Welding is a manufacturing process that uses various fusible substances to join metals or other thermoplastic materials such as plastics through intermolecular contact on their surfaces under heat (or pressure) without being completely melted. Welding equipment listed in the Harmonized System items in Item 84.68 and 85.15. However, welding machines are in these two items? Of course not! To know the classification of various welding machines, please follow the welding machine supplier to read on.
The most common welding methods, mainly divided into three categories.
Heating the workpiece to be joined so that it is partially melted to form a molten pool, the molten pool cools and solidifies, then joined, it is suitable for welding processing of various metals and alloys without pressure. Such as: gas welding, electric arc welding.
Welding process must be applied to the weld pressure, belonging to a variety of metals or other thermoplastic materials processing. Such as: resistance welding, friction welding.
The use of metal materials with a lower melting point than the base material as brazing material, the use of liquid brazing material wetting the base material, filling the joint gap, and with the base material to achieve mutual diffusion of link welding parts. It is suitable for welding processing of various materials, and also for welding processing of different metals or dissimilar materials. For example, soft brazing and hard brazing.
For these welding machines, the design is different, and it becomes impossible to judge whether they are welding machines from a specific design structure, so it is necessary to start from the working principle.
Heating is the process of transferring heat energy from a heat source to a colder object to make it hot, while welding is the process of combining two objects atomically by means of heat or pressure. Heating simply raises the temperature of the object, while welding is intended to bring the two together.
Although the welding process often also involves heating the material to be welded (except for pressurization), the scope of this heating is limited to the proposed location (point, line, or surface) of the two objects to be joined, and generally only the two surfaces need to be heated. The heating device, on the other hand, as I understand it, is undifferentiated heating, which generally speaking does not heat only a certain part of the item, but makes the whole product hot.
So, in a welding device, heating is the method and joining is the purpose. Whether or not it has a heating function, the ultimate purpose of the device's treatment of the material should be to join the two together.
