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1.
V. N. Antsiferov N. N. Maslennikov A. A. Shatsov V. B. Platonova 《Metal Science and Heat Treatment》1991,33(8):617-620
| 1. | The crack resistance of quenched powder steel SP50Kh3NM is not uniformly dependent on tempering temperature. |
| 2. | The published recommendation for tempering temperature (400°C) for quenched chromium-nickel-molybdenum steels with a porosity of 10–15% is apparently the optimum temperature for the given heat treatment method. However, the properties of the steel may be increased markedly by carrying out cooling after sintering in a flowing atmosphere. In this case the optimum tempering temperature increases and it is close to the tempering temperature for compacted structural steels of similar chemical composition. |
| 3. | Crack resistance parameter KIc for powder heat treated steel may be determined by using mechanical test data by the equation suggested. |
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.
Effect of titanium and silicon on the phase composition and properties of a high-chromium tool steel
| 1. | The presence of Ti (0.4–0.7%) and silicon (0.7–1.0%) in high-chromium die steels does not adversely affect the level of their manufacturing properties and leads to an increase in strength and wear resistance. |
| 2. | The mechanical properties of steel Kh12MST as a function of tempering temperature has two maximum which indicates that these steels can be used in die stamping equipment with high speed automated punching machines where the working sections can obtain temperatures as high as 400°C. |
| 3. | Steel Kh12MST is recommended for the manufacture of cold deformation dies which operate over a wide range of dynamic loading and also for the manufacture of the cutting parts of heavy-duty dies which operate under conditions of extreme wear. |
| 4. | The application of steel Kh12MST (ÉP952) in punching dies will increase their durability during the production of magnetic current plates made of electrotechnical steel by not less than 1.7 times. |
4.
T. V. Okhrimenko I. B. Kuznetsov A. A. Lanin V. V. Artamonov A. V. Pavlov 《Metal Science and Heat Treatment》1991,33(4):288-293
| 1. | In order to quench heat-resistant steels it is possible to use polymer agents based on sodium-carboxymethyl cellulose. |
| 2. | The safety factor for the technological strength of heat-resistant steels 15Kh11MF and 25Kh1MF, nk>1, which points to the possibility of quenching in agents based on Na-CMC for forgings and blanks of steels of the given grades without cracks. |
| 3. | The stress-rupture strength of steels 20Kh1M1F1TR and 25Kh1MF heat treated with the use of a polymer quenching agent is not lower than after heat treatment with oil quenching. |
| 4. | On introducing polymer quenching agents it is necessary for each grade of steel to determine the technological strength and to introduce adjustments to temperature-time heat treatment schedules. |
5.
V. M. Pereverzev V. M. Barten'ev V. N. Burmistrov 《Metal Science and Heat Treatment》1976,18(6):496-499
| 1. | The addition of soda to solid carburizer in place of barium carbonate leads to intercrystalline oxidation of chromium stainless steel (2Kh13) and accelerates the carburizing process. |
| 2. | At small chromium concentrations (steel ShKh15) carburizing in carburizers with soda is accompanied by internal oxidation (formation of globular carbides). |
| 3. | The oxidation of chromium steels in carburizers with soda sharply reduces the toughness, which can be restored by removal of the oxidized layer by grinding. |
| 4. | Chromium stainless steels should be carburized in carburizers containing the optimal concentration of soda (5–7%), and steels of the ShKh15 type in carburizers with barium carbonate but no soda. |
6.
| 1. | The action of a glow discharge plasma in carbonitriding of steel provides high kinetic effectiveness of the process, the parameters of which exceed those of vacuum carburizing by no less than 1.5 times and of gas carburizing by no less than 2.0 times at the same temperatures. |
| 2. | To provide the optimum structure of the hardened case in ion carbonitriding cyclic supply of the hydrocarbon gas is necessary. |
| 3. | Ion carbonitriding with direct quenching is most effective for type 18KhGT, 25KhGT, and 25KhGM alloy steels and is less effective for type 20Kh steels. |
7.
