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1.
M. M. Kantor C. B. Maslenko V. V. Khangulov N. I. Kazakova A. V. Abramyan B. D. Belyasov 《Metal Science and Heat Treatment》1989,31(10):790-793
| 1. | In alloys of the Mo-Re system liquation of rhenium is low (K=1.1) and it does not depend/either on the rhenium content or on the set of deoxidizing and microalloying additions contained in the alloy. |
| 2. | Liquation of tungsten in alloys of the Mo-W system is greater (K=–1.3), but it also does not depend on its content in the alloy. |
| 3. | In alloys of the system Mo-W-Re after single remelting liquation of rhenium is the same throughout the volume of the ingot. The degree of rhenium liquation in ternary alloy is the same as in binary alloys of the Mo-Re system. |
| 4. | The degree of tungsten liquation in an ingot of an alloy of the Mo-W-Re system after single-stage remelting is considerably higher in the central zone of an ingot than in the outer zones, and it exceeds the degree of its liquation in binary alloys of the Mo-W system. After secondary remelting tungsten liquation in ternary alloys is the same as in binary alloys, and it is also the same throughout the whole volume. |
| 5. | Inhomogeneous distribution of tungsten and rhenium in alloy of the Mo-W-Re system arising as a result of its nonuniform crystallization is also retained after ingot deformation. |
2.
A. V. Bezprozvannykh A. I. Kapustin I. V. Barysheva 《Metal Science and Heat Treatment》1989,31(2):134-136
| 1. | An austenitic dispersion-hardened chromium manganese die steel type 5Kh10G15SM2F2R has been developed whose thermal stability is 160–190°C higher than for the martensitic class steels 4Kh4VMFS and 5Kh2MNF used currently, for similar purposes. |
| 2. | Strengthening of steel 5Kh10G15SM2F2R occurs as a result of precipitation of carbide phases type VC, Cr23C6, and Mo2C during aging. |
| 3. | Steel type 5Kh10G15SM2F2R is recommended for hot-forming tools for alloys that are difficult to work, liquid forming of copper alloys, and for hot pressing of metal powders whose operating temperature does not exceed 830–850°C at pressures up to 700–800 MPa. |
3.
| 1. | Annealing (at 825–900°) for 24 h for hot-rolled and 15–18 h for cold-rolled high-speed steel lowers the quench hardness, secondary hardness, and red hardness. These properties are much more impaired after annealing at 900° than at 825°. |
| 2. | The effect of annealing depends on the amount and composition of M6C carbide, i.e., the chemical composition of the high-speed steel. The properties are most impaired for steel R18, where the carbide contains more tungsten, and less impaired for steels R12 and R6M5. |
| 3. | It is recommended that the annealing temperature not be higher than 850–860°, that the load in the furnace be limited so that the annealing time at temperatures over 800° does not exceed 10–18 h, and that the annealing time be still shorter for cold-rolled steels. |
4.
| 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. |
5.
| 1. | The unilateral nucleating role of primary phases in the formation of a eutectic structure in Ni–Ni3Ti alloys was shown. |
| 2. | The local chemical composition of primary and eutectic phases was determined in hypoeutectic and hypereutectic alloys. Substantial supersaturation in primary dendrites and slight supersaturation in platelets of eutectic phases were established. |
| 3. | The conformity of the nucleating properties of the phases and data on the interphase energy at the boundaries of the phases with the melt was experimentally confirmed for alloys of the Ni–Ni3Ti system. |
6.
I. P. Mozharenko L. A. Dolinskaya E. Ya. Veksler G. A. Legavets L. K. Gordienko Z. G. Fridman 《Metal Science and Heat Treatment》1976,18(1):3-5
| 1. | Mechanicothermal treatment of steel 12Kh1MF under the conditions given increases the dispersity of carbide particles without changing the phase composition of the metal and produces a polygonized substructure. The structural changes lead to an increase in the short-term strength characteristics of the steel at standard and high temperatures (up to 650°C). |
| 2. | Mechanicothermal treatment increases the time to failure of steel 12Kh1MF by 200–400% at all static stress levels tested. |
7.
| 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°. |
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.
