The non-equilibrium grain boundary segregation (NGS) concentrations of phosphorus in an industrial steel, 12Cr1MoV, at different solution temperatures, 1050 and 1300degreesC, were measured. The NGS kinetics curves of phosphorus at the isothermal holding temperature of 540degreesC are given. These results provide direct support for a NGS kinetic model, and also show that the higher the solution temperature, the higher the segregation concentration of phosphorus at the grain-boundaries, and also the longer the critical time. (C) 2004 Kluwer Academic Publishers.