Investigation of the Role of Nitrogen in Cr18Mn15Mo1.5N Marine Steel

Abstract

A new high-nitrogen steel (Cr18Mn15Mo1.5N) with a nitrogen content of 0.54% for marine engineering is prepared using a vacuum induction furnace and remelting furnace. The effects of nitrogen on the microstructure, yield strength, yield ratio, elongation, and corrosion resistance are studied by holding the experimental steel at 800, 900, 1000, 1100, and 1200 C for 1, 3, and 5 h, respectively, which are compared with 316 steel series. The results of solution treatment show that the second phase includes Cr 2 N precipitates at 800 and 900 C, the second phase dissolves at 1000 and 1100 C, and ferrite precipitates at 1200 C, respectively. The yield strength of Cr18Mn15Mo1.5N steel is 2.5 times that of 316 steel, and the plasticity is equivalent. The corrosion resistance of the experimental steel treated at 1100 C for 1 h is 7.94 times better than that of 316 steel.

Optimization of Mold Powders for High‐Nitrogen Stainless Steel Based on Mold Thermocouple Temperature Variation

“…The high initial solidification strength of HNSS may be related to N. N is mainly in the form of a solid solution in the steel, which causes lattice distortion and significantly improves the strength of the steel by pinning dislocations. [5,28] During the continuous casting, the N element cannot diffuse and be discharged due to the high cooling rate, further enhancing the solid solution strengthening effect. Some scholars have explained the formation mechanism of the slab surface depression using the liquid-level fluctuation theory, [18,29] as shown in Figure 8.…”

“…High-nitrogen stainless steel (HNSS) is widely used in manufacturing, biomedical, marine engineering, and military industries owing to its good mechanical and corrosion resistance. [1][2][3][4][5] As a strong austenite-stabilizing element, N has a favorable solid-solution strengthening effect. [6] Moreover, it can increase the strength of stainless steel by 2-4 times without affecting its ductility and toughness.…”