Influence of Heat Treatment on the Microstructure and Corrosion Resistance of 13 Wt Pct Cr-Type Martensitic Stainless Steel

Abstract

The effect of heat treatment on the microstructure and the electrochemical properties of a typical corrosion-resistant plastic mold steel in Cl À -containing solution were studied in this research. Through X-ray diffraction patterns, SEM and TEM analysis, it was found that the sequence of the precipitates in the steels tempered at 573 K, 773 K, and 923 K (300°C, 500°C, and 650°C) was h-M 3 C carbides, nano-sized Cr-rich M 23 C 6 carbides, and micro/submicron-sized Cr-rich M 23 C 6 carbides, respectively. The results of the electrochemical experiments showed that the pitting potential of the as-quenched martensitic stainless steels increased with the austenitizing temperature. However, the corrosion resistance of the steels would decreased after tempering, especially when tempered at 773 K (500°C), no passivation regime could be found in the polarization curve of the MSSs and no effective passive film could be formed on the steels in Cl À -containing environments. The present results suggested that the temperature around 773 K (500°C) should be avoided for tempering process of MSS used as plastic molds.

The effect of surface texture on the oxidation behaviour of polycrystalline Fe-Cr

“…This category of steel is a trade-off between good forming and corrosion resistance, as the chromium content approaches the threshold of 12%. The bulk corrosion resistance depends critically on applied thermal treatments such as hardening and tempering, which promote either the dissolution or growth of chromium carbides [6][7][8]. The microstructure of the oxide layer on Fe-Cr steel as subjected to severe corrosion conditions was reported, e.g.…”

Relationship between Microstructure and Corrosion Behavior of Martensitic High Nitrogen Stainless Steel 30Cr15Mo1N at Different Austenitizing Temperatures

“…Meanwhile, decarburization, grain coarsening and the formation of δ-ferrite should be avoided in selecting a suitable austenitizing temperature [ 19 , 22 ]. Several studies have been carried out about the effect of austenitizing treatment on the microstructure and corrosion resistance of nitrogen-free or low nitrogen martensitic stainless steels [ 20 , 21 , 23 ]. The results indicated that the reduction of undissolved Cr-rich carbides and the improvement in homogeneity of Cr distribution with increasing austenitizing temperature improved the corrosion resistance of steels.…”

“…The existence of Cr-depleted zones in matrix adjacent to Cr-rich precipitates acted as preferential sites for metastable pits. In addition, Lu et al [ 20 , 23 ] pointed out that the increased austenitizing temperature contributed to forming more protective and well-structural passive films on 13 wt % Cr-type MSSs. However, few studies can be found about the influence of austenitizing temperature on microstructure, composition of passive film, pit initiation and propagation of martensitic high nitrogen stainless steels.…”

Assessment of AISI 431Grade Stainless Steel properties by Vacuum Tempering Process

“…Nickel, molybdenum, and nitrogen are used to modify its structure and strengthen properties such as resilience and durability in formability (Seriks John 1979). Untempered martensitic steels, though very hard are too weak to be useful in most applications [1]. Most applications include the quenched part tempering, affecting some hardness and further enhancing ductility.…”