【摘要】 AP1000核电主管道材料为316LN,该钢种无法通过热处理细化晶粒,需在锻造过程中保证产品的晶粒度要求。该文研究了316LN钢单道次和多道次变形条件下的动态再结晶行为,获得316LN钢在锻造成形中的晶粒细化判据;提出了上平下V砧的改进砧形,对锻件采用大圆角V砧以及上下不等砧宽比进行拔长,采用数值模拟和物理模拟相结合的方法,研究了拔长过程应力应变分布规律,并确定合理的工艺参数,有效地提高锻件变形区域的等效应变及均匀分布,达到锻件变形均匀和晶粒细化的目的。该结果对核电主管道锻造工艺方案优化具有理论参考价值。更多还原

【Abstract】 The grains in 316LN steel used in the nuclear main pipes of the AP1000 cannot be refined by heat treatment.Consequently,forging is used to refine the grain structure.The grain refinement is related to the dynamic recrystallization behavior of 316LN steel for both single-pass and multi-pass deformation.Refined anvils for the upper flat and lower V-shaped anvil are used to give a large fillet and different blank width ratios with the stress and strain distributions then investigated using numerical and modeling simulations.Then,the appropriate process parameters are determined to improve the strain and homogeneity in the forging deformation area to give homogeneous deformation and grain refinement in the forgings.The results can be used to optimize the forging of nuclear main pipes.更多还原