O. A. Bannykh E. P. Pestryakova A. G. Rakhshtadt L. V. Barseg'yan V. M. Blinov 《Metal Science and Heat Treatment》1991,33(1):50-52
| 1. | It is established that the level of carbide and nitride phase dissolution in chromium-manganese steels of type Kh16G18 with a varible ratio of carbon and nitrogen in them reaches a maximum at 1150°C. With an almost identical lattice spacing the degree of its distortion in steel with nitrogen is greater and therefore the specific electrical resistivity of the steel is higher. |
| 2. | The degree of strain hardening for austenitic steel type Kh16G18 containing carbon and nitrogen depends on the relationship between these elements, and as a rule it is greater, the higher the nitrogen content, which is connected with the higher structural defect density and formation of -martensite in steel with nitrogen. |
| 3. | In chromium-manganese steel type Kh16G18 with the maximum nitrogen content (0.45%) after cold plastic deformation with tru = 1.2 a higher level of strengthening was achieved with retention of its nonmagnetic nature than for steel with 0.45% C. |
8.
V. N. Zhuravlev R. R. Faskhutdinov A. N. Chernyi 《Metal Science and Heat Treatment》1989,31(5):338-345
| 1. | The proposed method of production of die casting dies causes a six to seven times increase in their life and the design strength (thermal erosion resistance, oxidizability, interaction of the mold metal with the molten alloy,toughness and resistance of the metal to plastic deformation) of certain of the steels (20Kh13, 5KhNM, etc.) increases by up to 10 times. |
| 2. | The volumetric preliminary and accompanying compressive stresses created in the dies cause slowing of development of thermal erosion. The preliminary compressive stresses may be calculated by the finite element method with the use of the computer, which makes it possible to predict the degree of thermal erosion. |
| 3. | For built-up stressed dies the use of steels with a reduced alloy content and with an increased coefficient of thermal expansion such as 20Kh13, 4Kh5MFS, and 5KhNM is possible. |
| 4. | The new method and investigated steels are intended for production of dies in any branch of machine and automobile and tractor building. |
9.
V. I. Belyakova A. A. Vereshchagina I. P. Banas 《Metal Science and Heat Treatment》1991,33(11):803-807
| 1. | A method of hardening the surface of austenitic steel, which makes it possible to obtain a layer 0.4–0.7 mm thick with a hardness greater than 700 HV is developed. This method consists of diffusion saturation with carbon or carbon and nitrogen in accordance with a stepwise regime. Hardening of the layer is achieved primarily due to the segregation of special carbides during aging. |
| 2. | Steel 25Kh18N8V2 exhibits a higher ultimate rupture strength and resilience at 20–300°C, long-term strength, fatigue strength in bending, and wear resistance after diffusion-dispersion hardening than after nitriding. |
| 3. | After diffusion-dispersion hardening, steel 25Kh18N8V2 exhibits satisfactory corrosion resistance in a tropical chamber after grinding off a layer 0.1–0.15 mm thick. |
10.
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. |
11.
| 1. | Raising the temperature of preliminary homogenization of blanks produced by electroslag remelting of steel 38KhN3MFA from 1100 to 1180°C and extending it from 5 to 20 h causes, after double austenizing with tempering, an increase of impact toughness and crack resistance. The maximal values of a1 and at are attained after homogenization at 1800°C 20 h, and values close to them are attained with 1180°C 5 h. |
| 2. | To refine the austenitic grain in castings of ESR steel 38KhN3MFA, which had grown in high-temperature treatment, it is necessary and sufficient to apply double austenizing at 880–950 and 860–880°C. |
| 3. | Preliminary high-temperature treatment has a greater effect on the subcritical characteristics (maximal ductility, energy of crack nucleation) than on the supercritical ones (energy of crack propagation, stress intensity factor). Such treatment has practically no effect on the parameters of fatigue crack resistance. |
| 4. | The increase of ductility and energy content of fracture of steel under preliminary high-temperature treatment is accompanied by a substantial reduction of the proportion of intergranular fracture. The change in the nature of fracture is connected with the change of the morphology of the highly disperse sulfide phase, in particular with its coagulation in the process of holding at a high temperature. |
12.
