Showing papers on "Tempering published in 1969"
TL;DR: In this paper, the first stage of tempering of high-carbon martensites results in the precipitation of the metastable epsilon carbide; in low-carbon steels, it is generally considered that the carbide does not form during tempering and only cementite is observed.
30 citations
TL;DR: In this article, the structural changes occurring during the tempering of a 12%Cr-6%Mo-10%Co-0.1 %C steel have been investigated and it has been shown that an intermetallic compound R -phase is responsible for the marked secondary hardening but that the carbides M 2 X and M 6 C are also precipitated.
29 citations
Patent•
07 Oct 1969TL;DR: In this article, a glass-ceramic article is made from a glass composition, the glassceramic breaking or dicing like thermally tempered glass instead of producing fragments with sharp and pointed edges.
Abstract: A glass-ceramic article is made from a glass composition, the glass-ceramic breaking or dicing like thermally tempered glass instead of producing fragments with sharp and pointed edges. One method of making such a glass-ceramic article is by heat-treating a thermally crystallizable glass having the following composition: TO PROVIDE BY BULK CRYSTALLIZATION A GLASS-CERAMIC ARTICLE, IONEXCHANGING THE SURFACE OF THE ARTICLE, HEATING THE ION-EXCHANGED GLASS-CERAMIC ARTICLE TO PROVIDE ADDITIONAL CRYSTALLIZATION, AND THERMALLY TEMPERING THE RESULTANT ARTICLE.
28 citations
TL;DR: In this article, the influence of a new heat treatment, "Intercritical Hardening", on mechanical properties, microstructure and sulfide cracking behavior of C-75, 4140, and 4340 steels is described.
Abstract: The influence of a new heat treatment, “Intercritical Hardening”, on mechanical properties, microstructure and sulfide cracking behavior of C-75, 4140, and 4340 steels is described. This treatment involves heating above the lower critical AC1 temperature. Heating above the AC1 temperature introduced untempered martensite and drastically lowered sulfide cracking resistance. Newly formed martensite was then eliminated by tempering below the AC1 temperature. Tempering below AC1 after intercritical hardening increased strength and ductility and dramatically improved sulfide cracking resistance. Highest strength consistent with immunity to sulfide cracking was developed by the 4340 steel due to the fact that nickel lowered the initial temperature required to develop fresh martensite.
10 citations
Patent•
09 Sep 1969
TL;DR: In this article, the authors propose a process and a parallelus for coping with a body of a machine in a non-liquid environment by placing it against a liquid medium.
Abstract: A PROCESS AND APPARATUS FOR CHEMICALLY TEMPERING A BODY OF A MATERIAL AMENDABLE TO SUCH TREATMENT BY DISPOSING THE BODY IN A NON-LIQUID ENVIRONMENT, AND PROJECTING AGAINST THE BODY A CONTINUOUS SUPPLY OF A LIQUID TEMPERING MEDIUM AT A FLOW RATE SUFFICIENT TO CAUSE A CON- TINUOUS STREAM OF THE MEDIUM TO FLOW ACROSS THE SURFACES TO BE TEMPERED.
10 citations
TL;DR: In this article, the influence of tempering on the corrosion characteristics of low-C precipitation hardening martensitic stainless steel with those of plain 13%Cr steel was determined by a potentiostat circuit.
8 citations
TL;DR: In this article, it was shown that the decisive factor in the retention of the high hardness of alloy steels up to high temperatures is the inhibition of the decomposition of the γ-solid solution and the increased temperature of relaxation processes that induce a reduction of lattice distortion.
Abstract: 1.
After low-temperature tempering of high-alloy chromium steels Young's modulus begins to increase and then remains almost constant up to tempering temperatures of 525–550°C. The higher the chromium content of the steel, the smaller the initial increase and the longer the horizontal section of the curve.
2.
On the hardness curves one observes a small peak at 150°C and then a drop of the hardness. At 450–500°C one observes another peak, which is the result of processes in the carbide phase.
3.
