Welding knowledge 5

1. Why does the welding arc have a blow phenomenon?
Answer: During the welding process, the arc center deviates from the electrode axis due to the interference of airflow, the effect of magnetic field or the influence of electrode eccentricity.
2. What is magnetic blow?
Answer: Arc blow is caused by the electromagnetic force in the welding circuit during DC arc welding. The influence of magnetic blow can be weakened by changing the position of the ground wire or reducing the welding current and changing the electrode angle.
3. What is the self-regulation characteristic of the CO2 power arc system? Why is CO2 welding with fine wire?
Answer: Under the constant speed wire feeding system, when the arc length changes, the current and melting speed change, so that the arc length recovery effect becomes the self-regulation effect of the power arc system. The thinner the diameter of the wire used, the stronger the self-regulation effect of the arc, the more stable the arc, and the less spatter. This is the principle of using fine wire for CO2 welding. Tangshan Panasonic CO2 welding machine has the best self-regulation effect of the arc and the most stable performance through advanced control technology.
4. What is the load duration of a welding machine?
Answer: The load duration refers to the ability of the welding power source to work continuously under a certain current. The national standard stipulates that the rated load duration of manual welding is 60%, and that of automatic or semi-automatic welding is 60% and 100%. For example, the rated current of a 500KR2 welding machine is 500A when the rated load duration is 60%, and when the actual load duration is 100% (automatic welding), its maximum welding current is ≤387A.
5. What is the load duration of a welding gun?
Answer: It refers to the ability of a welding gun to work continuously under a certain current.
〈1〉For example, the rated load duration of a 350KR welding gun is 70% and the rated current is 350A when welding with CO2; when the actual load duration is 100% (automatic welding), its maximum welding current is ≤290A. In MAG welding, the rated load duration is 35%, and when the actual load duration is 100%, its maximum welding current is ≤207A.
<2> For example, the rated load duration of the 500KR welding gun is 70% and the rated current is 500A during CO2 welding; when the actual load duration is 100% (automatic welding), its maximum welding current is ≤418A. In MAG welding, the rated load duration is 35%, and when the actual load duration is 100%, its maximum welding current is ≤296A.
6. What is the positive connection method?
Answer: During DC arc welding, the connection method of connecting the workpiece to the positive pole of the output end of the welding machine and the welding gun (welding clamp) to the negative pole of the output end is called "positive connection method" or positive polarity.
7. What is the reverse connection method?
Answer: During DC arc welding, the connection method of connecting the workpiece to the negative pole of the output end of the welding machine and the welding gun (welding clamp) to the positive pole of the output end is called "reverse connection method" or reverse polarity. Alkaline electrodes (such as 507), carbon arc gouging, and CO2 welding all use the reverse connection method.
8. What is the delayed gas stop time?
Answer: It is the time after the welding arc is extinguished, the shielding gas is delayed for 0.3-5 seconds before stopping the gas supply; generally, the delayed gas stop time for TIG welding of aluminum, stainless steel, titanium and other metals is as long as 3-5 seconds.