Research on the precipitation characteristics and hazard control of FeTiP phase in phosphorus containing high-strength IF steel

This study systematically investigates the precipitation characteristics and associated fracture risks of the FeTiP phase in high-strength interstitial-free (HSIF) steel containing 0.08–0.10 wt% phosphorus. The research employed heating-quenching experiments, stress-induced precipitation tests using a Gleeble-3500 thermomechanical simulator, and controlled cooling rate protocols to analyse the dissolution behaviour, stress-induced precipitation kinetics, and the impact of cooling rate on FeTiP formation. Key findings reveal that the FeTiP phase completely dissolves above 950°C and exhibits a characteristic C-curve precipitation-time-temperature (PTT) diagram with a nose temperature at 850°C. Crucially, cooling rate significantly influences FeTiP precipitation – rapid cooling (≥30°C/s) effectively suppresses its formation at grain boundaries (GBs), while slow cooling (