Welding knowledge 1

1. What is welding?
Answer: The process of combining two or more materials (same or different) by heating or pressurizing or both to achieve the combination of atoms and form a permanent connection is called welding.
2. What is welding process? What does it contain?
Answer: A complete set of process procedures and technical regulations in the welding process. The contents include: welding method, pre-welding preparation, assembly, welding materials, welding equipment, welding sequence, welding operation, welding process parameters and post-welding treatment.
3. What is welding technology?
Answer: The general term for various welding methods, welding materials, welding processes and welding equipment and their basic theories is called welding technology.
4. What are the welding methods of electric welding (manual welding)?
Answer: Manual welding is manual arc welding, which is a manual welding method that uses arc as a heat source to melt the electrode and the base material to form a weld. According to the process standard of manual arc welding, it mainly includes four welding methods: flat welding, vertical welding, horizontal welding and overhead welding.
5. What is co2 welding?
Answer: The metal arc welding with CO2 of purity > 99.98% as the shielding gas is called CO2 welding.
6. What is a welding power supply?
Answer: In an electric welding machine, the device that supplies the electric energy required for welding and has electrical characteristics suitable for welding is called a welding power supply.
7. Why are there special requirements for arc welding power supplies? What are the requirements?
Answer: In order to ensure the stable burning of the welding arc and adapt to various welding process requirements, arc welding power supplies have the following special requirements:
〈1〉 The static characteristics (or external characteristics) of the arc welding power supply - that is, the relationship between the steady-state output current and the output voltage, with a falling characteristic (constant current characteristic) and a flat characteristic (constant voltage characteristic).
A. The external characteristics of the power supply for arc welding, TIG welding and carbon arc gouging are falling (constant current) characteristics;
B. The external characteristics of the CO2/MAG/MIG arc welding power supply are flat characteristics (constant voltage characteristics).
<2> Dynamic characteristics of arc welding power supply - when the load state changes instantaneously (such as short-circuit transition of molten droplet, particle transition, jet transition, etc.), the relationship between the output current and output voltage of the arc welding power supply and time is used to characterize the response ability to load transients (i.e. dynamic response ability), referred to as "dynamic
characteristics".
<3> No-load voltage - the voltage displayed by the power supply before arc ignition.
<4> Adjustment characteristics - change the external characteristics of the power supply to meet the requirements of welding specifications.