Maraging steel

About: Maraging steel is a research topic. Over the lifetime, 1728 publications have been published within this topic receiving 19886 citations. The topic is also known as: martensitic ageing steel.

Spark ablation inductively coupled plasma mass spectrometry analysis of minor and trace elements in low and high alloy steels using single calibration curves

Abstract: A unidirectional high current pulse spark with a very fast rise-time, ensuring a rapid and complete transfer of energy to the sample, was used as the sampling system for the analysis of carbon steels and highly alloyed steels with the same operating conditions. The sparking operating conditions were optimised and a restrictive path was designed to decrease the quantity of eroded material reaching the plasma, in order to prevent deposition of material in the torch injector, and to minimise sampling cone blockage and drift effects. Spark ablation sampling efficiency and effectiveness of the restrictive path were evaluated. To compensate for differences in the amount of material ablated or for a variation in drift, 57 Fe and 55 Mn were used as internal standards. The calibration procedure was applied to the analysis of the elements Al, B, Co, Cu, Mn, Nb, P, Si, and V, present in the following certified reference materials: BCS (Bureau of Analysed Samples) SS-456 to SS-460 (residual series); CRMs (European Committee for Iron and Steel Standardisation) No 285-2 (Maraging steel), No 292-1 (niobium stabilised steel), No 295-1 (highly alloyed steel), and No 296-1 (jethete steel). When plotting intensity ratios (I X /I IS ) versus concentration ratios (C X /C IS ) linear calibration curves over the entire range of tested concentrations, with correlation coefficients better than 0.999, were obtained. Determination limits below 1 µg g –1 were found and the precision was better than 2.8%. It has also been shown to determine carbon contents at concentration levels greater than 0.03% with RSD values below 3%. For the elements As, Sn, Ti, W and Zr, only present in one or two of the Standard Materials, the sensitivity was also evaluated. Furthermore, the possibility of obtaining reproducible transient signals from sparking periods of only a few seconds was demonstrated.

Hydrometallurgical process for producing finely divided spherical maraging steel powders containing readily oxidizable alloying elements

Abstract: A process for producing spherically shaped maraging steel powder particles containing a readily oxidizable metal comprises forming an aqueous solution containing the metal values of iron, cobalt, nickel and molybdenum, in a predetermined ratio, forming a reducible solid material from the solution reducing the solid material to form metallic poweder particles. These particles are agglomerated with a predetermined amount of a second group consisting of at least one readily oxidizable metal selected from the group consisting of aluminum, titanium and vanadium. The agglomerates are entrained in a carrier gas and fed into a high temperature zone and droplets are formed. The droplets are cooled to form essentially spherical shaped particles of a maraging steel alloy containing at least one readily oxidizable metal.

Effects of cutting parameters on roughness and residual stress of maraging steel specimens produced by additive manufacturing

Abstract: Additive Manufacturing of metallic parts by powder bed fusion (PBF) has great potential to build complex geometries with innovative materials in a broad field of applications; however, it also presents some limitations as residual stresses, porosities, microcracks, and high roughness that restrict your plateau of productivity. Therefore, an alternative to improve the surface condition of PBF parts is the post-processing as milling. Maraging steel 300 is an important material used in the PBF process, considering its application in different segments, like automotive, tooling, and aerospace. Although there are a few works that investigated the effects of cutting parameters on the surface condition of maraging steel 300 components produced by PBF, this work investigated the effects of different cutting speeds (vc) and feed per tooth (fz) on average roughness Ra and residual stress of maraging 300 specimens. The lowest roughness level of Ra = 0.31 μm was obtained with fz = 0.02 mm/tooth and vc = 250 m/min. Furthermore, the cutting speed had a relevant effect on the compressive behavior of residual stresses. The feed per tooth combined with the cutting speed improved the surface roughness and the compressive residual stress of the specimens, showing the importance of considering both these parameters in the milling process planning of PBF maraging steel parts.

Enhancement of the surface properties of selective laser melted maraging steel by large pulsed electron-beam irradiation

Abstract: The present work aimed to decrease the surface roughness of maraging steel (MS) by selective laser melting (SLM) using large pulsed electron-beam (LPEB) irradiation as a post-treatment. The MS samples were fabricated using different combinations of laser power, scanning speed, hatch distance, and build angle. The morphological features, surface roughness, phase content, and corrosion resistance of the MS samples in their as-fabricated (ASF) state were compared after LPEB irradiation. The ASF SLM-MS samples exhibit the presence of partially melted particles that spread over the entire surface and many cracks in both the longitudinal and transverse directions. A higher arithmetical mean height (Sa: 2−17 μm), large variations in Sa measured at various locations, and a strong dependence of Sa on build angle were also observed. Post-treatment by LPEB irradiation removed the partially melted particles, while reflow of the molten mass filled the cracks and voids and facilitated the formation of a uniform surface with a bright metallic finish. This has resulted in a significant decrease in Sa (0.50–4.50 μm) and a smaller variation in Sa measured at different locations. Body-centered cubic α-martensite was the predominant phase for the ASF SLM-MS samples, along with a small fraction face-centered cubic γ-austenite phase. After LPEB irradiation, the martensite was reverted to the austenite phase. The corrosion resistance of the LPEB-irradiated samples was moderately better than that of the ASF SLM-MS samples. The uniform surface morphology, removal of partially melted particles, absence of pores and cracks, decrease in Sa, and moderate improvement in corrosion resistance suggests that LPEB irradiation can be used as a post-treatment for SLM-MS samples.

Nitriding method for maraging steel and maraging steel product obtained thereby

Abstract: PROBLEM TO BE SOLVED: To obtain steel having high fatigue strength and wear resistance by previously forming a fluoride film by reaction gas contg. fluorine on the surface of steel and thereafter forming a nitrided hardened layer in a nitriding atmosphere in which the concn. of NH3 and temp. are specified. SOLUTION: At the time of forming a hard nitrided hardened layer on the surface of maraging steel, maraging steel is previously heated and held at about 300 to 400°C for about 5 to 30 min in an atmosphere of reaction gas contg. fluorine, e.g. a fluorine compd. such as NF3, BF3, CF4, HE, F2, or the like to form a fluoride film on the surface. Next, this maraging steel is treated at 400 to 500°C for about 15 min to 5 hr, preferably, in a nitriding atmosphere in which the concn. of NH3 lies in the range of 5 to 30 vol.% to the whole, on the surface, a nitride layer composed of nitride only is uniformly formed at a thickness of ≤1 μm, and, on the lower layer thereof, a diffused layer is formed. COPYRIGHT: (C)2000,JPO