J Mater Sci Technol ›› 2009, Vol. 25 ›› Issue (04): 513-515.

• Articles • Previous Articles     Next Articles

Improved Fatigue Behavior of Pipeline Steel Welded Joint by Surface Mechanical Attrition Treatment (SMAT)

Yu Wang1,2), Min Huang2), Lei Zhou3), Zhixin Cong2), Huilin Gao 2)†   

  1. 1) School of Materials Science and Engineering, Xi0an University of Architecture and Technology, Xi0an 710055, China
    2) School of Materials Science and Engineering, Xi0an Shiyou University, Xi0an 710065, China
    3) Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
  • Received:2008-11-03 Revised:2009-04-02 Online:2009-07-28 Published:2009-10-10
  • Contact: Yu Wang
  • Supported by:

    the CNPC (China National Petroleum Corporation) Innovation Foundation under grant No. 07E1015.

Abstract:

A pipeline steel X80 with welded joint was subjected to surface mechanical attrition treatment (SMAT). After SMAT, a nanostructure surface layer with an average grain size of about 10 nm was formed in the treated sample, and the fatigue limit of the welded joint was elevated by about 13% relative to the untreated joints. In the low and the high amplitude stress regimes, both fatigue strength and fatigue life were enhanced. Formation of the nanostructured surface layer played more important role in the enhanced fatigue behavior than that of residual stress induced by the SMAT.

Key words: Surface mechanical attrition treatment (SMAT), Pipeline steel X80, Welded
joint; Surface nanocrystallization,
Fatigue behavior