由于冶金条件的限制,钢中或多或少存在一定非金属夹杂物,如硫化锰等。由于硫化物的可塑性较好,当钢经轧制等压力加工后,硫化锰沿加工方向被拉长,呈线条状分布,起着割裂基体的作用。断裂时,它充当裂纹源,引起裂纹扩张,韧性降低,特别是对横向冲击韧性的影响最大。近几年来,多采用高温球化退火工艺来改 Due to the limitation of metallurgical conditions, some non-metallic inclusions exist in the steel, such as manganese sulfide. Due to the good plasticity of sulfide, when the steel is processed by pressure such as rolling, the manganese sulfide is elongated along the processing direction and distributed in the form of lines, which plays the role of splitting the matrix. Fracture, it acts as a source of cracks, causing crack expansion, reducing toughness, in particular, the greatest impact on the lateral impact toughness. In recent years, the use of high temperature ball annealing process to change