Nowadays, one of the advanced welding processes in the world is laser welding.
The laser welding equipment uses a single laser pulse of high efficiency energy to locally heat the raw materials in a small area. The kinetic energy of the laser radiation source guides the internal diffusion of the raw materials according to the heat transfer, melting the raw materials and creating a special molten pool. It is a new type of welding method. It mainly aims at the electric welding of thick wall raw materials and precision parts. It can complete welding, overlap welding, sealing welding, etc. It has a high ratio of depth to length to width, small total width of electric welding, small heat affected zone, faster electric welding speed, beautiful and generous, no treatment or simple treatment after welding, small focus points, high accuracy level, and easy to complete automation.
The traditional welding machine technology uses the characteristics of high temperature in electric welding, and then the effect of electric welding is poor because of the poor control of temperature and time. However, since the advent of laser welding equipment, its electric welding effect has been loved by everyone, and more and more enterprises use laser welding equipment to carry out processing and manufacturing.
What raw materials can be welded by laser welding equipment?
Carbon steel is welded by laser welding equipment with excellent results. The key to its welding quality is the residue content. In order to obtain excellent welding quality, it must be heated when the carbon content exceeds 0.25%. When steels with different carbon content are welded by electric welding, the welding torch can be slightly biased to the side of low-carbon materials to ensure the quality of the connector. Because the heating speed and cooling speed of laser welding equipment during electric welding are very fast, carbon steel is welded by electric welding. With the increase of carbon content, the welding crack and vacancy sensitivity will also increase. Medium and high carbon steels and ordinary carbon steels can be welded by laser, but heating and post welding treatment must be carried out to eliminate stress and prevent cracks.
For laser welding of low alloy high strength steel plates, only the main welding parameters selected are appropriate, can the connectors with the same physical properties as the original materials be obtained. In general, electric welding of stainless steel plate is easier to obtain high-quality connectors than conventional electric welding. Because of the high welding speed and small heat affected zone of laser welding, the adverse effects of overheating and large thermal expansion coefficient during stainless steel welding are alleviated, and there are no defects such as pores and inclusions in electric welding. Compared with carbon steel, stainless steel plate is easier to be welded by deep penetration narrow electric welding because of its low thermal conductivity index, high kinetic energy absorption rate and melting efficiency. By welding thin plates with low power laser, a connector with good appearance and smooth and elegant electric welding can be obtained. Welding copper and alloy copper by electric welding is easy to cause problems of no welding and no penetration, so the pyrogen with concentrated kinetic energy and high power shall be used and heating measures shall be taken; When the thickness of the product workpiece is thin or the bending stiffness of the structure is small, and there is no measure to avoid deformation, it is easy to cause large deformation after welding, and when the welded joint suffers from a large rigid tube bundle, it is easy to cause welding stress; Welding copper and alloy copper is also easy to cause hot cracks; Porosity is a common defect in copper and alloy copper welding.
Aluminum and aluminum alloys are highly reflective raw materials. During electric welding of aluminum and aluminum alloys, the solubility of hydrogen in aluminum increases significantly with the increase of temperature. The dissolved hydrogen becomes the defect source of electric welding. There are many air holes in electric welding, while cracks may occur at the root during deep penetration welding, and the weld formation is weak.