Showing papers on "Maraging steel published in 1981"
TL;DR: In this paper, the maximum permissible levels of rolling deformation in the direction of reinforcement were determined for these composites during both their fabrication and subsequent rolling sequences using the previously developed formability criteria.
12 citations
TL;DR: In this paper, the effect of cutting speed and tool wear land length on the mechanical and metallurgical state of the subsurface region of solution-treated and aged 18% Ni maraging steel machined under unlubricated and lubricated orthogonal conditions was determined.
11 citations
9 citations
01 Jan 1981
TL;DR: In this paper, the strength and ductility of an austenitic, a quenched and tempered and a maraging steel were investigated under tension over a wide range of strain rates till 5000 1/s using hydraulic, pendulum and fly wheel machines.
Abstract: The strength and the ductility of an austenitic, a quenched and tempered and a maraging steel were investigated under tension over a wide range of strain rates till 5000 1/s using hydraulic, pendulum and fly wheel machines.
8 citations
Patent•
04 Jun 1981
TL;DR: In this paper, an ultra high strength steel having superior delay breakdown resistance in a high strength region was obtained by making the Ti amount in alloy composition particularly high and selecting the aging treatment temp after solution heat treatment.
Abstract: PURPOSE:To obtain an ultra high strength steel having superior delay breakdown resistance in a high strength region by making the Ti amount in alloy composition particularly high and selecting the aging treatment temp. after solution heat treatment. CONSTITUTION:An alloy comprising =200kg/mm. of a high Ni maraging steel is improved.
7 citations
TL;DR: In this article, four grades of high strength maraging steel were tested in air and aqueous solutions for susceptibility to stress corrosion cracking and hydrogen embrittlement, and the strongest steels were the most susceptible to embrittlements.
Abstract: Four grades of high strength maraging steel were tested in air and aqueous solutions for susceptibility to stress corrosion cracking and hydrogen embrittlement. Electrochemical methods were used to characterize each alloy and to control the test conditions during slow strain rate tensile tests. Environment sensitive failure was observed under conditions in which either stress corrosion cracking or hydrogen embrittlement mechanisms were likely. The strongest steels were the most susceptible to embrittlement. Hydrogen was readily removed by baking which restores the original properties. Steels in the ‘soft’ condition were not susceptible. Protective oxide coatings were found to be ineffective in reducing hydrogen embrittlement but they improved the resistance to stress corrosion cracking under the anodic conditions used in these slow strain rate tests.
6 citations
TL;DR: In this article, a number of metal-metal composites were fabricated by either hot-pressing or roll-bonding techniques in line with previously developed formability criteria for the production of formable metal-metals composites.
6 citations
Patent•
30 Mar 1981
TL;DR: In this paper, a maraging steel ingot contg 3W20% Ni, 5W25% Co and 5W17% Mo, <20% W, <45% Ti and <25% Al and having ≥250kg/mm 2 tensile strength is heated to 1,100°C to thoroughly solubilize the precipitates of the contained strengthening elements in the austenite matrix.
Abstract: PURPOSE: To remarkably enhance the strength of a maraging steel by adding specified elements to the steel and subjecting the steel to heat treatment and working under specified conditions CONSTITUTION: A maraging steel ingot contg 3W20% Ni, 5W25% Co, 5W17% Mo, <20% W, <45% Ti and <25% Al and having ≥250kg/mm 2 tensile strength is heated to ≥1,100°C to thoroughly solubilize the precipitates of the contained strengthening elements in the austenite matrix The ingot is then hot worked at the temp W1,000°C to make the austenite grains fine The hot working is stopped in the temp range of 1,000W900°C During this time, the ingot is air- cooled, and when the temp reaches ≤900°C, the ingot is worked again ≥2 times at ≥50% degree of working Hardening and tempering are finally carried out to uniformly precipitate a fine intermetallic compound, whereby the material strength is increased remarkably COPYRIGHT: (C)1982,JPO&Japio
6 citations
TL;DR: In this paper, the characteristics of plastic deformation of 1700 N/mm2 grade maraging steel were revealed from the precise true stress-true strain curves and the strain hardening rate, and from the observation of dislocation structure.
Abstract: Synopsis : The characteristics of plastic deformation of 1700 N/mm2 grade maraging steel were revealed from the precise true stress-true strain curves and the strain hardening rate-true strain curves, and from the observation of dislocation structure. The factors affecting the uniform elongation were discussed. 1) The plastic deformation was mainly composed of the four kinds of fundamental stages. 2) In the solution-treated or under-aged steels, the plastic deformation was composed of the first stage which was affected by the martensite transformation and by the aging, and of the third and the fourth stages with linear hardening. The uniform elongation of these steels was determined by the character of the first stage. 3) In the over-aged steels, the second stage with high strain hardening rate due to coarse precipitate particles appeared, and so the uniform elongation increased largely. 4) The reverted austenite precipitated in over-aged steels increased slightly the uniform elongation.
5 citations
TL;DR: In this paper, the effect of strain rate on the tensile properties was investigated on a 13Ni-15Co-10Mo-0.2Ti maraging steel aged in the range from 400° to 575°C.
