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What are the stresses of the packaging steel strip during the heating and cooling process?
by：Hongmei
2021-03-15
What are the stresses of the packaging steel strip during the heating and cooling process?
In a continuous hot-dip galvanizing line, the steel strip undergoes heating, cooling, galvanizing, and cooling after plating-a series of microstructure changes and performance changes. There are also various tensile and bending stresses. At the same time, it has experienced a series of changes of thermal stress, phase change stress and mechanical stress. The deformation and stress of the original chilled plate will be changed, and new deformation and stress will be generated on this basis. Relatively speaking, thermal stress has the greatest influence on plate shape, followed by mechanical stress. Phase change occurs at high temperature, and the effect of phase change stress is not too great.
For steel strip, if the same temperature is maintained everywhere in the width direction during heating or cooling, that is, heating or cooling at the same time, no new stress will be generated. But in fact, the heating or cooling of the center part and the two edge parts of the steel strip is always uneven, and the temperature difference is large. Although there is no actual measurement data for this phenomenon, it can be known from analysis and is also confirmed by the shape of the steel strip annealed in the furnace. The main reasons include the non-uniformity of the gas temperature in the furnace and the edge heating effect during the heating or cooling of the steel strip.
In a continuous hot-dip galvanizing line, the steel strip undergoes heating, cooling, galvanizing, and cooling after plating-a series of microstructure changes and performance changes. There are also various tensile and bending stresses. At the same time, it has experienced a series of changes of thermal stress, phase change stress and mechanical stress. The deformation and stress of the original chilled plate will be changed, and new deformation and stress will be generated on this basis. Relatively speaking, thermal stress has the greatest influence on plate shape, followed by mechanical stress. Phase change occurs at high temperature, and the effect of phase change stress is not too great.
For steel strip, if the same temperature is maintained everywhere in the width direction during heating or cooling, that is, heating or cooling at the same time, no new stress will be generated. But in fact, the heating or cooling of the center part and the two edge parts of the steel strip is always uneven, and the temperature difference is large. Although there is no actual measurement data for this phenomenon, it can be known from analysis and is also confirmed by the shape of the steel strip annealed in the furnace. The main reasons include the non-uniformity of the gas temperature in the furnace and the edge heating effect during the heating or cooling of the steel strip.
