Showing papers on "Maraging steel published in 1979"

Source book on maraging steels: A comprehensive collection of outstanding articles from the periodical and reference literature

Abstract: Source book on maraging steels: a comprehensive collection of outstanding articles from the periodical and reference literature , Source book on maraging steels: a comprehensive collection of outstanding articles from the periodic... , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Maraging steel with superior stress corrosion crack resistance

Abstract: PURPOSE: To improve the stress corrosion crack resistance of a maraging steel contg. 12W18% Ni by regulating the impurity Cu content of the steel and adding a specified amount of Ti and Ca or a rare earth element. CONSTITUTION: 0.1W1.8% Ti and 0.001W0.1% Ca and/or Mg are added to a maraging steel contg. <0.03% C, <0.1% Si, <0.1% Mn, <0.01% P, <0.01% S, <0.01%Cu, 10.0W19.0% Ni, <9.0% Cr, 2.0W12.0% Mo, <16.0% Co and <0.5% Al. In place of the Ca or Mg a 0.003W0.1% rare earth element may be added, or 0.001W0.1% in total of Ca and/or Mg and a rare earth element may be added. The resulting steel has remarkably improved stress corrosion crack resistance as compared with a conventional maraging steel having a basic composition contg 12W18% Ni. COPYRIGHT: (C)1981,JPO&Japio

Alloy steel with superior strength and toughness and its manufacture

Abstract: PURPOSE: To enhance the strength and toughness of an Ni-contg. alloy steel by lowering the contents of C, Si, Mn, etc. of the steel, adding Mo, Ti, etc., and carrying out specified heat treatment to form martensite single-phase structure. CONSTITUTION: An alloy steel contg. 0.05W0.3% C, <0.1% Si, <0.1% Mn, 6.0W 12.0% Ni, 0.5W5.0% Mo, 0.1W2.0% Ti and 0.1W2.0% Al or further contg. 1.0W 8.0% Co is subjected to solubilizing treatment at ≥800°C to dissolve the Mo, Ti or Co in the matrix metal. The treated steel is cooled at ≥5°C/min cooling rate to form martensite single-phase structure, and then it is tempered at 100W700°C to provide high strength, toughness and weldability comparable to those of maraging steel. The lowered contents of C, Mn, Si, etc. result in enhanced toughness, and insufficient strength due to the lowered C content is compensated for by the precipitation of alloying elements such as Mo and Ti. COPYRIGHT: (C)1981,JPO&Japio

The Strain-Rate and Temperature Dependence of 18Ni(350) Maraging Steel Tensile Properties

Abstract: The influence of microstructure, strain rate, and test temperature on the tensile properties of 18Ni(350) maraging steel was examined. The strain-rate and temperature dependence of the yield strength is less than that observed in low-strength carbon steels. The results suggest that the thermally activated flow process involves both the by-passing of a linear barrier, i.e., the disruption associated with a dislocation core, and the by-passing of a localized obstacle, the latter being specific to the microstructure being examined. The tensile ductility of aged 18Ni(350) maraging steel also undergoes a ductile-brittle transition. The extent of this ductility loss depends upon the matrix solute content and the presence of either reverted austenite or a highly dislocated substructure.

Production of austenitic steel excellent in delayed breakage and high toughness

Abstract: PURPOSE:A Cr-Ni-Mn based steel consisting of austenite phase is used as raw material which is treated for solid-solutionizing followed by cold processing, thereby to provide a strength greater than 120kg/mm , an excellent antidelayed breakability and high toughness. CONSTITUTION:A Cr-Ni-Mn based steel consists of Cr equivalent about 18% as (Cr%+Mo%+1.5XSi%+0.5XNb%), Mn content 5 to 20%, Ni being reduced as much as possible to Ni equvalent 2 to 12% as (Ni%+0.5XMn%+30XC%+ 30XN%). In order to increase steel strength and to improve delayed breakage property, C and N are solid-solutioned as much as possible within a range of solid solution N<0.25%. Such steel consisting of austenite phase is treated for solutblizing at 1050 deg.C for one hour followed by cold processing of high reduction 70% or more, providing a high quality equivalent to maraging steel in hardeness, tensile strength, and anti-delayed breakage properties.

