CN104076065A - Online detection device for variation of metal melt structure caused by ultrasonic preprocessing - Google Patents
Online detection device for variation of metal melt structure caused by ultrasonic preprocessing Download PDFInfo
- Publication number
- CN104076065A CN104076065A CN201410143445.5A CN201410143445A CN104076065A CN 104076065 A CN104076065 A CN 104076065A CN 201410143445 A CN201410143445 A CN 201410143445A CN 104076065 A CN104076065 A CN 104076065A
- Authority
- CN
- China
- Prior art keywords
- ultrasonic
- melt
- metal bath
- resistance
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Abstract
The invention belongs to the technical field of the material science, and particularly relates to an online detection device for variation of a metal melt structure caused by the ultrasonic preprocessing. The detection device comprises a heating heat preserving system, a metal melt storage unit, a power ultrasonic system, a melt resistor or a resistivity detection system, a melt temperature signal collection system, a data collection and processing system and the like. By adopting the detection device, the metal melt structure variation caused by the ultrasonic can be detected and represented by utilizing a variable quantity delta r of physical parameters-resistance parameters of structure sensitivity, so that the insulation problem of a power ultrasonic lead-in pole can be successfully solved, the influence on an ultrasonic bar caused by utilizing a voltammetry to measure the resistance of ultrasonic metal melt can be overcome, the real-time, synchronous, continuous and high-precision automatic collection and processing of the resistance and temperature data can be realized by utilizing the advanced electronic measurement technology and computer technology, and the precise measurement can be realized by adopting a double-electrode method and a four-electrode method.
Description
Technical field
The invention belongs to materials science field, be specifically related to a kind of ultrasonic pre-service and cause the on-line measuring device that melt structure changes.
Background technology
The key that behavior is solidified in control is to control the nucleation process of metal bath.All methods that can improve nucleation rate all can realize the refinement of solidified structure.Melt pretreatment can change melt structure, improves nucleation rate, is therefore the common method that realizes as-cast structure refinement.The outfield pre-service refinement of metal bath is to promote homogeneous nucleation to realize the process of refinement, one of its mechanism be by change melt structure dynamic fluctuating equilibrium state with improve nucleation rate, that is to say, outfield apply the short range order structure that has changed metal bath, thereby realize refinement.
For the investigation of the thinning effect of melt pretreatment technique, generally optimize pretreatment process method and technical parameter scope by the relation of setting up between parameter of pre-treatment process and solidified structure.The problem of its existence is that pretreating effect is investigated and had hysteresis quality and a uncontinuity, the test period long, and cannot carry out whole process investigation to preprocessing process.In addition, as previously mentioned, melt pretreatment thinning effect is to change with melt structure the nucleation rate causing to change relevant in itself, and different melt pretreatment technique may cause the identical thinning effect that solidifies, be that pretreating process condition and melt structure may not be certain be single valued relation, and in the time that cooling condition is consistent, melt structure and nucleation rate and solidify thinning effect and but have single-valued relationship.Therefore, if can the variation of melt structure be investigated in real time, thereby set up the relation between melt structure and thinning effect, so as long as investigate the melt structure varied journey system that pretreatment condition obtains, i.e. measurable corresponding thinning effect.So not only can shorten the process optimization test period, and can make process optimization more become more meticulous.But, metal bath is mostly in the condition of high temperature, very difficult with detection to the experimental study of high-temperature metal melt, causes people more shallow to the cognition of metal bath, therefore the characterizing method, melt structure being quantitatively described and detection method thereof are one of focuses of research.
For the detection of melt structure, mainly contain directly and indirect test method.Direct-detection is to adopt the technology such as X-ray diffraction, neutron diffraction, synchronous radiation of light source, the absorption of Extended X-ray fine structure directly metal bath to be detected, can obtain the structural parameters information of liquid metal according to diffracted intensity, wherein most importantly obtain the radial distribution function of atomic distribution functions, thereby calculate the melt structure of metal, but, adopt spectrum diffraction direct-detection in experimental technique, but to have many difficulties, cause and be difficult to obtain accurately reliable, repeatable high detection data.To be metal bath there is at spectrum diffraction vertical direction the thickness that is difficult to avoid to its main difficulty is the film of tens microns, simultaneously also must sample chamber in vacuum or inflation environment with air insulated, ray enters by the window of sample chamber.For metal bath sample oxidizable or that vapor pressure is higher, diffraction result is difficult to get rid of sedimental impact on oxide film and diffraction window, therefore, detects data repeatable poor.The more important thing is, the direct diffraction of ray detects not only equipment complexity, and its spectral line must be through loaded down with trivial details data processing, is therefore difficult to realize continuously and detects in real time.
From statistical thermodynamics angle, the variation of melt micromechanism must cause the variation of macroscopic thermodynamics character, also must cause the variation of the physical property of metal bath, and the physical property of metal bath and the structure factor of melt are closely related.Resistance is the responsive physical quantity of melt structure, is also the physical quantity the most easily detecting in physical properties of melt.According to Ziman resistance theory, the resistivity of metal bath is the function of structure factor.Resistance measurement can be inferred indirectly from electronics level the structural change of research metal bath, and compared with additive method, electric-resistivity method can provide the more information about shortrange order aspect simultaneously.Therefore, process by studying additional physical field the resistance variations that metal bath causes, can characterize the melt structure variation that additional physical field causes, and then set up the resistance variations of metal bath and solidify the relation between thinning effect.Although relevant liquid metals is tested to study melt structure by resistance measurement and has been obtained many progress, but correlative study mainly concentrates on melt state changes impact on melt structure with composition, rarely has the resistance characterization method of additional physical field on melt structure impact and the research of detection method.
Because ultrasound wave is in the time that liquid medium is propagated, can produce cavitation effect, acoustic streaming effect and thermal effect, these nonlinear effects can cause liquid medium to produce series of physical or chemical change.Large quantity research shows, applies significantly its solidified structure of refinement of ultrasonic field in metal or alloy molten condition or process of setting, is one of most effectual way improving metal material mechanical property.Proposition can accurately characterize and ultrasonicly causes the conductive parameters that melt structure changes and realize it and facilitate Measurement accuracy, to the ultrasonic pretreating process optimization of metal bath and the equal tool of the research of Refining Mechanism is of great significance.
