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1.
L. A. Solntsev L. P. Ivanova T. L. Minyailo A. A. Pavlyuchenko 《Metal Science and Heat Treatment》1976,18(6):503-506
| 1. | Heating at temperatures below Ac 1 S leads to spheroidization and intensive dissociation of cementite in pearlite with formation of a structure that is mainly ferritic, which promotes some equalization of the microdistribution of silicon. |
| 2. | Heating in the intercritical range leads to formation of a special type of microstructure in the metallic matrix in which the austenite formed in ferrite is lamellar or acicular. With rapid cooling this type of structure is fixed at room temperature. Various decomposition products may be present in prior austenite sections. |
| 3. | The formation of the special microstructure in the intercritical range is accompanied by the formation of exceedingly fine silicon in the metallic matrix and thus a reduction of its embrittling effect. |
| 4. | Heat treatment in the intercritical range ensures a good combination of mechanical properties in magnesium cast iron. |
2.
I. A. Borisov 《Metal Science and Heat Treatment》1991,33(11):828-832
| 1. | We worked out a mathematical model of the change of strength properties of Cr–Ni–Mo–V steels during lengthy tempering (up to 1000 h). |
| 2. | The limiting degree of loss of strength of Cr–Ni–Mo–V steels in lengthy tempering depends on the initial structure. Steels with initial bainitic structure lose strength to 0.2=430–470 N/mm2, with pearlitic-bainitic structure to 0.2=320–N/mm2. |
| 3. | The change of impact toughness and of the semi-brittle point with longer tempering times is due to processes of polygonization and recrystallization of the -phase, and also to carbide transformations in tempering. |
3.
Yu. N. Taran P. F. Nizhnikovskaya O. R. Danichek T. M. Mironova M. A. Loiferman S. I. Belorusov G. F. Demchenko D. D. Khizhnyak 《Metal Science and Heat Treatment》1989,31(5):358-367
| 1. | In analyzing the deformation curves of cast irons with a ledeburite eutectic based on vanadium supersaturated and chromium alloyed cementite and of normal white irons a difference including oscillation of the flow stress was observed. |
| 2. | In addition to relaxation stresses in the matrix the character of the yield curves is determined by the phase transformations in the alloyed cementite occurring during deformation. |
| 3. | Plastification of the cementite as the result of the carbide transformation causes an increase in the total plasticity of the iron. The level of plasticity obtained makes it possible to work chrome-vanadium iron by rolling on reduction mills. |
| 4. | As economically alloyed cast irons with a plasticity imparted by the carbide transformation (PICT-irons) for production of rolled bars hypoeutectic while irons containing less than 5% carbide-forming elements may be recommended. |
| 5. | A method for production of rolled bars of white irons was developed. |
| 6. | Work rolls of wrought cast iron were produced and introduced on a 20-roll cold rolling mill. Their life was three and more times longer than of those produced from 9KhFSh steel. |
4.
P. A. Antikain L. I. Lepekhina V. E. Borisov T. N. Shevchenko Yu. D. Mikulina 《Metal Science and Heat Treatment》1988,30(8):627-630
| 1. | Cold bending of tubular blanks of 10Kh2M steel has an insignificant influence on the level of microdistortions, decreases the lattice parameter somewhat, does not change the phase composition of the carbides, and leads to cracking of the coarse M23C6 carbides. |
| 2. | Tempering at 710°C after bending reduces the level of microdistortions by more than three times and the intrinsic broadening of the (110) line by more than two times, increases the lattice parameter, and changes the phase composition of the carbide phase (M3C dissolves). |
| 3. | The stress-rupture strength of 10Kh2M steel coils in the unheat treated condition is higher at stresses exceeding 160 N/mm2 than in the heat treated condition, which is the result of the favorable kinetics of occurrence of structural transformations. With stresses below 160 N/mm2 and in service for 105 h at 505°C coils in the heat treated condition, that is, with a more stable structure, possess higher stress-rupture strength. |
5.
| 1. | The properties of large components made of chromium-nickel-molybdenum steels, in which it is highly probable that a bainitic component is present in the structure, are determine by carbide precipitation in bainitic ferrite with continuous slow cooling. Preparation of a bainitic structure without carbide provides high impact strength and metal strength in the lightly tempered condition. |
| 2. | In chromium-nickel-molybdenum steels containing 0.10–0.15% carbon with cooling at a rate of 300°K/h a bainitic structure free of carbide forms. |
6.
