Mechanism of Decrease in Impact Toughness in a Low-Carbon MnCrMoNiCu Plate Steel with Increasing Austenitizing Temperature

作者：Luo, Mi; Liu, Dongsheng^*; Cheng, Binggui; Cao, Rui; Chen, Jianhong

来源：Journal of Materials Engineering and Performance, 2018, 27(9): 4855-4870.

DOI：10.1007/s11665-018-3591-4

• austenitizing temperature
• cleavage fracture stress
• impact toughness
• mechanism
• packet size

In order to reveal how microscopic factors affect the toughness and the occurrence of cleavage fracture of a low-carbon MnCrMoNiCu alloyed steel, a series of thermal treatments was performed on the steel employing a thermomechanical simulator. These involved reheating samples at different temperatures (950-1250 degrees C), producing different prior austenite sizes, followed by a continuous cooling transformation process. The Charpy V-notch toughness was determined, and the effect of austenite grain size on the ductile-to-brittle transition temperatures of the steel was investigated. The microstructural evolution on the austenite sizes was studied, fracture features were characterized, the critical event for cleavage fracture was identified, and the local cleavage fracture stress sigma(f) was calculated. The impact toughness decreased as the austenitizing temperature increased. A quantitative relationship between sigma(f) and the size of the initial cleavage fracture facet (microcrack nucleus) a(f) in the lathy martensite+bainite microstructure has been developed.

• 出版日期2018-9
• 单位兰州理工大学