Effect Of Composition And Annealing Process On Microstructure And Mechanical Properties Of Low Carbon Cold Rolled Sheet

At present, many steel companies increased use of low-grade ore and scrapproportion, cause an increase in the content of residual elements in steel. For this reason,steel processing and product performance becomes worse. Annealing process, animportant part of the production of cold rolled sheet, has a significant impact on productperformance and energy consumption. To improve production levels, a research on theeffects of Cr, Ni and other residual element content increases and annealing process onthe properties has been carried out.An effect of Cr、Ni elements and deformation on recrystallization behavior of coldrolled low carbon steel sheets has been studied. Materials of cold rolled low carbon steelsheets are Q195hot rolled plate. The simulation of the bell type annealing process hasbeen carried out, to research about the effects of main component and annealing processon microstructure and mechanical properties. The main conclusions are as follows:With Cr、Ni element content increased by25%and94%respectively, the completerecrystallization temperature increase about20~40℃; When the cold deformationincreases from52%to80%, recrystallization driving force produced by the dislocationdensity increased by1.4×104J/m2, and the starting and complete recrystallizationtemperature both decrease20~40℃.When Cr content is within0.108%~0.365%, Cr elements have less effect on thedeformation resistance. Microstructure of annealing plate did not have a significantimpact with Cr、Ni content change. With the increase of content of Cr, Ni element,hardness and strength have a slight decline, but elongation and value of n unchanged;small amount of Mn、Si、P can have obvious reinforcement effect.Appropriate increase annealing temperature, annealing cooling and heating speedcan reduce the number of chain of pearlite. With the rise of heating temperature,recrystallization grain size increases, yield strength and tensile strength decrease, andelongation increases. Pearlite change is not obvious and grain size increase when holdingtime is extend, and yield strength and tensile strength decreased and elongation increases,but not change degree. With increasing of deformation, grain size decreases, hardnessand strength are declining, the more deformation change, the more strength change.