Showing papers on "Maraging steel published in 2002"
TL;DR: In this paper, a new high Ni, Ti and low Mo maraging steel based on 13Ni(400) was developed and the optimum heat treatment was found to be cryogenic treatment (CT) at 200 K followed by aging treatment at 773 K for 4 h in as-forged or solution condition.
62 citations
TL;DR: In this article, slow displacement rate tensile tests were performed to find out the influence of ageing condition and hydrogen-charging on the notched tensile strength and fracture characteristics of T-250 maraging steel aged at various conditions.
49 citations
TL;DR: In this article, the precipitation hardening effect occurring in Fe -12Ni -6Mn maraging steel has been quantified in the present work, and the model obtained can be applied to the entire aging period.
Abstract: The precipitation hardening effect occurring in Fe – 12Ni –6Mn maraging steel has been quantified in the present work. The model obtained can be applied to the entire aging period. Precipitate growth and precipitation fraction as functions of time and temperature have also been quantified. Time – temperature –precipitation diagrams with respect to precipitate size and fraction are proposed. The precipitation fraction at peak hardness has been estimated, together with the precipitate size. Results show that the precipitation process is far from complete when peak hardness is reached. At the lower temperature of 400 ° C, aging produces precipitates at a higher fraction and of larger size than those produced at 450 and 500 ° C, which explains why aging at 400 ° C gives a stronger hardening effect. MST/5022
28 citations
TL;DR: In this article, the precipitate hardening in an Fe-12Ni-6Mn maraging steel during overaging was quantified based on hardness measurements, which was calculated as a function of the hardness of the steel.
Abstract: Precipitation hardening in an Fe–12Ni–6Mn maraging steel during overaging was quantified in the current work. Based on hardness measurements, the precipitate size was calculated as a function of ti...
24 citations
25 Oct 2002-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the authors identify the back stress evolution for a Cr-Ni-Mo-Al-Ti maraging steel in the process of martensitic transformation under thermomechanical loading conditions.
Abstract: The quantitative identification of the back stress evolution is carried out for a Cr–Ni–Mo–Al–Ti maraging steel in the process of martensitic transformation under thermomechanical loading conditions. The evolution depends on the direction of the applied stress: tensile, compressive or shear. The iso-volume fraction lines (the iso- ξ lines) are determined between the transformation-start and -finish lines on the applied stress–temperature plane. The iso- ξ lines are composed of a tensile-branch and a compressive-branch, each of which is parallel to the martensite-start line. The interaction point of the tensile- and compressive-branches of the iso- ξ line shifts to the direction of the back stress evolution. The almost hold stress-independent martensite-finish line, identified in a previous paper (Mater. Sci. Eng. A308 (2001) 25) is proved to be attributed to the back stress evolution.
15 citations
TL;DR: In this paper, the results of measurement of mechanical properties of maraging steel Thyssen 1.2799 after precipitation annealing with a wide spectrum of temperature/time conditions were investigated.
Abstract: The paper deals with the results of measurement of mechanical properties of maraging steel Thyssen 1.2799 after precipitation annealing with a wide spectrum of temperature/time conditions. The purpose of the investigation conducted on the material for die-casting tools was to find out how the tool life could be extended depending on the heat-treatment conditions and the microstructure of the steel. Thus the influence of temperature/time conditions of precipitation annealing on tensile strength, hardness, and impact toughness of the steel was studied. The Charpy impact toughness test was carried out at a temperature of 200°C, which is, according to our assessment, an average operating temperature of the observed tool surface in die casting of aluminium alloys. Measurements of the mechanical properties were accomplished on three test pieces under each combination of annealing conditions. Special attention was paid to the correlation of the mechanical properties measured under individual precipitati...
14 citations
Patent•
13 Feb 2002
TL;DR: In this paper, a process for the heat treatment of a maraging steel with improved machinability, good weldability, and high corrosion resistance is described, as well as its use.
Abstract: Maraging steel with improved machinability, good weldability, and high corrosion resistance, a process for the heat treatment of such a steel, as well as its use. According to the invention this steel contains (in % by weight) 0.02-0.075% carbon; 0.1-0.6% silicon; 0.5-0.9% manganese; 0.08-0.25% sulfur; maximum 0.04%; phosphorus; 12.4-15.2% chromium; 0.05-1.0% molybdenum; 0.2-1.8% nickel; maximum 0.15% vanadium; 0.1-0.45% copper; maximum 0.03% aluminum; 0.02-0.08% nitrogen; as well as optionally one or more additional alloying elements up to maximum 2.0%, residual iron, and impurities caused in manufacturing, and a ferrite percentage in the structure of less than 28% by volume. A process is also provided for the heat treatment of a maraging steel with improved machinability, which process makes an object that is through-hardened even with a large cross-section, lies essentially in that a steel block with the above composition is subjected in a first step to an annealing treatment for the formation and adjustment of a ferrite percentage in the structure and in a second step a hot forming of the same takes place, after which in a third step a soft annealing and then a thermal tempering are performed.