M. Yakeshova 《Metal Science and Heat Treatment》1989,31(7):502-505
| 1. | The carbide phase in the steels investigated is paramagnetic alloyed cementite. The redistribution of alloying elements corresponds to their affinity for carbon: the content of Mn, Cr, V, and Mo and the content of Si and Ni are higher and lower, respectively, in the carbides than in the matrix. |
| 2. | It is mostly the carbides that are retained in the steel with the initial granularferrite structure after rapid heating and quenching, while the amount of carbiides diminishes after conventional quenching; in the specimens with an initial bainitic structure, the amount of carbides in the quenched steel is minimal, even after rapid heating. Additional quenching in liquid nitrogen does not alter the carbide content. |
| 3. | Mössbauer spectroscopy makes it possible to determine the carbides in steels with a higher sensitivity and accuracy than conventional methods, for example, radiography and metallography; the method is independent of the deformation, shape, and size of the particles. |
| 4. | The correction factor dC=1.02 was calculated for determination of the composition of the alloyed paramagnetic cementite by the method of scattering. |
7.
V. M. Pereverzev V. I. Kolmykov V. A. Vorotnikov 《Metal Science and Heat Treatment》1990,32(4):291-294
| 1. | The relationship of abrasive wear resistance of steels to carbide phase content in the 0 to 90% range in carburized cases is not a steady one. With a carbon content above the critical, increases very rapidly, which may be explained by the change in the mechanism of abrasive wear of ferrite-cementite structures. |
| 2. | With a carbide content of 0–50% wear occurs by microcutting of the ferrite matrix. The carbides removed from the surface are removed with the microchip while not having a significant influence on wear resistance. |
| 3. | With a carbide content of 50–75% wear occurs as the result of multiple crumpling of the ferrite matrix all the way to cracking of the carbides or formation in the ferrite of fatigue cracks on which surface microvolumes separate from the metal. |
| 4. | With a carbide content of more than 75% the ferrite matrix ceases to be plastic and wear occurs as the result of abrasion of the whole mass of carbides entering onto the surface. In this case the wear resistance increases by two orders of magnitide. |
8.
A. A. Gol'denberg A. N. Chekhovoi L. N. Antipova 《Metal Science and Heat Treatment》1989,31(2):129-133
| 1. | One of the causes of failure during low-cycle fatigue of type 0Kh4V2S2MFNYuT die steel is the formation of defective spaces around the carbide inclusions. This type of damage is evidently associated with the development of stresses at the boundary of the matrix and the inclusion during external cyclic loading. |
| 2. | The effective radius of the carbide inclusions linearly increases with increase of the logarithm of their sizes. |
| 3. | During cyclic loading at a frequency of f=1 Hz and c = +2400 to –300 N/mm2 the defective spaces are observed in steel 8Kh4V2S2MFNYuT around particles of size greater than 0.3 m. |
| 4. | During metallurgical production, one should avoid the accumulation of large carbides in the structure of die steels to be used for cold working. |
9.
L. I. Tushinskii E. N. Mironov L. B. Tikhomirova V. A. Ananin 《Metal Science and Heat Treatment》1988,30(9):666-671
| 1. | Steel 09G2S with ferritic-martensitic structure, subjected to stipulated thermoplastic strengthening (STPS), has high indices of structural strength; this opens up prospects of its use in building structures and pipelines. |
| 2. | As a result of STPS, consisting in combined deformation at temperatures of the austenitic region and of the intercritical interval, the structural components of the dualphase steel 09G2S become refined and a substructure forms in the ferrite; this doubles the threshold value of the stress intensity factor and reduces by a factor of about 1.8 the speed of fatigue crack propagation under cyclic load in comparison with the analogous characteristics of steel treated by the standard regime. At that u increases from 800 to 880 N/mm2; from 540 to 650 N/mm2; from 17 to 19%. |
10.
| 1. | Improved high-speed steels for the fabrication of a die tool that operates under high specific forces with impact loads are hypereutectoid, and not ledeburitic. Steel 11M5F is classed with this type of steels. |
| 2. | Quenching of a steel 11M5F tool should ensure dissolution of the M6C carbide and retention of the fine grain in this case; in addition to the absence of primary carbides in the structure, this ensures a high low-cycle-fatigue strength. |
| 3. | In addition to high strength and hardness, steel 11M5F also exhibits increased impact strength; its failure occurs with pronounced plastic deformation. |
| 4. | Use of steel 11M5F in lieu of steel R6M5 for the fabrication of cold-heading punches makes it possible to improve their resistance by a factor of two with a high resistance stability, and also to deform materials with u < 700=">2 in the cold. |
11.
