一、绪言具有铁素体+珠光体组织的低碳非调质细晶粒钢,可以期望随着铁素体晶粒的细化与珠光体数量的减少,而获得良好的低温冲击韧性。为了减少珠光体,要求尽量降低含碳量,在不致生成贝茵体的范围内尽量多地添加锰,使A_3转变点下降;进而加入微量的Nb、V、Ti、Al等细化晶粒元素,从而生产出细晶粒钢。 I. INTRODUCTION Low-carbon non-fine-grained fine grain steels with ferrite + pearlite structure can be expected to obtain good low-temperature impact toughness with the refinement of ferrite grains and the reduction of the amount of pearlite. In order to reduce the pearlite, it is required to reduce the carbon content as much as possible and to add manganese as much as possible to the extent that the bauxite is not formed, so that the A 3 transformation point is decreased; further, the fine grain elements such as Nb, V, Ti and Al are added , To produce fine grain steel.