东北大学学报（自然科学版）

东北大学学报:自然科学版 ›› 2018, Vol. 39 ›› Issue (1): 50-55.DOI: 10.12068/j.issn.1005-3026.2018.01.011

• 材料与冶金 • 上一篇    下一篇

P91厚壁钢管混晶组织分析

宁方坤1， 贾伟涛1， 朱伏先2， 王平1   

  1. (1. 东北大学 材料电磁过程研究教育部重点实验室， 辽宁 沈阳110819; 2. 东北大学 轧制技术及连轧自动化国家重点实验室， 辽宁 沈阳110819)
  • 收稿日期:2016-07-12 修回日期:2016-07-12 出版日期:2018-01-15 发布日期:2018-01-31
  • 通讯作者: 宁方坤
  • 作者简介:宁方坤(1990-)，男，山东泰安人，东北大学博士研究生； 朱伏先(1946-)，男，福建寿明人，东北大学教授，博士生导师； 王平(1964-)，男，黑龙江哈尔滨人，东北大学教授，博士生导师.
  • 基金资助:
    国家自然科学基金资助项目(51690161).

Analysis of Mixed-Grain Microstructure of P91 Thick-Walled Steel Pipes

NING Fang-kun1， JIA Wei-tao1， ZHU Fu-xian2， WANG Ping1   

  1. 1.Key Laboratory of Electromagnetic Processing of Materials， Ministry of Education， Northeastern University， Shenyang 110819， China; 2. State Key Laboratory of Rolling and Automation， Northeastern University， Shenyang 110819， China.
  • Received:2016-07-12 Revised:2016-07-12 Online:2018-01-15 Published:2018-01-31
  • Contact: WANG Ping
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摘要： P91厚壁钢管经金相检验时出现混晶现象，导致钢管的高温性能降低.对钢管热处理工艺、坯料种类和热轧过程中组织变化进行分析，结果表明:P91锻坯和连铸坯的种类不同并不会导致组织差异；钢管热轧后出现明显的混晶组织，仅通过传统正火+回火热处理工艺不能得到最优组织形态.将钢管的非平衡组织先转变为平衡组织，然后进行合理的热处理可有效优化组织均匀性;在同样的热轧工艺参数下，毛管中未出现混晶，而荒管中晶粒却发生了异常长大，则皮尔格轧制阶段为混晶的萌生阶段和改善组织均匀性的重要阶段.

关键词: P91厚壁钢管, 混晶, 热处理, 平衡组织, 皮尔格轧制

Abstract: A mixed-grain phenomenon was observed in the P91 thick-walled steel pipes， which would reduce the high-temperature properties of the pipes. Heat treatment process， the category of ingot and the microstructural evolution during hot rolling were analyzed. The results indicated that the difference of the categories for the P91 forging ingot and continuous casting ingot did not lead to microstructure difference. The pipes appeared obvious mixed-grain microstructure after hot rolling and the optimal microstructure could not be achieved only through the conventional normalizing and tempering treatment. The pipes’ microstructure uniformity can be optimized effectively by transforming from non-equilibrium microstructure to equilibrium one and rational heat treating process. The mixed-grain microstructure was not discovered in the steel pipes under the hot rolling process with the same processing parameters. However， abnormal grains growth was observed in the pipes after Pilger rolling.Therefore， the Pilger rolling process was the stage of mixed-grain initiation and improvement of microstructure uniformity.

Key words: P91 thick-walled steel pipes, mixed-grain, heat treatment, equilibrium microstructure, Pilger rolling

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