Channel steel is a kind of long steel strip with groove cross section, which is generally divided into ordinary channel steel and light channel steel. It is a kind of carbon structural steel for construction and machinery.
Because it is a kind of section steel with complex cross-section, and the cross-section shape is groove shape, the green billets for channel steel production are carbon steel or low alloy steel billets with carbon content less than 0.25% in the production process. Scrap channels shall be delivered after heat treatment forming, normalizing or hot rolling.
Channel steel can be divided into four types according to its shape: cold-formed equal edge channel steel, cold-formed unequal edge channel steel, cold-formed inner edge channel steel and cold-formed outer edge channel steel.
The specification of hot-rolled common channel steel is 5-40 × 3. Channel steel is usually used in combination with I-beam, mainly used in building structures, automobile manufacturing, other industrial structures, as well as fixed panels and cabinets.
In industry, galvanized channel steel is also widely used, that is, a layer of zinc is plated on the surface of channel steel, which can prevent rust and improve the service life of products.
At present, hot-dip galvanizing is the main way of galvanizing channel steel surface. Hot dip galvanizing is developed from the old hot dip galvanizing method. It has been 170 years since the application of hot dip galvanizing in industry in France in 1836. However, in the past 30 years, with the rapid development of cold-rolled strip, hot-dip galvanizing industry has been widely developed.
The technological process of hot-dip galvanizing channel steel includes: raw material inspection → pickling → cleaning → zinc additive → drying → galvanizing → cooling → passivation → cleaning → waste product inspection → packaging inspection. According to the Convention, hot-dip galvanizing process can be divided into off-line annealing and on-line annealing according to different pre plating methods.
According to different galvanizing processes, hot-dip galvanized channel steel can be divided into hot-dip galvanized channel steel and hot-dip galvanized channel steel. After rust removal, the steel parts are immersed in molten zinc at 440-460 ℃ to make the zinc layer adhere to the outer surface of the steel members, so as to achieve the purpose of anti-corrosion.