Degree Name

Master of Engineering (Hons.)


Department of Materials Engineering


An investigation of the grain coarsening characteristics has been carried out on samples of commercial C-Mn, Nb-V and Nb-V-Ti steels produced at PT. Krakatau Steel, Indonesia. The results have shown that the grain coarsening occurs at a low temperature in the cast C-Mn steel, which seems to be due to the low temperature of solution of the AIN grain boundary pinning particles. It was found that the grain coarsening temperature (GCT) can be raised by microalloy additions of Nb- V and Nb-V-Ti. Austenite structural evolution after single-pass rolling has also been investigated in the above steels, in the range of reductions from 20% to 60% and at temperatures of 950°C - 1150°C. The experimental procedure involved first heating the samples to 1200°C for 15 minutes, cooled to various temperatures (950°C - 1150°C), rolled and then subsequently quenching after the samples were held at the selected temperature for different times (3 -1800 sec.).