Due to the uneven furnace temperature of the annealing furnace, the insulation temperature of some steels is much lower than 680 ℃. Although the insulation time is long, the transformation from austenite to ferrite+carbide cannot occur during the insulation stage, and only the austenite state can be maintained. In the subsequent cooling process, although the speed is slow and the furnace temperature is low, the transformation from martensite still occurs. Therefore, there is a significant residual stress after cooling, and due to the slow cooling rate, thermal stress should be well released. In the residual stress, tissue stress dominates, with the core subjected to tangential compressive stress and the surface subjected to tangential tensile stress. When the residual stress exceeds the tensile strength, explosion occurs.
When inspecting the quality of a 22Cr duplex stainless steel forging flange, it was found that some forgings had particularly poor toughness. Analysis of the reasons revealed that the fundamental reason for the decrease in toughness of the 22Cr duplex stainless steel flange was the formation of intermetallic precipitates in its microstructure. When the intermetallic precipitates reach a certain level, the toughness of the material will significantly decrease.
In the ever-evolving world of metallurgy and manufacturing, the demand for stronger, more corrosion-resistant, and cost-effective materials continues to shape industrial practices. One such material that has been gaining considerable attention in forging applications is Stainless Steel SAF2304, a duplex stainless steel alloy known for its excellent combination of mechanical strength and corrosion resistance.