Metal bath resistance measurement method mainly contains Rotational magnetic field method (indirect method) and improves one's methods, and direct current four electrode method or improvement four electrode method (direct method).The former utilizes coil to produce the eddy current that alternating magnetic field produces in melt, and eddy current produces reversed magnetic field changes coil virtual impedance.Complete and the unique variation of reacting melt impedance of this variation.But owing to detecting the phase mutual interference with ultrasonic and mechanism with alternating magnetic field, indirect method cannot realize the ultrasonic accurate detection that causes metal bath resistance variations, and ultrasonic importing often adopts the ultrasonic bar of metal in metal bath, therefore, conventional DC four electrode method also cannot be got rid of ultrasonic bar and conducts electricity the interference causing.
Summary of the invention
The problem existing for prior art, the invention provides a kind of ultrasonic pre-service and cause the on-line measuring device that melt structure changes, this device can in metal bath preprocessing process and ultrasonic processing after whole stroke in resistance or resistivity over time rule carry out in real time, online, continuous detection, by the resistance or the resistivity-time curve that obtain, acquisition can characterize resistance or change in resistance amount and the variable quantity situation over time that melt structure that ultrasonic processing causes changes, thereby the power of the ultrasonic processing of accurate evaluation, the technology condition such as processing time and treatment temperature melt structure is changed and the stability of the unstable state structure that obtains affect rule, thereby the tissue to the applicable casting time of this melt and after solidifying is predicted.
The ultrasonic device that causes metal bath increased resistance value of detection of the present invention, comprises heating and thermal insulation system, metal bath storage unit, power ultrasonic system, melt resistance or resistivity detection system, melt temperature signal acquiring system and data Collection & Processing System; Wherein, described heating and thermal insulation system is by box resistance heated holding furnace and the phase composition of resistance heated holding furnace temperature control cabinet, described metal bath storage unit is placed in resistance heated holding furnace, offer two electrode patchholes and ultrasonic importing bar patchhole, electrode patchhole and ultrasonic importing bar patchhole are connected by a horizontally disposed circular hole, and metal bath is stored in the space that electrode patchhole, ultrasonic importing bar patchhole and horizontally disposed circular hole form; Described power ultrasonic system imports bar by ultrasonic generator, ultrasonic transducer and ultrasonic amplitude of fluctuation and forms, ultrasonic generator is connected with ultrasonic transducer, ultrasonic transducer imports bar with ultrasonic amplitude of fluctuation and is connected, ultrasonic amplitude of fluctuation imports in the ultrasonic importing bar patchhole of bar insertion metal bath storage unit, contacts with metal bath; Described melt resistance detection system is made up of resistance meter, potential electrode and connection wire, one end electrode insertion patchhole of potential electrode, and the other end is connected with resistance meter; Described melt temperature signal acquiring system is made up of temperature thermocouple and temperature analog signal acquisition tables, and melt inside is inserted in temperature thermocouple one end, and one end is connected with temperature analog signal acquisition tables; Resistance meter is connected with data Collection & Processing System with melt temperature signal acquiring system respectively with temperature analog signal acquisition tables.
Wherein, the rated power of described resistance heated holding furnace and resistance heated holding furnace temperature control cabinet is 12kW, rated voltage is 380V, the power supply of employing three-phase supply, temperature-controlled precision is ± 2 DEG C, covers the corresponding preformed hole in position offering with metal bath storage unit hole on resistance heated holding furnace.
The fire resistive material that the bonding agent that what described metal bath storage unit was 97wt% by massfraction the have magnesia casting material MgO of different grain size and massfraction is 3wt% mixes, or alumina silica refractory, through high pressure ramming and be prepared from high-temperature calcination; Two electrode patchholes of described metal bath storage unit are straight down symmetrical, and ultrasonic importing bar patchhole is the vertical circular hole between two electrodes insert in the hole, and the degree of depth of described ultrasonic importing bar patchhole is 4/5 of the electrode patchhole degree of depth.
The part surface spraying that described ultrasonic amplitude of fluctuation importing bar contacts with metal bath has the insulating coating that resistance to metal bath corrodes, and insulating coating kind is ZrO
2-CaO, ZrO
2-MgO, ZrO
2-Y
2o
3or ZrO
2-CeO
2.
The Measurement Resolution of described resistance meter is 1 μ Ω or 0.1 μ Ω, and has RS232 interface.
The quantity of described potential electrode is 2 or 4, 2 potential electrode are inserted respectively two electrode patchholes, the electric current of resistance meter is all connected with same electrode with voltage port, or 4 potential electrode be divided into two pairs respectively electrode insertion insert in the hole, the electric current port of resistance meter be connected away from two electrodes of ultrasonic importing bar patchhole one side, voltage port is connected away from two electrodes of ultrasonic importing bar patchhole one side with close, potential electrode is molybdenum bar, tungsten bar, iron staff or copper rod, potential electrode is exposed to the above part of metal bath surface and all adopts high temperature oxidation resisting coating or jacket protection.
Described temperature thermocouple is K type thermopair, imports bar patchhole be inserted in metal bath from the ultrasonic amplitude of fluctuation of metal bath storage unit, and described temperature analog signal acquisition tables is the digital displaying temperature table with RS485 or RS232 communication interface.
Described data Collection & Processing System is made up of the acquisition software of the computer hardware with AD/DA high-speed data acquisition card and real-time continuous demonstration and memory resistor and temperature data, and data collecting card is connected with the RS-485 interface of resistance meter interface and temperature analog signal acquisition tables.
Described metal bath is simple metal melt or alloying metal melt.
