阅读说明：本技术 一种熔融金属喷溅试验仪及试验方法 (Molten metal splash tester and test method ) 是由 冯剑平 方海素 于 2021-07-30 设计创作，主要内容包括：本发明涉及熔融金属喷溅试验技术领域,提供了一种熔融金属喷溅试验仪及试验方法,该熔融金属喷溅试验仪包括送丝机构,以及用于安置待测试样的样品支架；还包括用于对焊丝加热并形成熔滴的高频感应加热系统；高频感应加热系统包括加热感应线圈和与加热感应线圈相连的变频电源；加热感应线圈设置于送丝机构的末端,用以通过变频电源使位于加热感应线圈中的焊丝产生涡流来发热；通过采用高频电源在线圈中产生高频的交变电场,利用导体在高频电场中的涡流热效应对焊丝进行加热,该加热方式相比于传统的火焰加热,提高了测试的安全性,更加环保,精度进一步提高,降低了检测的失败率,大大提高了检测的效率,增加了检测的可信度,简化了仪器的操作。(The invention relates to the technical field of molten metal splash tests, and provides a molten metal splash tester and a test method, wherein the molten metal splash tester comprises a wire feeding mechanism and a sample support for placing a sample to be tested; the high-frequency induction heating system is used for heating the welding wire and forming molten drops; the high-frequency induction heating system comprises a heating induction coil and a variable-frequency power supply connected with the heating induction coil; the heating induction coil is arranged at the tail end of the wire feeding mechanism and used for enabling the welding wire in the heating induction coil to generate eddy current through the variable frequency power supply so as to generate heat; through adopting the high frequency power supply to produce the alternating electric field of high frequency in the coil, utilize the vortex thermal effect of conductor in the high frequency electric field to heat the welding wire, this heating method compares in traditional flame heating, has improved the security of test, and environmental protection more, the precision further improves, has reduced the failure rate that detects, has improved the efficiency that detects greatly, has increased the credibility that detects, has simplified the operation of instrument.)

1. A molten metal splash tester comprises a wire feeding mechanism for feeding welding wires and a sample support for placing a sample to be tested; the high-frequency induction heating system is characterized by further comprising a high-frequency induction heating system for heating the welding wire and forming molten drops; the high-frequency induction heating system comprises a heating induction coil and a variable-frequency power supply connected with the heating induction coil; the heating induction coil is arranged at the tail end of the wire feeding mechanism and used for enabling the welding wire in the heating induction coil to generate eddy current through the variable frequency power supply so as to generate heat.

2. A molten metal splash tester as recited in claim 1, further comprising a guide mechanism for receiving a dropped droplet and directing it toward the test specimen; the guide mechanism is funnel-shaped, and the guide mechanism is located between the wire feeding mechanism and the sample support.

3. A molten metal splash tester as claimed in claim 2, wherein the sample holder is disposed obliquely or vertically below the guide means when a sample is being tested, such that the sample held on the sample holder intersects the droplet trajectory; the guide mechanism ensures that the molten drops accurately drop to a designated area on the sample through the funnel-shaped guide surface.

4. A molten metal splash tester as recited in claim 1, wherein the wire feeder includes two pairs of rollers for feeding wire, a fixing plate for fixing the rollers, and a motor for driving one of the rollers, which are arranged in a vertical direction.

5. A molten metal splash tester as recited in claim 4, further comprising a motor speed control device; the motor rotation speed control device includes:

the welding wire feeding standard parameter setting unit is used for inputting a standard parameter w for welding wire feeding;

a welding wire density input unit for inputting an actual density ρ of a welding wire used for a test;

the wire feeding speed calculation unit is used for calculating an initial wire feeding speed V according to a formula V which is w/rho according to input standard parameters of welding wire feeding and actual density of the welding wire;

the motor rotating speed calculating unit is used for calculating the initial rotating speed n of the motor according to a formula n-V/pi/D, wherein D is the outer diameter of the roller; and

and the motor driving unit controls the motor to rotate at the initial rotating speed according to the calculation result.

