Abstract
The paper details the factors affecting on mechanical properties of soft martensitic stainless steel castings which have lower carbon contents and increased nickel contents of up to 6% compared with normal martensitic stainless steel castings. The effect of alloying elements and impurities on the microstructural features and tempering characteristics has been considered in detail, with special reference to reverted austenite and temper embrittlement. The mechanical properties have also been investigated and it has been shown that the best combination of strength and toughness is obtained when tempered at around 900K. Addition of Mo have been shown to improve toughness degradation due to slow cooling from the tempering temperature. Lowering P and S contents lead to superior toughness and fatigue properties. The threshold stress intensity range has been shown to decrease with increasing stress ratio depending on P content.
