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.

Microstructure Characterization and Corrosion Resistance Behavior of New Cobalt-Free Maraging Steel Produced Through ESR Techniques

Abstract: In this study, two different grades (M23 and M29) of cobalt-free low nickel maraging steel have been produced through electroslag remelting (ESR) process. The corrosion resistance of these ESR steels was investigated in 1 M H2SO4 solution using linear potentiodynamic polarization (LPP) and electrochemical impedance spectroscopy (EIS) techniques. The experiments were performed for different immersion time and solution temperature. To evaluate the corrosion resistance of the ESR steels, some significant characterization parameters from LPP and EIS curves were analyzed and compared with that of conventional C250 maraging steel. Irrespective of measurement techniques used, the results show that the corrosion resistance of the ESR steels was higher than the C250 steel. The microstructure of ESR steels was composed of uniform and well-distributed martensite accompanied with little amount of retained austenite in comparison with C250 steel.

High strain rate behaviour of carbon fibre composites

Abstract: This thesis describes a study of the dynamic mechanical properties of two types of carbon fibre composite: IM7/977-2 with 977-2 toughened thermoset resin, and IM7/APC2 with thermoplastic PEEK resin, both using Hercules IM7 carbon fibres with a volume fraction of 62%. The Split Hopkinson Pressure Bar (SHPB) is used to produce dynamic strain rates ranging from 103 to 5xl03 s-', while Instron and Hounsfield screw driven · machines are used to give a constant strain rate of about 2 x 10-3s-1 for comparative quasi-static loading. The Split Hopkinson Pressure Bar (SHPB) technique uses specimens in the form of a cylinder, sandwiched between two maraging steel bars. One of the maraging steel bars is subjected to an impact produced by a projectile. The Instron and Hounsfield machine used the same form of specimen. A strain gauge method has also been used to record the strain directly by attaching a strain gauge on to the specimen under test. Three different fibre orientations have been investigated: unidirectional fibre with loading parallel (0°) to the axis of the specimen; transverse loading (90°) where the fibres are perpendicular to the axis of specimen; and quasi-isotropic with transverse loading . The dynamic stress-strain properties of the carbon fib~e composites have been investigated experimentally at room temperature under quasistatic condition and at the high strain rates produced in the SHPB method using loading pulses of about 100 μS duration and rise time of 12 μS. The effects of strain rate on stiffness, yield stress and strength for the composites have been determined and compared with those obtained from a mathematical model (Rule of Mixtures). The longitudinal carbon fibre composite had the highest stiffness, followed by the quasi-isotropic composite, and then the transverse composite. For compressive strength, the quasi-isotropic had the highest strength followed by the longitudinal and then the transverse. The fracture energy has also been obtained indicating that for the quasi-isotropic composites, IM7/977-2 has a considerably high fracture energy than IM7/APC2. The bulk temperature rise has also been predicted up to the fracture stress.

Kinetics of Reverted Austenite in 18 wt.% Ni Grade 300 Maraging Steel: An In-Situ Synchrotron X-Ray Diffraction and Texture Study

Abstract: In this study, we investigated the transformation kinetics of martensite → reverted austenite in 18 wt% grade 300 Ni maraging steel The kinetics was evaluated based on the in situ synchrotron x-ray diffraction data collected during isothermal heat treatment at 570°C The onset of transformation martensite → reverted austenite was detected after ~ 5 min of aging The austenite fraction increased as a function of annealing time and reached approximately 30 vol% after 3 h of heat treatment The electron backscatter diffraction technique revealed that reverted austenite is formed preferentially on both the martensitic lath boundaries and sub-grain boundaries inside the laths, in particular in those with high Taylor factor values The reverted austenite maintains an orientation relationship with the prior austenite; however, variant selection can take place

Maraging steel with high fatigue strength, and maraging steel strip using it

Abstract: PROBLEM TO BE SOLVED: To provide maraging steel having high fatigue strength and excellent nitriding property and weldability, in which TiN to be a starting point of fatigue fracture in a high cycle region is decreased and nitriding treatment is facilitated to increase surface hardness and compressive residual stress in a surface nitrided layer is increased to improve bending fatigue strength and, further, old austenite grains are refined to secure high strength and ductility. SOLUTION: The maraging steel having high fatigue strength has a composition consisting of, by mass, ≤0.01% C, ≤0.1% Si, ≤0.1% Mn, ≤0.01% P, ≤0.005% S, 17.0 to 22.0% Ni, 0.1 to 4.0% Cr, 3.0 to 7.0% Mo, >10.0 to 20.0% Co, ≤0.05% Ti, <0.1% Al, ≤0.03% N, ≤0.005% O, ≤0.01% (not including 0%) B and the balance Fe with inevitable impurities and satisfying Al+Ti<0.1% and Co/3+Mo=8.0 to 15.0%. COPYRIGHT: (C)2007,JPO&INPIT