6. A molten metal splash tester as recited in claim 5, further comprising a droplet detection device; the droplet detection device comprises a detection device and a control device,

the infrared detector or the vibration sensor is used for detecting the dripping molten drop value and recording the dripping time of each time;

the molten drop frequency calculation unit is used for recording the dropping times of the molten drops and the interval duration through an infrared detector or a vibration sensor to calculate the dropping frequency of the molten drops; and

the temperature measuring unit is used for detecting the temperature rise of the reverse side of the molten drop impact sample area;

and the motor driving unit compares the result obtained by the molten drop detection device with a preset value and controls the motor to increase or decrease the rotating speed according to the comparison result and preset conditions.

7. A molten metal splash tester as recited in claim 6,

when the dripping frequency of the molten drops obtained by the molten drop frequency calculation unit is less than 20 drops/63 s, the motor driving unit controls the rotating speed of the motor to increase by one adjustment unit;

when the dropping frequency of the molten drops obtained by the molten drop frequency calculation unit is more than 20 drops/57 s, the motor driving unit controls the rotating speed of the motor to be reduced by one adjustment unit;

when the drop frequency of the molten drops obtained by the molten drop frequency calculation unit is between 20 drops/63 s and 20 drops/57 s, the motor drive unit controls the rotation speed of the motor to be constant.

8. A molten metal splash tester as recited in claim 7, wherein the variable frequency power supply is activated at a first power when the motor is operating at an initial rotational speed;

when the rotating speed of the motor is increased or decreased by one adjusting unit, the variable frequency power supply is synchronously increased or decreased by one power adjusting unit.

9. A molten metal splash tester as claimed in claim 6, wherein the droplet detection means includes an electronic weighing unit for recording the weight of each droplet.

10. A molten metal splash test method using the molten metal splash tester as claimed in any one of claims 1 to 9; which is characterized by comprising

S1: obtaining the density and the diameter of a welding wire, and feeding the welding wire at a motor rotating speed controlled by the feeding amount of 10 +/-1 g/min;

s2: starting a variable frequency power supply, controlling the output power of the variable frequency power supply and the rotating speed of a motor, and ensuring that the frequency f of the formed metal molten drops is 20 drops/(60 +/-3 s);

s3: recording the number X of molten drops required by the temperature rise of the back surface of the sample to be 40K;

s4: replacing the sample, repeating the steps and recording the test result;

s5: the results of the 10 test specimens were averaged.

Technical Field

The invention relates to the technical field of molten metal splash tests, in particular to a molten metal splash tester and a test method.

Background

The high temperature resistant heat insulation protective clothing is used for special design aiming at a special heating source in special construction occasions to prevent heat damage such as heat transfer, radiation and the like of a heat source or a fire source to a human body. The high temperature resistant heat insulation protective clothing not only needs to be flame retardant, but also needs to have the characteristics of heat insulation, electric insulation, high voltage breakdown resistance, high temperature resistance, no melting, ventilation, softness and the like.

Aiming at the safety requirements of the high-temperature resistant heat-insulating protective clothing, special evaluation standards are internationally provided, for example, ISO11611 protective fabrics for welding and similar processes stipulates various safety index requirements of the high-temperature resistant heat-insulating protective clothing and fabrics thereof. One of the key indicators is: the molten metal splashing influence is determined according to ISO9150 'Performance determination of protective clothing fabric-material under impact of small molten metal particles', and the standard tests show that when a welder wears the protective clothing to work, a small amount of molten metal continuously splashes to the same position on the cloth, the fabric can be kept from being burnt to the extent that the molten metal enters the protective clothing to cause human body burn, or the heat of the molten metal is transmitted to the surface of the skin of the human body through the fabric to cause burn although the molten metal is not burnt.