11 citations
TL;DR: In this article, the authors investigated the influence of reversion austenite on crack initiation and its propagation of maraging steel and found that the increase in fatigue strength was large near the fatigue limit.
Abstract: Rotating bending fatigue tests were carried out for 18%Ni maraging steel in order to investigate the influence of reversion austenite on crack initiation and its propagation of maraging steel. Fatigue strength was increased by formation of reversion austenite. The increase in the fatigue strength was large near the fatigue limit. This was caused from that the crack initiation and its early propagation were suppressed by the formation of reversion austenite and the suppression was marked with decrease in stress level. Although the fatigue strength decreased by humidity, the formation of reversion austenite relieved the sensitivity of fatigue strength for humidity.
8 citations
TL;DR: In this article, the authors investigated the influence of reversion austenite on the notch sensitivity of Ni maraging steel and found that the influence was very small and that the increase in the fatigue strength was large near the fatigue limit.
Abstract: Rotating bending fatigue tests were carried out for 18% Ni maraging steel in order to investigate the influence of reversion austenite on notch sensitivity of maraging steel. Fatigue strength was increased by formation of reversion austenite. The increase in the fatigue strength was large near the fatigue limit. In the range of notch radius ρ larger than 0.05 mm, fatigue limit was determined by the limit for crack initiation in the material without reversion austenite, whereas a non-propagating crack was observed in only the notched specimen of ρ=0.05 mm in the material formed reversion austenite. These were caused by suppressions of the crack initiation and its early propagation due to formation of reversion austenite. However, the influence of reversion austenite on notch sensitivity was very small.
5 citations
Patent•
28 Feb 2002
TL;DR: In this paper, a manufacturing method of layered rings capable of obtaining the rings having the excellent surface hardness at a low cost was proposed, where ends of a maraging steel thin plate 1 are welded to each other, and an obtained cylindrical drum 2 is cut to a predetermined width to form rings 4.
Abstract: PROBLEM TO BE SOLVED: To provide a manufacturing method of layered rings capable of obtaining the rings having the excellent surface hardness at a low cost. SOLUTION: Ends of a maraging steel thin plate 1 are welded to each other, and an obtained cylindrical drum 2 is cut to a predetermined width to form rings 4. The rings 4 are rolled and subjected to the solution treatment. The solution treated rings 4 are corrected in length to a predetermined circumferential length. The circumferential length corrected rings 4 are aged. The aged rings 4 are nitrided under a mixed atmosphere of the inert gas and ammonia. The circumferential length correction is performed to the solution treated rings 4 at the circumferential length correction ratio of 0.2-0.9%.
5 citations
Journal Article•
TL;DR: In this paper, the influence of heat treatment on the microstructure and mechanical properties of a 2000 MPa grade Co-free 18Ni maraging steel has been investigated, and the strengthening and toughening mechanisms were discussed.
Abstract: The influence of heat treatment on the microstructure and mechanical properties of a 2000 MPa grade Co-free 18Ni maraging steel has been investigated, and the strengthening and toughening mechanisms were discussed. The experimental results show that the hardness of the steel in solution condition is independent of both the solution temperature and the time. A combination of high strength and good toughness can be reached under the peak-aged condition, where the ultimate strength is over 2100 MPa, and the elongation and KIC are 9% and 70 MPa· m1/2, respectively. The TEM observation revealed that a great deal of nanometer size precipitates, such as Ni3(Mo, Ti), is distributed in a high density dislocation matrix of the steel treated with peak-aged condition, which realizes a better match of strength and toughness. The precipitation strengthening in the present steel obeys the modified Orowan mechanism.
Journal Article•
TL;DR: In this paper, the relationship between prior austenite grain size and tensile properties in both solutions and aging conditions was examined, and the mechanism was also discussed, and it was shown that the prior grain size normally and consistently increases with increase of solution treatment temperatures.
