Abstract
The unique combinations of high toughness and high strength available with the maraging steels have made them desirable for structural applications. However, it was very difficult to produce the high performance maraging steels by conventional powder metallurgy (P/M) processes because of hard material. Metal Injection Molding (MIM) process alleviates the need for secondary working operations because of providing the net shape components, which is a suitable production route for hard materials. In this paper, the characteristics of debinding, sintering and aging behavior were studied for injection molded maraging steel compacts, and also the mechanical properties were investigated by tensile and impact test. The results are summarized as follows:
1) By using the continuous process which went on through thermal debinding and sintering at 1623K for 3.6ks in hydrogen atmosphere, the compacts were considerably densified to a relative density of 96%.
2) Aging hardness at 758K for 10.8ks reached to HRC46.5 which was as hard as the densified steels by HIP, and this aging condition was lower temperature and shorter time as compared to the condition of conventional P/M process.
3) Optimum aged MIM maraging steel showed the same strength of 1640MPa as the wrought steels, but the ductility and toughness were considerably poor.
