Effect of nickel additions on microstructure evolution and mechanical properties of low-alloy Cr-Mo cast steel

Abstract

This paper presents investigation of nickel additions on the low-alloy Cr-Mo cast steel which was normalized at temperature of 920 °C. In this experiment, approximately 0.3, 0.5, and 1.0 wt% Ni was added into the Fe-1.0Mn-0.8Cr-0.4Mo cast steel. The microstructure of low-alloy Cr-Mo cast steel was observed by optical microscope and scanning electron microscope, and the phase compositions were identified by EDX analysis. Tensile, hardness, and Charpy impact tests were conducted to investigate correlation between nickel additions to microstructure characteristics and mechanical properties. The results show that increasing nickel from 0.3 to 1.0 wt% on the alloys has improved the strength without sacrificing the impact toughness. Ni addition into low alloy steel increased the austenite stability due to the grain refinement. The strength was found increase linearly with Ni addition which may caused mainly by solid solution strengthening due to Ni dissolved into the ferrite matrix.

Evaluation of High Strength Cast Steel Welded Joints Suitable to Mooring Components

“…Besides the lower carbon and carbon equivalent contents presented by the cast steel, it is worth noting the higher nickel content, while rolled steel depends on the C and Mn contents to improve the mechanical strength. As well known, the nickel exerts a decisive effect on the refinement of the microstructure [48][49][50][51]. The higher nickel content also favors the presence of martensite.…”

“…Besides the lower carbon and carbon equivalent contents presented by the cast steel, it is worth noting the higher nickel content, while rolled steels used a balance of carbon, manganese, and chromium to improve the mechanical strength. Thus a refined martensitic microstructure and high impact toughness are expected [48][49][50][51][52][53].…”