微合金钢第Ⅲ脆性区的形成机理

发布时间：2018-01-19 08:13

  本文关键词： 微合金钢 连铸坯 第Ⅲ脆性区 机理 裂纹　出处：《钢铁研究学报》2017年02期 　论文类型：期刊论文

【摘要】：为研究微合金钢第Ⅲ脆性区形成机理及其影响因素,控制连铸坯的表面裂纹,采用Gleeble热力模拟机测定了S355微合金钢在不同温度下的抗拉强度及断面收缩率。使用扫描电镜对拉伸断口进行观察分析,同时采用透射电镜对析出物进行观察分析。在此基础上对拉伸试样进行金相实验,对第二相析出进行热力学计算,分析了组织状态及第二相析出规律对脆性区的影响。结果表明,在第Ⅲ脆性区(660~850℃)内,拉伸断口呈冰糖状,韧窝较浅,形貌表现为沿晶脆性断裂。铁素体网膜沿奥氏体晶界优先析出、第二相沿晶界析出是第Ⅲ脆性区形成的主要原因。
[Abstract]:In order to study the formation mechanism of the third brittleness zone of microalloyed steel and its influencing factors, the surface crack of continuous casting billet was controlled. Tensile strength and cross section shrinkage of S355 microalloyed steel at different temperatures were measured by Gleeble thermal simulator. Tensile fracture was observed and analyzed by scanning electron microscope (SEM). At the same time, the precipitates were observed and analyzed by transmission electron microscope. On the basis of this, metallographic experiments were carried out on the tensile samples, and thermodynamic calculations of the second phase precipitation were carried out. The effect of the structure state and the precipitation law of the second phase on the brittle zone is analyzed. The results show that the tensile fracture surface is ice-sugar shaped and the dimple is shallow in the third brittleness zone (660,850 鈩，

本文编号：1443360