东北大学学报（自然科学版）

东北大学学报:自然科学版 ›› 2019, Vol. 40 ›› Issue (3): 334-339.DOI: 10.12068/j.issn.1005-3026.2019.03.006

• 材料与冶金 • 上一篇    下一篇

超快冷下X65管线钢微观组织演变及强化机制分析

王学强1,2， 赵金华3， 袁国1， 王国栋1   

  1. (1. 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; 2. 首钢股份公司迁安钢铁公司， 河北 迁安064404; 3. 太原科技大学 材料科学与工程学院， 山西 太原030024)
  • 收稿日期:2018-01-20 修回日期:2018-01-20 出版日期:2019-03-15 发布日期:2019-03-08
  • 通讯作者: 王学强
  • 作者简介:王学强(1983-)，男，山东潍坊人，东北大学博士研究生； 袁国(1979-)，男，山东泰安人，东北大学教授，博士生导师.
  • 基金资助:
    国家科技支撑计划项目(2012BAF04B01).

Microstructural Evolution and Strengthening Mechanism of X65 Pipeline Steel Processed by Ultra-fast Cooling

WANG Xue-qiang1,2， ZHAO Jin-hua3， YUAN Guo1， WANG Guo-dong1   

  1. 1. State Key Laboratory of Rolling and Automation， Northeastern University， Shenyang 110819， China; 2. Shougang Qian′an Iron & Steel Co.，Ltd.， Qian′an 064404， China; 3. School of Materials Science and Engineering， Taiyuan University of Science and Technology， Taiyuan 030024， China.
  • Received:2018-01-20 Revised:2018-01-20 Online:2019-03-15 Published:2019-03-08
  • Contact: YUAN Guo
  • About author:-
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摘要： 基于热连轧生产线开发了X65管线钢超快冷新工艺，系统表征了该工艺下实验钢的微观组织特征，并进一步讨论了其强化机制.结果表明，超快冷下X65管线钢微观组织为细小针状铁素体(AF)+准多边形铁素体(QPF)+M/A岛+弱化珠光体(DP)混合组织，有效晶粒尺寸为2.93μm，大角晶界百分比为31.5%;实验钢组织亚结构为细小的块状铁素体，铁素体尺寸分布在200~1000nm;在铁素体基体上析出了大量尺寸＜10nm的Nb(C，N)粒子;实验钢各项力学性能均满足API SPEC 5L标准要求.超快冷工艺下X65管线钢的主要强化机制为细晶强化、固溶强化、位错强化及纳米析出强化的耦合强化，其中纳米析出强化强度贡献值为96.1MPa.

关键词: 热连轧, 超快冷, X65管线钢, 针状铁素体, 强化机制

Abstract: Based on the hot-rolling production line， a novel processing of ultra-fast cooling(UFC)was developed to produce X65 pipeline strip. Microstructure of the experimental steel after the new processing was studied and the strengthening mechanism was further discussed. The results showed that microstructure of the UFC processed X65 pipeline strip primarily consists of fine acicular ferrite(AF)， quasi-polygonal ferrite(QPF)， martensite/austenite(M/A)and degenerate pearlite(DP). The effective grain size is 2.93μm and the proportion of the high-angle boundary in the microstructure is 31.5%. Small block ferrite with the size ranging from 200 to 1000nm is observed in the substructure. A large fraction of nano-sized Nb(C，N)particles(＜10 nm) are observed in the ferrite matrix. Moreover， mechanical properties of the experimental steel met to the API SPEC 5L standard. The main strengthening mechanism for the UFC processed X65 pipeline strip is composed by grain refining strengthening， solid solution strengthening， dislocation strengthening and precipitation strengthening， where the strengthening contributed by nano-sized precipitations is 96.1MPa.

Key words: hot strip rolling, ultra-fast cooling, X65 pipeline steel, acicular ferrite, strengthening mechanism

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