The on-line measuring device that adopts ultrasonic pre-service of the present invention to cause melt structure variation detects the ultrasonic method that causes melt structure variation to carry out according to following steps:
(1) potential electrode is inserted in the hole along the preformed hole electrode insertion of resistance heated holding furnace upper cover, until electrode contact to electrode patchhole bottom and be fixed, connects and detects loop;
Temperature thermocouple is imported to bar patchhole from ultrasonic amplitude of fluctuation to be inserted into horizontally disposed center of circular hole position and to fix;
Ultrasonic amplitude of fluctuation is imported to bar and import bar patchhole by ultrasonic amplitude of fluctuation and be inserted into and belong to storage melt unit, and be placed in horizontally disposed circular hole top;
Resistance heated holding furnace is heated up and is preheated to the temperature of fusion of metal to be measured, open holding furnace upper cover, the alloy melt that is heated in advance above 150～250 DEG C of liquidus curve is poured in metal bath storage unit, until metal bath liquid level reaches apart from storage unit 10mm suitable for reading, again cover bell;
(2) open computer system move acquisition software, the ultrasonic power of ultrasonic generator is adjusted to desired value, regulating resistance heating and thermal insulation furnace temperature, until metal bath temperature stabilization is in temperature T to be measured, and is at least incubated 30min;
(3) the melt temperature T and the resistance value R that obtain when acquisition software
0or electricalresistivityρ
okept constant, temperature fluctuation range be less than ± 1 DEG C, when be less than ± 1 μ Ω of resistance value fluctuation range, open ultrasonic generator metal bath is applied to ultrasonic field, and keep apply state until set application time point Δ t
0turn-off immediately ultrasonic generator, stop ultrasonic applying, after applying ultrasonic end, ultrasonic amplitude of fluctuation importing bar does not shift out ultrasonic amplitude of fluctuation importing bar patchhole, keep computer system to continue image data, apply ultrasonic time numerical value before until the resistance value of metal solution to be measured or resistivity value revert to, and more than keeping 15-20min, then preserve image data file;
(4) gathered data file is depicted as to metal bath resistance R R (t) function curve diagram that t changes in time, or electricalresistivityρ's ρ (t) function curve diagram that t changes in time, obtain the Δ R of this alloy melt under temperature T and ultrasonic treatment conditions by R (t) function curve diagram, Δ r, Δ t
0, Δ t
1, Δ t
2with Δ t, wherein Δ R representative apply ultrasonic during, detect the resistance of the metal bath obtaining with respect to R
0transient changing amount, Δ r representative stop applying ultrasonic after, the resistance value that metal bath still retains is with respect to R
0lasting variable quantity, Δ t
1representing the time span that Δ r remains unchanged, is ultrasonic metastable structure stationary phase or ultrasonic optimum phase, the Δ t of breeding of causing
2representing that Δ r diminishes gradually until be 0 time span, is ultrasonic metastable structure rehabilitation period or the ultrasonic degradation period that breeds of causing, Δ t=Δ t
1+ Δ t
2that after ultrasonic stopping, what melt structure changed retains the stage, is called the ultrasonic metastable structure that causes and retains phase or the ultrasonic term of validity that breeds;
Obtain this alloy melt under temperature T and ultrasonic treatment conditions by ρ (t) function curve diagram, Δ ρ, Δ t
0, Δ t
1, Δ t
2with Δ t, wherein Δ ρ ' representative apply ultrasonic during, detect the resistivity value of the metal bath obtaining with respect to ρ
otransient changing amount, Δ ρ representative stop applying ultrasonic after, the resistivity value that metal bath still retains is with respect to ρ
olasting variable quantity, Δ t
1representing the time span that Δ ρ remains unchanged, is ultrasonic metastable structure stationary phase or ultrasonic optimum phase, the Δ t of breeding of causing
2representing that Δ r diminishes gradually until be 0 time span, is ultrasonic metastable structure rehabilitation period or the ultrasonic degradation period that breeds of causing, Δ t=Δ t
1+ Δ t
2that after ultrasonic stopping, what melt structure changed retains the stage, is called the ultrasonic metastable structure that causes and retains phase or the ultrasonic term of validity that breeds;
(5), in order to improve the repeatability of measurement data, repeat step (3) and step (4) is measured some groups of data.
In measuring process, above metal bath liquid level to be measured, pass to Ar or CO
2blanket gas.
Compared with prior art, feature of the present invention and beneficial effect are:
Ultimate principle of the present invention is as shown in Figure of description Fig. 1, for the ultrasonic processing technique of metal bath, goal in research is the intensity of variation of ultrasonic caused melt structure, and be not the key of problem to the configuration state of metal bath itself, therefore, that need Measurement accuracy is resistance or the change in resistance amount Δ r that can characterize structural change, and resistance R or the electricalresistivityρ of reflecting the melt structure factor are stablized as long as keep in testing process, under so identical ultrasonic treatment conditions | " R| value is definite value to Δ r|=|R, therefore, it measures the four-probe measurement method of not only can using, also can use bipolar electrode method.
Can adopt as the bipolar electrode of Fig. 2 or as Fig. 3 four-probe measurement mode for the above-described ultrasonic designed device that can accurately detect in real time melt increased resistance value in ultrasonic pretreated whole process of detection that causes melt structure variation.The device of these two kinds of metering systems is all mainly made up of heating and thermal insulation system, metal bath storage unit, power ultrasonic system, melt resistance or resistivity detection system, melt temperature signal acquiring system and detection data Collection & Processing System etc., device of the present invention can apply state and carry out in real time, continuously, accurately detect without resistance or the resistivity of the ultrasonic metal bath that applies state ultrasonic, and its accuracy of detection can meet the accuracy requirement of the ultrasonic transient changing amount Δ R that causes melt resistance or resistivity and lasting variation delta r.
