J Mater Sci Technol ›› 2006, Vol. 22 ›› Issue (02): 149-152.

• Research Articles • Previous Articles     Next Articles

Mathematical Modelling of Carbonitride Precipitation during Hot Working in Nb Microalloyed Steels

Yunbo XU, Yongmei YU, Xianghua LIU, Guodong WANG   

  1. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110004, China
  • Received:2004-10-12 Revised:2005-01-25 Online:2006-03-28 Published:2009-10-10
  • Contact: Yunbo XU

Abstract: Based on thermodynamics and kinetics, precipitation behavior of microalloyed steels was analyzed. Deformation greatly promotes isothermal carbonitride precipitation and makes C-curve shift leftwards. The position and shape of C-curve also depend on the content of Nb and N. C-curve shifts leftwards a little when N content increases and the nose temperature is raised with increasing Nb content. Deformation shortened precipitation start time during continuous cooling, raised precipitation start temperature, accelerated precipitation kinetics of carbonitrides. With decreasing the finishing temperature and coiling temperature, the precipitates volume fraction increases and strength increment is raised during hot rolling. The simulated results are in agreement with experiment results.

Key words: Nb microalloyed steels, Precipitation kinetics, Precipitation-temperature-time curve...