V. K. Narva N. S. Loshkareva M. N. Kryanina T. A. Belokonova 《Metal Science and Heat Treatment》1989,31(10):739-741
| 1. | Laser treatment ensures the elimination of residual porosity and substantial strengthening of the surface of carbide steels containing 10 or 20% TiC. |
| 2. | The thickness and hardness of the strengthened zone of carbide steels decreases with increasing initial porosity of the alloy. With the porosity of carbide steels increasing to 15% their wear resistance changes imperceptibly. |
| 3. | Preliminary heat treatment of carbide steels before laser treatment leads to impaired hardness and wear resistance. |
10.
| 1. | The presence of chemical inhomogeneity causes in the initial stage of oxidation local growth on the surface of NiO oxide together with Cr2O3 oxide. |
| 2. | Under equilibrium conditions in the 700–1200°C range the origin and change in structure of the scale on Ni–Cr alloys and alloys with addition of a rare earth metal are similar. The single-layer Cr2O3 scale gradually changes into scales with a two- and even three-layer structure. The mechanism of scale formation on these alloys is primarily vacancy and grain boundary transfer of cations to the front of the embryo of the oxide layer. |
| 3. | As the result of the low level of vacancy concentration and mobility of cations at 700°C the formation of a three-layer scale on Ni–Cr alloys is in principle impossible and only a transformation from a single-layer to a two-layer structure is experimentally observed. |
| 4. | Rare-earth metal additions reduce the vacancy concentration of the alloy and also the grain-boundary mobility of the cations, as the result of which from the first minutes of oxidation the adhesion properties of the primary Cr2O3 layer improve and both the growth rate of Cr2O3 oxide and the rate of transition from a simple Cr2O3 scale to a scale with a more complex structure of Cr2O3 and NiCr2O4 decrease by approximately an order of magnitude. |
| 5. | On Ni–Cr alloys at 1200°C thin films peel off according to the Wood mechanism at the alloy-scale interface. Such a failure of scale is not observed on alloys with a rare-earth metal addition. |
| 6. | Thick films with a multilayer structure on Ni–Cr and Ni–Cr-rare-earth metal alloys formed as the result of long oxidation fail by separation within the scale and a dense layer of Cr2O3 oxide always remains on the surface of the alloys and fulfills its protective function. |
11.
K. A. Lanskaya V. V. Yarovoi O. V. Basargin L. V. Kulikova 《Metal Science and Heat Treatment》1988,30(1):19-23
| 1. | When steel 12Kh1MF is alloyed with 0.14% of REM, the amount of supercooled austenite increases in the low-temperature region. In this case, the position of the critical points Ac1n, Ac3k, and Ar3n does not vary, and the temperature Ar1k is lowered by 40°C. |
| 2. | REM in steel 12Kh1MF are bonded primarily in nitrides ranging from 120 to 200 nm in size. |
| 3. | The introduction of 0.14% REM in the steel leads to a reduction in the average size of the vanadium carbide particles from 24 nm (in the REM-free steel) to 14 nm, and contributes to the formation of a uniform ferritic-bainitic structure. |
| 4. | The presence of REM in the steel improves its properties during short-term and prolonged testing. |
12.
| 1. | Up to 0.08% N is assimilated in high-speed steels from ferrochromium added during open melting. This amount of nitrogen is retained in the process of plastic deformation and annealing. |
| 2. | The nitrogen in high-speed steel forms vanadium and tungsten (molybdenum) carbonitrides, isomorphous with vanadium carbides MC and binary tungsten (molybdenum) carbides M6C. The nitrogen tends to form vanadium carbonitrides rather than tungsten or molybdenum carbonitrides. |
| 3. | With increasing amounts of vanadium carbide the effects of nitrogen and carbon are identical with equiatomic substitution. |
13.
| 1. | Powder metallurgy alloys produced from carbonyl iron possess higher structural and chemical homogeneity than similar alloys produced from electrolytic iron. This may be explained by the higher degree of mixing with the use of carbonyl iron and the more complete occurrence of the diffusion processes in sintering, which is related to the dispersion of the powder particles. |
| 2. | The relationship of the character of fracture in the alloys to manganese content for the carbonyl iron-base alloys is close to the similar relationship for cast alloys. |
| 3. | The presence in the powder metallurgy materials of a critical porosity above which the rules of the mechanics of a continuum do not act was established. The critical porosity of carbonyl iron-base sintered iron-manganese alloys is about 15% and of electrolytic ironbase ones less than 9%. With a porosity below the critical the character of fracture is determined by the properties of the solid solution itself and the ductile-to-brittle transition temperature while with a porosity above the critical by the number of diffusion contacts (pseudoductility). |
| 4. | The advantages revealed of carbonyl iron-base alloys make it possible to recommend this powder for production of sintered iron-manganese alloys. |
14.