Thermomechanical treating method for maraging steel

Abstract: PURPOSE:To partially vary the lengthwise elastic modulus E of a maraging steel plate by subjecting the plate to soln. heat treatment and plastic working; holding one side at the soln. heat treatment temp. while cooling the other side;aging the whole plate; and air cooling it.

Stabilization and destabilization of austenite in Cr−Ni−Co−Mo maraging steel

Abstract: 1. For the Cr−Ni−Co−Mo steels investigated the character of the martensitic transformation changes with decreasing MS (induced by slight changes in chemical composition) — the isothermal transformation is superposed on the athermal transformation. 2. The rate of the isothermal transformation increases with decreasing MS and evidently for this reason the susceptibility of austenite to thermal stabilization increases in the process of cooling and during repeated heating after quenching. 3. For steels with>15% retained austenite after the original quenching the cooling conditions after austenitizing must be strictly controlled (cooling with compressed air, for example), since the amount of retained austenite may be affected by stabilization and destabilization processes and also stresses that occur in the process of cooling during quenching. 4. Steels of the transition class investigated cannot be heated in the temperature range of 200–500° (welding, cutting, et al.) before the cold treatment.

Manufacture of semihard magnet material

Abstract: PURPOSE:To manufacture the title material having sufficient magnetic characteristics stable to a change in temp. and sufficient mechanical strength by soln.-heat- treating Ni maraging steel followed by heat treatment at a specified temp. CONSTITUTION:18% Ni maraging steel is soln.-heat-treated consiting of, by wt., N; 17-19%, Co; 7-14%, Mo; 3-7%, Ti; 0.1-2.5%, Al .

Improving method for corrosion resistance of nickel maraging steel

Abstract: PURPOSE:To enhance the corrosion resistance of nickel maraging steel to UF6 gas and to prevent the leakage rupture, etc. by heating the steel in a CO2 gas atmosphere at a specific temp. to form an oxide film on the surface. CONSTITUTION:18% Nickel maraging steel is surface cleaned by ultrasonic washing or the like and heat treated in a CO2 atmosphere at 450-550 deg.C to form an oxide film which has very good corrosion resistance and does not undergo corrosion even in a UF6 gas atmosphere. Occurence of troubles such as hydrogen rupture is prevented which is due to residual hydrogen in steel treated with superheated steam. The oxide film is dense and has good adherence to the base metal. When the steel is heated at above 550 deg.C, the strength is lowered remarkably. In case the heating temp. is below 450 deg.C, the resulting oxide film has good corrosion resistance but predetermined mechanical characteristics can not be held.

Anisotropy of 250 maraging steel shear-spun tubes.

Abstract: Two tubes of 250 maraging steel, one forward shear-spun and the other backward-spun, were studied both in the cold-worked state and after two different heat treatments: i) solution treatment followed by aging; ii) aging directly after cold working. X-ray measurements of preferred orientation and the calculation of the Crystallite urientation Distribution Function (CODF) were used as input for computation of Young's Modulus and the yield-stress anisotropy of the tubes. The predicted anisotropy of Young's Modulus in the tube wall was low but plastic properties were predicted to show higher anisotropy. After cold working, as well as after subsequent aging, higher uniaxial yield values are predicted for loading in the axial tube direction than in the tangential direction. Solution treatment between cold working and aging is predicted to change the yield behaviour, which is expected to become nearly isotropic. In all cases the through-thickness yield-stress is predicted to be lower than either the axial or the tangential yield-stress.

Chemicothermal treatment of economically alloyed maraging steels

Abstract: 1. Chemicothermal treatment substantially increases the surface hardness of economically alloyed maraging steel 04Kh2N5MFYu. 2. The use of steel 04Kh2N5MFYu makes it possible to reduce the nitriding, chromizing, and boriding times by a factor of three in comparison with similar processes for standard steels. The possibility of using slower cooling to obtain a martensitic structure and the formation of lamellar low-carbon martensite greatly reduce the tendency of the boride layer to crack. 3. The secondary hardening effect is observed in tempering at 500–560° after carburizing and quenching of steel 04Kh2N5MFYu, which permits the use of high-temperature tempering after carburizing and quenching. 4. After chromizing, the diffusion coating consists of alloyed ferrite, which is hardened by precipitation hardening in the course of aging.