Effect of tempering temperature on the mechanical properties and microstructure of an copper-bearing low carbon bainitic steel

Aimin Guo~(1)Xinli Song~(2)Jinquan Tang~(2)Zexi Yuan~(2) (1)School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China (2)Hubei Province Key Laboratory of Ceramics and Refractories,Wuhan University of Science and Technology,Wuhan 430081,China

摘 要：<正>The effect of tempering temperature on the microstructure and mechanical properties of ultra-high strength,copper- bearing,low-carbon bainitic steel has been investigated in the experiment.The results showed that the microstructure was mainly the laths of bainite in the as-quenched steel.The bainitic laths were restored and combined after the steel tempered at various tempera- tures.There were martensite/austenite（M/A）islands and numerous dislocations within and between the bainitic laths,while very fine precipitates ofε-Cu were also observed within the laths.With increasing the tempered temperature from 400 to 600℃,the yield strength（YS）increased from 877 to 957 MPa,whereas the ultimate tensile strength（UTS）decreased from 1020 to 985 MPa.The Charpy V-notch（CVN）varied from 68.5 to 42 J,and the value was minimal for the steel tempered at 500℃.

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