Reasons for unqualified mechanical properties of cold rolled continuous strip steel

Using methods such as metallographic examination and mechanical property testing, the reasons for the unqualified mechanical performance indicators such as yield strength, tensile strength, and elongation after fracture of cold-rolled strip steel were analyzed. The results show that when the annealing rate was slow, the temperature of the open flame section strip increased. When the strip temperature exceeded the start austenitizing temperature of pearlite by 30 ℃, the pearlite in the structure tended to undergo spheroidization transformation, and the strength of the material significantly decreased. When the annealing rate was fast, the temperature of the open flame section of the strip decreased. When the temperature of the strip was 10 ℃ lower than the start austenitizing temperature of pearlite, grain recrystallization or incomplete grain growth occurred, resulting in higher material strength and lower elongation after fracture.