合金结构钢在连续冷却或等温处理时,常常会出现一种块状铁素体的基体上,分布着呈不规则形状排列的岛状组织,这种混合组织称之为粒状贝氏体。粒状贝氏体的出现给机械性能和工艺性能带来一定的影响。通常认为由于一定量的粒状贝氏体的存在,降低了钢的冲击韧性和抗疲劳裂纹的能力,降低了钢的屈强比(即σ_s/σ_b),提高了钢的回火抗力。 Alloy steel in the continuous cooling or isothermal treatment, there will often be a massive ferrite matrix, the distribution of irregularly arranged island organization, this mixed organization called granular bainite. The appearance of granular bainite has a certain impact on the mechanical properties and process performance. It is generally believed that due to the presence of a certain amount of granular bainite, the impact toughness and fatigue crack resistance of the steel are reduced, the yield ratio of the steel (σ_s / σ_b) is reduced and the tempering resistance of the steel is increased.