研究了一种用于汽车车体的高强、高塑性中C-高Mn系孪晶诱发塑性(TWIP)钢, 有助于达到汽车减排、节能和安全的目的. 通过单向拉伸实验和OM观察, 分析研究了水淬工艺对TWIP钢的力学性能和微观组织的影响规律, 采用SEM和TEM对不同变形程度TWIP钢的精 细结构进行了分析. 结果表明, 随着水淬温度的提高, 退火孪晶体积分数和晶粒尺寸增大, 塑性、加工硬化性提高, 而试件的强度和屈强比降低, 可以获得抗拉强度960 MPa, 延伸率60.5%, 具有优异的综合力学性能(强塑积最高达6.096×104 MPa?%)的试件; 具有大量退火孪晶的奥氏体在变形过程中产生大量的形变孪晶, 提高了TWIP钢的强度和塑性.
In order to reduce greenhouse gas emissions, improve fuel economy and enhance safety of automobiles, a new high–strength and high–plasticity twinning induced plasticity (TWIP) steel containing medium carbon and high manganese has been developed. The effects of water quenching
process on the microstructures of such TWIP steels and deformed ones were observed by OM, SEM and TEM, and effects on the mechanical properties were investigated by unidirectional tensile. The experimental results show that the volume fraction of annealing twins and the average size of grains, the plasticity and the strain hardening capability of TWIP steel increase with the increase of water quenching temperature, but the strength and the yield ratio decrease with it. Therefore, the samples could be obtained with a better comprehensive property, that is, the tensile strenth is 960 MPa, the elongation percentage is 60.5% and the strength–plasticity product achieves the maximum value of 6.096 ×104 MPa·%. It is also found that the austenite with a loof annealing twins can be transformed into deformation twins with the increase of the deformation degree, so that the strength and plasticity of TWIP steel are improved.