After tempering at 525–550°C the hardness decreases and Young's modulus increases. Up to 700°C the increase of Young's modulus for steel 4Kh13 averages 6%, and 12% for steel 9Kh18.
4.
The rapid increase of Young's modulus after tempering at 525°C and the simultaneous decrease of the hardness confirm the data in [14] indicating that the decisive factor in the retention of the high hardness of alloy steels up to high temperatures is the inhibition of the decomposition of the γ-solid solution and the increased temperature of relaxation processes that induce a reduction of lattice distortion.
8 citations
7 citations
Patent•
21 Apr 1969
TL;DR: In this paper, the authors describe a SPRING STEEL of stronger resistances to relaxation in service, and show that it is more resistant to stress at a higher temperature than RC 47.
Abstract: COILED STEEL INTERNAL COMBUSTION ENGINE VALVE SPRINGS ARE PRODUCED BY HARDENING CARBON STEEL WIRE, TEMPERING THE HARDENED WIRE TO AN RC HARDNESS OF 50 TO 51 AT ABOUT 700*F., COILING THE TEMPERED WIRE INTO SPRINGS, AND THEN STRESS RELIEVING THE COILED SPRINGS AT A TEMPERATURE ABOVE THE TEMPERING TEMPERATURE AND TO A HARNESS NOT SIGNIFICANTLY GREATER THAN RC 47. THIS RESULTS IN A SPRING STEEL OF DEFINITELY HIGHER RESISTANCE TO RELAXATION IN SERVICE.
6 citations
TL;DR: In this article, it is shown that to obtain a high impact toughness, and particularly a low cold brittleness threshold, it is necessary to neutralize the harmful effect of the elevated nitrogen concentration (up to 0.018%) in such steels by adding nitride-forming elements.
Abstract: 1.
The toughness of low-carbon (C<0.10%) high-manganese (6–9%) steel depends not only on the heat treatment but also the melting and deoxidizing conditions.
2.
The optimal heat treatment, ensuring the highest impact toughness, is tempering in the intercritical range, which results in a structure consisting of a fine mixture of ferrite and austenite highly alloyed with manganese as well as a small amount of ɛ-phase.
3.
To obtain a high impact toughness, and particularly a low cold brittleness threshold, it is necessary to neutralize the harmful effect of the elevated nitrogen concentration (up to 0.018%) in such steels by adding nitride-forming elements — aluminum (0.04–0.07%) or titanium (0.04–0.07%).
4.
To obtain a high impact toughness it is important not only to combine the nitrogen into stable nitrides but also to use melting and crystallizing procedures ensuring finely dispersed and evenly distributed nitrides. This can be achieved by electroslag remelting.
6 citations
TL;DR: In this article, the development of flaws and a considerable change in the structural state of a commercial glass, due to severe tempering in different liquid media, is revealed. But the authors do not reveal the cause of these flaws.
Abstract: The present investigation reveals the development of flaws and a considerable change in the structural state of a commercial glass, due to severe tempering in different liquid media.
TL;DR: In this paper, a detailed fractographic study of a commercial 1 1/2 Ni-Cr-Mo steel and a high purity laboratory-made steel of similar alloy content tested in uniaxial alternating and pulsating loading is presented.
Abstract: Results are given of a detailed fractographic study of a commercial 1 1/2 Ni-Cr-Mo steel (S95 Specification) and a high purity laboratory-made steel of similar alloy content tested in uniaxial alternating and pulsating loading. The specimens were hardened by oil quenching and tempering to strength levels of 1544 and 1930 MN/m2 (100 and 125 tonf/sq. in.). tested at room temperature and the fractures examined by scanning-electron and optical microscopes and by the electron microscope employing a two stage replication technique.
TL;DR: In this paper, the changes in the magnetic properties of Ticonal 600 and the evolution of the microstructures, as observed on thin foils by transmission electron microscopy, were studied at room temperature before and after double tempering.