The sources of metal melting heat are specified in the ISO/national standards mentioned above as sources of fuel gas, oxygen and acetylene. At present, oxygen and acetylene are stored by a steel cylinder, and in the using process, the gas pressure fluctuation is slight, for example, in the using process, the gas pressure in the steel cylinder can be reduced along with the use and discharge of gas, and the like, so that the gas flow debugged in advance can be slightly changed in the using process, the testing condition (deviation from the debugging value) can be directly influenced, and the result has larger deviation. And the flame of the welding torch is very sensitive to the change of the oxygen acetylene flow, and needs to be adjusted by a high-precision flow regulator, even so, the flame of the welding torch is difficult to keep stable all the time, and the accuracy of test data is directly influenced, and the test failure can be caused if the quality and the frequency of each molten drop are changed.

Although microcomputer negative feedback control is added in the current testing process, for example, the size and the frequency of a molten drop are attempted to be controlled by automatically adjusting oxygen flow and the like, because the molten drop melts a welding wire by flame of a welding torch, the flame is in a jet shape in the melting process, and the molten drop drops into a guide mechanism in an arc shape to impact a sample for testing when falling, the guide mechanism and the welding wire are not on the same straight line, and the center of the guide mechanism has a deflection angle. When the flame of the welding torch is unstable, the quality and the dropping frequency of molten drops are difficult to ensure, and the molten drops are easy to directly blow out of the guide mechanism, so that the test fails.

In addition, individual molten drops can rotate for many times in the guide groove due to the collision angle and fall, and the temperature of the molten drops is reduced and the molten drops are irregularly split in the process of rotating for many times, so that the temperature rise of the sensor is counted by a computer, and the frequency is calculated incorrectly. These problems often occur during actual testing, which results in invalid tests, affects data accuracy, and even makes it difficult to obtain valid results.

Therefore, although ISO has established this standard very early, international agencies capable of performing this test are rare, requiring multiple tests to reduce test errors, with low success rates, low data efficiency, time consuming, and expensive testing. The test conditions also put high demands on the performance of the test instrument, so that the production cost is high.

Therefore, a molten metal sputtering tester which is easy to operate, high in precision, small in error and low in cost is urgently needed.

Disclosure of Invention

The invention aims to overcome the defects caused by using a fuel gas source as a heat source in the conventional molten metal splash tester and provide the molten metal splash tester and the test method which are easy to operate, high in precision, high in reliability, small in error, high in safety, lower in cost and simple in structure.

In order to achieve the above object, the first aspect of the present invention is achieved by the following technical solutions: a molten metal splash tester comprises a wire feeding mechanism for feeding welding wires and a sample support for placing a sample to be tested; the high-frequency induction heating system is used for heating the welding wire and forming molten drops; the high-frequency induction heating system comprises a heating induction coil and a variable-frequency power supply connected with the heating induction coil; the heating induction coil is arranged at the tail end of the wire feeding mechanism and used for enabling the welding wire in the heating induction coil to generate eddy current through the variable frequency power supply so as to generate heat.

The further preferable scheme of the invention is as follows: the device also comprises a guide mechanism for receiving the dropped molten drops and guiding the dropped molten drops to the sample; the guide mechanism is funnel-shaped, and the guide mechanism is located between the wire feeding mechanism and the sample support.

The further preferable scheme of the invention is as follows: the guide mechanism is provided with a guide surface, and the symmetric center of the guide surface and the welding wire on the wire feeding mechanism are positioned on the same vertical plane.

The further preferable scheme of the invention is as follows: when a sample is tested, the sample support is obliquely or vertically arranged below the guide mechanism, so that the plane of the sample fixed on the sample support is intersected with the droplet track at an angle of 45 degrees; the guide mechanism ensures that the molten drops accurately drop to a designated area on the sample through the funnel-shaped guide surface.