L. L. Pyatakova I. I. Mints T. G. Berezina M. A. Sirotkina 《Metal Science and Heat Treatment》1976,18(1):47-51
| 1. | The addition of small amounts of boron (0.002%) and its distribution in the boundaries of zones and its interaction with carbon make it possible to obtain a substructure of martensite that is finer and more even in size after quenching of highly deformed medium-carbon steel, and a more dispersed substructure of martensite and carbides precipitated during low-temperature tempering of the steel. |
| 2. | The effect of boron on the structural parameters facilitates, along with other factors, obtaining high values of the notch toughness (a=8 kg-m/cm2) and high values of the work of crack propagation in medium-carbon steel of the 40G type with high strength (ob=180 kg/mm2). |
12.
L. M. Storozheva D. A. Burko E. M. Grinberg Yu. E. Rodionova R. Bode K. Esher 《Metal Science and Heat Treatment》2000,42(7):267-271
Conclusions
Translated from Metallovedenie i Ternicheskaya Obrabotka Metallov, No. 7, pp. 14–17, July, 2000. 相似文献
| 1. | Recrystallization of steels after hot rolling with a low reeling temperature begins and ends at a higher temperature and a longer hold than in steels obtained with reeling at a higher temperature. |
| 2. | After hot rolling with a high reeling temperature the recrystallization of steel not bearing excess elements in the solid solution (Nb/C ef ≅1) begins and ends much more rapidly than recrystallization in the other steels. |
| 3. | After continuous annealing, the ferrite grains in steel with Nb/C ef ≅1 have a maximumsize, which is connected with the leading recrystallization of this steel. |
| 4. | The growth of ferrite grains in steel subjected to high-temperature reeling is accompanied by a decrease in the yield point and an increase in the specific elongation and coefficient of normal plastic anisotropy. Steels with Nb/C ef ≅1 have maximum mechanical properties. |
13.
V. P. Gubchevskii A. P. Frolov É. D. Nemkina E. V. Radyukevich L. I. Chernykh 《Metal Science and Heat Treatment》1991,33(3):244-249
| 1. | The optimum properties of masks may be obtained with tann=770–820°C, and regardless of chemical analysis of the steel and the conditions of preliminary cold rolling the minimum tensile strength and coercive force, the maximum ferritic grain size, and the sharpest crystallographic structure, providing good formability of the strip, are provided. |
| 2. | A reduction in carbon content from 0.05 to 0.004% under otherwise similar conditions leads to a reduction in tensile strength of 7–10 N/mm2, in coercive force of 20–25 A/m, and in microhardness of 3–5 N and an increase in the P(111)/P(100) ratio of 2–3 relative units with a reduction in elongation on the area of flow of 2–3%. |
| 3. | The use in production of the strip of double cold rolling with an intermediate anneal in the production line with a second rolling with =29% has a significant influence on the properties of the finished masks. In comparison with single rolling the tensile strength drops by 50 N/mm2, the coercive force by 50 A/m, and the microhardness by 5–8 N while the average grain size increases by not less than twice and the P(111)/P(100) ratio by five to six times. |
| 4. | Use of double cold rolling of strip and annealing of the masks at 770–820°C but not above the Ac3 provides an approximately 20% reduction in scrap for nonuniform transparency and tear defects in spherization. |
14.
| 1. | The optimal quenching temperature for Cu–Ni–P and Cu–Ni–P–Zr alloys is in the range of 750–900°, and the aging temperature is 400–450°. Cold deformation before aging increases the strength of the aged alloys. With increasing deformation the aging temperature should be lowered from 450 to 350° and the aging time should be shortened. |
| 2. | The strength characteristics after heating (during brazing, for example) can be restored to a substantial extent by aging (without quenching). |
| 3. | The alloys can be used in the electrical and electronic industries in cases where high strength (b ~ 40 kg/mm2) and good electrical conductivity (60% that of pure copper) are required after heating at 800–1000° and good strength at temperatures up to 450°. |
15.
| 1. | Structural inheritance results from the fact that recrystallization is inhibited by phase strain hardening during initial quenching, precipitation of particles of second phase, and redistribution of alloying elements with repeated heating. |
| 2. | Structural inheritance should occur in all polymorphous alloys with heating of a solid solution supersaturated with interstitial elements, since the precipitated particles of second phase are completely dissolved only at temperatures above Ac3. The temperature range of inheritance varies with the thermal stability of the second phase. |
| 3. | Recrystallization that eliminates structural inheritance occurs by means of the growth of austenite nuclei with another orientation, usually at boundaries of ferrite with carbide, and partially by means of the fusion of subboundaries, leading to an increase in the angle of turn at the boundary. |
16.
