Improvement of stamping performance of H13 steel by compound-layer free plasma nitriding

Abstract

In this study, a self-designed test for evaluating the thermal fatigue resistance was developed according to the cooperator's requirements, and plasma nitriding at low temperature was conducted for H13 steel. The treated samples were characterised by optical microscopy, X-ray diffraction, the self-designed thermal fatigue test and indentation test. The results showed that a nitriding layer with only diffusion zone was formed on the surface while nitriding at a low temperature of 470°C. The thermal fatigue resistance and impact toughness were greatly enhanced; without premature failure resulted from cracking and peeling of the compound layer at the outmost surface. Meanwhile, the developed novel low temperature plasma nitriding technology was applied to hot stamping dies, and the results showed that the service life of dies was increased about 10 times, from stamping 1800–2000 increased to 18,000–20,000 automobile components by adopting this non-compound layer plasma nitriding technology.