New heat-treatment method for improving the hardness of A286 stainless steel : Student Work

A286 alloy is an iron-base superalloy widely used for the gas turbine industry at intermediate elevated temperature service. It is nominally a 25 wt.% Ni and 15wt.% Cr austenitic alloy containing Ti, Al and other minor alloying additives. It is mainly strengthened by an ageing treatment which precipitates the ordered fcc gamma' phase, Ni3(Ti, Al). For the application in automotive industry, Rockwell C hardness of this class of material should be above 32 HRC. However, when there is deplete of Ti element due to (Ti,Nb)C carbide precipitation, it is very difficult to achieve such requirement. In our research, we developed new aging treatment process which enable to increase the hardness of A286 above 34 HRC. This work was actively performed by Mr. Kim Do Hoon who is a undergraduate student at Hanbat Naitonal Univeristy.