Influence of Solution Annealing on Microstructure and Mechanical Properties of Maraging 300 Steel

Abstract

Maraging 300 belongs to a family of metallic materials with extremely high mechanical strength and good toughness. Some works have been published about aging temperatures that improve ultimate strength resistance with acceptable toughness levels in this steel family, where the prior austenite grain size obtained by different solution annealing temperature influence in the final mechanical properties. Solution annealing temperatures ranging from 860 °C to 1150 ºC and were kept constant until the aging temperature. These treatments were used in order to investigate their influence on the microstructure and mechanical properties of maraging steel 300, especially with regard to toughness. The characterization of the microstructure was performed by optical microscopy, scanning electron microscope (SEM) and X-ray diffraction (XRD). Mechanical properties were evaluated by Rockwell C hardness and Charpy impact tests. The results showed that there is a temperature range where one can get some improvement in toughness without a large loss of mechanical strength.

Characterization Study of an Oxide Film Layer Produced under CO2/Steam Atmospheres on Two Different Maraging Steel Grades

“…It is understandable that a higher amount of titanium oxide was found in Mar350 maraging steel due to the higher amount of this element in the chemical composition of this steel; however, the increase in the amount of molybdenum oxide cannot be associated with the amount of molybdenum in the chemical composition of this steel. The molybdenum content was almost identical in both steels, and this increase could thus be due to the greater amount of cobalt that was used to decrease the solubility of molybdenum in steel, which produces a greater amount of intermetallic precipitates rich in molybdenum and titanium during the aging heat treatment [18][19][20][21]; therefore, it is possible that on the surface of the maraging steel, this phenomenon provided a greater quantity of these elements that reacted and formed these oxides. The Fourier transform infrared (FT-IR) spectra collected for the oxides of both steels are shown in Figure 12.…”

Microstructural characterization of grade 300 and grade 350 maraging steels and electrochemical study in hydrofluoric solution

“…This transformation occurs because of the high nickel content, the low carbon content and the shear phenomenon, and it is a structural modification that occurs with any cooling rate. The martensite formed is softer and more resistant than the tetragonal one (BCT) [14,17,18]. Fig.…”

“…According to the results, steels in the solution annealing condition have an average hardness lower than in the aged condition, and among them grade 350 maraging steel showed slightly higher values when compared with grade 300 maraging steel. This difference could be explained by the chemical composition of the steels, according to Lima Filho [17], who analyzed the solution treatment at various temperatures, indicating that at temperatures above 1000 °C, Ni 3 Ti precipitation could occur in grade 300 maraging steels. With a temperature of 840 °C, the considerable increase of titanium content in grade 350 maraging steel (twice as much as grade 300 maraging steel) could have caused the formation of this compound at the temperature used in this work.…”

Improved Process Efficiency in Laser-Based Powder Bed Fusion of Nanoparticle Coated Maraging Tool Steel Powder

“…Solution annealing is performed to generate a sufficient high solution state of alloying elements like Ti, Mo, and Ni. The high solution state is required because these elements are needed to form precipitations of intermetallic phases like Ni 3 (Ti,Mo) of a specific sizes to achieve a maximum precipitation hardening effect during subsequent aging [48]. The formation of the intermetallic phases during additive manufacturing processes and subsequent heat treatments is described in detail in the work of Jägle et al [49].…”