大罐钢12MnNiVR探伤不合原因分析及工艺优化  

Cause analysis and improvement measures of unqualified ultrasonic flaw detection for large-size storage tank steel 12MnNiVR

作　　者：廖纲 廖广府 李建立[2] LIAO Gang;LIAO Guangfu;LI Jianli(Ezhou Iron and Steel Company of Baowu Group,Ezhou 436002,China;Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]宝武集团鄂钢公司,湖北鄂州436002 [2]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室,湖北武汉430081

出　　处：《炼钢》2022年第3期69-72,共4页Steelmaking

基　　金：湖北省自然科学基金资助项目(2019CFB697)。

摘　　要：根据大罐钢12MnNiVR钢板日常超声波探伤结果,发现探伤不合点集中在钢板厚度1/4处和厚度1/2位置。采用金相显微镜、扫描电镜等检测手段对超声波探伤不合样品进行了检测分析,发现位于厚度1/4位置的探伤不合缺陷主要是由宏观非金属夹杂物引起;而位于厚度1/2位置的探伤不合缺陷是由钢板较严重的中心偏析导致后续轧制组织异常引起。通过优化RH真空处理完毕后喂钙量、降低连铸中间包钢水过热度、增加钢板缓冷等技术措施,有效提高了12MnNiVR钢成品钢板探伤合格率。According to the ultrasonic flaw detection results of large tank steel 12 MnNiVR,it was found that the flaw detection nonconformity positions were concentrated at 1/4 and 1/2 of the steel plate thickness. Metallographic microscope and scanning electron microscope were used to detect and analyze the non-conforming samples of ultrasonic flaw detection. It was found that the non-conforming defects at the position of 1/4 of the thickness were mainly caused by macro non-metallic inclusions, and the non-conforming defects at the position of 1/2 of the thickness were caused by the abnormal subsequent rolling structure caused by the serious central segregation of the steel plate. By optimizing the amount of calcium feeding after RH vacuum treatment, reducing the superheat of molten steel in continuous casting tundish and increasing the slow cooling of steel plate, the qualified rate of flaw detection of 12 MnNiVR steel is effectively improved.

关 键 词：大罐钢 探伤不合 宏观夹杂 中心偏析 

分 类 号：TF764[冶金工程—钢铁冶金]