V. M. Goritskii G. R. Shneiderov V. I. Bogdanov 《Metal Science and Heat Treatment》1991,33(5):353-357
| 1. | Adding 0.02–0.03% Ti and 0.002–0.003% B to the 08Kh4N2M martensitic steel significantly reduces the tendency to thermal embrittlement. The increase in the critical embrittlement temperature (T50) for this steel with 0.009–0.020% P after soaking for 2000 h at 450°C was no more than 15°C. |
| 2. | The favorable effect of coalloying with titanium and boron on the resistance to thermal embrittlement is maintained in the 08Kh4N2M with an increased phosphorus concentration (0.035%). |
| 3. | The excellent resistance to thermal embrittlement of the 08Kh4N2M steel due to Ti and B additions is due to the fact that boron prevents phosphorus segregation along the grain boundaries. Concurrently, the titanium combines with the nitrogen to improve the boron activity. |
13.
O. V. Goslavskii A. G. Derzhavin I. N. Shcherbinin 《Metal Science and Heat Treatment》1989,31(11):822-825
| 1. | Maraging steel 05Kh13N7D2 with a different degree of strengthening exhibits quite high impact strength. With an increase in aging temperature from 450 to 600°C the impact strength a0.25 increases from 49 to 118 J/cm2. |
| 2. | Prolonged soaking at 300°C leads to the embrittlement of steel aged at 550°C for 10 h. The critical brittleness temperature T50 is –80°C in the original condition and it remains practically unchanged. |
| 3. | Fracture toughness KIC and critical crack opening c for steel 05Kh13N7D2 are at quite a high level at temperatures to –125°C. |
14.
| 1. | The gasdynamic and energetic parameters of discharge in ion nitriding of steel were optimized. |
| 2. | The structure and phase composition of the diffusion layer can be controlled by changing the pressure and the composition of the saturating atmosphere. |
| 3. | In ammonia plasma the depth of the diffusion layer is largest on commercial iron and steels 40Kh and 38KhMYuA at a pressure of 2 mm Hg at temperatures of 520–570° and at 6 mm Hg at 650°. |
| 4. | The addition of argon to ammonia plasma makes it possible to obtain a nitrided layer on a base of high-nitrogen solid solution. Nitriding in mixtures with 5–15% NH3 and 95–85 vol. % Ar at pressures of 0.3–0.6 mm Hg provide a depth 50% larger than nitriding in ammonia plasma. |
| 5. | Nitriding in a mixture of ammonia and carbon-containing gas increases the depth of the nitride zone. With 40 vol. % or more propane in the mixture the interaction of the plasma with the surface of the part ceases. The optimal concentration of propane in the mixture with ammonia is 8–12 vol. %. |
15.
L. G. Razgovorova L. A. Andreev E. A. Kalashnikova D. G. Brodkin 《Metal Science and Heat Treatment》1989,31(2):91-95
| 1. | The ferrite-carbide interphase boundaries in low-alloy 25Kh2NMFA steel are not zones of increased hydrogen concentration. |
| 2. | The process of hydrogen liberation from specimens of 25Kh2NMFA steel depend substantially upon the surface stage of this process. |
| 3. | The presence of alloying components and ferrite-carbide interphase boundaries in 25Kh2NMFA steel does not influence the diffusion coefficient of hydrogen. |
16.
