25Mn钢Φ185mmx13mm冷拔管内表面麻点状缺陷的分析和控制工艺

特殊钢 ›› 2017, Vol. 38 ›› Issue (6): 23-26.

25Mn钢Φ185mmx13mm冷拔管内表面麻点状缺陷的分析和控制工艺

邓明明¹，彭其春¹，肖云清¹，彭自胜²，肖鸿光²，范其良²

1. 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，武汉430081 ；
2. 华菱集团衡阳钢管(集团)有限公司，衡阳421001

出版日期:2017-12-01 发布日期:2022-07-09
作者简介:邓明明(1992-)，男，硕士研究生,2015年武汉科技大学(本科)毕业,铸坯与轧材质量控制研究。

Analysis on Mottled Spots Defect of Internal Surface of Φ185mmx13mm Cold-Drawn Tube of Steel 25Mn

Deng Mingming¹, Peng Qichun¹, Xiao Yunqing¹, Peng Zisheng², Xiao Hongguang², Fan Qiliang²

1. Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry Education, Wuhan University of Science and Technology, Wuhan 430081；
2. Hengyang Steel Tube Co Ltd, Hualing Group, 421001

Published:2017-12-01 Online:2022-07-09

摘要/Abstract

摘要： 25Mn钢（/%:0.24C,0.25Si,0.87Mn,0.016P,0.011S）冷拔管的生产流程为铁水预处理-90tEAF-LFVD-Φ250mm圆坯HCC-穿孔-热轧至Φ197mm×17mm管-冷拔至Φ185mm×13mm管。采用光学、扫描电子显微镜、能谱仪和电子探针分析了25Mn钢冷拔管内表面麻点状缺陷。结果表明,麻点状缺陷呈翘皮状和凹坑状,翘皮状缺陷成因是CaO-Al₂O₃-（MgO）复合夹杂与钢基体变形量不一,凹坑状缺陷成因是Al₂O₃-MnS-CaS复合夹杂聚集长大后磨削加工过程中脱落。通过将原铝脱氧精炼工艺优化成硅钙合金脱氧工艺,使精炼渣碱度由原6.76降至2.26,精炼渣中（MgO）由原5.33%提高至7.23%,（Al₂O₃）由26.05%降低至12.76%,使钢中的硬脆性夹杂转变为延展性优良的硅酸盐类夹杂,消除了25Mn钢冷拔管内表面麻点状缺陷。

关键词: 25Mn钢, Φ185mmx13mm冷拔管, 麻点状缺陷, 复合夹杂, 硅钙线脱氧, 精炼渣碱度

Abstract: The production flowsheet for cold-drawn tube of steel 25Mn(/%: 0.24C, 0.25Si, 0.87Mn, 0.016P, 0.011S) is hot-metal pretreatment-90t EAF-LF-VD-Φ250mm round bloom HCC-piercing-hol rolling to Φ197mmx17mm tube-cold rolling to Φ185mmx13mm tube. The mottled spots delect of internal surface of steel 25Mn cold-drawn tube is analyzed by using optical microscope, scanning electron microscope (SEM) , energy spectnam meter and electron probe analyzer. Results show that the mottled spots defect is warped skin and concave pitting；the warped skin defect is caused by aggregated CaO-Al₂O₃-(MgO) compound inclusions which deformation is different from base steel and the aggregated growing up of Al₂O₃-MnS-CaS compound inclusions fall off in cutting process to form concave pitting. With optimizing the original aluminium deoxidizing process to silico-calcium alloy deoxidizing process, decreasing the refining slag basicity from original 6.76 to 2.26, increasing the refining slag (MgO) from 5.33% to 7.23% and decreasing the ( Al₂O₃ ) from 26.05% to 12.76% to modify the brittle inclusions in steel to silicate inclusions with better ductility, therefore the internal mottled spots defect of internal surface of steel 25Mn cold-drawn tube is eliminated.

邓明明, 彭其春, 肖云清, 彭自胜, 肖鸿光, 范其良. 25Mn钢Φ185mmx13mm冷拔管内表面麻点状缺陷的分析和控制工艺[J]. 特殊钢, 2017, 38(6): 23-26.

Deng Mingming , Peng Qichun , Xiao Yunqing, Peng Zisheng, Xiao Hongguang, Fan Qiliang. Analysis on Mottled Spots Defect of Internal Surface of Φ185mmx13mm Cold-Drawn Tube of Steel 25Mn[J]. Special Steel, 2017, 38(6): 23-26.

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