研究了355MPa级超细晶低碳钢热连轧板拉伸性能和晶粒尺寸之间的关系，结果表明屈服强度σs与晶粒尺寸d成HallPetch关系；经验证，对晶粒尺寸在3μm～10μm范围的低碳钢热连轧板，其屈服强度σs的计算值与测量值偏差较小，HallPetch关系具有很好的适用性。

The relationship between the grain size and the tensile strength of continuous rolling low carbon sheet with ultrafine grains was studied. The results show that it matches the HallPetch relationship. It was verified that the measured and calculated yield strength value of low carbon continuous rolling steet with the 3～10 μm grain size has little error, HallPetch relationship has good applicability.