Abstract: Tensile properties and resistivity changes during isothermal aging have been investigated mainly on a 13Ni-15Co-10Mo-0.2Ti maraging steel aged in the range from 400° to 575°C. A crosshead speed has been varied from 1mm/min to 0.005mm/mim, in order to investigate the effect of strain rate on the tensile properties.The embrittlement caused by the decrease in strain rate is found in the tensile properties of the maraging steel containing fine and coherent precipitates. The ductility of the overaged 13Ni-15Co-10Mo-0.2Ti maraging steel is also decreased at a lower strain rate. When this steel is averaged after cold rolling to 40%, the ductility parallel to the rolling direction is not decreased by the decrease in strain rate. Tensile properties insensitive to strain rate are obtainable after aging for about 10-100min in the range from 525° to 575°C.Investigation carried out on 14Ni-10Co-10Mo and 14Ni-15Co-7Mo maraging steels is included in order to consider the effect of chemical composition on the strain rate sensitivity. The maraging steels containing fine and coherent precipitates are also embrittled by the decrease in strain rate. The 14Ni-15Co-7Mo maraging steel continues to precipitate coherent precipitates for longer times at a certain aging temperature than does the 14Ni-10Co-10Mo one.
5 citations
Patent•
03 Apr 1981
TL;DR: In this article, the authors proposed a method to obtain a dense oxidized coating having a superior corrosion resistance by heating at a fixed temperature in the atmosphere after treating maraging steel by a fixed acid solution and activating its surface.
Abstract: PURPOSE:To easily obtain a dense oxidized coating having a superior corrosion resistance, by heating at a fixed temperature in the atmosphere after treating maraging steel by a fixed acid solution and activating its surface CONSTITUTION:Maraging steel composed of 17-18% Ni, 8-13% Co, 3-5% Mo, 005-015% Al, 05-02% Ti, residual percent Fe, is impregnated in nitric acid, hydrochloric acid or its mixed solution and the surface is activated Next, said steel is heated at 425-525 degC temperature in the atmosphere for one hour or more and black dense oxidized coating having a superior corrosion resistance, is formed on the surface
TL;DR: In this article, the effect of cold rolling prior to aging on the strength and toughness of an ultra-high strength 13Ni-15Co-10Mo maraging steel was evaluated and it was concluded that the good combination of strength and strength could be obtained at the 60% cold reduction.
Abstract: A study was conducted to determine the effect of cold rolling prior to aging on the strength and toughness of an ultrahigh strength 13Ni-15Co-10Mo maraging steel. The smooth tensile strength of cold rolled and aged maraging steel increased continuously with increasing amount of cold reduction. The cold rolled maraging steel exhibited anisotropy in properties; the tensile strength in the transverse direction was higher than in the longitudinal direction, whereas the reduction of area and elongation showed lower values in the transverse direction. The notch tensile strength and plane strain fracture toughness KIC also increased with increasing amount of cold reduction, taking maximum value at the 60-70% reduction. For example, longitudinal KIC value increased from 34Mpa•m1/2 for 0% reduction to 63Mpa•m1/2 for 70% reduction. The large amount of KIC increase was attributable to the formation of delaminations running parallel to the rolling plane. In the presence of delaminations, it is considered that the KIC test specimen behaved as the sum of a number of thin plates and each thin plate fractured under the plane stress condition. Based on these results, it was concluded that the good combination of the strength and toughness could be obtained at the 60% cold reduction.
TL;DR: In this article, an investigation was made of the susceptibility of two commercial 350 grades of maraging steel to cracking in an environment of gaseous uranium hexafluoride and hydrogen fluoride at 70 C. The failure stress decreased with increasing pressure of hydrogen fluoride.
Abstract: An investigation was made of the susceptibility to cracking of two commercial 350 grades of maraging steel. Tensile tests were carried out on samples of the steels at very slow strain rates, and the load at failure was used to assess the susceptibility of the steels to cracking in an environment of gaseous uranium hexafluoride and hydrogen fluoride at 70 C. Good resistance to cracking was observed in dry uranium hexafluoride gas but cracking occurred when hydrogen fluoride was present at partial pressures above about 1 kPa. The failure stress decreased with increasing pressure of hydrogen fluoride. Scanning electron microscopy revealed brittle fracture surfaces in all cases where failure occurred at low stress, while failures at high stress were usually ductile in appearance. In view of the susceptibility of these steels to hydrogen embrittlement, it is suggested that the mechanism of failure in the presence of HF was associated with reaction-produced hydrogen. Oxide coated samples prepared by ai...
TL;DR: In this paper, the tensile properties and their strain rate sensitivity have been investigated over the temperature range -76° to 150°C with strain rates ranging from 7.5×10-6 to 15.2× 10-4sec-1.
Abstract: The tensile properties and their strain rate sensitivity have been investigated over the temperature range -76° to 150°C with strain rates ranging from 7.5×10-6 to 15.2×10-4sec-1. The tensile properties at room temperature have also been investigated with strain rates ranging from 7.5×10-6 to 45.6×10-3sec-1.Embrittlement caused by decreasing strain rate is found in the maraging steels containing fine and coherent precipitates, and is also found in the overaged 13Ni-15Co-10Mo-0.2Ti maraging steel. The embrittlement appears most evidently at or just below room temperature. The ductilities of the maraging steels containing fine and coherent precipitates are increased by increasing strain rate at room temperature. Accordingly, the embrittleness at lower strain rates is attributable to the hydrogen embrittlement observed in steels.