The further preferable scheme of the invention is as follows: the wire feeding mechanism comprises two pairs of rollers for feeding wires, a fixing plate for fixing the rollers and a motor for driving one of the rollers, wherein the two pairs of rollers are arranged in the vertical direction.

The further preferable scheme of the invention is as follows: each pair of rollers comprises a movable roller and a fixed roller; the axle center of the fixed roller is fixed on the fixed plate, and the movable roller leans against the fixed roller through the force application device.

The further preferable scheme of the invention is as follows: the force application device drives the movable roller to lean against the fixed roller through an elastic piece or gravity.

The further preferable scheme of the invention is as follows: the device also comprises a motor rotating speed control device; the motor rotation speed control device includes:

the welding wire feeding standard parameter setting unit is used for inputting a standard parameter w for welding wire feeding;

a welding wire density input unit for inputting an actual density ρ of a welding wire used for a test;

the wire feeding speed calculation unit is used for calculating an initial wire feeding speed V according to a formula V which is w/rho according to input standard parameters of welding wire feeding and actual density of the welding wire;

the motor rotating speed calculating unit is used for calculating the initial rotating speed n of the motor according to a formula n-V/pi/D, wherein D is the outer diameter of the roller; and

and the motor driving unit controls the motor to rotate at the initial rotating speed according to the calculation result.

The further preferable scheme of the invention is as follows: the device also comprises a molten drop detection device; the droplet detection device comprises a detection device and a control device,

the infrared detector or the vibration sensor is used for detecting the dripping molten drop value and recording the dripping time of each time;

the molten drop frequency calculation unit is used for recording the dropping times of the molten drops and the interval duration through an infrared detector or a vibration sensor to calculate the dropping frequency of the molten drops; and

the temperature measuring unit is used for detecting the temperature rise of the reverse side of the molten drop impact sample area;

and the motor driving unit compares the result obtained by the molten drop detection device with a preset value and controls the motor to increase or decrease the rotating speed according to the comparison result and preset conditions.

The further preferable scheme of the invention is as follows: when the dripping frequency of the molten drops obtained by the molten drop frequency calculation unit is less than 20 drops/63 s, the motor driving unit controls the rotating speed of the motor to increase by one adjustment unit;

when the dropping frequency of the molten drops obtained by the molten drop frequency calculation unit is more than 20 drops/57 s, the motor driving unit controls the rotating speed of the motor to be reduced by one adjustment unit;

when the drop frequency of the molten drops obtained by the molten drop frequency calculation unit is between 20 drops/63 s and 20 drops/57 s, the motor drive unit controls the rotation speed of the motor to be constant.

The further preferable scheme of the invention is as follows: when the motor works at an initial rotating speed, the variable frequency power supply is started at a first power;

when the rotating speed of the motor is increased or decreased by one adjusting unit, the variable frequency power supply is synchronously increased or decreased by one power adjusting unit.

The further preferable scheme of the invention is as follows: the droplet detection device comprises an electronic weighing unit for recording the weight of each droplet.

The present invention provides in a second aspect a molten metal splash test method using a molten metal splash tester as described in the first aspect; comprises the steps of (a) preparing a mixture of a plurality of raw materials,

s1: obtaining the density and the diameter of a welding wire, and feeding the welding wire at a motor rotating speed controlled by the feeding amount of 10 +/-1 g/min;

s2: starting a variable frequency power supply, controlling the output power of the variable frequency power supply and the rotating speed of a motor, and ensuring that the frequency f of the formed metal molten drops is 20 drops/(60 +/-3 s);

s3: recording the number X of molten drops required by the temperature rise of the back surface of the sample to be 40K;

s4: replacing the sample, repeating the steps and recording the test result;

s5: the results of the 10 test specimens were averaged.