Pick-up unit of the present invention is conducive to test operation in order to ensure insulation and temperature control effect simultaneously, the convenient rate of temperature fall of controlling melt, and heating rate can be used temperature-controlling system control;
The main region that the metal bath of the horizontal circular hole internal memory storage in the metal bath storage unit of apparatus of the present invention is ultrasonic processing, this region is away from metal bath surface, the impact of the meniscus having formed because of wetting state and liquid level while having avoided liquid level oxide film and potential electrode to insert metal bath on resistance or measurements resistivity, and be easy to ensure the temperature consistance of measured zone metal bath, can significantly improve the repeatability of detection; The design that ultrasonic amplitude of fluctuation imports bar patchhole has realized ultrasonic upper importing, has facilitated insertion that metal ultrasonic amplitude of fluctuation when in molten condition imports bar and has withdrawn and the accurate adjusting of insertion depth;
Power ultrasonic system of the present invention Main Function be that power frequency supply is changed into the high frequency electric source that can drive ultrasonic transducer, ultrasonic transducer is magnetostrictive transducer or piezoelectric ceramic transducer, its effect is that electric energy is converted to ultrasonic energy, it is ferrous material preparation that ultrasonic amplitude of fluctuation imports bar, and its effect is that the ultrasonic energy that transducer is produced efficiently imports in metal bath.Because ferrous material may produce serious ultrasonic erosion in the metal target melt of measuring, simultaneously, in the time of resistance or resistivity measurement, due to the electric action of ultrasonic importing bar, must affect and detect loop, therefore, ultrasonic importing bar immerses and partly adopts surface spraying to have the insulating coating that resistance to metal bath corrodes;
In melt resistance of the present invention or resistivity detection system, electrode material is selected the main reactivity of considering its material and metal bath, be chosen in the metal material in high-temperature metal melt with good stability, simultaneously, also should consider to adopt the metal material with low-resistivity, reduce as far as possible all-in resistance or the all-in resistance rate of measuring circuit, to can adopt small-range to measure gear, to improve Measurement Resolution.This is most important in the time adopting bipolar electrode method to measure.According to metal bath difference, can be molybdenum bar, tungsten bar, iron staff or copper rod, on may the affecting of measurement result, all adopt high temperature resistant see oxide covering or jacket protection being exposed to more than metal bath surface part for overcoming metal material electrode long-term oxidation behavior of being difficult to avoid of being on active service in hot environment;
Data Collection & Processing System of the present invention be by the computer hardware system with AD/DA high-speed data acquisition card and can real-time continuous demonstration and the software systems of memory resistor and temperature data form, software systems are based on Microsoft Visual Basic6.0 establishment exploitation, window interface is as shown in Figure of description Fig. 5, the RS232 interface of data collecting card and resistance or resistivity detection system and the RS-485 interface of temperature analog signal acquisition tables are connected, and realize communication by corresponding communications protocol, in measuring process, the collection step-length scope of data is 0.5s～1s, after having tested, data storing is Excel file.
Compared with prior art, the invention provides one can detect and utilize the variation delta r of structure sensitive physical parameter-resistance (or resistivity resistivity) to characterize the ultrasonic pick-up unit that melt structure changes that causes, this pick-up unit has successfully solved the Insulation Problems of power ultrasonic importing bar, overcome the ultrasonic bar impact utilizing when voltammetry measurement is ultrasonic causes metal bath resistance, and utilize advanced electronic measurement technique and computer technology to realize the real-time of resistance and temperature data, synchronously, continuous and High Precision Automatic acquisition and processing, and adopt bipolar electrode method and four electrode method all can realize accurate measurement.
Brief description of the drawings
Fig. 1 be of the present invention under temperature constant state resistance or the change in resistance rule schematic diagram of metal bath in ultrasonic preprocessing process and after ultrasonic processing;
Wherein: R: the resistance of metal bath itself or resistivity; R
0, R ', R ": be respectively apply ultrasonic before, apply ultrasonic during and ultrasonic metal bath resistance or resistivity after stopping; Δ R representative apply ultrasonic during, detect the resistance of the metal bath obtaining with respect to R
0transient changing amount, t: melt reaches the time that starts timing after constant temperature; Δ r representative stop applying ultrasonic after, the resistance value that metal bath still retains is with respect to R
0lasting variable quantity, Δ t
1representing the time span that Δ r remains unchanged, is ultrasonic metastable structure stationary phase or ultrasonic optimum phase, the Δ t of breeding of causing
2representing that Δ r diminishes gradually until be 0 time span, is ultrasonic metastable structure rehabilitation period or the ultrasonic degradation period that breeds of causing, Δ t=Δ t
1+ Δ t
2that after ultrasonic stopping, what melt structure changed retains the stage, is called the ultrasonic metastable structure that causes and retains phase or the ultrasonic term of validity that breeds; Δ t
0represent ultrasonic application time;
Fig. 2 is that the present invention detects the ultrasonic bipolar electrode checking device that melt structure changes that causes;
Fig. 3 is that the present invention detects the ultrasonic four electrode checking devices that cause melt structure;
Wherein 1: ultrasonic generator; 2: ultrasonic transducer; 3: ultrasonic amplitude of fluctuation imports bar; 4: thermometric is invited galvanic couple; 5: potential electrode; 6: resistance heated holding furnace upper cover; 7: metal bath storage unit; 8: box resistance heated holding furnace; 9: resistance meter; 10: temperature analog signal acquisition tables; 11: data acquisition and process computer system; 12: resistance heated holding furnace temperature control cabinet;
Fig. 4 is the front view of the metal bath storage unit in Fig. 2 and Fig. 3;
Fig. 5 is the vertical view of Fig. 4;
Wherein: 13: ultrasonic amplitude of fluctuation imports bar patchhole; 14: ultrasonic processing Metal Melting tagma; 15: metal bath liquid level; 16: electrode patchhole; 17: fire resistive material;
Fig. 6 is to be shape and the high temperature insulation coating position schematic diagram of the ultrasonic amplitude of fluctuation importing bar of Fig. 2 and Fig. 3;
Wherein: 18: high temperature insulation coating;
Fig. 7 is the software interface that detects data Collection & Processing System;
Wherein: A: electrical resistance collection setting area; B: temperature acquisition setting area; C: resistance aircraft pursuit course; D: temperature aircraft pursuit course;
Fig. 8 is the time dependent ρ-t of resistivity curve while Pb-20wt.%Sn metal bath being applied to different ultrasonic power in the embodiment of the present invention 1;
Fig. 9 is the ultrasonic power that obtained by Fig. 7 curve on specific resistance of metal melt transient changing amount Δ ρ ' and lasting variation delta ρ impact;
Figure 10 is that the ultrasonic power being obtained by Fig. 7 causes the stable retention time Δ t that metal bath metastable structure is stationary phase
1cause with ultrasonic the curve that the metastable structure phase of retaining is Δ t impact effective time of the term of validity;
Figure 11 is the time dependent ρ-t of resistivity curve while Pb-20wt.%Sn metal bath being applied to ultrasonic time difference in embodiment 2;
Figure 12 is the ultrasonic application time Δ t being obtained by Figure 10
0on the curve of specific resistance of metal melt transient changing amount Δ ρ ' and lasting variation delta ρ impact;
Figure 13 is the ultrasonic application time Δ t being obtained by Figure 10
0to the stable retention time Δ t of melt structure intensity of variation
1curve with Δ t impact effective time;
Figure 14 is that in embodiment 3, the Pb-20wt.%Sn metal bath to different temperatures applies resistivity-time ρ-t curve when ultrasonic;
Figure 15 is the metal bath temperature that obtained by Figure 13 curve on specific resistance of metal melt transient changing amount Δ ρ ' and lasting variation delta ρ impact;
Figure 16 is the metal bath temperature obtained by Figure 13 stable retention time Δ t to melt structure intensity of variation
1curve with Δ t impact effective time.
