Welding Rod Core
Welding Rod Core
Welding rod (covered electrode) is a metal strip that is melted and filled in the joint of the welding workpiece during gas welding or electric welding. The material of the welding rod is usually the same as the material of the work piece.
The metal core covered by the coating in the welding rod (covered electrode) is called the welding core. The welding core is generally a steel wire with a certain length and diameter. When welding, the welding core has two functions: first, it conducts the welding current and generates an arc to convert electrical energy into heat energy; second, the welding core itself melts as a filler metal and fuses with the liquid base metal to form a weld.
When welding with electrodes, the core metal accounts for part of the entire weld metal. Therefore, the chemical composition of the welding core directly affects the quality of the weld. Therefore, the grade and composition of the steel wire used as the core of the welding rod are separately specified.
If it is used as filler metal in fusion welding methods such as automatic submerged arc welding, electroslag welding, gas shielded welding, and gas welding, it is called welding wire.
What is a Covered Electrode?
The welding rod (covered electrode) is a coated molten electrode used for arc welding. It is composed of two parts: a coating and a welding core. The coating at the front end of the welding rod has a chamfer of about 45°, which is to facilitate arc ignition.
There is a section of exposed welding core at the tail, which accounts for about 1/16 of the total length of the electrode, which is convenient for holding the welding clamp and conducts electricity.
The diameter of the welding rod actually refers to the diameter of the welding core), which is usually 2, 2.5, 3.2 or 3, 4, 5 or 6mm. The most commonly used ones are small 3.2, small 4 and small 5, and their length is “L “Generally between 200 and 550 mm.
Welding rod (covered electrode) is to apply coating (coating) evenly and centripetally on the metal welding core on the welding core. The welding core is the metal core of the welding rod. In order to ensure the quality and performance of the weld, there are strict regulations on the content of each metal element in the welding core. In particular, the content of harmful impurities (such as sulfur, phosphorus, etc.) should be strictly regulated. limitations, better than the parent material.
The welding rod consists of two parts: welding core and coating
Different types have different welding cores. The composition of the welding core directly affects the composition and performance of the weld metal, so the harmful elements in the welding core should be as small as possible. The welding core for welding carbon steel and low alloy steel generally uses low carbon steel as the welding core, and adds manganese, silicon, chromium, nickel and other ingredients (see the national standard for welding wire G1300-77 for details).
The reason for using low carbon is that on the one hand, the steel wire has good plasticity when the carbon content is low, and it is easier to draw the welding wire. On the other hand, it can reduce the CO content of the reducing gas, reduce spatter or pores, and increase the temperature of the weld metal when it solidifies. Good for overhead welding. Adding other alloying elements is mainly to ensure the comprehensive mechanical properties of the weld. It also has a certain effect on the welding process performance and the removal of impurities. For high-alloy steel and other metal materials such as aluminum, copper, cast iron, etc., the welding core composition must be similar to that of the metal to be welded, and the content of impurities must also be controlled, and certain alloying elements are often added according to process requirements.
- It is easy to start the arc, ensure the stability of the arc, and reduce the spatter during the welding process.
- The melting speed of the coating should be slower than the melting speed of the welding core to create a trumpet-shaped sleeve (the length of the sleeve should be smaller than the diameter of the welding core), which is conducive to the transfer of droplets and the creation of a protective atmosphere;
- The specific gravity of the molten slag should be smaller than the specific gravity of the molten metal, the solidification temperature should also be slightly lower than the metal solidification temperature, and the slag shell should be easy to remove;
- It has alloying and metallurgical processing functions;
- Suitable for welding in various positions.
Eternal Bliss Alloy Casting & Forging Co, Ltd.
Our What’s app: 0086- 182 6227 4295