Abstract: The changes in the magnetic properties of Ticonal 600 (Fe‐24% Co‐14% Ni‐8% Al‐3% Cu) and the evolution of the microstructures, as observed on thin foils by transmission electron microscopy, both resulting from the interruption of the magnetic cooling by a water quench from temperatures in the range 850°–600°C, were studied at room temperature before and after double tempering. These data were used in connection with a system of approximated relations to estimate the saturation magnetization, σs1 and σs2, and the compositions of α1 and α2 phases, respectively. During the magnetic cooling, σs1 first decreased slightly, between 850°–800°C, and then increased, while σs2 decreased continuously over the entire temperature range. Tempering induced a decrease in σs1; and an increase in σs1; however, the latter effect become less important as the prior magnetic treatment progressed to lower temperatures. Cooling down to 600°C followed by tempering resulted in a σs2 value of the order of 93–100 emu/g, while σs1 was...
TL;DR: The hardness of the alloy as cast, annealed, and quenched is approximately the same (HRC 40-45) as mentioned in this paper, and the hardness is increased to HRC 67 at a red hardness of Kr58 up to 720°C and strength up to 240 kg/mm2, and the cutting and technological properties are high.
Abstract: 1.
The iron-base tool alloy (0.3–0.4% C, 20% W, 20% Co, 4% Cr), which is hardened by precipitation of intermetallic and carbide phases, consists of Feα phase, M6C carbide, and the intermetallic compound Co7W6 in the annealed condition.
2.
The extent of decarburizing can be determined from the relative intensities of the Co7W6 and M6C lines on the x-ray patterns.
3.
During heating to quenching temperature the Co7W6 is dissolved first, and then M6C. All the Co7W6 is dissolved at 1150°C, while part of the M6C remains in the form of excess carbide even after quenching from 1350°C.
4.
The Ms-Mf points of the alloy are 130–150°C higher than for high-speed steels of the usual composition and the Mf point is above room temperature, due to which the quenched alloy contains practically no residual austenite.
5.
The hardness of the alloy as cast, annealed, and quenched is approximately the same (HRC 40-45).
6.
The absence of residual austenite after quenching permits single tempering of the alloy.
7.
The alloy is hardened in tempering at 560–630°C due to the precipitation of carbide and inter-metallic phases. The hardness is increased to HRC 67 at a red hardness of Kr58 up to 720°C and strength σbend up to 240 kg/mm2, and the cutting and technological properties are high.
01 Jun 1969
TL;DR: In this article, the fatigue-crack propagation behavior of heat-treated 4340 steel has been studied as a function of tempering temperature from 400 to 800 F and at +80 and -50 F test temperatures.
Abstract: : The fatigue-crack propagation behavior of heat-treated 4340 steel has been studied as a function of tempering temperature from 400 to 800 F and at +80 and -50 F test temperatures. Fracture mechanics analysis of the data was used for through-thickness cracks in center-notched sheet specimens. Special emphasis was placed on the phenomenon of tempered martensite embrittlement, which occurs in the 500 to 700 F range of tempering temperatures, to see if it can be detected by fatigue testing. (Author)
TL;DR: In this paper, the characteristics of the resistance to microplastic deformation under brief and prolonged loading conditions are fairly sensitive to structural changes in the surface layer of bearing steels after mechanical and thermal treatments and can be used as indicators of the operating characteristics of bearings.
Abstract: 1.
The characteristics of the resistance to microplastic deformation under brief and prolonged loading conditions are fairly sensitive to structural changes in the surface layer of bearing steels after mechanical and thermal treatments and can be used as indicators of the operating characteristics of bearings.
2.
Steel ShKh15P has the highest resistance to microplastic deformation after tempering at 250°C and steel 11Kh18M after tempering at 350–400°C.
3.
Increasing the tempering temperature and time after polishing raises the elastic limit of steels ShKh15P and 11Kh18M, which points to the formation of a more stable fine structure in the surface layer during tempering.
4.
The variation of the elastic limit through the depth of the surface layer points to structural heterogeneities in the surface layer after polishing. The minimal value of the elastic limit, and thus the highest structural instability, is observed at depth of 2–3 μ.
5.
After treatment under the optimal conditions steel 11Kh18M has the higher relaxation resistance, characterizing a more stable structure, as compared with steel ShKh15P.
