate No. 407252, CL G 01 R 33/02, 09.07.71.
3. USSR author's certificate No. 834635, CL G 01 R 33/12 (prototype).
Attached ferromagnetic coercimeter containing U-shaped core with magnetizing and demagnetizing winding, the indicator element in the form of at least one ferromagnetic cumulative counter and compares the device, wherein the indicator element is designed in the form of two ferromagnetic cumulative counters with accumulation factors of opposite signs, mounted on the side bars of the U-shaped core, the outputs of which are connected with the input of the comparing device, and magnetizing, she demagnetizing coil is installed on the middle rod.
FIELD: measurement technology.
SUBSTANCE: cylindrical conductor with radius of r and specific conductivity of δ is connected to secondary winding of step-down transformer through reference resistor. Primary winding of step-down transformer is connected with ac generator with f frequency. Longitudinal resistance Z of tested cylindrical conductor is measured at 1-meter length section. Magnetic conductivity μ is determined from the relation of μ=(Z²r²υ)/(2f10‾7).
EFFECT: reduced labor-intensity due to measurement of conductor's resistance.
SUBSTANCE: device has magnetic system, pipe, made of non-magnetic material, portion of which is placed in magnetic field between end pieces of magnetic system, radio-frequency coil, electronic signals processing block, pressure sensor and temperature sensor, while portion of pipe which is positioned in magnetic field between poles of magnetic system, made with such a diameter, where conditions for realization of nuclear magnetic resonance are realized, i.e. relative change of magnetic induction in any direction within that volume does not exceed 10-3, radio-frequency coil, positioned between Faraday screens and connected to electronic signals processing block, is positioned coaxially inside central pipe portion in such a way that axes of inter-polar space of magnetic system and radiofrequency coil were positioned perpendicularly to each other, while center of coil constructively is positioned in the center of inter-polar space of magnetic system.
EFFECT: higher precision, higher efficiency, simplified construction, lesser dimensions and weight.
4 cl, 9 dwg
FIELD: measuring engineering.
SUBSTANCE: device comprises re-magnetizing winding made of two sections spaced at a distance equal to their radii. The winding comprises the additional compensating winding that is connected with the controllable DC power source and provided with a mechanism for control of magnetic axis. The measuring winding is wound on two frames arranged within the length of the specimen to be tested. The windings are connected with the input of the second amplifier. The magnetic axes of the windings are parallel. The voltage controller and the source of reference power have indicators of the amplitude of the re-magnetizing field and value of the field of remagnetization.
EFFECT: enhanced accuracy of measuring.
FIELD: engineering of magnetic-force scanning probing microscopes, possible use for measuring local magnetic characteristics of a sample with nanometer resolution in external magnetic field.
SUBSTANCE: in accordance to invention, magnetic-force microscope with variable magnet contains control block, probe indicator holder with probe indicator and sample holder, mounted with possible mutual movement, and also variable magnet, including measuring duct with polar end pieces. At least one polar end piece is spatially separated from magnetic duct. In accordance to one variant of invention realization, spatially separated polar end piece is built into sample holder, while another polar end piece is mounted so, that probe indicator is positioned between polar end pieces. In accordance to another variant, both polar end pieces are built into sample holder, while both polar end pieces are spatially separated from magnetic duct.
EFFECT: increased resolution of magnetic-force scanning probing microscope with variable magnet.
3 cl, 2 dwg
FIELD: measurement technology.
SUBSTANCE: method involves determining magnitude and angle of longitudinal resistance to conductor Z under study. The magnetic permeability is determined from relation μ=(Z2r2σ/2f10-7)e-j*2(45-φ).
EFFECT: high accuracy of measurement.
FIELD: magnetic measurements.
SUBSTANCE: structurescopy method can be used for investigation of physical properties of materials as well as of their structure and composition. Method is based upon detection of crystalline nano-phase in amorphous array of nano-crystalline material; for the purpose parameters of Barkhauzen' jumps are used. Method concludes in re-magnetization of checked material by variable magnetic field, in registration of Barkhauzen's jumps, on measurement of their parameters and in judgment on structure of material on base of characteristics of the parameters. Checked material is re-magnetized locally by variable magnetic field with frequency of 10 kHz. Oscillogram of envelope of flow of Barkhauzen's jumps is taken as measured parameter received from primary converter. Shape of oscillogram is used to judge on presence of crystalline nano-phase in amorphous array of nano-crystalline material. According to preferable version of manufacture, local re-magnetization is carried out by attached primary converter.
