Journal of Northeastern University(Natural Science) ›› 2021, Vol. 42 ›› Issue (10): 1414-1420.DOI: 10.12068/j.issn.1005-3026.2021.10.007

• Materials & Metallurgy • Previous Articles     Next Articles

Effect of Quenching and Tempering Treatment on Mechanical Properties of V-microalloyed Steel for Oil Well Pipe

CAI Zhi-hui1, 3, WEN Guang-qi2, HAN A-kang2, ZHANG Kai-hua3   

  1. 1. School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China; 2. School of Materials Science & Engineering, Northeastern University, Shenyang 110819, China; 3. Pangang Group Research Institute Co., Ltd., Panzhihua 617000, China.
  • Revised:2021-01-04 Accepted:2021-01-04 Published:2021-10-22
  • Contact: CAI Zhi-hui
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Abstract: In order to cope with in complex and harsh work environments, a new-typed steel for oil well pipe has been developed, whose tensile strength, compressive strength and collapse resistant can reach steel grade of Q125.The effect of quenching and tempering(Q&T)treatment on microstructure and mechanical properties of the V-microalloyed steel was studied. The results show that the microstructure of the experimental steel after Q&T treatment contains tempered martensite, a little bainite and a large number of carbide precipitations, so that the steel has good comprehensive mechanical properties. Lower tempering temperature and longer tempering time can increase the amount of of carbide precipitations, leading to a higher precipitation hardening. Mechanical properties of the steel after tempering at 610℃ for 70min has the best performance, where the yield strength, tensile strength and elongation can reach 954MPa, 989MPa and 13.5%, respectively. The impact energy at 0℃ is 25J in transverse direction and 46J in rolling direction, which meets the requirements of steel grade of Q125 for oil well pipe.

Key words: steel for oil well pipe; V-microalloying; quenching and tempering treatment; microstructure; mechanical properties

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