Abstract: Variations of the grain size and its distribution of an ultra-purified 18Ni(2200 MPa grade) maraging steel under different solution treatment temperatures(STT) have been investigated, and the relationships between prior austenite grain size and tensile properties in both solutions and aging conditions were examined, and the mechanism was also discussed. The results show that the prior austenite grain size normally and consistently increases with increase of STT. Effects of the prior austenite grain size on strength and ductility are nearly independent of STT for the maraging steel in unaged state, and the thermal brittle at high solution temperature resulting from the segregation of inclusions, such as Ti(C, N), at prior austenite grain boundary is avoided because trace elements were removed to extremely low level. However, the Hall桭etch relationship is obeyed in aged condition, and the increase in prior austenite grain size induced the segregation of precipitates on grain boundary and aging brittle.
Patent•
14 May 2002
TL;DR: In this paper, a belt for a continuously variable transmission subjected to nitriding treatment by the same method is provided. But the belt is not suitable for a continuous variable transmission.
Abstract: PROBLEM TO BE SOLVED: To provide a nitriding treatment method for maraging steel by which the fatigue strength and wear resistance of maraging steel can be improved, and to provide a belt for a continuously variable transmission subjected to nitriding treatment by the same method. SOLUTION: In the nitriding treatment method for hardening the surface of maraging steel, nitriding treatment is performed in a nitriding atmosphere where the concentration of residual ammonia is increased from COPYRIGHT: (C)2004,JPO
Patent•
09 Jan 2002
TL;DR: In this article, a cylindrical drum is formed by welding ends of a maraging steel sheet to a predetermined width, and the rings 4 are then heat treated in the temperature range of 550 deg.C-620 deg.
Abstract: PROBLEM TO BE SOLVED: To provide a manufacturing method of a laminated ring having tensile strength, surface hardness and internal hardness equivalent to the conventional ones and difficult to break even when notches or cracks occur. SOLUTION: Rings 4 are formed by cutting a cylindrical drum 2 formed by welding ends of a maraging steel sheet 1 to a predetermined width. The rings 4 are rolled. The rolled rings 4 are heat treated. The heat-treated rings 4 are aging treated and nitrided. The reverse transformation austenitic phase is generated by heat treating the rolled rings 4 in the temperature range of 550 deg.C-620 deg.C.
01 Jan 2002
TL;DR: In this paper, an extensive experimental program on a 9 % Ni, 12% Cr, 2% Mo steel maraging steel is introduced for the specific purpose of studying the physical phenomenon of transformation induced plasticity.
Abstract: An extensive experimental program on a 9 % Ni, 12% Cr, 2% Mo steel maraging steel is introduced For the specific purpose of studying the physical phenomenon of transformation induced plasticity this material exhibits some very desirable features: The martensite start temperature (M s ) can be found around 150°C; the martensitic finish temperature (M f ) is at ca 80°C The material has a yield stress of about 200 MPa at ca 200°C (fully austenitic state) and of ca 900 MPa at room temperature (fully martensitic state) Plastification is accompanied by rather small hardening up to a strain of roughly 8 % Since the martensitic transformation takes place at a low temperature level upon cooling on air only, this material can be considered as an ideal testing material with practically no creep effects during and after transformation First of all dilatation tests are demonstrated for two types of specimens: longitudinal, also called axial specimens with a fiber texture and radial specimens, as shown in Figure lb A material characterization using M s and M f lines, ie martensite start and finish temperature monitored for different loading conditions and stress levels reveals the influence of the type of loading (tension, shear, compression) Consequently two different loading histories are tested:
loading above M s and then cooling, accompanied by partial or full unloading,
loading at a constant temperature in the transformation temperature interval
TL;DR: In this article, the results of Auger spectroscopy of grain boundary elemental composition of maraging steel 11Cr10Ni2TiMo after typical heat treatment followed by thermal cycling are presented.
Patent•
21 Jun 2002
TL;DR: In this article, the nitriding treatment is performed in an atmospheric gas obtained by adding an organic-based chloride to the atmosphere of a NN atmosphere for maraging steel.
