Compared with traditional welding technology, laser welding technology has the advantages of concentrated energy density, small residual stress and deformation, non-contact welding, high welding efficiency, good welding surface forming, etc., and is gradually widely used in electronic parts, automobile manufacturing, aerospace and other equipment manufacturing fields, and continues to expand to more material processing industries.
As we all know, in the welding process, welding quality control is extremely important! However, in the welding process, due to the influence of coal bonding process, environment and other factors, the welding joint will produce non-dense, discontinuous, notch and other phenomena, called welding defects.
There are many kinds of welding defects, so there are different classification methods
1.Classification by location: there are surface defects, internal defects
2.According to the distribution area classification: weld deficiency, fusion zone deficiency, heat affected zone deficiency and base material deficiency!
3.According to the forming and performance classification: there are forming deficiencies (porosity spatter, poor forming consistency), connection deficiencies (cracks, biting edges), performance deficiencies, etc
4.According to the causes of classification: there are structural deficiencies, technological deficiencies and gold deficiencies
5.Classification according to the mechanism affecting the fracture: there are plane defects (non-fused, linear slag inclusion, etc.) and non-plane defects (such as pores, circular slag inclusion, etc.)
For these welding deficiencies, it is necessary to improve them according to the actual needs of welding and actual debugging. Next, Riselaser mainly talks about some common welding performance defects and their solutions.
1.Porosity: Welding porosity will seriously affect the air tightness and welding strength of welding, and it is most likely to appear when welding materials with strong thermal conductivity.
General treatment method: before welding, remove the surface oil, oxide, water, rust and other dirt, which can reduce the tendency of stomata; The quality of the welding pool can be improved by slowing down the cooling time properly and giving sufficient time for the gas produced in the welding process to overflow.
2.Crack: The welding is caused by a large shrinkage force before complete solidification, and the common welding cracks are transverse cracks, longitudinal cracks, and final cracks.
General treatment method: reduce the internal stress by preheating before welding, annealing after coal, and adjust the process parameters to slow down the start and end time and reduce the end crack.
3.Splash: There is oil on the material before welding or the material itself contains low boiling point elements, forming a closed space during the welding process, resulting in gas expansion inside the space. Splashing will affect the forming effect, contaminate the lens, etc
General treatment method: appropriately reduce the power to ensure the depth of penetration, appropriately increase the welding speed, appropriately increase the defocusing amount, and reduce the laser power density on the surface of the workpiece
4.Edge biting: The welding speed is too fast, and the liquid metal at the back of the hole pointing to the center is too late to redistribute, forming a depression on both sides of the weld
General treatment method: appropriately increase the laser heat input, reduce the welding speed, and slow down the cooling of the molten pool
The principle of laser welding is that the high energy density laser beam is shot at the surface of the welder, and the workpiece is welded and instantly melted to form a melt pool. By controlling the relative motion of the laser beam and the welding position, the welding will have welding defects in some application scenarios. For example, external defects can be found from the surface of the workpiece without the aid of instruments (such as cracks, pores, biting edges, welding bumps, flying measurements, etc.). The seam of the internal defect is difficult to be observed by the human eye, and the defect that does not meet the standard requirements must be detected by means of the instrument (such as slag inclusion, non-penetration, non-fusion, internal porosity, etc.).
With the continuous deepening of laser welding technology research, laser welding has also made great breakthroughs in terms of technology, process treatment, defect solutions, etc. RiseLaser has been focusing on laser cutting and laser welding for many years, based on the actual needs of customers, and constantly improve and optimize products, can provide customers with customized solutions and professional technical support services.