In conclusion, the invention has the following beneficial effects: the high-frequency alternating electric field is generated in the coil by adopting the high-frequency power supply, the welding wire is heated by utilizing the eddy current heat effect of the conductor in the high-frequency electric field, compared with the traditional flame heating method, the heating mode has the advantages that the test safety and reliability are improved, the environment is protected, the precision is further improved, the failure rate of detection is reduced, the data efficiency is improved, the detection efficiency is greatly improved, the detection reliability is increased, and the operation of an instrument is simplified.

Drawings

FIG. 1 is a schematic view of the structure of a molten metal splash tester described in example 1.

FIG. 2 is a schematic view of the wire feeder according to embodiment 2.

Fig. 3 and 4 are flowcharts of the operation of the molten metal splash tester.

FIG. 5 is a schematic view of the structure of the molten metal splash tester described in example 3.

FIG. 6 is a schematic view showing the structure of a conventional molten metal splash tester.

Wherein:

100. a wire feeder; 200. heating the induction coil; 300. a guide mechanism; 400. and (4) a sample support.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The present embodiment is only for explaining the present invention, and it is not limited to the present invention, and those skilled in the art can make modifications without inventive contribution to the present embodiment as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present invention.

Example 1:

as shown in fig. 1, there is shown a molten metal splash tester including a wire feeder 100 for feeding a welding wire, a guide 300 for receiving and guiding a dropped droplet toward a sample, a sample holder 400 for holding the sample to be tested, and a high-frequency induction heating system for heating the welding wire and forming the droplet.

The high-frequency induction heating system includes a heating induction coil and a variable frequency power supply connected to the heating induction coil 200. The heating induction coil is arranged at the tail end of the wire feeding mechanism and used for enabling the welding wire in the heating induction coil to generate eddy current through the variable frequency power supply so as to generate heat and melt metal to finally form molten drops required by a test. The variable frequency power supply outputs a relatively pure sine wave by converting alternating current in commercial power through AC → DC → AC, and the output frequency and voltage are adjustable within a certain range so as to adjust the magnitude of output power according to requirements.

The guide mechanism is provided with a molten drop guide groove which consists of two parts, wherein the upper end is in a semi-cylindrical shape, the lower end is in a conical shape, and molten drops fall from the upper end and slide out from the lower end. The molten drop guide groove is inclined for 45 degrees, the symmetrical center (plane) of the molten drop guide groove in the vertical direction and the welding wire above the symmetrical center (plane) are located on the same vertical plane, when molten drops formed by the tail ends of the welding wires drop down, the molten drops can slide out along the shortest path in the molten drop guide groove and impact a sample on the sample support, so that the residence time of the molten drops in the molten drop guide groove can be reduced, excessive temperature loss caused by too long residence time (contact) is avoided, the possibility of impact splitting of the molten drops is reduced, and the detection precision of temperature rise on the sample can be improved.

The sample support is vertically arranged at the tail end of the guide mechanism, so that the molten drops can impact a designated area (on the front side) of a test sample fixed on the sample support after sliding out from the molten drop guide groove. And a molten drop collecting tank is arranged below the sample support and used for collecting the metal molten drops which drop.

In this embodiment, the wire feeding mechanism includes two pairs of rollers for feeding wire, a fixing plate for fixing the rollers, and a motor for driving one of the rollers, which are vertically disposed. Each pair of rollers comprises a movable roller and a fixed roller, the axle center of the fixed roller is fixed on the fixed plate through a bearing, and the movable roller leans against the fixed roller through a force application device. The wire feeding can be realized through the two pairs of rollers, and the welding wire can be kept in a vertical state (perpendicular to the horizontal plane) all the time in the wire feeding process, so that the tail end position of the welding wire which is fed vertically all the time is fixed and is only dropped under the action of gravity after being melted, and the dropping point of the welding wire on the droplet guide groove has no deviation basically, so that the path of the welding wire on the droplet guide groove is highly matched, the dropping point finally impacted on a sample is very accurate and is always concentrated to one point, the temperature rise of the point is convenient to detect, and the detected temperature rise is relatively accurate.