TL;DR: The ductility of forged semifinished products of steel 03Kh9K14N6M3D is satisfactory in a broad temperature range, from 800 to 1200° as mentioned in this paper, and the increase in the grain size during heating of the steel does not have a negative effect on the hot ductility.
Abstract: 1.
The ductility of forged semifinished products of steel 03Kh9K14N6M3D is satisfactory in a broad temperature range — from 800 to 1200°.
2.
During hot working of the metal the deformation is more even than concentrated. For this reason, the reduction of semifinished products of steel 03Kh9K14N6M3D by free forging should be limited to ∼20–30%.
3.
The increase in the grain size during heating of the steel does not have a negative effect on the hot ductility of forged semifinished products.
Patent•
25 Mar 1981
TL;DR: In this paper, the authors proposed a procedure in which an 18Ni type maraging steel composed of specific components, e.g., Ni, Co, etc., is subjected to solution heat treatment and then to cold plastic processing, reverse transformation treatment, aging treatment, etc.
Abstract: PURPOSE:To obtain the steel excellent in strength, ductility, and toughness by a procedure in which an 18Ni type maraging steel composed of specific components, e.g., Ni, Co, etc., is subjected to solution heat treatment and then to cold plastic processing, reverse transformation treatment, aging treatment, etc., by given methods. CONSTITUTION:The 18Ni type maraging steel, composed of 16-20% Ni, 6-13% Co, 2-6% Mo, 0.1-2% Ti, 2% Al, and the balance Fe, is subjected to the usual solution heat treatment, to cold plastic processing by cooling it to room temperature, for example, in a martensitic state, to transformation heat treatment to form reverse transformed austenite in its partial part, to a recold treatment in two- phase mixed state consisting of a martensite phase and an austenite phase, and then to an usual aging treatment. Thus, a steel which is excellent in strength, ductility, and toughness can be obtained, which could not ogtained by the conventional heat treating method.
TL;DR: In this paper, an economically alloyed maraging steel based on Fe + 5% Ni and Fe+ 5% Mn has a good combination of strength and ductile characteristics after oil quenching from 970° and aging at 550°.
Abstract: 1.
Economically alloyed maraging steel based on Fe+5% Ni and Fe+5% Mn has a good combination of strength and ductile characteristics after oil quenching from 970° and aging at 550°.
2.
Fe-Ni-Mn maraging steels have low values of the fracture toughness after aging; it is expedient to use them only after quenching.
3.
All the steels tested can be used as martensitic steels after quenching or normalization. In this case the quantily of elements inducing aging can be reduced considerably or eliminated altogether.
TL;DR: For the optimal structure of austenite in maraging steels they should be subjected to rolling with a final rolling temperature not over 900°, rapid heating to Ac3+30°, and rapid cooling.
Abstract: For the optimal structure of austenite in maraging steels they should be subjected to rolling with a final rolling temperature not over 900°, rapid heating to Ac3+30°, and rapid cooling.
TL;DR: In this article, the strength characteristics of the new 06Khl3N7D2 constructional maraging steel necessary for soundly based use of it in critical parts for atomic power were obtained.
Abstract: 1.
Under elevated operating temperatures (300 and 350 °C) the strength characteristics (short-term strength and ductility, long-term strength, and fatigue resistance) of the new 06Khl3N7D2 constructional maraging steel necessary for soundly based use of it in critical parts for atomic power were obtained.
2.
The loss of strength influence of long aging at 300 and 350 °C for 2000 h on the short-term strength, ductility, and fatigue resistance of the investigated steel was determined. It was established that a long hold at increased operating temperatures led to a reduction in the strength properties σt and σ0.2, which was greater (9–14%) for short-term strength. The change in the characteristics of ductility δ and ψ after aging is not the same: δ increases and ψ decreases. Long aging for 2000 h also caused a 15–30% reduction in fatigue resistance with a. base of 107 cycles.
TL;DR: In this paper, it is shown that when Ni-Mn-Mo steel is heated in theα+γ range, recovery occurs, reestablishing the mechanical properties at the level resulting from heating in the same range immediately after normalization.
Abstract: 1.
To remove the stresses after normalization of large castings of high-strength maraging steel 08N6G4ML with walls differing in thickness the castings can be tempered at temperatures up to 320° or at 660°. The mechanical properties differ negligibly after such tempering.
2.
The low rate of hardening during aging makes it possible to control the time the heat-affected zone remains in the embrittlement temperature range by special welding methods.
3.
When Ni-Mn-Mo steel 08N6G4ML embrittled after aging is heated in theα+γ range, recovery occurs, reestablishing the mechanical properties at the level resulting from heating in the same range immediately after normalization. Heating in theα+γ range can be used to improve the properties of the heat-affected zone in weldments of steel 08N6G4ML.