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Austenitization behaviors of X80 pipeline steel with high Nb and trace Ti treatment

  • Qing-you Liu
  • Xin-jun Sun
  • Shu-jun Jia
  • Lu-lin Zhang
  • Guo-jian Huang
  • Yi Ren
Article

Abstract

The austenitization behaviors of two high niobium-containing X80 pipeline steels with different titanium contents, including the dissolution of microalloying precipitates and the austenite grain growth, were investigated by using physical-chemical phase analysis method and microstructural observation. The results illustrated that most niobium could be dissolved into austenite during soaking at 1 180 °C, whereas little amount of titanium could be dissolved. It was found that during soaking, the austenite grain growth rate was initially high, and then decreased after soaking for 1 h; moreover, the austenite grains grew up more rapidly at temperatures above 1 180 °C than below 1 180 °C. The results show that the steel with titanium content of 0.016% has a larger austenite grain size than that with titanium content of 0.012% under the same soaking conditions, which is explained by considering the particle size distribution.

Key words

high Nb steel X80 pipeline steel austenite grain growth dissolution microalloying precipitate 

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Copyright information

© China Iron and Steel Research Institute Group 2009

Authors and Affiliations

  • Qing-you Liu
    • 1
  • Xin-jun Sun
    • 1
  • Shu-jun Jia
    • 1
  • Lu-lin Zhang
    • 2
  • Guo-jian Huang
    • 2
  • Yi Ren
    • 2
  1. 1.Central Iron and Steel Research InstituteBeijingChina
  2. 2.Anshan Iron and Steel Group CorporationAnshan, LiaoningChina

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