V. M. Goritskii G. R. Shneiderov A. D. Shur V. A. Yukhanov 《Metal Science and Heat Treatment》1992,34(1):3-9
| 1. | Thermal embrittlement of steels 10G2N2MFA and 15Kh2NMFA-A is caused by variation in the size and distribution of disperse-phase particles. During holding to 3000 h at 350°C, finely disperse carbides are segregated in the body of ferrite grains, block the dislocations, strengthen the steel in turn, and, correspondingly, increase its semibrittleness temperature. A further increase in holding (right up to 10,000 h) leads to coagulation of the carbides, and to a reduction in the resistance to plastic deformation and in the semi-brittleness temperature of the steel. In steel 10G2N2MFA, a monotonic increase in T50 during holding at 350°C is caused by preferential segregation of carbide particles along the ferrite-grain boundaries. |
| 2. | A different pattern of variation in the semibrittleness temperature during holding at 350°C for steels 15Kh2NMFA-A and 10G2N2MFA is governed by differences in the structure of the metal in the initial state. Steel 15Kh2NMFA-A has a preferentially subgrain-cellular structure, whereas steel 10G2N2MFA, in addition to a subgrain structure, has a significant amount of recrystallized ferrite grains; in this case, the dislocation density is three times lower in steel 10G2N2MFA than in steel 15Kh2NMFA-A. |
| 3. | The relation between the degree of thermal embrittlement and the percentages of intercrystalline fracture in the brittle fracture zones of impact specimens of the steels under investigation is ascertained. |
17.
Yu. D. Litinskii M. I. Dzyuba L. E. Sheludker Yu. S. Shmelev 《Metal Science and Heat Treatment》1976,18(5):435-438
| 1. | We investigated the conditions for the development of segregation in centrifugally cast austenitic stainless steels. |
| 2. | The composition of the excess phase in steel 0Kh10N20T2 was established. |
| 3. | In castings with a two-zone macrostructure the development of segregation and the formation of excess phase in the inner surface lower the plasticity and increase the possibility of defects in hot rolling. |
| 4. | Centrifugally cast stainless steels should have a one-zone macrostructure of columnar crystals. |
18.
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. |
19.
N. M. Suleimanov B. Yu. Aivazov S. N. Suleimanova 《Metal Science and Heat Treatment》1999,41(11):483-485
Conclusions
Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 18–20, November, 1999. 相似文献
| 1. | Two-stage quenching (with subsequent tempering) provides an increase in the impact toughness, bending strength, and hardness of steel Kh12M compared to single-stage quenching, and especially to standard quenching in oil. Use of two-stage quenching and tempering instead of the standard heat treatment increases the hardness of the steel by 0.5HRC e and doubles the impact toughness and the bending strength. |
| 2. | The optimum combination of properties of steel Kh12M (within the study performed) has been provided by two-stage quenching by a regime of 1030°C→250°C 5 min →560°C 60 min. |
| 3. | Two-stage quenching by the latter regime increases the tempering resistance of steel Kh12M by suppressing the processes of segregation and coagulation of cementite-type carbides in the range of tempering temperatures of 200–350°C. |
| 4. | Two-stage quenching of steel Kh12M has been shown to double the service life of dies relative to the standard heat treatment. |
20.
Dobatkin S. V. Kaputkina L. M. Ryklina E. P. Shneiderov G. R. 《Metal Science and Heat Treatment》1989,31(6):449-455
| 1. | Obtaining a polygonized structure in hot forming of austenite in a cycle of HTMT of steels 40Kh, 40KhN, and 40KhN2MA causes an increase of the resistance to brittle failure: after low tempering and embrittling tempering at 500°C (for 200 h) the level of impact toughness increases at normal as well as subzero temperatures; the critical brittle point is lowered; the fraction of crystalline component in the fracture decreases. |
| 2. | Hot forming of structural steels with 0.4% C at the steady state of dynamic polygonization (50%) even with partial development of dynamic recrystallization (up to 30% vol. %) is more preferred for reducing disposition to temper brittleness than at the stage of nonsteady dynamic polygonization (25%). Obtaining fully dynamically recrystallized austenite with finer grain than the initial one reduces to a lesser extent the disposition of steels to temper brittleness. |
| 3. | The lowering of the critical brittle point T20 as a result of HTMT of steels is directly proportional to the decrease of the fraction of intergranular failure. |