The upper part is provided with a first fixed roller and a first movable roller, and the lower part is provided with a second fixed roller and a second movable roller. The force application device drives the movable roller to lean against the fixed roller through an elastic piece or gravity.

Specifically, the force application device located above includes a sliding groove provided on the fixed plate, a slider provided in the sliding groove, and a spring. The sliding groove is horizontally arranged, the first movable roller positioned above the sliding groove is connected with the sliding block in the sliding groove through the bearing, and the sliding block is driven by the spring to drive the first movable roller to lean against the first fixed roller. The welding wire passes through the first movable roller and the first fixed roller, so that the welding wire can be tightly clamped from two sides when the first movable roller leans against the first fixed roller, the shaft of the motor is in transmission connection with the first fixed roller, and the welding wire can be driven to move up and down when the first fixed roller rotates.

In another exemplary embodiment, as shown in fig. 2, the force application device located above in embodiment 2 may also be arranged such that: the fixing plate is provided with an inclined sliding groove, the first movable roller can slide in the sliding groove along the sliding groove through the sliding assembly, and the lower end of the sliding groove is deviated to the first fixed roller. So set up, when using, can break off with the fingers and thumb first movable roller outward with the hands, make the clearance that the welding wire passed between first movable roller and the first definite roller, loosen the hand after waiting to pass the welding wire, first movable roller receives the action of gravity, and its gravity makes it lean on to first definite roller and tightly presses the welding wire on first definite roller along the component force of sliding tray direction.

In order to realize a better wire feeding effect in this embodiment, a wedge-shaped groove (or a groove of other shapes, such as a semicircular cross section) is formed in the first movable roller, the welding wire is placed in the wedge-shaped groove, and the circumferential side surface of the welding wire is in contact with (three surfaces of) the wedge-shaped groove (including the groove bottom surface and the groove two sides, the groove two sides are used for positioning and preventing the welding wire from being separated from the groove). Vertical teeth for increasing resistance of a contact surface of the vertical teeth and a welding wire are arranged on the outer circumferential surface (cylindrical surface) of the first fixed roller, the vertical teeth are perpendicular to the welding wire, and the contact area is reduced through the vertical teeth, so that the pressure on a unit area is increased to increase the friction resistance.

Specifically, the force application device positioned below comprises a torsion bar and a torsion spring, the upper end of the torsion bar is connected with the fixing plate through the torsion spring, and the second movable roller is arranged at the lower end of the torsion bar. Through the cooperation of the torsion bar and the torsion spring, the upper end of the torsion bar is used as the center, the lower end of the torsion bar can drive the second movable roller to lean against the second fixed roller by means of the elastic potential energy of the torsion spring, and the welding wire is statically pressed on the second fixed roller, so that the tail end of the welding wire feeding process (in the vertical direction) cannot shake, and the formed molten drops can also drip to the same position.

In order to facilitate debugging and calibration of the device before the test, the molten metal splash tester in this embodiment further includes a motor rotation speed control device. The motor rotating speed control device comprises a welding wire feeding standard parameter setting unit, a welding wire density input unit, a wire feeding speed calculating unit, a motor rotating speed calculating unit, a motor driving unit and a display unit for displaying input parameters and a motor state.

The welding wire feeding standard parameter setting unit may be a (physical) keyboard with numbers, a display screen with a touch function (a virtual keyboard capable of displaying numbers), or a conventional parameter setting means such as a knob, and is not limited herein, and the purpose of the welding wire feeding standard parameter setting unit is mainly used for inputting the welding wire feeding standard parameter w. The standard parameter may be determined by the formula w ═ 4 r/pi/d ^2, where: and r is 10 +/-1 g/min, is the standard amount of welding wire feeding, and d is the diameter of the welding wire and has the unit of mm.

