Copper is a widely used material in industry. There are many types of segmentation. Due to its wide application, laser welding is a problem faced by laser welding machine manufacturers. Next, Tongfa Laser will share its experience in laser welding of brass, bronze, and white copper.

Welding performance of welded brass

The liquid solid crystallization interval of brass is small, making it difficult to analyze and produce low melting eutectic during welding, so the tendency for hot cracking is smaller than that of pure copper and bronze. In addition. Brass has high strength, high coefficient of linear expansion, and high stress during welding, which can induce cold cracking.

The biggest welding problem with brass is the evaporation and burning of zinc, which not only reduces the mechanical properties and corrosion resistance of the joint. Zinc oxide white smoke hinders operation due to increased pore tendency and is harmful to the health of welders, and preventive measures must be taken.

Welding performance of copper

There are various types of bronze, and their welding performance also has its own characteristics. Now, the welding performance of the main bronze varieties is introduced as follows:

1. Silicon bronze has good deoxygenation ability, good fluidity of liquid metal, and thermal conductivity is only about 1/10 of pure copper, close to low-carbon steel. Therefore, preheating is generally not required before welding. Silicon bronze has the best welding performance among copper and copper alloys. Except for oxygen acetylene gas welding, all conventional welding methods can be used for welding.

2. The main alloy component of tin bronze, tin, oxidizes at high temperatures to form Sno2 and melts into the molten pool, resulting in significant segregation during weld crystallization. After the surface of the weld is heated and melted, the low melting point segregation will precipitate small spherical tin beads in the early stage, reducing the strength and corrosion resistance of the joint. Another function of tin is to expand the crystal gap of the alloy, which can easily generate coarse and fragile dendritic grain gaps during the crystallization process, leading to loosening of the weld structure and even the formation of pores and thermal cracks. Visible poor weldability.

3. The main difficulty in welding aluminum bronze is that the dense high melting point oxide film of aluminum oxide product Al2O3 adheres to the droplet, hindering the transition of the droplet and the fusion between the droplet and the base metal. The oxide film on its surface can affect the heating of the molten pool by the heat source, disrupt the stability of the arc, and further exacerbate the formation of the weld seam. The weldability of aluminum bronze is also the worst among various types of bronze.

Welding performance of welded white copper

The conductivity and thermal conductivity of white copper are similar to those of carbon steel, therefore it has good welding performance. Preheating is not required before welding. Welding rod arc welding, various gas shielded welding and plasma arc welding can be used. However, white copper is very sensitive to Pb, P, S, and other impurities, and the low melting crystals formed by them may cause thermal cracks under welding stress. Therefore, it is necessary to strictly control the impurity content in the welding material.