The thermocouple welding machine welds the thermocouple wire to the hardware for how many degrees it

It depends on what model you have of thermocouple wire.

There are several types of indexing numbers of thermocouple wires, such as S, R, B, N, K, E, J, T, etc. Among them, S, R, and B belong to *** thermocouples, and N, K, E, J, and T belong to inexpensive metal thermocouples.

The characteristics of the S index number are strong antioxidation performance, and it is suitable for continuous use in oxidizing and inert atmospheres, with a long-term use temperature of 1400 and a short-term temperature of 1600. Of all thermocouples, the S-graduation number has the highest accuracy class and is often used as a standard thermocouple;

Compared with the S index, the R-graduation number is about 15% larger except for the thermal electromotive force, and the other properties are almost identical;

The thermal electromotive force of the b-index number is very small at room temperature, so there is generally no need to compensate the wire when measuring. It has a long-term use temperature of 1600 and a short-term temperature of 1800. It can be used in oxidizing or neutral atmospheres, and can also be used for short periods of time under vacuum conditions.

The characteristics of the N index number are strong oxidation resistance at high temperature at 1300, good long-term stability of thermal electromotive force and reproducibility of short-term thermal cycle, good resistance to nuclear radiation and low temperature resistance, and can partially replace the S index thermocouple;

K index number is characterized by strong oxidation resistance, suitable for continuous use in oxidizing and inert atmosphere, long-term use temperature 1000, short-term 1200. The most widely used of all thermocouples;

The E-index number is characterized by the fact that among commonly used thermocouples, its thermal electromotive force is the largest, that is, the highest sensitivity. It should be used continuously in an oxidizing and inert atmosphere, with a temperature of 0-800;

The characteristics of the J index number are that it can be used in both oxidizing atmosphere (upper limit of 750 temperature) and reducing atmosphere (upper limit of 950 temperature), and is resistant to H2 and CO gas corrosion, and is mostly used in oil refining and chemical industry;

The T-graduation number is characterized by the highest accuracy class of all inexpensive metal thermocouples and is typically used to measure temperatures below 300.

If it is iron, there is no problem below 400 degrees.

There are usually several welding methods for the measuring end of a thermocouple:

1 Gas welding, (acetylene welding).

2. Graphite powder welding method;

3. Mercury arc welding method;

4. Brine arc welding method;

5. DC arc welding method;

6.Find a voltage regulating transformer, adjust to 24V, and then remove the carbon rod of the No. 1 battery, sharpen the head, this end is connected to the 24V end of the voltage regulator, and the other end is connected to the thermocouple of the twisted pair, recognize the fire and zero line of the regulator to ensure safety, and use the tip of the carbon rod and the thermocouple of the twisted pair to collide, that is, use the arc of the tip discharge to weld the thermocouple of the twisted pair, and wear sunglasses to protect the eyes when welding. If you practice it a few times, you will be able to weld well.

I used this method to weld platinum rhodium-platinum thermocouples back in the 70's. However, the welded thermocouple can only be used after passing the calibration.

7.After the even wire is broken and twisted, it is welded with argon arc, so that if you are not a good welder, you should ask a professional to weld, because the welding point is required to be smooth. The size is appropriate.

The requirements for solder joints are: the solder joints should be firm, the surface should be smooth, no stains, no slag inclusions, no cracks The size of the solder joints should be as small as possible to reduce the heat transfer error and dynamic error.

In DC welding, the thermocouple is connected to the positive electrode of the power supply, and the carbon rod (spectral) is connected to the negative electrode of the power supply, and the carbon rod is used to contact the top of the thermoelectrode instantaneously to start the arc, and the measuring end is melted into a ball shape and quickly leaves the carbon rod. This welding method is simple, easy to operate, and the measuring end is not easy to stain, and is used for the welding of thermocouples.

AC welding is suitable for welding inexpensive metal thermocouples. Before welding, the oxide of the 25-30mm section of the measuring end should be carefully removed, and then the top of the two electrodes should be brought together and twisted into a twist shape. When welding, dip the top of the thermoelectrode with flux, melt it in the arc flame for 3-5s, and quickly take it out after it becomes a ball, and clearly remove the residue on the solder joint.

This method is simple and easy to operate, but the thermocouple weld and nearby electrode carburizing stains.

The argon arc welding device is composed of five parts: DC welding power supply, high-frequency oscillator, welding gun, butt welding power supply, and work fixture. During welding, the cerium-tungsten wire protruding from the nozzle of the welding gun is used as the negative electrode, and the welded thermocouple is fixed on the fixture as the positive electrode. When the two poles pass through high frequency and high voltage, the arc will be ignited, the thyristor voltage regulation is used to control the arc intensity, the arc discharge is generated between cerium-tungsten and the welded thermocouple under the protection of argon, and the end face of the thermocouple wire is melted into a ball by using the high temperature generated by the arc.

To facilitate the alignment of the thermocouple with the electrode, the work fixture and torch can be moved horizontally and vertically in space. The welding torch is equipped with cerium-tungsten electrodes with a diameter of 1 mm and can be used for thermocouple welding of different diameters.

When using gas welding, the top of the thermoelectrode should be heated and dipped in flux (for example, the flux of nickel-chromium-nickel-silicon couple is mixed with sodium tetraborate and quartz sand), and then the thermoelectrode should be placed in an acetylene or hydroxide flame, and then quickly taken out after melting into a ball, and immediately put it into hot water to wash off the residue on the welding joint. This method is simple to operate and widely used. It is suitable for the welding of inexpensive metal thermocouples.

The toner welding device is similar to arc welding, except that one pole of the power supply is not connected to a carbon rod, but to a graphite crucible containing toner, and the other pole is connected to a thermocouple to be welded. For welding, the thermoelectrode is inserted into the graphite powder and it is ready to weld in a few seconds. This welding method is more convenient than arc welding, but it is easy to cause brittleness of the hot electrode.

This method is suitable for the welding of low-metal thermocouples.

A beaker is filled with sodium chloride solution, and a platinum wire is placed in the aqueous solution as one electrode and a thermoelectrode as the other electrode. When welding, put the top of the thermocouple in contact with the solution slightly, turn on the power supply, and quickly disconnect the power supply after the arc starts. This welding method is suitable for welding thermocouples with finer diameters.

I hope it can give you a reference.