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The effect of Ce on hot ductility of Cu-As bearing steel in the temperature ranging from 700 to 1100 °C was investigated using Gleeble-3800 thermal-mechanical simulator. The hot ductility evaluation and fracture morphology observation showed that the hot ductility was obviously improved as Ce content increased from 0 to 0.0290 wt%. Detailed, the upper limit temperature of the ductility trough was decreased from 1057 to 765 °C, and the temperature corresponding to the minimum reduction of area was decreased from 850 to 750 °C. The fracture morphology was overall transformed from the dominantly intergraular brittle failure to the ductile failure characterized by the large and deep dimples. Analysis of metallographic, inclusions and grain boundary elements suggested that increasing Ce content inhibited the proeutectoid ferrite formation, which enhanced hot ductility of the steel bearing Cu and As. Moreover, the competitive grain boundary segregation of the solute Ce and As in steel with 0.0022 wt% Ce without arsenious rare earth inclusions decreased the quantity of As distributed at grain boundaries and thereby improved the hot ductility. When the Ce content reached 0.0290 wt%, a large number of arsenious rare earth inclusions were formed, and the grain boundary segregation of As was further decreased As, which was more beneficial to hot ductility than that with the lower Ce content in austenite single phase region. [ABSTRACT FROM AUTHOR]

In order to depress the embrittlement induced by grain boundary segregation of arsenic in steel, the effect of Ce addition on the formation of arsenious inclusions and arsenic concentration at grain boundaries were systematically investigated in iron melts. The results showed that different types of arsenious rare earth inclusions were formed with different Ce content. As Ce content increased from 0.037 to 0.095wt%, the dominant inclusion in the melt was changed from the Ce-S-O inclusion fully coated by Ce-S-As inclusion to the Ce-S-As inclusion completely covered by Ce-As inclusion. Simultaneously, the single Ce-S-As and Ce-As inclusions were also detected when Ce content was more than 0.055 wt%. The amount and average size of inclusions increased with increasing Ce content. Transmission electron microscope analysis indicated that the Ce-As inclusion was the CeAs phase, which was formed during solidification process. Furthermore, concentration of arsenic on grain boundaries after adding Ce was decreased to the level of the matrix. [ABSTRACT FROM AUTHOR]