1. What is arc striking? What are the ways to start an arc? What should you pay attention to when striking an arc?
The process of igniting and producing a stable arc is called arc ignition. There are two arc ignition methods: scratch arc ignition method and direct arc ignition method.
For the scratch arc ignition method, align the end of the welding rod with the arc ignition point, and then use your wrist force to lightly scratch the welding rod on the surface of the weldment like a match. The scratching distance is 10-20 mm, and lift the welding rod 3-3 mm.
For the direct arc ignition method, first align the welding rod with the part to be welded and gently touch it, and then lift the welding rod 2-3 mm in time to ignite.
When igniting the arc, lift the welding rod quickly, otherwise it will easily stick to the workpiece. If stickiness occurs, shake the welding rod left and right and pull it apart. If it cannot be connected, loosen the welding clamp, cut off the welding circuit, and wait until the weldment is slightly cold before processing.
The following points should be noted when striking an arc:
1 After arc ignition, it should be ensured that the arc length does not exceed the diameter of the welding rod. Do not use excessive force when igniting the arc to prevent the coating at the arc ignition end from cracking or even falling off, affecting arc ignition and welding.
2 Do not ignite the weldment at will when striking the arc, especially high-strength steel, low-temperature steel, and stainless steel. This is because arc scratched parts can easily cause hardening or micro-cracks, and stainless steel will reduce corrosion resistance.
3 When igniting the arc, if the welding rod and the weldment are connected together and cannot be removed by shaking, the welding clamp should be removed immediately. After the welding rod cools, it can be easily removed.
2. What is spot fixing before welding?
In order to fix the relative position of the two weldments, positioning welding (usually called point fixing) is performed on both ends of the workpiece before welding.
After solidification, the residue should be cleaned up. If the weldment is long, a welding spot can be fixed every 200-300mm.
3. What is direct connection? What is reverse connection?
During the welding process, the two poles of the arc welding machine are connected to the welding rod and the weldment respectively, forming a complete welding circuit.
For a DC welder, one is extremely positive and the other is extremely negative. When the weldment is connected to the positive electrode and the welding clamp (rod) is connected to the negative electrode, it is called the positive connection method (referred to as positive connection), and vice versa is called the reverse connection method (referred to as reverse connection).
For AC welding machines, since the polarity of the power source is alternating, there is no problem of forward and reverse connection.
4. How to start welding with arc welding rod?
The beginning of the weld is the beginning of the weld. Due to the low temperature of the weldment, the temperature of the weldment cannot be raised quickly after arc ignition. Generally, this part of the weld has a slightly higher residual height, shallower penetration, and may even suffer from poor fusion and slag inclusion. Therefore, after arc ignition, the arc should be slightly stretched to preheat the workpiece, and then the pressure arc can be used for normal welding.
The reflow method is mostly used for flat welding and alkaline electrodes. The arc is struck from 10 mm away from the starting point, and the arc is gradually lowered while the arc is reflowed to the starting point. At the same time, the electrode swings slightly to achieve the required weld width, and then normal welding is performed.
5. What is the welding arc voltage? What does it do?
The voltage drop between the two ends of the arc (the two electrodes) is called the arc voltage. It includes cathode voltage drop, anode voltage drop and arc column voltage drop, and is numerically equal to the sum of the three voltage drops.
The arc voltage mainly depends on the arc length. The arc voltage is larger when the arc is longer, and the arc voltage is smaller when the arc is short. The larger the arc voltage, the larger the welding width, and the smaller the arc voltage, the smaller the welding width.
During the welding process, in order to obtain appropriate penetration width and penetration, as the welding current increases, the arc voltage should be increased accordingly.
6. What is the welding speed? What does it do?
The length of a single weld completed per unit time is called the welding speed. The speed of welding depends on the size of the welding current. Large welding current can increase the welding speed, but do not mistakenly think that the welding production efficiency depends on the welding speed;
It is not that the higher the welding speed, the higher the welding production efficiency, but the welding current determines the level of welding production efficiency. The greater the welding current, the greater the amount of metal melted per unit time, and the higher the welding production efficiency.
Under a certain welding current, the welding speed affects the thickness of the weld bead. The higher the welding speed, the thinner the weld bead, and the lower the welding speed, the thicker the weld bead.
Post time: Feb-06-2026