Working principle of molybdenum alloy spot welding head

The molybdenum spot welding is composed of two pieces of metal with good conductive function. The center of the two pieces of metal is insulated. As long as there is a contact at the top, this contact constitutes a small resistance at the bottom of the welding head. Is  flat and lubricated. When operating the machine, when the molybdenum spot welding head is pressed on the enameled wire by pneumatic means or with a foot pedal, the pressure will continue to increase. When the reaction fore of the enameled wire on the welding head reaches the set welding pressure, Will trigger a pulse current, the current time is very short, usually between of few milliseconds to ten milliseconds, and the magnitude is about tens to more than one hundred amperes. The current flows through the bottom of the welding head, and there is a contact resistance at the top of the welding head. When the resistance is contacted, it will generate heat and sparks. This heat can remove the varnish of the enameled wire and a lot of heat will be transferred to the copper wire inside the enameled wire superior, part of the current will flow from the bottom of the welding head through the burnt-out copper wire. The copper wire itself is also heating. The temperature of the copper wire will reach the melting point before the melting point in a short time. Under the effect of pressure, it will form a new metal with the underlying metal. The nugget, in this way, the enameled wire is connected to the metal substrate.

Molybdenum has very low vapor pressure under the working temperature and pressure of the vacuum furnace. Therefore, the molybdenum parts have less pollution to the workpieces or working materials in the furnace, and the evaporation loss must not limit the service life of high molybdenum parts such as heating elements and heat insulation encapsulation. The high strength of molybdenum in the production of glass products makes it an ideal electrode and processing and processing equipment during rapid heating. Molybdenum is chemically compatible with most glass components, and will not cause harmful color effects due to a small amount of molybdenum dissolved in the glass melting tank. As the heating electrode in the glass melting furnace, its life span can be as long as 3 to 5 dears. However, the technology content of molybdenum products has also been continuously improved, and molybdenum products are widely used.

Molybdenum and molybdenum alloys have high strength, good electrical and thermal conductivity, and low coefficient of thermal expansion (similar to electron tube glass), and also have the advantage of easy processing. Therefore, plates, strips, foils, tubes ans rods produced by conventional processing methods, Wires and profiles are obtained in electronic tubes(grid and anode), electric light source( support material) parts, metal processing tools（ die-casting and extrusion dies, forging dies, perforated plugs, liquid metal filter screens) and turbine discs widely used.