Teach you how to choose welding materials

11 Oct 2021

With the rapid development of the welding industry, we divide the welding technology into: electric welding, argon arc welding, gas shielded welding, and oxygen cutting, etc. The welding materials used will be different for different welding technologies. In order to adapt to the ever-increasing market competition, the welding material products of welding machine in the future will gradually replace manual products with high-efficiency and high-quality products with a higher degree of automation, and develop in the direction of high strength, high toughness, low hydrogen, and environmental protection to meet different types Welding structure, different welding technical requirements under different service conditions.

In welding, the welded components will inevitably undergo various forming and cutting processes during the manufacturing process, such as stamping, rolling, bending, turning, planing and other processing procedures, which requires the welded joint to have a certain plastic deformation ability And cutting performance, high temperature comprehensive performance, etc. The welding process is based on the difference of the weldability of the base material, requiring the welding material to have good process performance and have the corresponding ability to resist defects such as cracks. These performance requirements cannot be ignored. The selection of welding materials and the quality of their process performance directly affect the quality of welding. In order to obtain high-quality welding results, how should we choose welding materials?

To choose the right welding material, we need to know what is the welding material? Welding materials refer to the general term for materials consumed during welding. Welding materials include all materials involved in the welding process, including welding rods, welding wires, fluxes, shielding gases, electrodes, fluxes, etc. To select welding materials, firstly, we must meet the performance of the welded joints, and secondly, we must meet some requirements on the welding process performance and manufacturing process performance of the welded joints. Finally, the selection of welding materials should be reasonable and economical.

The welding material we are talking about today is welding rod. The welding rod is a melting electrode coated with a coating for gas welding and electric welding. It is composed of a coating and a welding core, which melts the metal strip filled at the joint of the welding workpiece. The metal core covered by the coating in the welding rod is called the welding core. The welding core has two functions: one is to conduct welding current, generating an arc to convert electrical energy into heat, and the other is to melt the welding core itself as a filler metal to fuse with the liquid base metal to form a weld. Electrode coating refers to the coating layer applied on the surface of the welding core. The coating is decomposed and melted in the welding process to form gas and slag, which play a role in mechanical protection, metallurgical treatment, and improvement of process performance. There are three classification methods for welding electrodes: classification according to the purpose of the electrode, classification according to the main chemical composition of the coating, and classification according to the characteristics of the slag after the coating is melted. From this point of view, how to choose a welding rod?

The selection of welding rod must ensure the safety and feasible use of the welding structure, according to the chemical composition, mechanical properties, plate thickness and joint form of the welded material, the characteristics of the welding structure, the state of force, and the requirements for the performance of the structure. , After comprehensive examination of welding construction conditions and technical and economic benefits, the welding rods should be selected in a targeted manner, and weldability tests should be carried out if necessary. It can be concluded that there are several requirements for selecting welding rods: 1. It is easy to start the arc, to ensure the arc is stable, and the spatter is small during the welding process; 2. The melting speed of the coating should be slower than the melting speed of the welding core to create a horn-shaped sleeve , Is conducive to the droplet transition and creates a protective atmosphere; 3. The specific gravity of the slag should be less than that of the molten metal, the solidification temperature should also be slightly lower than the solidification temperature of the metal, and the slag shell should be easy to come off; 4. It has alloying and metallurgical treatment Function; Fifth, adapt to welding in various positions.

Through the above introduction, we have understood what welding material is, what is welding rod, and how to choose welding rod. According to these knowledge and requirements, we can accurately select the better welding rod that meets the conditions, contribute to the welding effect, and pave the way for becoming a better welder.

Keywords: welding machine

Originally published 11 Oct 2021, updated 11 Oct 2021.

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