Showing papers on "Maraging steel published in 1983"
01 Jan 1983
TL;DR: Maraging steels are high strength steels containing a very low percentage of carbon The strengthening effect is achieved by precipitation of substitutional alloying elements in the iron-nickel martensite, which occurs during the aging process.
Abstract: Maraging steels are high strength steels containing a very low percentage of carbon The strengthening effect is achieved by precipitation of substitutional alloying elements in the iron-nickel martensite, which occurs during the aging process The metallurgical behaviour of these steels is associated with the thermal hysteresis between the formation of martensite and its reversion to austenite in the Fe-Ni alloys Maraging steels show some excellent properties in the annealed and the fully heat-treated conditions such as high strength-to-weight ratio, superior toughness at high strength levels, good resistance to hydrogen embrittlement and to stress corrosion cracking A steep rise in the price of cobalt which is also a strategic material stimulated development of a new cobalt-free maraging steel which possesses strength and ductility properties very similar to 18Ni(250) maraging steel but lower toughness
13 citations
TL;DR: In this paper, the composition profiles and binding energies of pure Ti and Mo, as well as 250 grade maraging steel, were heat treated in superheated steam at 485°C for 3 h.
9 citations
9 citations
TL;DR: In this article, the effect of prior austenite grain size on fracture toughness in 2 750MPa grade 13Ni-15Co10Mo maraging steel has been investigated.
Abstract: Synopsis : The effect of prior austenite grain size on fracture toughness (KO in 2 750MPa grade 13Ni-15Co10Mo maraging steel has been investigated. The prior austenite grain size was varied in the range of 7•`60OƒÊ using both thermomechanical treatment and solution treatment. KIC increased with increasing the grain size. For example, KIC increased from 20MPa•Em1/2 for 8ƒÊ to 30MPa •E m1 2 for 500ƒÊ and varied linearly with the reciprocal square root of the grain size. The acoustic emission measurement during fracture toughness test and fracture surface observation at the tip of fatigue precrack revealed that subcritical crack growth of intergranular fracture mode occurred as the grain size increased and ICI, was apparently increased due to the microbranching effect of the crack front. On the basis of the above observation, it was suggested that true grain size dependence of KIC in 13Ni-15Co-10Mo steel might be less than the experimentally obtained result.
7 citations
5 citations
4 citations
Patent•
13 Oct 1983
TL;DR: In this paper, the authors proposed a method to recover an alloy having the same purity as that of electrolytic metal from the scrap of maraging steel for reuse, by removing Mo with a predetermined ratio or more from a liquid containing Fe, Ni and Co prepd.
Abstract: PURPOSE:To recover an alloy having the same purity as that of electrolytic metal from the scrap of maraging steel for its reuse, by removing Mo with a predetermined ratio or more from a liquid containing Fe, Ni and Co prepd. by dissolving the scrap of maraging steel in hydrochloric acid or the like, and then electrolyzing the residual liquid. CONSTITUTION:The cast flashes, machining chips, scraps or the like of maraging steel comprising Fe, Ni, Co, Mo, Ti, etc. are dissolved in dil. sulfuric or hydrochloric acid until the liquid comes in the vicinity of pH=1.5-3.5 at a room temp., for instance. Hence almost all of Ti is precipitated, while Mo is precipitated to a degree such that it remains at a ratio of 20-1,200ppm in the liquid depending on conditions. Thereafter, the precipitates are removed, and the acid dissolved liquid of Mo content at 0-6mg/l is electrolyzed. Consequently, a Fe-Ni-Co alloy having the same purity as that of electrolytic metal useful as a raw material for melting maraging steel requested to have high-grade quality is recovered.
4 citations
Patent•
28 Mar 1983
TL;DR: In this article, a hot rolled 18%Ni maraging steel is subjected to a soln heat treatment by heating to a temp above the recrystallization temp of austenite phase such as 850-950 degC and cooled to ordinary temp to provide a martensite structure, and by relieving the work strain, the structure is made homogeneous.
