The as-cast ZGMn13 and ZGMn17 liners produced by lost foam casting were treated with water toughening.The influence of different water toughening process on the structure and performance of the liner was investigated using optical microscope and micro-hardness tester.The change rules of microstructure and properties before and after the water toughening were analyzed comparatively.The results reveal that the properties of the liners are better under water toughening treatment for 1 h.As the water toughness temperature increases

the network carbide is gradually decreased

and the content of single-phase austenite is firstly increased and then decreased.The optimum water toughness treatment of ZGMn13 high manganese steel and ZGMn17 ultra-high manganese steel are to heat up to 1 080℃for 1 hand then conduct water quenching.Under the process

the microstructure is homogeneous without carbides

and hardness reaches 210 HB and 220 HB

respectively.