TL;DR: The steel is more susceptible to hydrogen absorption after tempering at 20-450°C and the highest absorption capacity was found in the steel with a structure of troostite as discussed by the authors.
Abstract: 1
The steel is more susceptible to hydrogen absorption after tempering at 20–450°C The highest absorption capacity was found in the steel with a structure of troostite; the hydrogen absorption was minimal after tempering at 550–650°C
2
Vacuum arc remelting reduces hydrogen absorption due to the higher purity of the metal
3
The main factor in the absorption capacity of the steel is the presence of stresses, which sharply intensify the hydrogen absorption process
Patent•
24 Feb 1969TL;DR: Hardenable 14-16 percent chromium heat-resistant steel containing cobalt, silicon, molybdenum and tungsten in a special balanced composition for extended high temperature service life.
Abstract: Hardenable 14-16 percent chromium heat-resistant steel containing cobalt, silicon, molybdenum and tungsten in a special balanced composition for extended high temperature service life. May also contain manganese, nickel, vanadium, and boron. Heat treated by austenitizing, air hardening and tempering. Martensitic structure tempered above 1,100*F. is free of any detrimental delta ferrite, sigma phase, coalesced carbide network and retained austenite. Useful as precision cast articles of equipment for handling, forming or otherwise contacting hot plastic or molten glass in the manufacture of glassware.
Patent•
01 Oct 1969
TL;DR: In this paper, an alloy steel consists, in per cent by weight, of C 0A 1-0A6 6 Mn 0A25-5 Al 0A 5-2 Mo 0A5-3 Si 0A1-2 V 0A01-1 Alternatively Cu 1-3 Fe and impurities such as Ni, Cr, S and P -balance, and the steel may be heat-treated by soaking above the AC 3 point, and either quenching and tempering, or cooling to a temperature within the austenite range of the steel
Abstract: 1,166,042. Alloy steels. NATIONAL RESEARCH DEVELOPMENT CORP. March 22, 1967 [Dec.22, 1965], No.54329/65. Heading C7A. An alloy steel consists, in per cent by weight, of C 0A1-0A6 6 Mn 0A25-5 Al 0A5-2 Mo 0A5-3 Si 0A01-2 V 0A01-1 optionally Cu 1-3 Fe and impurities such as Ni, Cr, S and P - balance. The steel may be heat-treated by soaking above the AC 3 point, and either (a) quenching and tempering, or (b) cooling to a temperature within the austenite range of the steel, ausforming, quenching and tempering. The steel may also be nitrided. Applications specified are torsion bars, springs, gears and tools.
TL;DR: In this article, the fatigue limit for carburized steel 20Kh2N4A was found to be higher after carburizing temperature without high-temperature tempering and quenching in a hot medium than after treatment 6.
Abstract: 1.
When the excess carbides in the case of steel 20Kh2N4A are in the form of fine spheroids, an increase of the carbon concentration in the surface zone from 0.8 to 1.5% does not reduce the fatigue limit.
2.
After heat treatment (quenching from carburizing temperature and repeated quenching from 800°C) the fatigue limit of steel 20Kh2N4A is higher than after the commercial treatment, No. 6 (carburizing+high-temperature tempering+quenching+low-temperature tempering).
3.
With quenching from the carburizing temperature without high-temperature tempering before quenching and quenching in a hot medium the fatigue limit is lower than after treatment 6.
4.
Cold treatment after quenching results in the lowest fatigue limit.
5.
At the higher low-temperature tempering temperatures the brittleness of the case is reduced and also the residual compressive stresses. The fatigue limit for carburized steel 20Kh2N4A is highest after tempering at 140°C. An increase of the tempering time at 140°C from 1 to 4 h has no effect on the fatigue limit.
01 Jun 1969
TL;DR: In this paper, the development of reversible and irreversible temper brittleness in 3 percent nickel-chromium gun steel was studied using sections of two 175-mm M113 gun tubes.
