Showing papers on "Maraging steel published in 1975"
TL;DR: In this paper, the interfacial strengths for these particles in their respective matrices were evaluated by the methods described in the two preceding papers, and the results showed that interfacial strength of the separated particles is distinctly larger than the average diam of the whole population.
Abstract: Experiments were performed on spheroidized 1045 steel, Cu-06 pct Cr alloy, and maraging steel containing respectively Fe3C, Cu-Cr, and TiC particles of nearly equiaxed shape The local interfacial stresses for separation of these particles during plastic deformation were evaluated by the methods described in the two preceding papers The results show that the interfacial strengths for these particles in their respective matrices are 242, 144, and 264 ksi In the spheroidized steel the average diam of the separated particles is distinctly larger than the average diam of the whole population This is quantitatively explained by the enhanced interfacial stresses developed in regions of above average volume fraction of second phase which frequently occur in very dense populations of particles No such effect was observed in the other two systems which is consistent with their much lower volume fraction of second phase Some tension experiments have also been performed with the spheroidized 1045 steel at elevated temperature, giving results qualitatively similar to those at room temperature
299 citations
TL;DR: In this paper, a model for fatigue crack propagation is presented which incorporates low cycle fatigue, mechanical properties and a microstructurally-associated process zone, and a comparison of the model to published date for 4340 (hard and soft), a series of TRIP steels, Ti-6A1-4V, 2024-T6 and 300 grade maraging steel shows good agreement.
111 citations
TL;DR: In this paper, the cyclic σ-e curves of annealed and aged maraging steels were determined using incremental step testing and stable hysteresis loop tip measurements.
Abstract: The cyclic stress-strain curves, the low cycle and high cycle fatigue lives and the fatigue crack growth rates of annealed (1 h 820°C) and aged (3 h 480°C) maraging steel 300 were determined. Incremental step testing and stable hysteresis loop tip measurements were used to determine the cyclic σ-e curves. Both annealed and aged maraging steels were found to cyclically soften at room temperature over a plastic strain range from 0.1 to 20 pct. The S-N curves were determined from 10 to 107 cycles to failure by plastic strain controlled low cycle fatigue tests performed in air and load controlled high cycle fatigue tests performed in dry argon. The test results compared very well with the theoretical lifetime predictions derived from Tomkins’ theory. Fatigue crack growth rates were measured in air and dry argon for the annealed and aged alloys. Crack growth rates of annealed maraging steel were found to be equal to those of aged maraging steel at rates between 10-7 and 10-5 in./cycle. A significant difference in crack growth rates in the two environments was found at low stress intensity factor ranges, indicating a high susceptibility to corrosion fatigue in the presence of water vapor. The mechanisms of cyclic softening in the two alloys are discussed in terms of dislocations rearrangement in the annealed alloy and dislocation-precipitate interactions in the aged alloy.
55 citations
TL;DR: In this paper, the fracture toughness of quenched and tempered steels such as AISI 4340, AisI 4130 and 300M can be increased by 50-100% by minor changes in heat treating procedures.
52 citations
TL;DR: In this article, the authors observed that the intensity of acoustic emission generated during martensite formation decreased markedly as the carbon content of the steel decreased, becoming nearly undetectable in a maraging steel.
Abstract: Acoustic emission was monitored during phase transformations that occur during cooling in a wide variety of steels. Acoustic emission was generated during the formation of martensite but not during the formation of ferrite, bainite, or pearlite. This observation is consistent with the rapid, diffusionless, shear-like nature of martensite formation and the slow, diffusion-controlled growth of ferrite, bainite, or pearlite. The martensite start temperatures, and the temperature range of martensite formation determined by acoustic emission were in good agreement with those determined by metallographic or dilatometric methods. The intensity of acoustic emission generated during martensite formation decreased markedly as the carbon content of the steel decreased, becoming nearly undetectable in a maraging steel. This decrease in intensity correlates with a morphological change from large plate-shaped martensite units to smaller lath-shaped martensite units as the carbon content of the steel is decreased.
19 citations
TL;DR: The optimal heat treatment for heat 2 to obtain the best resistance to cyclic impact loading with acting stress σ≥180 kg/mm2 is aging at 490° for 3 h, and aging at 510° at lower stresses as mentioned in this paper.
Abstract: 1.
Heat 2 has a higher resistance to cyclic impact loading and crack propagation than heats 1, 3, and 4.
2.
The optimal heat treatment for heat 2 to obtain the best resistance to cyclic impact loading with acting stress σ≥180 kg/mm2 is aging at 490° for 3 h, and aging at 510° for 3 h at lower stresses.
