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What is the difference between the grains of the chilled plate and the hot rolled plate of the packaging steel strip?
by：Hongmei
2021-03-15
What is the difference between the grains of the chilled plate and the hot rolled plate of the packaging steel strip?
The steel strip is deformed under high temperature during hot rolling. Although the shape of the crystal grains is distorted after hot rolling, the approximate round equiaxed crystals are rolled into fibrous crystal grains, but the final rolling temperature is relatively high. High, about 850-900℃, the internal energy of the steel strip is relatively high at such a high temperature, the crystal grains will quickly recover, and then recrystallization will occur, the microstructure will be locally deformed, the distortion of the crystal grains will disappear, and the energy will be released , The grains will appear new equiaxed grain structure, the final structure is more uniform, the internal stress is smaller, so the hardness of the hot-rolled product is lower, the cut is better, and it can be used as the final product, as shown in Figure 5-1 Shown.
During cold rolling, the steel strip is deformed by the high pressure of the rollers at room temperature. The uniform equiaxed grains of the original hot-rolled plate are deformed by pressure deformation, and the grains are squashed, broken, and pulled. Long, becoming an elliptical or even fibrous structure. At the same time, there are some parallel slips inside the crystal grains. Such crystal grains have more internal defects and greater internal stress. However, due to low temperature and low internal energy, the crystal grains cannot automatically return to the equiaxed crystal weave. Therefore, the final product is a fibrous structure deformed during cold rolling, with higher hardness and poor plasticity. This kind of hardening of the structure caused by pressure processing is called the 'work hardening' phenomenon. Since the chilled plate cannot meet the needs of general use, it must be heated to obtain energy from the internal structure, thereby recovering, releasing energy, and then crystallizing into an equiaxed crystal structure. The annealing of chilled plates includes periodic operation of cover annealing, and continuous production line operation of continuous annealing. The product is called cold-rolled plate, which can be used as the final product for occasions that do not require high corrosion resistance. On the modern production line, chilled plates can be used as raw materials to continuously perform the two main processes of annealing and galvanizing to produce galvanized sheets.
The steel strip is deformed under high temperature during hot rolling. Although the shape of the crystal grains is distorted after hot rolling, the approximate round equiaxed crystals are rolled into fibrous crystal grains, but the final rolling temperature is relatively high. High, about 850-900℃, the internal energy of the steel strip is relatively high at such a high temperature, the crystal grains will quickly recover, and then recrystallization will occur, the microstructure will be locally deformed, the distortion of the crystal grains will disappear, and the energy will be released , The grains will appear new equiaxed grain structure, the final structure is more uniform, the internal stress is smaller, so the hardness of the hot-rolled product is lower, the cut is better, and it can be used as the final product, as shown in Figure 5-1 Shown.
During cold rolling, the steel strip is deformed by the high pressure of the rollers at room temperature. The uniform equiaxed grains of the original hot-rolled plate are deformed by pressure deformation, and the grains are squashed, broken, and pulled. Long, becoming an elliptical or even fibrous structure. At the same time, there are some parallel slips inside the crystal grains. Such crystal grains have more internal defects and greater internal stress. However, due to low temperature and low internal energy, the crystal grains cannot automatically return to the equiaxed crystal weave. Therefore, the final product is a fibrous structure deformed during cold rolling, with higher hardness and poor plasticity. This kind of hardening of the structure caused by pressure processing is called the 'work hardening' phenomenon. Since the chilled plate cannot meet the needs of general use, it must be heated to obtain energy from the internal structure, thereby recovering, releasing energy, and then crystallizing into an equiaxed crystal structure. The annealing of chilled plates includes periodic operation of cover annealing, and continuous production line operation of continuous annealing. The product is called cold-rolled plate, which can be used as the final product for occasions that do not require high corrosion resistance. On the modern production line, chilled plates can be used as raw materials to continuously perform the two main processes of annealing and galvanizing to produce galvanized sheets.