Embodiment
The ultrasonic device that causes melt structure variation of detection of the present invention, as Figure 2-Figure 5, formed by heating and thermal insulation system, metal bath storage unit (7), power ultrasonic system, melt resistance or resistivity detection system, melt temperature signal acquiring system and data Collection & Processing System etc.;
Wherein, described heating and thermal insulation system is connected and forms with resistance heated holding furnace temperature control cabinet (12) by box resistance heated holding furnace (8), offers the corresponding preformed hole in position with the hole of metal bath storage unit (7) on resistance heated holding furnace upper cover (6);
Described metal bath storage unit (7) agent structure is rectangular parallelepiped as shown in Figure 4, on rectangular parallelepiped, offer two symmetrical square openings straight down as electrode patchhole (16), in the middle of two electrode patchholes (16), offer a vertical circular hole as ultrasonic importing bar patchhole (13), electrode patchhole (16) and ultrasonic importing bar patchhole (13) are connected by a horizontally disposed circular hole, the degree of depth of described electrode patchhole (16) is less than the height of rectangular parallelepiped, the degree of depth of described ultrasonic importing bar patchhole (13) is 4/5 of the electrode patchhole degree of depth, metal bath is stored in the space that electrode patchhole (16), ultrasonic importing bar patchhole (13) and horizontally disposed circular hole form, the fire resistive material that the bonding agent that the material of metal bath storage unit (7) is to be 97wt% by massfraction the have magnesia casting material MgO of different grain size and massfraction is 3wt% mixes, or alumina silica refractory, through high pressure ramming and be prepared from high-temperature calcination,
Described power ultrasonic system is by ultrasonic generator (1), ultrasonic transducer (2) and ultrasonic amplitude of fluctuation import bar (3) composition, ultrasonic generator (1) is connected with ultrasonic transducer (2), ultrasonic transducer (2) imports bar (3) with ultrasonic amplitude of fluctuation and is connected, ultrasonic amplitude of fluctuation imports in the ultrasonic importing bar patchhole (13) of bar (3) insertion metal bath storage unit (7), contact with metal bath, as shown in Figure 5, the part surface spraying contacting in metal bath at ultrasonic amplitude of fluctuation importing bar has the insulating coating (17) that resistance to metal bath corrodes, coating kind is ZrO
2-CaO, ZrO
2-MgO, ZrO
2-Y
2o
3or ZrO
2-CeO
2,
Described melt resistance detection system is by resistance meter (9), potential electrode (5) and be connected wire and form, and the Measurement Resolution of resistance meter (9) is for being 1 μ Ω or 0.1 μ Ω, and has RS232 interface; The quantity of potential electrode (5) is 2 or 4, as shown in Figures 2 and 3,2 potential electrode (5) are inserted respectively two electrode patchholes (16), the electric current of resistance meter (9) is all connected with same electrode with voltage port, or 4 potential electrode (5) are divided in two pairs of difference electrode insertion patchholes (16), the electric current port of resistance meter be connected away from two electrodes of ultrasonic importing bar patchhole one side, voltage port with near being connected away from two electrodes of ultrasonic importing bar patchhole one side;
Described melt temperature signal acquiring system is connected to form by compensation galvanic couple line by temperature thermocouple (4) and temperature analog signal acquisition tables (10), described temperature thermocouple (4) is K type thermopair, import bar patchhole (13) from the ultrasonic amplitude of fluctuation of metal bath storage unit (7) and be inserted in horizontally disposed circular hole, described temperature analog signal acquisition tables (10) is the digital displaying temperature table with RS485 or RS232 communication interface;
Described data Collection & Processing System is made up of the acquisition software of the computer hardware with AD/DA high-speed data acquisition card and real-time continuous demonstration and memory resistor and temperature data, and data collecting card is connected with the RS-485 interface of resistance meter interface and temperature analog signal acquisition tables.
(12) rated power of described resistance heated holding furnace (8) and resistance heated holding furnace temperature control cabinet is 12kW, and rated voltage is 380V, adopts three-phase supply power supply, and temperature-controlled precision is ± 2 DEG C.
Described potential electrode (5) is molybdenum bar, tungsten bar, iron staff or copper rod, and potential electrode is exposed to the above part of metal bath surface and all adopts high temperature oxidation resisting coating or jacket protection.
In the embodiment of the present invention, ultrasonic generator is ultrasonic as the mangneto of magnetostrictive transducer for nickel, and ultrasonic input power range is 0～1000W, adjustable continuously, and ultrasonic frequency is 20 ± 2kHz;
The ultrasonic amplitude of fluctuation adopting imports bar as shown in Figure 6, for by the processing of No. 45 steel and through the round bar of modifier treatment, the diameter of lead-in portion is Φ 20mm, the length of sound conduction portion is 325mm, total length is 375mm, insulating coating position comprises that importing bar bottom surface and side height are less than in the scope of 110mm, and coating material is ZrO
2-CaO shaped material;
The resistance meter of selecting is the micro-resistance meter of RESISTOMAT2316 type high resolving power of BURSTER company, this resistance instrument adopts Kelvin bridge design, measures with 20m Ω shelves, and corresponding resolution is 1 μ Ω, measuring current is 1A, measuring accuracy be not more than reading ± 0.03%;
Temperature analog signal acquisition tables is selected BT-9MODBUS-RTU Intellectual Thermal Transmitter, measurement range :-200 DEG C～800 DEG C, measuring accuracy is 0.1%FS, carries out communication by RS-485 communication interface with MODBUS-RTU communications protocol.The sampling step length of resistance and temperature is 1s;
Test metal bath in the embodiment of the present invention is Pb-Sn bianry alloy, and metal bath storage unit is magnesia fire resistive material; Test electrode is Φ 16mm tungsten bar, and more than metal bath surface, part adopts the protection of coating high temperature resistant cement.