3.
Surface hardening (shotpeening) increases the resistance to impact loading more substantially for heat 1 than heat 3.
11 citations
TL;DR: In this paper, it was shown that opposed, supported maraging steel anvils are capable of generating pressures in excess of the upper bismuth transition at 75 kilobar, and InAs transition at 85 kilobar.
Abstract: It is shown that opposed, supported maraging steel anvils are capable of generating pressures in excess of the upper bismuth transition at 75 kilobar, and in excess of the InAs transition at 85 kilobar, or more than four times the compressive yield stress of the material.
5 citations
4 citations
TL;DR: The strain-cycling fatigue behavior of 10 different structural alloys and metals was investigated in liquid helium, liquid nitrogen, and ambient air at room temperature as mentioned in this paper, and 80 percent of the fatigue data obtained at cryogenic temperatures 80 percent were predicted within a life factor of 3.
Abstract: The strain-cycling fatigue behavior of 10 different structural alloys and metals (two aluminum alloys, two titanium alloys, two stainless steels, a maraging steel, a high-nickel alloy, pure nickel, and pure copper) was investigated in liquid helium, liquid nitrogen, and ambient air at room temperature. Cylindrical hourglass-shaped specimens were loaded in compression and tension about zero mean strain to produce the desired strain ranges. Tensile properties were also obtained for each material and environmental temperature so that they could be used with the Manson-Hirschberg method of universal slopes to predict the fatigue behavior at each temperature. At high cyclic fatigue lives, fatigue resistance increased with decreasing temperature for all the materials investigated. At low cyclic fatigue lives, fatigue resistance generally decreased with decreasing temperature for the materials investigated. At low cyclic fatigue lives, fatigue resistance generally decreased with decreasing temperature for the materials investigated. Only for Inconel 718 did the fatigue resistance increase with decreasing temperature over the entire life range investigated. Comparison of experimental fatigue behavior with that predicted by the Manson-Hirschberg method of universal slopes showed that the strain-cycling fatigue behavior of the materials at cryogenic temperatures can be predicted with an accuracy comparable to that achieved in earliermore » investigations conducted at room temperature. Of the fatigue data obtained at cryogenic temperatures 80 percent were predicted within a life factor of 3.« less
4 citations
Patent•
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30 Dec 1975
TL;DR: A cast maraging steel containing correlated percentages of nickel, cobalt, molybdenum, silicon, aluminum, titanium, carbon and iron as well as iron is described in this article.
Abstract: A cast maraging steel containing correlated percentages of nickel, cobalt, molybdenum, silicon, aluminum, titanium, carbon and titanium as well as iron.
3 citations
TL;DR: In this article, the kinetics and characteristics of the solid phase interaction of AD1 aluminum with reinforcing filaments of maraging steel N16K4M5T were investigated.
Abstract: Metallographic and microprobe analysis were used to investigate the kinetics and characteristics of the solid-phase interaction of AD1 aluminum with reinforcing filaments of maraging steel N16K4M5T.
01 Oct 1975
TL;DR: In this article, the effects of superficial plastic deformation (SPD) on the bending fatigue strength of shafts and gears made from maraging steels were investigated. And the results indicated that the high static strength of MARA steels can be utilized effectively under fatigue conditions only if special surface toughening methods such as SPD are used to produce compressive stresses on the surface.
Abstract: A study was carried out on the effects of superficial plastic deformation (SPD) on the bending fatigue strength of shafts and gears made from maraging steels. SPD was applied to the shafts by roller treatment and to the gears by shotblasting. 00N18K8M3T (18 Ni, 8.6 Co, 3.6 Mo) was used to make the shafts; 00N18K8M3T and 00N18K6M5T (18 Ni, 6.3 Co, 5.7 Mo) were used to make the gears. Results indicate that the high static strength of maraging steels can be utilized effectively under fatigue conditions only if special surface toughening methods such as SPD are used to produce compressive stresses on the surface. (DLC)
TL;DR: The maximum plasticity at 240o (cooling) is due to the initial stages of the martensitic γ→α transformation, and at 650o to the shift of the fracture mechanism (from intergranular to transcrystalline) as mentioned in this paper.
Abstract: 1.
Two peaks were observed on the curves of plasticity vs testing temperature during heating and cooling.
2.
The maximum plasticity at 240o (cooling) is due to the initial stages of the martensitic γ→α transformation, and at 650o to the shift of the fracture mechanism (from intergranular to transcrystalline).
3.
The maximum plasticity at 600o (heating) is due to the initial stages of the reverse α→γ martensitic transformation, and at 740o to the development of recrystallization processes.