Carburizing of Duplex Stainless Steel (DSS) Under Compression Superplastic Deformation

A new surface carburizing technique which combines superplastic deformation with superplastic carburizing (SPC) is introduced. SPC was conducted on duplex stainless steel under compression mode at a fixed 0.5?height reduction strain rates ranging from 6.25?×?10^?5?to 1?×?10^?3?s^?1?and temperature ranging from 1173?K to 1248?K (900?°C to 975?°C). The results are compared with those from conventional and non-superplastic carburizing. The results show that thick hard carburized layers are formed at a much faster rate compared with the other two processes. A more gradual hardness transition from the surface to the substrate is also obtained. The highest carburized layer thickness and surface hardness are attained under SPC process at 1248?K (975?°C) and 6.25?×?10^?5?s^?1?with a value of (218.3?±?0.5)???m and (1581.0?±?5.0) HV respectively. Other than that, SPC also has the highest scratch resistance.