Abstract: PURPOSE:To considerably enhance the rupture toughness of an 18%Ni maraging steel by combinedly carrying out a soln heat treatment at a temp above the recrystallization temp of austenite and a soln heat treatment at a temp below the recrystallization temp of austenite CONSTITUTION:A hot rolled 18%Ni maraging steel is subjected to a soln heat treatment by heating to a temp above the recrystallization temp of austenite phase such as 850-950 degC It is cooled to ordinary temp to provide a martensite structure, and by relieving the work strain, the structure is made homogeneous The steel is then reheated at a temp below the recrystallization temp of austenite phase such as 800-850 degC and cooled to ordinary temp to form martensite By repeating the soln heat treatment by heating >=2 times, an 18%Ni maraging steel with superior rupture toughness is obtd
4 citations
TL;DR: In this article, the structural applications as opposed to uses involving the chemical or physical properties of cobalt, in the light of the competitive aspects of various materials, are reviewed, and the purpose of this paper is to review structural applications.
Abstract: During the last few decades cobalt has conquered a major status as a material necessary in a number of high-technology applications. The purpose of this paper is to review the structural applications as opposed to uses involving the chemical or physical properties of cobalt, in the light of the competitive aspects of various materials.
3 citations
TL;DR: The presence of evenly distributed retained austenite in amounts not over 30% in high-strength maraging steels leads to an increase of the ductility with retention of fairly high strength.
Abstract: 1.
The presence of evenly distributed retained austenite in amounts not over 30% in high-strength maraging steels leads to an increase of the ductility with retention of fairly high strength.
2.
It is expedient to use rapid heating for heat treatment of MS in order to prevent decomposition of martensite and redistribution of the components in the biphase (α+γ) region.
3 citations
TL;DR: Doppler broadening measurements of the γ-ray emmision from positron annihilations have been made on a 17 nickel maraging steel, heat treated to Rockwell hardness, C Scale 49, and subsequently cathodically charged with hydrogen.
Abstract: Doppler broadening measurements of the γ-ray emmision from positron annihilations have been made on a 17 nickel maraging steel, heat treated to Rockwell hardness, C Scale 49, and subsequently cathodically charged with hydrogen. Changes in the positron annihilation γ-ray spectra were measured using a line shape parameter (S) based on the ratio of central to total spectra area. The recovery of the S parameter as a function of time after hydrogen charging is correlated with hydrogen egress from the metal. The observed sensitivity of this Doppler broadening positron annihilation technique to hydrogen content is attributed to hydrogen compensation of lattice defects (dislocations) in the maraging steel.
TL;DR: In this paper, a fracture toughness of at least 0.3 MJ/m2 in longitudinal samples was obtained by quenching from 1100°; heating to and cooling from this temperature must be rapid.
Abstract: 1.
Intermetallic phase is formed in steel 05Kh12K14N5M5T in the temperature range of 800–1050°, sharply reducing the fracture toughness.
2.
To obtain a fracture toughness of at least 0.3 MJ/m2 in longitudinal samples the steel must be quenched from 1100°; heating to and cooling from this temperature must be rapid.
01 Jan 1983
TL;DR: In this article, the effect of time at a sensitizing temperature of 1175°K has been investigated using two steels of differing residual element content, and a significant loss of toughness was measured after 300 s. sensitization; this is larger for steel of the highest impurity content.
Abstract: Thermal embrittlement effects in aged MAR350 steels have been studied using KIC fracture toughness measurements. In particular, the effect of time at a sensitizing temperature of 1175°K has been investigated using two steels of differing residual element content. A significant loss of toughness was measured after 300 s. sensitization; this is larger for steel of the highest impurity content. Microstructural and fractography studies are reported which describe the weakening effect of the Ti(CN) precipitation at prior austenite boundaries.