冷轧TRB薄板的连续退火工艺试验研究

摘要

To explore the effect of continuous annealing on microstructure and properties of TRB sheet, a reversible four high cold rolling mill was used to roll a single variable gauge zone TRB sheet in laboratory. The differences of microstructure and mechanical properties of various thickness zones were investigated by continuous annealing experiments of cold rolled DP590 dual phase steel and 22 MnB5 hot forming steel TRB sheet, which were analyzed by optical microscope and scanning electrical scope and tested by tension and hardness experiments. Results show that the maximum thickness deviation in variable gauge zone of TRB sheet is less than 0. 03 mm, length deviation is less than 1 mm. The temperature of the thin zone of TBR sheet is below 57-20℃ than the variable thickness zone and thick zone during cooling and over-aging phase of continuous annealing. It leads to the higher tensile strength and elongation in thin zone than others, and the almost same yield strength as that of in thick zone for DP590 steel, but higher yield and tensile strength for 22MnB5 steel. There are small changes of Vickers hardness in the variable gauge zone. The continuous annealing process should be determined by the thickness of the thick zone for cold rolled DP590 dual phase steel TRB sheet, which is more conducive to the mechanical properties control. Batch annealing is suggested for 22MnB5 hot forming steel TRB sheet.%为了探索连续退火工艺对TRB板组织与性能的影响,在实验室采用四辊可逆式冷轧机进行单厚度过渡区TRB板轧制,对轧制的DP590双相钢和22MnB5热成形钢TRB薄板进行模拟连续退火试验,利用光学显微镜和扫描电镜,以及拉伸和硬度试验方法研究钢板退火后各厚度区的组织与力学性能差别.研究表明：TRB板变厚度区的最大厚度偏差为0.03 mm,长度误差<1.0 mm. TRB板在连续退火的冷却段和过时效段,其薄区温度较过渡区和厚区的温度偏低57~20℃,导致DP590钢板薄区的抗拉强度和伸长率较高,屈服强度与厚区的相当,而22MnB5钢TRB板的屈服与抗拉强度偏高.在TRB板的变厚度区内维氏硬度波动较小.根据厚区的厚度来制定冷轧DP590双相钢TRB薄板的连续退火工艺,将更有利于保证钢板的组织与力学性能,对22MnB5热成形钢TRB薄板建议采用罩式退火.