Continuously annealed or hot galvanized cold rolled transformation induced plasticity steel plate and preparation method thereof

The invention provides a continuously annealed or hot galvanized cold rolled transformation induced plasticity steel plate and a preparation method thereof. The steel plate comprises the following components: 0.1-0.5% of C, 0.2-2.0% of Al, 0.5-2.5% of Mn, 0.02-0.12% of P, not more than 0.02% of S, not more than 0.01% of N and the balance of Fe. The method comprises smelting, rolling and continuous annealing or hot galvanizing and is characterized in that the hot rolling heating temperature is 1100-1250 DEG C; the heat is preserved for 1-4 hours; the initial rolling temperature is 1100 DEG C; the finish rolling temperature is 750-900 DEG C; the coiling temperature is less than 700 DEG C; accumulated cold rolled reduction is 40-80%; the continuous annealing temperature is 700-(Ac3+50) DEG C; the heat is preserved for 30-360 seconds; the cooling rate is 10-150 DEG C/s; the aging temperature is 250-600 DEG C; the aging time is 30-1200 seconds; the steel plate is cooled to the room temperature at a rate of 5-100 DEG C/s; the hot galvanizing and annealing temperature is 700-(Ac3+50) DEG C; the heat is preserved for 30-360 seconds; the cooling rate is 10-150 DEG C/s; the steel plate is cooled to 400-500 DEG C and enters into a zinc pot after the heat is preserved for 10-300 seconds; the zinc pot temperature is 450-500 DEG C; the impregnation time is 1-10 seconds; the steel plate is cooled to the zinc liquid temperature to be galvanized; the impregnation temperature is 450-500 DEG C; and the impregnation time is 1-10 seconds. The steel plate has good strength, plasticity, forming property, welding property and galvanizing property and is suitable for industrial production.