High-temperature mechanical properties of near-eutectoid steel

The high-temperature mechanical properties of near-eutectoid steel were studied with a Gleeble-1500 simulation machine. Zero strength temperature (ZST), zero ductility temperature (ZDT), hot ductility curves, and strength curves were measured. Two brittle zones and one plastic zone were found in the temperature range from the melting point to 600°C. Embrittlement in zone I is caused by the existence of liquid film along dendritic interfaces. Ductility loss in zone III mainly results from precipitates and inclusions as well as S segregation along grain boundaries. Pearlite transformation also accounts for ductility deterioration in the temperature range of 700–600°C. Moreover, the straightening temperature of the test steel should be higher than 925°C for avoiding the initiation and propagation of surface cracks in billets.