Thermodynamic analysis of BN, AlN AND TiN Precipitation in boron-bearing steel

Abstract

In this paper, the precipitation behavior of BN, AlN and TiN particles in boron-bearing steel was studied based on thermodynamic calculation. During solidification process, precipitation amount of BN has a positive relationship with boron content, while has negative relationship with temperature. The binding capacity of boron and nitrogen is greater than that of aluminum and nitrogen, BN is preferentially precipitated as boron added to steel. BN particle reduces the free nitrogen content in steel and then prevents the formation of AlN particle. Combination of titanium and nitrogen element is more precedence than of boron and nitrogen element. Formation of TiN particle precedes BN particle, and the precipitation amount of BN is significantly reduced by adding titanium element to boronbearing.

Keywords

• B-bearing steel
• Thermodynamic
• BN, AlN, TiN precipitates
• SEM, TEM, SIMS
• cracks