CSP流程生产经济型热轧双相钢的工艺与组织性能

Technology and Microstructure-Mechanical Properties of Economical Hot Rolled Dual Phase Steel By CSP Process

为了在CSP产线上开发新一代经济型热轧双相钢,并确定生产的最佳成分和工艺,介绍了在武钢CSP生产线进行580MPa级热轧双相钢的工业化生产试制情况。分别采用C-Mn-Si系和C-Mn-Si-Cr系钢为原料,通过控制轧制和基于超强冷却设备的控制冷却工艺,成功开发出抗拉强度580MPa级热轧双相钢。通过比较分析2种成分钢的力学性能和微观组织,结果表明:经济型的C-Mn-Si系钢相对于C-Mn-Si-Cr系钢具有屈服强度低、屈强比小、伸长率大的特点,虽然马氏体量相对较少,但具有马氏体呈岛状更加均匀分布在铁素体晶界上等典型双相钢的特征,同时提出了生产过程中控制铁素体析出量和促进马氏体形成的具体措施。

In order to develop new generation economical DP steel and obtain the optimum composition and processing parameters in CSP line,the pilot production of 580 MPa hot-rolled dual phase strip at WISCO CSP Plant was introduced.Two series of dual phase steel,such as plain C-Mn-Si and C-Mn-Si-Cr steel,were produced successfully by controlled rolling and controlled cooling with ultra fast cooling capacity.The tensile strength of both series of DP steel achieves 580 MPa.Comparison of mechanical properties and microstructure between two steels,the results show that the cost of C-Si-Mn steel is lower than C-Si-Mn-Cr steel,C-Si-Mn steel has lower yield stress,lower yield strength/tensile strength ratio and higher elongation.Although obtained martensite fraction in C-Si-Mn steel was lower,the island martensite distributed among the ferrite grain boundaries was more uniform.The specific measures of controlling ferrite formation and promoting martensite transformation were put forward.