Abstract: Hardfacing material of maraging steel metal powder-cored wire was deposited by pulse TIG on aluminum die cast dies to improve the dies'properties and extend its service life.Microstructure and phase characteristics were analyzed by using SEM,TEM and XRD.After aging,the metal got super-high strength,hardness and thermal fatigue resistance by intermetallic compoundNi₃Ti,Ni₃(Al,Ti)precipitating in Fe matrix.Metastable phases such as,(Ni_2.9Fe_0.1) Ti and,(Ni_0.7Fe_0.3) were found.Thermal fatigue experimental results showed that maraging steel deposited by metal-cored wire has higher thermal fatigue resistance properties than that of H13 solid wire and 18Ni maraging steel.