Aim To study the ageing behaviour

precipitation of strengthing phase and phase transition of the basemetal of the GH8607 duplex iron base alloy. Methods Testing methods such as high temperature X ray diffraction

thermal expansion detection

TEM etc.

are adopted. Results GH8607 hardens fast as it is aged. The precipitated phases are the carbide M 23 C 6

M 6C) and metalloid (Laves phase

X phase) the δ→γ transition occurred during the ageing process will form lamellar martensite after subsequent cooling. Strengthening phases are precipited in the martensite during the repeated heating and cooling operations after ageing. Conclusion Due to its higher ageing temperature and high temperature strength

GH8607 is suitable for manufacturing heated extruding dies working under 850 ℃.