Abstract: : Sections of two 175-mm M113 gun tubes were utilized to study the development of both reversible and irreversible temper brittleness in 3 percent nickel-chromium gun steel. Relative material toughness indicated by the 100 percent fibrous transition temperature was determined on numerous groups of specimens tempered between 900 and 1200 F for various times.
TL;DR: The elastic limit of structural steels 38KhMYuA and 40KhN2SVA is highest after tempering at 300-350°C following quenching or HTTMT as discussed by the authors.
Abstract: 1.
HTTMT of alloy structural steels leads not only to higher tensile and yield strengths but, particularly, to an increase of the elastic limit, which characterizes the resistance to low plastic deformation. The elastic limit of structural steels 38KhMYuA and 40KhN2SVA is highest after tempering at 300–350°C following quenching or HTTMT.
2.
After HTTMT the relaxation resistance of structural alloy steels increases substantially in the first testing period (300–400 h at 150°C).
TL;DR: Precipitation-hardening alloy V20K30 has a threshold of red hardness 100-120°C higher than that of high-speed steel R18 and an almost identical strength.
Abstract: 1.
Precipitation-hardening alloy V20K30 has a threshold of red hardness 100–120°C higher than that of high-speed steel R18 and an almost identical strength.
2.
The alloy has good ductility in the heated condition, can be quenched from substantially lower temperatures, and can be quenched both in oil and in heated media. The residual deformation after quenching and tempering is less than that of the high-speed steel.
3.
The shortcomings of the alloy are its very low ductility at room temperature, the difficulty of treatments involving plastic deformation (drawing, pressing), which limits the size of bars. At the present time it is possible to manufacture the alloy in the form of hot-rolled rods with a diameter over 8 mm. The alloy has a limited hardenability and can be used to manufacture tools with diameters of 70–140 mm.
31 Mar 1969
TL;DR: In this paper, an extensive electron fractographical investigation was carried out of a series of fatigue failures in a 4340 type steel, where high stresses and high tempering temperatures promote the formation of striations.
Abstract: An extensive electron fractographical investigation was carried out of a series of fatigue failures in a 4340 type steel. Low tempering temperatures and low stresses promote intergranular fatigue fractures. High stresses and high tempering temperatures promote the formation of striations.
TL;DR: In this paper, the effect of strain aging on the mechanical properties of steel 38Kh5MSFA was analyzed and shown to increase the ultimate strength and yield strength and decrease the elongation.
Abstract: 1.
After small plastic deformation (0.2\2-1.2%) and aging, steel 38Kh5MSFA is susceptible to strain aging, which is manifest in an increase of the ultimate strength and yield strength and decrease of elongation. The yield strength increases more than the ultimate strength. At a deformation of 0.6% and higher, followed by aging, σ0.1/σb is close to unity.
The effect of strain aging on the mechanical properties is manifest in the different original conditions after low- and high-temperature tempering. However, the effect is stronger after low-temperature tempering.
2.
Strain aging occurs at room temperature but is more evident at higher aging temperatures up to 300\dgC.
3.
Strain aging raises the cold-brittleness threshold but has little effect on the work of crack propagation.
01 Jan 1969
TL;DR: In this article, the effects of quenching temperature, tempering temperature and time on the hardness of three die steels of similar carbon contents but having increasing chromium percentages were investigated.
Abstract: This paper present studies on the effects of quenching temperature, tempering temperature and time on the hardness of three die steels of similar carbon contents but having increasing chromium percentages While tempering in the range of 150°C to 400°C it was observed that hardness decreased as quenching temperature was raised All the steels showed secondary hardening phenomenon in relation to the variables mentioned above It was also observed that on tempering the steels above 450°C, after prior quenching from increasing temperatures, hardness gradually increased upto the quenching temperature of 1100°C, beyond which followed a decrease in hardness This phenomenon was the decrease in hardness This phenomenon was the same at all tempering temperatures upto 601°C, but the increase in hardness from low quenching temperatures to the maximum quenching temperature was less at 450°C than at the higher temperatures and attained a maximum at 600°C secondary hardening decreased with the increase of quenching temperature