Abstract: Microstructure and properties of novel N-alloyed and the traditional Cr13 corrosion resistant plastic die steels were investigated and compared by means of optical microscope, scanning electron microscope, hardness test, impact test and salt spray corrosion test. The results show that the novel N-alloyed Cr13 steel contains, except for the N, other alloying elements such as Ni, Mo and V. The difference in cleanliness between the novel N-alloyed Cr13 steel and traditional Cr13 steel is not significant, but the annealed novel N-alloyed Cr13 steel has a more uniform microstructure, lower hardness and thus the better cutting performance. Under the same heat treatment, the microstructure of the novel N-alloyed Cr13 corrosion resistant plastic die steel is more uniform, the amount of undissolved carbides reduces. The conventional Cr13 steel has a hardness of 52.7 HRC and an impact absorbed energy of 6.9 J, while the novel N-alloyed Cr13 steel has a comparable hardness with the value of 51.8 HRC but a much better toughness (12.3 J). After salt spray corrosion for 120 h, the novel N-alloyed Cr13 steel has fewer corrosion pits and the corrosion rate is 0.0594 g/(m²·h), while there are obvious corrosion pits on surface of the traditional Cr13 corrosion resistant plastic die steel and the corrosion rate is 0.1136 g/(m²·h), which means that the corrosion resistance of the novel N-alloyed Cr13 steel is better than that of the conventional Cr13 steel.

Key words: corrosion resistant plastic die steel, nitrogen-alloying, microstructure, mechanical properties, corrosion resistance