Embodiment 1
(1) potential electrode is inserted in the hole along the preformed hole electrode insertion of resistance heated holding furnace upper cover, until electrode contact to electrode patchhole bottom and be fixed, connects and detects loop;
Temperature thermocouple is imported to bar patchhole from ultrasonic amplitude of fluctuation to be inserted into horizontally disposed center of circular hole position and to fix;
Ultrasonic amplitude of fluctuation is imported to bar and import bar patchhole by ultrasonic amplitude of fluctuation and be inserted into and belong to storage melt unit, and be placed in horizontally disposed circular hole top;
Resistance heated holding furnace is heated up and is preheated to the temperature of fusion of Pb-20wt.%Sn, open holding furnace upper cover, the alloy melt that is heated in advance above 150 DEG C of liquidus curve is poured in metal bath storage unit, until metal bath liquid level reaches apart from storage unit 10mm suitable for reading, again cover bell;
(2) open computer system move acquisition software, the ultrasonic power of ultrasonic generator is adjusted to desired value, regulating resistance heating and thermal insulation furnace temperature, until metal bath temperature stabilization is 450 DEG C of temperature to be measured, and is incubated 30min;
(3) melt temperature and the electricalresistivityρ that obtain when acquisition software
okeep constant, open ultrasonic generator metal bath is applied to ultrasonic field, the frequency that applies power ultrasonic is 20kHz, ultrasonic power is respectively 400W, 600W and 800W, time is 300s, turn-off immediately ultrasonic generator, stop ultrasonic applying, after applying ultrasonic end, ultrasonic amplitude of fluctuation importing bar does not shift out ultrasonic amplitude of fluctuation importing bar patchhole, keep computer system to continue image data, apply ultrasonic time numerical value before until the resistivity value of metal solution to be measured reverts to, and more than keeping 15-20min, then preserve image data file;
(4) gathered data file is depicted as to electricalresistivityρ's ρ (t) function curve diagram that t changes in time, as shown in Figure 7, the impact of thus obtained ultrasonic processing power on Δ ρ ' and Δ ρ, and ultrasonic processing power is to Δ t
1with Δ t as Fig. 8 and Fig. 9, as can be seen from the figure, in the power ultrasonic of 400W, 600W and 800W, power is larger, the metal bath microstructure change degree causing is larger, the stability of the melt metastable structure of acquisition is better, it is ultrasonic that to breed the term of validity longer.
Embodiment 2
(1) potential electrode is inserted in the hole along the preformed hole electrode insertion of resistance heated holding furnace upper cover, until electrode contact to electrode patchhole bottom and be fixed, connects and detects loop;
Temperature thermocouple is imported to bar patchhole from ultrasonic amplitude of fluctuation to be inserted into horizontally disposed center of circular hole position and to fix;
Ultrasonic amplitude of fluctuation is imported to bar and import bar patchhole by ultrasonic amplitude of fluctuation and be inserted into and belong to storage melt unit, and be placed in horizontally disposed circular hole top;
Resistance heated holding furnace is heated up and is preheated to the temperature of fusion of Pb-20wt.%Sn, open holding furnace upper cover, the alloy melt that is heated in advance above 150 DEG C of liquidus curve is poured in metal bath storage unit, until metal bath liquid level reaches apart from storage unit 10mm suitable for reading, again cover bell;
(2) open computer system move acquisition software, the ultrasonic power of ultrasonic generator is adjusted to desired value, regulating resistance heating and thermal insulation furnace temperature, until metal bath temperature stabilization is 450 DEG C of temperature to be measured, and is incubated 30min;
(3) melt temperature and the electricalresistivityρ that obtain when acquisition software
okept constant, opened ultrasonic generator metal bath is applied to ultrasonic field, the frequency that applies power ultrasonic is 20kHz, and ultrasonic power is 400W, time Δ t
0be respectively 180s, 300s, 420s and 600s, turn-off immediately ultrasonic generator, stop ultrasonic applying, after applying ultrasonic end, ultrasonic amplitude of fluctuation importing bar does not shift out ultrasonic amplitude of fluctuation importing bar patchhole, keep computer system to continue image data, apply ultrasonic time numerical value before until the resistivity value of metal solution to be measured reverts to, and more than keeping 15-20min, then preserve image data file;
(4) gathered data file is depicted as to electricalresistivityρ's ρ (t) function curve diagram that t changes in time, as shown in Figure 7, as shown in figure 10, the impact of thus obtained ultrasonic processing time on Δ ρ ' and Δ ρ, and the ultrasonic processing time is to Δ t
1with Δ t as Figure 11 and Figure 12, as can be seen from the figure, Δ t during ultrasonic applying
0, resistivity obviously declines, and along with the increase of ultrasonic application time Δ t0, Δ ρ and Δ t become large.Illustrate that power ultrasonic application time is longer, the metal bath microstructure change degree causing is larger, and ultrasonic to breed the term of validity longer.
Embodiment 3
(1) potential electrode is inserted in the hole along the preformed hole electrode insertion of resistance heated holding furnace upper cover, until electrode contact to electrode patchhole bottom and be fixed, connects and detects loop;
Temperature thermocouple is imported to bar patchhole from ultrasonic amplitude of fluctuation to be inserted into horizontally disposed center of circular hole position and to fix;
Ultrasonic amplitude of fluctuation is imported to bar and import bar patchhole by ultrasonic amplitude of fluctuation and be inserted into and belong to storage melt unit, and be placed in horizontally disposed circular hole top;
Resistance heated holding furnace is heated up and is preheated to the temperature of fusion of Pb-20wt.%Sn, open holding furnace upper cover, the alloy melt that is heated in advance above 150 DEG C of liquidus curve is poured in metal bath storage unit, until metal bath liquid level reaches apart from storage unit 10mm suitable for reading, again cover bell;
(2) open computer system move acquisition software, the ultrasonic power of ultrasonic generator is adjusted to desired value, regulating resistance heating and thermal insulation furnace temperature, until metal bath temperature stabilization is in temperature to be measured, and is incubated 30min;
(3) melt temperature and the electricalresistivityρ that obtain when acquisition software
okept constant, opened ultrasonic generator metal bath is applied to ultrasonic field, metal bath probe temperature is respectively 300 DEG C, 350 DEG C, 400 DEG C and 450 DEG C; The frequency that applies power ultrasonic is 20kHz, and ultrasonic power is 400W, time Δ t
0for 300s, turn-off immediately ultrasonic generator, stop ultrasonic applying, after applying ultrasonic end, ultrasonic amplitude of fluctuation importing bar does not shift out ultrasonic amplitude of fluctuation importing bar patchhole, keep computer system to continue image data, apply ultrasonic time numerical value before until the resistivity value of metal solution to be measured reverts to, and more than keeping 15-20min, then preserve image data file;
(4) gathered data file is depicted as to electricalresistivityρ's ρ (t) function curve diagram that t changes in time, as shown in figure 13, the impact of thus obtained ultrasonic processing time on Δ ρ ' and Δ ρ, and the ultrasonic processing time is to Δ t
1with Δ t as shown in Figure 14 and Figure 15, as seen from the figure, Δ t during ultrasonic applying
0, resistivity obviously declines.Temperature is higher, Δ ρ, Δ ρ ' and Δ t
1larger.Illustrate that power ultrasonic application time is longer, the metal bath microstructure change degree causing is larger, and ultrasonic to cause metal bath metastable structure longer stationary phase.
