Thermal stability and thermal fatigue resistance improvement of new high toughness 5% Cr hot working die steel
Year: 2024
Type: article
Abstract: This work developed a new high toughness 5% Cr martensitic hot working die steel (GYDCK-20), which exhibits better thermal stability and thermal fatigue resistance than AISI H13 steel. Comparative researches were conducted on the evolution of microstructures and mechanical properties of two steels during the 60-hour holding process at 600°C, as well as the thermal fatigue behavior under the cyclic heating-water quenching conditions. The experimental results showed the decrease in hardness of GYDCK-20 was lower than that of H13 by 2.23 HRC after 60 hours of holding process, the room temperature V-notch impact energy absorption of GYDCK-20 was higher than that of H13 by more than 20 J during the whole process. After thermal cycling was increased from 1000 to 2000 times, the average crack length growth rate of GYDCK-20 was 31.8% lower than that of H13 and the maximum crack width growth rate was 35.1% lower than that of H13. It was found that thermal fatigue cracking was dominated by transgranular propagation at lower cycle numbers, while more inclined to propagate along the grain boundaries at higher cycle numbers. It is mainly attributed to the lower V content of GYDCK-20 steel, which reduces the density of large-sized MC primary carbides. On the other hand, the lower Si content promotes the dissolution of cementite particles, and the secondary carbides precipitate in a smaller and uniformly distributed form, which hinders the propagation of thermal fatigue cracks, while also delays the coarsening of the fatigue-adverse phase M23C6 carbides.
Authors: Yingnan Di, Dangshen Ma, Hongxiao Chi, Jinbo Gu, Bo Fu, Jian Zhou
Institution: China Iron and Steel Research Institute Group
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,430
OpenAlex ID: W4403000418