Abstract: PROBLEM TO BE SOLVED: To provide a nitriding method for maraging steel by which the stability of its quality, operability and cost effectiveness are improved, simultaneously, its fatigue strength is improved, and, its fatigue life is elongated SOLUTION: In the nitriding method for maraging steel, the nitriding treatment is performed in an atmospheric gas obtained by adding an organic-based chloride to a nitriding atmosphere Preferably, the treatment is performed at a treatment temperature of the age precipitation temperature or lower for a soaking time in the range of 15 to 60 min More preferably, as the organic- based chloride, methylene chloride is used, and its amount to be added is 30 to 100 mL per m3 of the volume in a furnace
TL;DR: 1緒 言 の鋼はマルテンサイト基地中にCo,Mo,Ti,Al等 の合金 元素を過飽和 に固溶 した状態をつ くり,こ れを時効すること によ りNiあ
Abstract: 1緒 言 マルエージング鋼はインターナショナルニッケル社が1959 年に発表した極低炭素,高Niの 超高張力鋼で1.4~2.OGPaの 強度を持ち,か つ靭性,と くに切 り欠き靭性に優れた鋼であ る.こ の鋼はマルテンサイト基地中にCo,Mo,Ti,Al等 の合金 元素を過飽和 に固溶 した状態をつ くり,こ れを時効すること によ りNiあ るいはFeと これらの元素 との金属間化合物を析 出させて強化するものである.Niの 含有量によって12Ni系 か ら25Ni系 まで用いられている.粉 末冶金法でマルエージング 鋼を加工する方法として,合 金粉を用いたMIM法 が行われて いる1).一方混合粉を用いた加工法としては以前(1965~1975 年頃)に かな り多 く行われた例があるが,原 料粉としてかな り粗い粉末を用いているため,1300°C,5hの 焼結で相対密度 は最大96%程 度で,焼 結体の組織 も不均一であることが報告 されている.この他に均一な合金化 を目指 してNiやCoを フェ ロアロイ粉の形で添加混合する方法も行われているが,こ の 場合 も理論密度に近い高密度の焼結体は得に くいようである. マルエージング鋼はFe,Niが 主成分であるから,こ の素粉 の混合体の金型成形は容易である.そ のため混合粉圧粉体の 焼結によ り高密度化 と均一な合金化が達成できるのであれば これも有効な方法として意味があると考えられる. 以上のことを考慮 し本論では15Ni系 のマルエージング鋼を 混合粉を用いて作製することを試みた.こ の際Ti粉 を除 く原 料粉として,か な り微細な粉末を用い,さ らにボール ミルに よる混合条件などを工夫することによって高密度で均一に合 金化 した焼結体 を得 ることにつとめた.
Patent•
08 Jan 2002
TL;DR: In this article, a maraging steel plate having an excellent vibration insulating property for a golf club head and using the same for the head of the golf club was provided. But the chemical composition of the maraging plate was not discussed.
Abstract: PROBLEM TO BE SOLVED: To provide a maraging steel plate having an excellent vibration insulating property for a golf club head, and to provide the golf club head using the same. SOLUTION: The chemical composition of this maraging steel plate contains 15-19 mass % Ni, 8-15 mass % Co, 4-7 mass % Mo, 0.2-1.8 mass % Ti, and the balance substantially the as essential constituents, and either of a Ti segregation ratio or a Mo segregation ratio in the plate thickness direction is 1.3 or more while both of them are 2.5 or less. In the golf club head 1, a face part 4 having a ball hitting surface S is formed in a head body 2, and at least the face part 4 is formed of the maraging steel plate.
Patent•
25 Oct 2002
TL;DR: In this paper, the authors describe a belt for a continuously variable transmission used in a motor vehicle consisting of a number of elements arranged against each other and supported by two laminated rings, each of which is made from a welded thin maraging steel band.
Abstract: A belt for a continuously variable transmission used in a motor vehicle comprises a number of elements arranged against each other and supported by two laminated rings each comprising a number of rings engaged with each other and made from a welded thin maraging steel band. At least one of the two surfaces of the ring is hardened by pre-stressed shot blasting. The surface of the ring hardened by shot blasting can be nitrided. The thickness of the ring is 100-300 microns, and the depth of the hardened surface is less than 50 microns. At least one hardened surface of the ring has a surface hardness of more than 900 HV, and a residual compressive stress of more than 500 MPa. The maraging steel comprises (in weight %) nickel 13-22; cobalt at most 18; molybdenum 3-12; titanium at most 2; aluminum at most 3, and iron and unavoidable manufacturing impurities the remainder. An Independent claim is given for a process for producing a ring according to the invention.
TL;DR: In this paper, the Δ KII effective can be estimated and data obtained with varying friction conditions can be rationalized by measuring the displacement profile along the crack sides, and changes in mode II crack growth rate and growth stability are obtained.
Abstract: Mode II fatigue crack growth tests have been carried out at different frequencies, in air and in vacuum, in the case of a maraging steel. By changing the experimental conditions, the tribological behaviour at the fatigue crack sides is modified and changes in mode II crack growth rate and growth stability are obtained. By measuring the displacement profile along the crack sides, Δ KII effective can be estimated and data obtained with varying friction conditions can be rationalized.
Patent•
25 Mar 2002
TL;DR: The martensite type stainless steel has equal tensile strength, yield strength and hardness as maraging steel, and corrosion resistance which is superior than 304 stainless steel and comparable to 316 stainless steel as mentioned in this paper.
