Phase Transformation of Cu-containing Bridge Weathering Steels
Xin-liang FU Gui-qin DENG Zhi-yin LIN Guang-ming ZHU Miao-yong
School of Materials and Metallurgy, Northeastern University College of Materials and Metallurgy, Northeastern University College of Materials and Metallurgy, Northeastern University School of Materials and Metallurgy, Northeastern University
Abstract： In order to understand phase transformation of Cu-containing bridge weathering steels, continuous cooling transformation (CCT) diagrams of bridge weathering steels with different Cu contents were studied by using optical microscope and microhardness measurement. The results showed that Cu could reduce bainite transformation temperature, but had little effect on initial transformation temperature. The increase of Cu content refined ferrite and bainite grain size, and enhanced the microhardness of ferrite, but the microhardness of bainite was reduced by about 20 Hv. With the increase of cooling rate, ferrite grain size was changed from 10 to 6 mm, and volume fraction from 58% to 17%. The microhardness of ferrite had little change, kept at about 240 Hv. The microhardness of bainite was increased from 250 to 300 Hv.