JCOE制管与防腐过程对抗大变形钢性能的影响

摘要

Microstructure and properties of three kinds of high deformability steel plate(A, B, C) are compared. In B and C structure the polygonal ferrite content was higher, and it possessed greater high deformation resistance. Due to strong hardening effect, the yield strength and Y/T ratio increased significantly after JCOE, uniform elongation and strain hardening exponent decreased. By thermal simulation method, the effect of strain aging in coating process was studied. The results showed that the degree of strain aging was in connection with structure, strain aging in A was more obvious, and the continuous yield behavior of A was not obvious after strain aging. Compared the final properties, it found that C possessed dual phase microstructure of polygonal ferrite and bainite layered overlapping distribution, its high deformation resistance ability was the best, Y/T ratio(0.79) was the lowest, uniform elongation(7.5％)and strain hardening exponent(n=0.12)were the highest.%比较了A,B和C三种抗大变形钢板组织及性能,B和C组织中多边形铁素体含量更高,抗大变形能力较好.JCOE制管中三种钢板加工硬化明显,制管后屈服强度、屈强比显著上升,均匀延伸率、形变强化指数下降.通过热模拟方法研究了钢管防腐中应变时效作用.研究发现,应变时效程度与钢的组织有关,其中以针状铁素体为主的A试样应变时效更显著,时效后拉伸曲线中连续屈服行为不再明显.对比时效后钢管最终性能,C试样具有多边形铁素体与贝氏体层状交叠分布的双相组织,抗大变形能力最佳,屈强比(0.79)最低,均匀延伸率(7.5%)及形变强化指数(n=0.12)最高.