Galvanized channel steel has some defects on the surface, such as uneven surface or small zinc particles. What is the reason for the rough surface of galvanized channel steel?
1. The effect of pre plating treatment on the surface roughness of the galvanized layer of channel steel, resulting in "acid washing".
After pickling, "the surface of the steel is roughened or bean marks appear, which is one of the reasons for the roughness of the workpiece surface after Hot-dip galvanization.
2. Excessive zinc bath temperature or soaking time can affect the surface roughness of the galvanized layer on channel steel.
When the temperature of the zinc bath is too high, the zinc immersion time is too long, or due to the influence of channel steel composition and Saint Delin effect, there are too many or uneven Zn-Fe alloy phases, and the surface roughness is also caused. The thicker the zinc coating, the rougher the surface.
After being taken out of the zinc liquid, the Hot-dip galvanization channel steel cools slowly, or the steel part is too thick, or the channel steel does not accumulate immediately after Hot-dip galvanization, and the surface may be rough.
The processing technology of channel steel is relatively complex. During processing, the main technology is heat treatment. Heat treatment is not only heating, but also has many limitations. In order to complete the structural transformation, dissolution of carbides, and homogenization of austenite composition of the internal and external parts of the workpiece, it is necessary to heat it for a certain period of time during the treatment process.
Channel steel is usually subjected to heat treatment technology during the processing. Heat treatment technology generally requires a temperature of up to Baidu, or even several thousand degrees Celsius, which requires high-performance processing technology for processing. In the heat treatment technology in production practice, in addition to the general principles, factors such as the chemical composition technical requirements, size and shape, original structure, heating equipment, and cooling medium of channel steel should also be considered, and the heating temperature should be adjusted appropriately.