ISSN:1003-8620

CN:42-1243/TF

主管:中信泰富特钢集团股份有限公司

主办:大冶特殊钢有限公司

特殊钢 ›› 2022, Vol. 43 ›› Issue (2): 55-58.

• 工艺技术 • 上一篇    下一篇

LD-氩站流程生产Q235B钢连铸板坯中间裂纹的分析与控制

黄 华1,2, 时朋召1, 徐李军1, 夏春祥2, 赵英杰2   

  1. 1钢铁研究总院连铸技术国家工程研究中心,北京100081;
    2唐山燕山钢铁有限公司,迁安064403
  • 收稿日期:2021-07-14 出版日期:2022-04-01 发布日期:2022-06-10
  • 作者简介:黄华(1985-),男,博士生,工程师,2009年山东科技大学(本科)毕业,品种钢冶炼工艺研究。

Analysis and Control of Intermediate Cracks in Q235B Steel Continuous Casting Slab Produced by LD-Ladle Argon Blowing Route

Huang Hua1,2, Shi Pengzhao1 , Xu Lijun1, Xia Chunxiang2 , Zhao Yingjie2   

  1. 1 National Engineering Research Central for Continuous Casting Technology, Central Iron and Steel Research Institute, Beijing 100081 ;
    2 Tangshan Yanshan Iron & Steel Co Ltd, Qian'an 064403
  • Received:2021-07-14 Published:2022-04-01 Online:2022-06-10

摘要: 针对LD-氩站流程生产Q235B钢230 mm连铸板坯出现的中间裂纹,利用光学显微镜、扫描电镜和能谱仪对中间裂纹宏观和微观特征进行了系统分析。结果表明,判断扇形段接弧不良、辊缝精度差、辊子错位等是中间裂纹形成的外因;裂纹带上有粗大的晶粒,且有明显的Mn、S等元素以及复合夹杂物形态聚集是铸坯产生中间裂纹的内因。通过控制接弧精度≤±0.3mm、辊缝精度≤±0.5 mm、二冷比水量0.50 L/kg、成品[S]≤0.030%、[Mn]/[S]≥15等工艺措施,减少甚至杜绝板坯中间裂纹的发生,提高了连铸板坯的心部质量。

关键词: Q235B钢, 连铸板坯, 中间裂纹, 外因, 内因

Abstract: Based on the intermediate cracks in continuous casting Q235B steel 230 mm slab produced by LD-Ar route, a series of analyses the macroscopic and microscopic characteristics in intermediat cracks are done by optical microscope ,SEM and EDS. The results show that irregular arc of segments and low precision of roll gap as well as misalignment of the supporting rollers are the outer causes of forming and extending in intermediate cracks, and coarse grains and serious element segregations such as manganese, sulfur and complex inclusion compound accumuleted at the crack band are the inner causes of producing intermediate cracks. With the process measures including control segments arc ≤ ±0.3 mm, roll gap ≤ ±0.5 mm, secondary cooling water ratio 0.50 L/kg, [S] ≤0.030% , [Mn]/[S]≥15, it is available to decrease and avoid the occurrence of the cracks. As a result, the quality of the slab center quality is enhanced.