Influence of Low Tempering Temperature on Fracture Toughness of Ultra High Strength Boron Steel for Hot Forming
The influence of low tempering temperature (TT) on mechanical properties and fracture toughness of ultra high strength boron steel 22MnB5 for hot forming was investigated by tensile and Kahn tearing experiments. Compared with the conventional quenchable boron steel, The results show that the toughness of tested steel are both preferable when tempered at 200 , 40min. When TT between 100 ～200 , The tear strength (TS) and unit propagation energy (UPE) of quenched steel heightened along with the temperature raised, but in 200~350 temperature range, the toughness appears negatively growth. Appropriate TT could improve the mechanical properties and fracture toughness obviously, and the temper brittleness can be avoided.
Sihai Jiao, Zhengyi Jiang and Jinglong Bu
L. Ying et al., "Influence of Low Tempering Temperature on Fracture Toughness of Ultra High Strength Boron Steel for Hot Forming", Advanced Materials Research, Vols. 146-147, pp. 160-165, 2011