细小渗碳体颗粒对温轧碳钢退火后拉伸性能的影响

Effect of Fine Cementite Particles on Tensile Properties of Carbon Steel after Warm Rolling and Annealing

利用扫描电子显微镜(SEM)、电子背散射衍射(EBSD)仪和电子拉伸试验机研究了细小渗碳体颗粒在温轧碳钢中的作用。结果表明:淬火45钢经温轧及退火后,得到超细晶结构,具有高的强度和塑性;工业纯铁在温轧后强度获得明显提高,但塑性很差。淬火45钢经温轧及退火得到高强度归因于细小的晶粒和细小分散的渗碳体颗粒;温轧工业纯铁强度的提高同样归因于晶粒的细化。而经加工过的45钢具有更好的塑性,这主要是在铁素体基体上形成了大量分散的细小渗碳体颗粒,其造成加工硬化能力的提高使均匀延伸率提高。

The effects of fine cementite particles in warm rolled carbon steel were investigated by scanning electron microscopy （SEM）, electron backscatter diffraction （EBSD） instrument and electronic tensile testing machine. The results show that： ultrafine-grained structures are acquired in the quenched 45 steel after warm rolling and annealing, and the steel has high strength and ductility. The strength of industrial pure iron after warm rolling is obviously increased, but the plasticity is very poor. The high strength of quenched 45 steel after warm rolling and annealing is attributed to the ultrafine grains and the dispersive cementite particles. The increase of the strength of industrial pure iron in warm rolling also attributed to the grain refinement. The processed 45 steel has better plasticity. This is mainly due to the formation of a large number of fine dispersed cementite panicles in the ferrite matrix, which is caused by the increase of the work hardening ability, resulting in the increase of uniform elongation.