Manual arc welding (abbreviated as manual arc welding) is a method of welding that uses a manually operated welding rod and the workpiece being welded as two electrodes, and melts the metal using the arc heat between the welding rod and the workpiece.

Welding process: Manual arc welding consists of a welding power source, welding cable, welding tongs, welding rod, welding piece, and arc forming a circuit. During welding, the welding rod and workpiece are in contact to ignite the arc, and then the welding rod is lifted and kept at a certain distance. Under the appropriate arc voltage and welding current provided by the welding power source, the arc burns stably, producing high temperature, and the welding rod and workpiece are locally heated to a molten state. The melted metal at the end of the welding rod and the melted metal of the welded component fuse together to form a molten pool. In welding, the arc moves with the welding rod, and the liquid metal in the molten pool gradually cools and crystallizes to form a weld seam, and the two welded parts are welded together.

In welding, the core of the welding rod melts and transitions into the molten pool in the form of droplets, while the coating of the welding rod produces a certain amount of gas and liquid slag. The generated gas fills around the arc and molten pool, isolating the air. Liquid slag has a lower density than liquid metal and floats on top of the melt, thus protecting the melt. When the metal in the molten pool cools and solidifies, the slag also solidifies to form welding slag covering the surface of the weld, preventing the high-temperature weld metal from being oxidized and reducing the cooling rate of the weld. During the welding process, liquid metal undergoes complex metallurgical reactions such as deoxidation, desulfurization, dephosphorization, and dehydrogenation with liquid slag and gas, in order to obtain the appropriate chemical composition and structure of the weld metal.

characteristic

1. The equipment is simple.

2. Flexible and convenient operation.

3. Capable of all position welding suitable for welding various materials.

4. The drawback is low production efficiency and high labor intensity.

Welding rods can be used under AC or DC power supply. Not all DC welding rods can be used under AC power supply, but AC welding rods can usually be used under DC power supply.

There are two types of welding power sources: DC arc welding power sources and AC arc welding power sources. Welding rods are divided into two categories: acidic welding rods and alkaline welding rods. Acidic welding rods can use both DC and AC welding power sources, while alkaline welding rods must use DC arc welding power sources. There are two connection methods: direct current positive connection and direct current reverse connection. If there is a bias magnetic blow during the welding process, the replacement connection method will have a significant improvement. AC welding power sources generally do not produce biased magnetic blowing.

The voltage is generally between 20 and 35 volts, and the current depends on the thickness of the welding material, the specifications of the welding rod, and the welding structure, ranging from 15 to 400 amperes.