摘要
为分析Q450NQR1钢板经折弯加工后表面出现裂纹的原因,采用金相显微镜、扫描电镜及能谱仪、光谱分析仪对Q450NQR1钢板裂纹处的金相组织、显微形貌及夹杂物、化学成分的类型进行分析。结果表明裂纹深度约40~50μm、裂纹底部存在氧化物圆点,裂纹近表面组织一侧明显脱碳,带状组织不明显裂纹周围存在大量的氧化圆点,因此认为引起加工后表面出现裂纹的基体缺陷不是在轧制过程中产生的,是铸坯中就存在的。进一步分析表明缺陷可能是由于连铸坯存在皮下气泡或者近表面存在微裂纹,在轧制前加热过程中被氧化,经轧制贴合于钢板表面,随后折弯延伸时缺陷区不能参与同步变形而最终形成表面裂纹缺陷。
In order to analyze the causes of cracks on the surface of Q450NQR1 steel plate af⁃ter bending,metallurgical microscope,scanning electron microscope,energy spectrometer and spectral analyzer were used to analyze the metallurgical organization,micro-morphology and types of inclusions and chemical composition of caracks of Q450NQR1 steel plate.The results show that the crack depth is about 40-50μm,the presence of oxide dots at the bottom of the cracks,the obvi⁃ous decarburization of cracks near the surface,the presence of a large number of oxidation dots in the cracks that does not have evident banding.Therefore,it is considered that the matrix defects that cause cracks on the surface of the processed surface are not produced in the rolling process,but ex⁃ist in the casting billet.Further analysis shows that the defects may be due to the continuous casting billet sub-skin bubbles or near-surface micro-cracks,which are oxidized during the heating pro⁃cess before rolling,and then adhered to the surface of the steel plate after rolling,and then the de⁃fective area cannot participate in the synchronous deformation when bending and extending and eventually form surface crack defects.
作者
文亮
白丽杨
戴思源
彭正波
陈勇
WEN Liang;BAI Liyang;DAI Siyuan;PENG Zhengbo;CHEN Yong(Maanshan Iron&Steel Co.,Ltd.,Maanshan,Anhui 243000,China)
出处
《冶金动力》
2024年第5期77-82,共6页
Metallurgical Power
关键词
裂纹
耐候钢
折弯开裂
cracking
weathering steel
bending cracking