Similarly, the specific implementation of the welding wire density input unit can refer to a welding wire feeding standard parameter setting unit, which is not described in detail, and the purpose of the welding wire density input unit is mainly used for inputting the actual density rho of the welding wire used in the test.

The wire feeding speed calculating unit is a modular electric circuit formed by discrete components, and may also be a digital integrated circuit, such as a single chip microcomputer, the circuit has a logical operation capability, and is not limited herein, and the main purpose of the circuit is to calculate the initial wire feeding speed V according to the formula V ═ w/ρ according to the input standard parameter of the wire feeding and the actual density of the wire.

In the same way, the specific embodiment of the motor rotation speed calculation unit refers to the wire feeding speed calculation unit, which is not described in detail herein, and the purpose of the calculation is to calculate the initial rotation speed n of the motor according to the formula n ═ V/pi/D, where D is the outer diameter of the roller.

And the motor driving unit controls the motor to rotate at the initial rotating speed according to the calculation result. In this embodiment, the motor is a stepping motor, and the motor driving unit is a stepping motor driving circuit (or referred to as a stepping motor controller).

In order to be able to detect the molten drop so as to count the test result, the molten metal splash tester in this embodiment further includes a molten drop detection device. The molten drop detection device comprises an infrared detector (or a vibration sensor), a molten drop frequency calculation unit and a temperature measurement unit.

The probe of the infrared detector is aligned with the falling track of the molten drop, the molten drop with high temperature can be detected by the infrared detector and the time of each dropping of the molten drop can be recorded when passing through the probe, the dropping frequency of the molten drop can be calculated through the number of times of the molten drop and the interval duration, and then the frequency can be obtained. In addition, a vibration sensor can be adopted, the vibration sensor is arranged on the test sample (or the sample support), vibration and sound can be generated when the molten drops impact the test sample, and the molten drops can be detected through the vibration sensor (or the sound sensor).

And comparing the result obtained by the molten drop detection device with a first preset value, and controlling the motor to increase or decrease the rotating speed by the motor driving unit according to the first comparison result and a first preset condition, wherein the specific control mode is shown in fig. 4.

When the dropping frequency of the molten droplets obtained by the molten droplet frequency calculation unit is less than 20 droplets/63 s, the motor drive unit controls the rotation speed of the motor to increase by one adjustment unit.

When the droplet dropping frequency of the droplets obtained by the droplet frequency calculating unit is greater than 20 droplets/57 s, the motor driving unit controls the rotation speed of the motor to be decreased by one adjustment unit.

When the drop frequency of the molten drops obtained by the molten drop frequency calculation unit is between 20 drops/63 s and 20 drops/57 s, the motor drive unit controls the rotation speed of the motor to be constant.

As for the power of the variable frequency power supply, the variable frequency power supply is started with a first power when the motor is operating at an initial rotational speed. When the rotating speed of the motor is increased or decreased by an adjusting unit, the variable frequency power supply is synchronously increased or decreased by a power adjusting unit

In addition, the molten drop detection device also comprises an electronic weighing unit, wherein the electronic weighing unit is used for recording the weight of each molten drop, and the electronic weighing unit adopts an electronic scale with the precision of 0.01 g. The electronic scale is arranged below the sample, and the molten drop collecting tank is arranged on a tray of the electronic scale.

In the embodiment, due to the adoption of the high-frequency induction heating system, the tail end of the welding wire overcomes the viscous force (and the tension on the surface of the molten drop) of liquid generated by viscosity by means of the self gravity after the molten drop is formed, the size of a single molten drop is related to the diameter of the welding wire, the larger the diameter of the welding wire is, the larger the contact area of the molten drop and the welding wire is, the larger the resultant force of the viscous force and the tension to be overcome during dropping is, and the larger the gravity (the larger volume) of the finally dropped single molten drop is. It can be calibrated before the experiment by means of an electronic weighing cell, while data are recorded for verification during the experiment.