EFFECT: improved reliability of measurement of parameters.
2 cl, 4 dwg
FIELD: physical-chemical research of solid, liquid and gaseous samples of materials.
SUBSTANCE: device for detecting and measuring magnetic penetrability μor relative magnetic penetrability μr, or relative magnetic susceptibility (μr-1) of sample contains sample chamber and at least two inductance coils, where aforementioned two coils surround aforementioned chamber for samples, and aforementioned chamber for samples has at least one aperture for insertion of sample or vessel for samples which contains a sample, where aforementioned device is also provided with an electric circuit, which measures the difference in inductance between two coils.
EFFECT: increased sensitivity of detector.
2 cl, 2 dwg
FIELD: processes for heat treatment of cast iron parts with spheroidal graphite.
SUBSTANCE: method comprises steps of testing initial structure by means of coercive force meter and selecting heat treatment modes on base of testing results. Parts are subjected to austenization at 880 - 930°C; interim cooling of parts in furnace till temperature in range Ar3 - Ar1 ; cooling at rate 5 -10°C per minute till temperature in range between temperature of starting A - P conversion and temperature exceeding by 50°C maximum-stability of temperature of austenite being converted to upper bainite or troostite. Then part is subjected to isothermal soaking at such temperature till maximally possible degree of A - P conversion. After cooling structure is inspected by means of coercive force meter for detecting tendency of pearlite and tempered bainite to changes at further nitriding. Depending upon inspection results tempering mode is selected and after such tempering final testing of structure by means of coercive force meter is realized according to index values of scale developed on base of investigating relationship of readings of coercive force meter from initial structure and its changes at nitriding process and also from growth and warping of parts at nitriding.
EFFECT: possibility for producing stable structure resistant against changes at nitriding process.
2 cl, 1 ex
FIELD: non-destructive testing.
SUBSTANCE: coil inductance is measured together with cylindrical samples having the length ls five times more than their diameter ds(Lc.s. ). then the samples are removed from the coil and the coil inductance is measured in the ambient air (Lc.a.), the magnetic permeability of chosen zone material μs= Lc.s./ Lc.a. is determined; the sample electrical Rs resistance is measured and its material conductivity σ is calculated by formula σs=4ls/πRs(ds)2 at that beforehand the transducer is affixed to the particular zone, the inductance of the transducer with the part Lp is measured and using the value of transducer ambient air inductance La the conditional part magnetic permeability in chosen zone is calculated by formula μp.c..=Lp/La then the correction coefficient is calculated by formula Kμ=μs /μp.c.. After that transducer is affixed to the zones of remaining i parts of the lot and Lpi is measured; then the zone conditional part magnetic permeability of every i-th part of the lot μp.c.i =Lp.i/La is calculated and magnetic permeability μp.i = μp.c.i.Kμ is determined. In addition in the chosen zone of entire parts on the base equal to ls and on a frequency of ωs.=l/π(ds)2μs σs the electrical resistance Rp is measured in the layer with thickness ds; the conditional specific conductivity of the particular zone.
EFFECT: SUBSTANCE: σc=ls/2Rp(ds)2 and the correction coefficient Kσ=σs/ σc are calculated For the remaining parts of the lot as well as for parts used in the articles in the same zones on the base ls and on the same frequency of ωs the Rpi is measured and σci is calculated, then the zone specific conductivity of every i-th part is determined by formula σip=Kσσci.
EFFECT: development of the effective express method of magnetic permeability and non-destructive testing of specific conductivity in parts particular zones.
SUBSTANCE: invention pertains to measurement of alternating magnetic values and magnetic properties of samples and products and can be used for determining coercive force of ferromagnetic materials. The add-on device of the coersimeter consists of a magnetising element and a magnetometric unit with magnetic field measuring device. The magnetising element is autonomous, rigid or hinged to the magnetometric unit. The device is made with provision for displacement relative the controlled product in the direction from the magnetometric unit to the magnetising element.
EFFECT: wider functional capabilities of the device; lowering of its power consumption; increased efficiency of control and documentation of the measuring results.
15 cl, 9 dwg