反常组织对Q235钢力学性能的影响

Effects on the Properties of Abnormal Microstructure in Q235 Steel

对Ｑ２３５ 钢中反常组织的形成及对力学性能的影响进行了试验研究。结果表明，反常组织的形成与多个因素有关，关键因素是等温温度及冷却方式；反常组织降低材料的强度及冲击韧性，细晶（８—９ 级）状态下，反常组织对钢材的断裂性质影响不大，粗晶（５—６ 级）状态下反常组织的危害极大，并导致材料发生室温脆性断裂。

The formation and effects on the properties of abnormal microstructure in Q235 plain carbon steel were studied. The results show that the formation of abnormal microstructure results from some factors, but the key factor is cooling rate and isothermal temperature. The strength and impact toughness of the steel decreases seriously caused by abnormal microstructure, but its plasticity fracture behavior has no variety in the case of fine grain (8_9 grade). However, in coarse grain state(5_6 grade), abnormal microstructure lead to Q235 steel bringing on brittle fracture at the room temperature.