[China Aluminum Network] There are many types of streaks in extruded aluminum profiles, and the formation factors are also more complicated. Here are some common causes and solutions for common streaks. Tape Measure Springs,Rewind Springs,Carbon Steel Springs,Clock Springs Ningbo Yunsheng Elastic Components Co.,Ltd , https://www.yunshengsprings.com
First, the friction pattern die each time the light die on the machine, the lines can not be a one-to-one correspondence, there are light and heavy.
The main reason is that in the extrusion process, the profile exits the die hole closely to the working belt momentarily, forming a pair of dry friction pairs in the hot state, and the working belt is divided into two zones - the adhesive zone and the sliding zone. . In the adhesive zone, the metallic dots are subjected to forces from at least two aspects: friction and shear. When the friction force of the metal point in the adhesion zone is greater than the shear force, the metal dot will adhere to the surface of the work zone in the adhesion zone, and the surface of the profile will be scratched to form a friction pattern.
Solution 1. Adjust the working angle of the die with the outlet angle α so that it is in the range of -1° to -3°. This can reduce the height of the work zone with the adhesive zone, reduce the friction in the zone, and increase the slide zone.
2. Efficient mold nitriding treatment to keep the hardness of the mold surface above HV900; the surface sulfur permeability of the working belt can reduce the friction in the adhesive area and reduce the friction pattern.
Second, the main reasons for the formation of stripe analysis Cast ingot microstructure is not uniform, segregation of components, the ingot surface under the existence of more serious defects, the ingot ratio is not fully processed, etc., in the subsequent extrusion process leads to uneven surface composition of the profile , so that the coloring ability of the profile after oxidation is not the same, forming tissue stripes.
Solution 1. Perform the casting process reasonably to eliminate or reduce tissue segregation.
2. Ingot surface wagon;
3, serious ingot homogenization.
Third, the metallic bright lines appear bright in the oxide white material, and in most cases, they are straight and have an indefinite width. In the oxidation coloring material, the stripes are light-colored stripes.
Main reason analysis When the friction or deformation of the metal flow occurs extremely violently, the local temperature of the metal will rise very high. In addition, the uneven flow of the metal will cause the grain to break violently, and then recrystallization will occur, resulting in a change in the structure of the site. Oxidation treatment results in the appearance of longitudinal bright streaks on the surface of the profile, which causes the profile to appear uncolored or to appear light-colored stripes.
Solution 1, rational design mold structure;
2, mold processing should pay attention to the transition of the work belt, to prevent the emergence of work with a gap;
3, to ensure that the model bridge was drop-shaped, eliminating corners.
Fourth, the weld stripe weld stripe, also known as the weld, straight long, in the oxidation of white materials, more light gray, more coloring material light color.
Analysis of the main reasons 1. The design of die orifices is too small;
2. The depth of the welding chamber is not enough, and there is no guarantee that there will be enough pressure;
3. Insufficient supply of aluminum material in the mold welding room during extrusion;
4, extrusion process is not reasonable, improper lubrication.
Solution 1, rational design mold structure;
2. Pay attention to the coordination of extrusion temperature and extrusion speed;
3, to reduce lubrication or not lubrication.