L. V. Lagutina 《Metal Science and Heat Treatment》1989,31(7):506-510
| 1. | Strengthening in steel 12Kh11V2MF occurs as a result of precipitation of two phases: M23C6 carbide phase and intermetallic Fe2W Laves type phase. Presence of one or other strengthening phase makes it possible to estimate the condition of the metal with a prescribed heating temperature. |
| 2. | The temperature-time boundaries of precipitation for M23C6 carbides and intermetallic Fe2W type phase in steel 12Kh11V2MF in the range 600–750°C have been determined. At 750°C the Fe2W phase does not decompose over about 70 h, and at 600°C over more than 70,000 h. Carbide phase M23C6 is less stable at 600–750°C than Fe2W phase. |
| 3. | Strength properties of the steel on heating mainly depend on kinetics for precipitation and dissolution of M23C6 carbide phase particles. However, formation of finely dispersed particles of Fe2W Laves type phase in the later stages of aging compensates for carbide phase coalescence, as a result of which the strength properties decrease insignificantly. |
| 4. | During operation under the effect of stresses the intensity of Fe2W type phase formation in the steel increases. Dissolution of this phase over the whole operating period of (100,000 h at 545°C) is not observed. Presence of finely dispersed Fe2W Laves type phase in the steel provides its high-temperature strength during operation and the minimum creep rate. |
15.
| 1. | To simplify the thermomagnetic treatment of alloys YuNDK38T8 and YuNDK40T8 it is necessary to separate the step of nuclei formation from the stage of decomposition. |
| 2. | Nuclei of phase can be formed in alloys YuNDK38T8 and YuNDK40T8 without magnetic field with cooling at a rate of 125–280 deg/min in the range of 900–600°. |
| 3. | The thermomagnetic treatment developed consists of cooling from the single-phase region to 800–600° at a rate of 125–280 deg/min and high-temperature tempering in magnetic field at 830–850° for 12 min. The thermomagnetic treatment is completed by triple tempering in the range of 650–550°. |
| 4. | This method of TMT makes it possible to obtain high magnetic properties in alloys YuNDK38T8 and YuNDK40T8. |
16.
V. N. Degtyarev 《Metal Science and Heat Treatment》1990,32(5):363-368
| 1. | By the method of Auger spectroscopy in combination with ionic pulverization we plotted distribution profiles of the concentrations of phosphorus and of alloying elements in the region of the interface between eutectic carbide and the matrix in cast steel R6M5. |
| 2. | In the region of the phase boundary we find higher content of phosphorus, chromium, and vanadium (than in both the matrix and the carbide). The width of the phosphorus segregation on the side of the carbide is about 2 nm, and of chromium and vanadium 4 nm. |
| 3. | The phosphorus concentration on the phase boundary of carbide type M2C is almost two orders of magnitude greater than the mean phosphorus concentration in steel. |
17.
| 1. | The cyclic instability associated with the alloys tested is a function of their structural instability at the test temperature. |
| 2. | The increase in the cycle threshold amplitude for structurally unstable alloys at high temperatures is due to the increased friction stress that prevents movement by the dislocations. The increased friction stress is related to the pinning of the dislocations by precipitates. |
18.
V. L. Aleksandrov V. N. Konyshev Yu. M. Palei V. Yu. Zibert L. M. Red'kin 《Metal Science and Heat Treatment》1988,30(3):172-176
| 1. | Preliminary heat treatment of the wire rod provides an improvement in the combination of mechanical properties of the wire which it acquires after high-temperature thermomechanical working and in the service properties of the springs. |
| 2. | In preparation of the structure of the steel for high-temperature thermomechanical working it is necessary to create a uniform ferritic-pearlitic structure with lamellar or rodshaped carbide particles 0.01–0.05 m thick. |
| 3. | For 51KhFA steel the highest combination of properties after high-temperature thermomechanical working is obtained with the use of normalizing with heating in a salt bath and also of patenting with subsequent tempering at the patenting temperature as the preliminary heat treatment. |
| 4. | Cold deformation after preliminary heat treatment does not have a significant influence on the properties of high-temperature thermomechanically worked wire. |
19.
| 1. | The defect "bright ring" in fracture is not due to incomplete fusion, as has been commonly assumed. |
| 2. | The defect "bright ring" originates at places where there are carbide bands in high speed steel near the welding seam. |
| 3. | Carbide bands form in consequence of overheating of high speed steel in friction welding. |
| 4. | To eliminate the defect "bright ring," the heating temperature has to be reduced in welding. |
20.
V. V. Cherkasov L. G. Kornelyuk P. P. Pobezhimov L. P. Nefedova 《Metal Science and Heat Treatment》1992,34(12):758-761
| 1. | In alloys of the Al–Zn–Mg system (at Zn>Mg) a zone stage in the decomposition process of the solid solution can be clearly observed during artificial aging. |
| 2. | In alloys of the Al–Mg–Zn system having increased concentrations of the Mg, the zone stage actually occurs simultaneously with the phase formation process. |