The temperature measuring unit is a temperature sensor, is arranged on the sample support and is positioned on the back of the sample, the temperature sensor is aligned to the foot point of the molten drop on the sample, and the resolution ratio of the temperature sensor is +/-0.5K.

Example 3:

as shown in fig. 5, another embodiment of the molten metal splash tester is shown, the main differences of the molten metal splash tester described in example 3 compared to the molten metal splash tester described in example 1 are: the arrangement mode of the guide mechanism is different.

The guide mechanism in example 3 is funnel-shaped and located between the wire feeder and the sample holder, ensuring that the droplet landing path is vertically downward. Correspondingly, the sample support is arranged below the guide mechanism in a 45-degree inclined mode, so that the sample fixed on the sample support is intersected with the molten drop track, and the guide mechanism ensures that the molten drops accurately drop to a specified area on the sample through the funnel-shaped guide surface. Here, the effect of guiding mechanism is mainly at the horizontal direction calibration drop point position, can not change the melt droplet orbit by a wide margin (the melt droplet only has vertical velocity, does not have horizontal velocity), and its contact time with the melt droplet is very short, and the guiding mechanism in embodiment 1 can change the melt droplet orbit (change vertical direction drip into slope downwards, with the orbit impact sample of parabola behind the guiding mechanism when the melt droplet breaks away from, has the horizontal velocity), so can influence the drop point position.

The invention also provides a molten metal sputtering test method, which uses the molten metal sputtering tester; mainly comprises the following steps of (1) carrying out,

s1: and (4) obtaining the density and the diameter of the welding wire, and feeding the welding wire according to the rotating speed of a motor controlled by the feeding amount of 10 +/-1 g/min.

S2: starting the variable frequency power supply, controlling the output power of the variable frequency power supply and the rotating speed of the motor, ensuring that the frequency f of the formed metal droplets is 20 droplets/(60 +/-3 s), and controlling the mass of the generated single droplets to be 0.5 +/-0.05 g.

S3: recording the number X of molten drops required by the temperature rise of the reverse side of the sample to be 40K, and recording the temperature rise and the number of drops before burning if the sample is burnt without the temperature rise of 40K.

S4: the sample was replaced, the above steps were repeated and the test results recorded.

S5: the results of the 10 test specimens were averaged.

The control of the motor speed and the adjustment of the output power of the variable frequency power source in steps S1 and S2 are shown in fig. 3 and 4, and will not be described in detail here.

As shown in fig. 6, for the existing molten metal splash tester to use flame to heat the welding wire and form the partial schematic view of the molten drop, because the flame generated by gas is used, the airflow generated by the flame can horizontally act on the molten drop, so the horizontal acting effect of the flame on the molten drop needs to be corrected by keeping the horizontal distance D between the symmetric center of the guiding mechanism and the welding wire.

The two devices were subjected to comparative tests using the same specification of test specimens according to the above-described device configuration.

The experimental conditions are as follows:

wire density: 0.6228 g/cm; wire speed; 2.7 mm/s; the diameter of the iron wire is 3.2;

the results of the experiment are as follows:

wherein, the high-frequency induction heating method (the scheme of the invention) adopts a TGG 15-KW high-frequency induction heating machine, the inner diameter of an induction coil is 20mm, the number of turns is 3, the maximum heating power is 15Kw, and the highest frequency is as follows: 30 KHz.

From the experimental result data, the welding torch method (existing scheme) is used for testing, the data yield is only 30% according to the standard (ISO9150), the standard deviation of the data is 3, and the dispersion is relatively large, namely the error is large. Compared with the traditional flame heating, the high-frequency induction heating has higher heating precision, more stable test, no influence of external conditions, 100 percent of data qualification rate, less than 1 standard deviation and good reproducibility. In addition, because the method does not adopt high-pressure gas and open fire, the operation is safer, and the method is more friendly to testers and environment.