Claims (9)
1. ultrasonic pre-service causes the on-line measuring device that melt structure changes, and it is characterized in that comprising heating and thermal insulation system, metal bath storage unit, power ultrasonic system, melt resistance or resistivity detection system, melt temperature signal acquiring system and data Collection & Processing System; Wherein, described heating and thermal insulation system is by box resistance heated holding furnace and the phase composition of resistance heated holding furnace temperature control cabinet, described metal bath storage unit is placed in resistance heated holding furnace, offer two electrode patchholes and ultrasonic importing bar patchhole, electrode patchhole and ultrasonic importing bar patchhole are connected by a horizontally disposed circular hole, and metal bath is stored in the space that electrode patchhole, ultrasonic importing bar patchhole and horizontally disposed circular hole form; Described power ultrasonic system imports bar by ultrasonic generator, ultrasonic transducer and ultrasonic amplitude of fluctuation and forms, ultrasonic generator is connected with ultrasonic transducer, ultrasonic transducer imports bar with ultrasonic amplitude of fluctuation and is connected, ultrasonic amplitude of fluctuation imports in the ultrasonic importing bar patchhole of bar insertion metal bath storage unit, contacts with metal bath; Described melt resistance detection system is made up of resistance meter, potential electrode and connection wire, one end electrode insertion patchhole of potential electrode, and the other end is connected with resistance meter; Described melt temperature signal acquiring system is made up of temperature thermocouple and temperature analog signal acquisition tables, and melt inside is inserted in temperature thermocouple one end, and one end is connected with temperature analog signal acquisition tables; Resistance meter is connected with data Collection & Processing System with melt temperature signal acquiring system respectively with temperature analog signal acquisition tables.
2. a kind of ultrasonic pre-service according to claim 1 causes the on-line measuring device that melt structure changes, it is characterized in that described resistance heated holding furnace and the rated power of resistance heated holding furnace temperature control cabinet are 12kW, rated voltage is 380V, the power supply of employing three-phase supply, temperature-controlled precision is ± 2 DEG C, covers the corresponding preformed hole in position offering with metal bath storage unit hole on resistance heated holding furnace.
3. a kind of ultrasonic pre-service according to claim 1 causes the on-line measuring device that melt structure changes, the fire resistive material that having of it is characterized in that described metal bath storage unit is 97wt% by the massfraction bonding agent that the magnesia casting material MgO of different grain size and massfraction are 3wt% mixes, or alumina silica refractory, through high pressure ramming and be prepared from high-temperature calcination; Two electrode patchholes of described metal bath storage unit are straight down symmetrical, and ultrasonic importing bar patchhole is the vertical circular hole between two electrodes insert in the hole, and the degree of depth of described ultrasonic importing bar patchhole is 4/5 of the electrode patchhole degree of depth.
4. a kind of ultrasonic pre-service according to claim 1 causes the on-line measuring device that melt structure changes, it is characterized in that the part surface spraying that described ultrasonic amplitude of fluctuation importing bar contacts with metal bath has the insulating coating that resistance to metal bath corrodes, insulating coating kind is ZrO
2-CaO, ZrO
2-MgO, ZrO
2-Y
2o
3or ZrO
2-CeO
2.
5. a kind of ultrasonic pre-service according to claim 1 causes the on-line measuring device that melt structure changes, and it is characterized in that the Measurement Resolution of described resistance meter is 1 μ Ω or 0.1 μ Ω, and has RS232 interface.
6. a kind of ultrasonic pre-service according to claim 1 causes the on-line measuring device that melt structure changes, the quantity that it is characterized in that described potential electrode is 2 or 4, 2 potential electrode are inserted respectively two electrode patchholes, the electric current of resistance meter is all connected with same electrode with voltage port, or 4 potential electrode be divided into two pairs respectively electrode insertion insert in the hole, the electric current port of resistance meter be connected away from two electrodes of ultrasonic importing bar patchhole one side, voltage port is connected away from two electrodes of ultrasonic importing bar patchhole one side with close, potential electrode is molybdenum bar, tungsten bar, iron staff or copper rod, potential electrode is exposed to the above part of metal bath surface and all adopts high temperature oxidation resisting coating or jacket protection.
7. a kind of ultrasonic pre-service according to claim 1 causes the on-line measuring device that melt structure changes, it is characterized in that described temperature thermocouple is K type thermopair, import bar patchhole from the ultrasonic amplitude of fluctuation of metal bath storage unit and be inserted in metal bath, described temperature analog signal acquisition tables is the digital displaying temperature table with RS485 or RS232 communication interface.
8. a kind of ultrasonic pre-service according to claim 1 causes the on-line measuring device that melt structure changes, it is characterized in that described data Collection & Processing System is made up of the acquisition software of the computer hardware with AD/DA high-speed data acquisition card and real-time continuous demonstration and memory resistor and temperature data, data collecting card is connected with the RS-485 interface of resistance meter interface and temperature analog signal acquisition tables.