Abstract: PURPOSE: Martensite type stainless steel for head of a golf club is provided to increase flying distance of a golf ball, feel much soft ball hitting feeling, maintain clean appearance and manufacture a lower priced golf club compared to an existing material by using head material of the golf club which has superior mechanical properties than the conventional head materials of the golf clubs. CONSTITUTION: Martensite type stainless steel for head of a golf club consists 12 to 16 wt.% of Cr, 3.0 wt.% or less of Ni, 1.5 to 5 wt.% of Mo, 0.5 wt.% or less of V, 2.0 wt.% or less of Si, 2.0 wt.% or less of Mn, 0.1 to 0.6 wt.% of C, 0.1 to 0.3 wt.% of N, and a balance of Fe and inevitable impurities. A martensite type stainless steel for head of a golf club is superior than 431 martensite stainless steel, precipitation hardened stainless steel or titanium alloy. The martensite type stainless steel has the equal tensile strength, yield strength and hardness as maraging steel, and corrosion resistance which is superior than 304 stainless steel and comparable to 316 stainless steel.
Patent•
22 Nov 2002
TL;DR: In this article, a method for salt bath nitriding of a ferrous metal by using the molten salt composition was proposed. But the method required the metal to be treated with a salt bath of the above molten salt compositions at 350 to 470°C.
Abstract: PROBLEM TO BE SOLVED: To provide a molten salt composition for salt bath nitriding capable of minimizing the variation in the thickness of a nitride layer due to an intra-furnace setting position and forming the uniform nitride layer without forming a compound layer detrimental to durability on an endless metallic belt consisting of a maraging steel liable to form an oxide film and to provide a method for salt bath nitriding of a ferrous metal by using the molten salt composition. SOLUTION: The molten salt composition for salt bath nitriding of the maraging steel contains, as an anion-component, 3 to 20mass% cyan (CN - ) and 30 to 50mass% cyanic acid (CNO - ), and carbonic acid (CO 3 2- ) in the balance of the anion-component, and further contains, as a cation-component, at least sodium or potassium. The method for nitriding the maraging steel includes treatment of the maraging steel with a salt bath of the above molten salt composition at 350 to 470°C. COPYRIGHT: (C)2004,JPO
Patent•
21 Jun 2002
TL;DR: In this paper, a solution treatment is applied to a rolled metallic ring after rolling the metallic ring formed by cutting an annular drum formed by welding both end parts of a thin plate of maraging steel into a prescribed width.
Abstract: PROBLEM TO BE SOLVED: To provide a method for heat-treating a metallic ring with which deformation of the metallic ring can be reduced in a cooling-treatment after applying a solution treatment SOLUTION: The solution treatment is applied to a rolled metallic ring 4 after rolling the metallic ring 4 formed by cutting an annular drum 2 formed by welding both end parts of a thin plate 1 of maraging steel into a prescribed width After applying the solution-treatment, the cooling from the starting temperature of martensitic transformation to the completing temperature of martensitic transformation in the metallic ring 4, is performed at 3-50 degC/min cooling speed The above cooling is desirably performed at 5-50 degC/min, further desirably performed at 10-50 degC/min cooling speed
Patent•
24 Oct 2002
TL;DR: In this article, a maraging steel is subjected to a cold plastic working to have a predetermined dimension, to a solution treatment for 60 minutes or more at a temperature of 750 to 800 DEG C, and to an aging.
Abstract: A method for producing a steel material having a high fatigue strength and given a uniform residual stress by a rapid treatment. A maraging steel is subjected to a cold plastic working to have a predetermined dimension, to a solution treatment for 60 minutes or more at a temperature of 750 to 800 DEG C, and to an aging.
Patent•
12 Sep 2002
TL;DR: Golf club head is made from a rust-free age-hardened maraging steel having a martensitic temperature MS of at least 130 degrees C and a ferrite content of less than 3 %.
Abstract: Golf club head is made from a rust-free age-hardened maraging steel having a martensitic temperature MS of at least 130 degrees C and a ferrite content of less than 3 %. The maraging steel contains (in weight %) 6.0-9.0 nickel, 11.0-15.0 chromium, 0.1-0.3 titanium, 0.2-0.3 beryllium, and a balance of iron. The steel has a tensile strength of more than 2000 MPa and a creep limit of more than 1900 MPa. An Independent claim is also included for a process for the production of a maraging steel for a golf club head comprising melting a maraging steel alloy and casting to form a cast block, hot deforming the block to form a green body, solution annealing, cooling, grinding to remove beryllium-deficient edge zones, cold deforming, and heat treating.