Effect of Cleanliness on Ductile-Brittle Transition of Medium Carbon Low-Alloy Steels
ZHOU Chao1, 2, HUI Wei-jun 1, WANG Mao-qiu1, WANG Lei2
1. National Engineering Research Center of Advanced Steel Technology, Central Iron and Steel Research Institute, Beijing 100081, China 2. Faculty of Materials and Metallurgy, Northeastern University, Shenyang 110819, Liaoning, China
Abstract��The effect of cleanliness on the ductile-brittle transition of 38CrMoAl steel was studied by optical microscopy, scanning electron microscopy and series impact test. The results show that for the low purity of electric furnace steel and the high purity of double vacuum steel, the ductile-brittle transition temperature is both �C60 ��C. Nevertheless, in the entire scope of series impact test, toughness of DV (double vacuum) specimens is higher than that of EF (electric furnace) specimens. For the upper platform of ductile-brittle transition, the toughness of DV specimens is about 25 J higher than that of EF specimens, and with decreasing temperature, the gap is shrunk. Between the upper platform and the lower platform, the former is about 5�C10 J higher than the latter. In the scope of the lower platform, the gap become less and less. The lower S, P elements contents and the less amounts of MnS and AlN are the main reason for that the toughness of DV steel is higher than that of EF steel.
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ZHOU Chao, , HUI Wei-jun , WANG Mao-qiu, WANG Lei. Effect of Cleanliness on Ductile-Brittle Transition of Medium Carbon Low-Alloy Steels. Chinese Journal of Iron and Steel, 2014, 32(3): 9-13.