| Title |
Research Paper - Transformations - : The Precipitation Behvior and Mechanical Properties of Boron - added Direct Quenched Steels |
| Authors |
안병규(Byeong Kyu Ahn); 이경섭(Kyung Sub Lee) |
| Abstract |
The structures and mechanical properties of direct quenched martensitic 0.12C-0.30Si-1.00Mn-0.01Ti steels containing from 0 to 80 ppm of B were investigated. Tensile and impact tests were carried out and precipitation behavior of B on prior austenite grain boundary was studied using auger electron spectroscopy (AES) and scanning electron microscopy (SEM). The main results obtained are as follows. (1) Precipitation of B on prior austenite grain boundary was detected when more than 10 ppm B was added and the precipitates were consist of Fe, C and B. (2) Precipitation of Ti-rich phase was also observed on prior austenite grain boundary. (3) Ultimated tensile strength and impact energy increased as boron was added up to 10 ppm, however, the impact energy decreased rapidly after then. (4) The best combination of strength and toughness was obtained in 0.12C-0.30Si-1.00Mn-0.5Mo-0.01Ti-0.001B steel. |