9. a kind of ultrasonic pre-service according to claim 1 causes the on-line measuring device that melt structure changes, and it is characterized in that described metal bath is simple metal melt or alloying metal melt.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410143445.5A CN104076065B (en) | 2014-04-10 | 2014-04-10 | A kind of ultrasonic pretreatment causes the on-line measuring device of melt structure change |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410143445.5A CN104076065B (en) | 2014-04-10 | 2014-04-10 | A kind of ultrasonic pretreatment causes the on-line measuring device of melt structure change |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104076065A true CN104076065A (en) | 2014-10-01 |
| CN104076065B CN104076065B (en) | 2016-08-17 |
Family
ID=51597472
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410143445.5A Active CN104076065B (en) | 2014-04-10 | 2014-04-10 | A kind of ultrasonic pretreatment causes the on-line measuring device of melt structure change |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104076065B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105204918A (en) * | 2015-07-15 | 2015-12-30 | 济南大学 | Method for automatically processing electrical resistivity data |
| CN108717023A (en) * | 2018-07-17 | 2018-10-30 | 东北大学 | The device and method of magnesium alloy plate and belt beaming limit and springback capacity is tested simultaneously |
| CN110049813A (en) * | 2016-12-12 | 2019-07-23 | 伊苏瓦尔肯联铝业 | Improve liquid metal to the method for the wetting on the surface of solid substrate |
| CN111024772A (en) * | 2019-12-03 | 2020-04-17 | 西安科技大学 | Laser cladding molten pool micro-resistance distribution imaging method and device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103464706A (en) * | 2013-09-26 | 2013-12-25 | 上海大学 | Method and device for continuously casting and preparing high-oriented uniform fine-crystalline structure |
| CN203448652U (en) * | 2013-08-27 | 2014-02-26 | 广东工业大学 | Ultrasonic agitation composite smelting equipment for low-melting-point alloy |
| CN103628016A (en) * | 2013-12-18 | 2014-03-12 | 江苏科技大学 | Protection method for high-temperature corrosion resistance of ultrasonic amplitude transformer |
| CN203526525U (en) * | 2013-10-25 | 2014-04-09 | 西南交通大学 | Device for manufacturing gradient materials |
-
2014
- 2014-04-10 CN CN201410143445.5A patent/CN104076065B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203448652U (en) * | 2013-08-27 | 2014-02-26 | 广东工业大学 | Ultrasonic agitation composite smelting equipment for low-melting-point alloy |
| CN103464706A (en) * | 2013-09-26 | 2013-12-25 | 上海大学 | Method and device for continuously casting and preparing high-oriented uniform fine-crystalline structure |
| CN203526525U (en) * | 2013-10-25 | 2014-04-09 | 西南交通大学 | Device for manufacturing gradient materials |
| CN103628016A (en) * | 2013-12-18 | 2014-03-12 | 江苏科技大学 | Protection method for high-temperature corrosion resistance of ultrasonic amplitude transformer |
Non-Patent Citations (1)
| Title |
|---|
| 宛建军: "超声处理对Pb-Sn合金熔体电阻的影响", 《中国优秀硕士学位论文全文数据库 工程科技I辑》, no. 3, 15 March 2013 (2013-03-15), pages 3 - 5 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105204918A (en) * | 2015-07-15 | 2015-12-30 | 济南大学 | Method for automatically processing electrical resistivity data |
| CN110049813A (en) * | 2016-12-12 | 2019-07-23 | 伊苏瓦尔肯联铝业 | Improve liquid metal to the method for the wetting on the surface of solid substrate |
| CN108717023A (en) * | 2018-07-17 | 2018-10-30 | 东北大学 | The device and method of magnesium alloy plate and belt beaming limit and springback capacity is tested simultaneously |
| CN108717023B (en) * | 2018-07-17 | 2023-10-27 | 东北大学 | Device and method for simultaneously testing bending limit and resilience of magnesium alloy plate and strip |
| CN111024772A (en) * | 2019-12-03 | 2020-04-17 | 西安科技大学 | Laser cladding molten pool micro-resistance distribution imaging method and device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104076065B (en) | 2016-08-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104076065A (en) | Online detection device for variation of metal melt structure caused by ultrasonic preprocessing | |
| Zhang et al. | Simultaneous measurements of the thermal conductivity and thermal diffusivity of molten salts with a transient short-hot-wire method | |
| CN201681119U (en) | Data collecting system for electro-migration voltage at welding spot | |
| CN104166047B (en) | Synchro measure mangneto metal bath resistance and the apparatus and method of electric potential difference change | |
| CN101782544A (en) | Device for testing metal melt electrical resistivity and testing method therefor | |
| CN205670108U (en) | A kind of HTHP gravity sensing formula falling ball method liquid viscosity tester | |
| CN109187628A (en) | The test method of thermal contact resistance between micro-/ nano thin material is measured based on 3 ω methods | |
| CN107044999A (en) | A kind of battery core specific heat capacity test system and method | |
| CN107727311A (en) | Plasma pressure sensor and system | |
| CN109357973A (en) | A kind of magnetorheological liquid viscosity test device and test method | |
| CN101871900A (en) | Sensor for measuring heat conduction coefficient | |
| CN108020578A (en) | A kind of detection device and its assembling, detection method of Iron Ore Powder assimilation temperature | |
| Dong et al. | Study of Single-Power, Two-Circuit ESR Process with Current-Carrying Mold: Development of the Technique and Its Physical Simulation | |
| Allia et al. | Magnetic relaxation in amorphous ribbons prepared with different quenching rates | |
| CN108225970A (en) | The detection device and detection method of solid content in high concentrated liquid | |
| CN111982960A (en) | High-temperature-resistant heat probe device for online measurement of heat conductivity coefficient based on hot wire method | |
| Zheng et al. | An Online Contactless Investigation of the Meniscus Velocity in a Continuous Casting Mold Using Lorentz Force Velocimetry | |
| Kadjo et al. | A new transient two-wire method for measuring the thermal diffusivity of electrically conducting and highly corrosive liquids using small samples | |
| Lyons et al. | A method for the accurate determination of the thermal product (ρck) 1/2 for thin film heat transfer or surface thermocouple gauges | |
| Zhang et al. | Short-hot-wire method for the measurement of the thermal conductivity of a fine fibre | |
| CN207318394U (en) | A kind of Measured Results of Thermal Conductivity experimental system | |
| CN201707394U (en) | Device for testing specific resistance of metal melt | |
| RU2535525C1 (en) | Electrical resistivity determination method and device for its implementation | |
| CN203084577U (en) | Constant temperature control system of high-frequency sample melting device | |
| Heyn et al. | Using electrochemical noise for corrosion testing: Determination of critical pitting temperatures |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |