Microstructure development for brittle fracture control in Nb microalloyed line pipe steel

摘要：

EBSD characterization of density and dispersion of high angle boundaries was carried out in niobium microalloyed steels of HTP base chemistry with 0.09 wt ％ Nb, which were thermo-mechanically processed under laboratory conditions. Similar studies were carried out in higher grade (X-100 and above) line pipe steels with different chemistries, which were processed under simulation of industrial rolling conditions. The twin objectives are (i) to understand the effect of chemistry and processing parameters on the density and dispersion of high angle boundaries, and (ii) to correlate the microstructure and density of high angle boundaries with strength and fracture properties.The present studies confirm that refinement of austenite grain size prior to pancaking, large strain accumulation in austenite conditioning, alloy design with high hardenability and high cooling rates are essential to control high density and uniformity of dispersion of high angle boundaries in the final microstructure in order to achieve high strength, toughness, low DBTT and consistently 100％ ductile shear in DWTT in thermo-mechanically rolled higher grade line pipe steels.

关键词： line pipe steel brittle fracture EBSD DBTT high angle boundaries microalloying niobium

作者: Sundaresa Subramanian Laurie Collins Chengliang Miao Chengjia Shang Jitendra Patel

作者单位: Department of Mat.Sci.and Engg.,McMaster University, Hamilton,Canada Research Department,Evraz Inc.NA,Regina,SK,Canada School of Mat.Sci.and Engg,University of Sci.and Tech.,Beijing,China International Metallurgy Ltd,Nottingham,U.K.

会议类型: 国际会议

会议名称: The 6th International Conference on High Strength Low Alloy Steels(第六届高强度低合金钢国际会议HSLA Steels2011)

会议地点: 北京

会议语种:英文

页码: 225-228

在线出版日期: 2011-05-31（万方平台首次上网日期，不代表论文的发表时间）