Factors Affecting the Mechanical Properties Variation after Annealing Of Cold Rolled Steel Sheet

Abstract

Cold rolled steel industry in type of batch annealing furnace, the mechanical properties of steel sheet have variation by each position. The parameters of annealing temperature and time were analysed to work out the source of mechanical properties variation. This experiment is using low-carbon steel sheet that were cold rolled at the same reduction ratio. Then annealed applying by different annealing temperature and soaking time in laboratory furnace. The mechanical properties which were examined. Yield strength, Tensile strength, %Elongation and Hardness. The result showed that (1) Increasing the annealing temperature could remarkably decrease the yield strength, tensile strength and hardness, whereas the %Elongation could be increased. (2) Increasing the soaking time could slightly effect on mechanical properties. (3) The annealing temperature of 650°C with soaking time of 2 hr should be applied to provide the mechanical properties close to target value (4) Grain size of the workpieces trended to be grown from the annealing temperature of 610°C.The experiment it can be concluded that annealing temperature and soaking time have significant effect on the mechanical properties variation in batch annealing.

Comparative Study on the Elongation of Low-Carbon Steel and Stainless Steel at Different Creep Temperatures

“…Note from the figure the relation between hardness and elongation is inverse relationship, as the lower hardness value, due to the difference in the brittleness of the metal, where at temperature of 600℃, the elongation value (0.76) of the hardness reached maximum (225BHN), While for the elongation value (1.47) the hardness number obtained (199BHN), and that was proved by Brnic et al [13]. For the sample shown in Figure 11 the graphic relationship between temperature and elongation with Brinell hardness number for low carbon steel specimen by fixing time 10 minutes, note from the figure the relation between hardness and elongation is inverse relationship As the lower the hardness value, due to the difference in the brittleness of the metal, where at temperature of 600℃, the elongation value (0.81) of the hardness reached maximum (106BHN), While for the elongation value (1.9) the hardness number obtained (87BHN), and that was proved by Wichienrak and Puajindanetr [14] and Ahmad et al [15]. By depending on heat equilibrium diagram [16], it was note that when specimens heated to (660-723) ℃ for low carbon steel, the (Ferrite + Perlite) phase was appear, the (alpha) ferrite is ductile phase therefore it has low hardness.…”