V. V. Atamanyuk O. V. Zaitsev S. V. Ivashchuk P. A. Yakovishin 《Metal Science and Heat Treatment》1991,33(2):97-100
| 1. | Hardened steel ShKh15 contains a comparatively large amount of residual austenite which decomposes within a fairly large temperature range. There are two regions of high stability of austenite, and between them there is an interval of its instability. |
| 2. | Formation of cementite begins at comparatively low (for chromium steels) tempering temperatures (250°C). The most intense formation of cementite begins above 350°C, and the range of carbide tranformations is larger than with carbon steels. |
| 3. | The obtained data can be used in the examination of transformations occurring in the working subsurface layers of rolling-contact bearings of steel ShHKh15 in operation, and also in the solution of problems of ensuring stability of quality, increased wear resistance, reliability, and service life of rolling-contact bearings. |
17.
G. M. Sorokin S. N. Bobrov I. U. Tsvetkov V. V. Evdokimov 《Metal Science and Heat Treatment》1988,30(5):356-358
| 1. | For work under alternating loads it is possible to use medium-carbon alloy steels whose ultimate strength reaches 2000 N/mm2. |
| 2. | The use of case-hardened steel for work with prolonged alternating loads does not result in a marked increase of fracture toughness because of the presence of high brittleness of the superficial high-carbon layer. |
18.
M. V. Pridantsev V. N. Kopernikova L. A. Grigorenko 《Metal Science and Heat Treatment》1976,18(2):136-139
| 1. | Aluminum nitride (0.079%) and vanadium nitride (0.125%) refine the grains in steels of the 17GS type and increase the yield strength by 4.5–7 kg/mm2, substantially increasing the toughness of the steel and also the work of crack initiation and crack propagation, which lowers the ductile—brittle transition temperature by 17–58°. |
| 2. | In contrast to nitrides, excess carbides, carbonitrides, and copper phase, which increase the strength characteristics, lower the toughness and raise the ductile—brittle temperature of the steels. |
| 3. | The embrittling effect of copper phase in steel of the 17GSND type is slight at copper concentrations up to 0.5%, but increases at larger copper concentrations. |
19.
| 1. | The yield of austenitic high-manganese steels can be raised by 100–250 N/mm2 as a result of disperse-carbide segregation when they are alloyed with tungsten. |
| 2. | Steels with 15–20% Mn, 10% W, and more than 0.65% of C possess the best combination of mechanical properties in the initial and quenched states. |
| 3. | Cold plastic deformation makes it possible to increase the yield point to 1500–1600 N/mm2 with satisfactory plasticity. |
20.
| 1. | Alloying steels of the system Fe-Mn-Cr-V-C with nitrogen promotes austenite grain refinement after austenitizing, an increase in strength, and a reduction in ductility properties. With 0.6% C the relative elongation and reduction of area are at a maximum, which is due to occurrence of deformation twinning. |
| 2. | During aging carbon-nitrogen steels are strengthened at a slower rate than for carbon steel, which is due to preparation of increased 5 and with quite a low level of strength. Steels of the optimum composition type 60G14Kh9AF2 (0.2% N) after aging have the following mechanical properties: f =1350 N/mm2, 0.2,= 980 N/mm2,5 =40% =40%. |
| 3. | Aging of unstable carbon-nitrogen steels increases the stability of austenite towards strain-induced martensitic -transformation. |
| 4. | Partial substitution of carbon with nitrogen causes a slow down in the austenite grain growth rate and an increased stability of the steel structure towards overheating. Nitrogen promotes an increase in solubility of substitution alloying elements in solid solution during austenitizing which during subsequent aging prevents formation of coarse excess phases along grain boundaries. This provides preparation of high ductility and toughness properties. |
| 5. | Carbon-nitrogen steel compared with carbon steel after austenitizing with the same ductility is stronger, but after aging with the strength it is more ductile. The optimum austenitizing temperature for steel 60G14Kh9AF2 is 1200°C. |