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1.
| 1. | Lowering of the tempering temperature of high-strength steel 40Kh bolts to t<400°c leads=" to=" a=" marked=" reduction=" in=" their=" longevity=" in=" a=" slightly=" aggressive=" atmosphere=" that=" causes=" the=" metal=" to=" absorb=" hydrogen=" during=" electrochemical=" corrosion.="> |
| 2. | The tendency of high-strength steel 40Kh bolts tempered in the interval of irreversible temper brittleness to failure, which is elevated in a slightly aggressive medium, is caused by additional weakening of the boundaries of former austenite grains under the action of hydrogen that is absoorbed onto them. |
| 3. | Steel 40Kh bolts with 0.37–0.43% C are not inclined to corrosion cracking in a slightly aggressive industrial atmosphere after tempering at 470°C. |
2.
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. |
3.
A. V. Mikhailov 《Metal Science and Heat Treatment》1991,33(11):845-847
| 1. | Hydrogen may be effectively utilized as a production atmosphere in hardening of 03Kh12N10MT steel for the purpose of a directed change in phase composition, an increased quantity of residual austenite. Without reducing the strength and plasticity this makes it possible to reduce the hydrogen permeability and increase the fracture toughness of the steel, important characteristics of its effectiveness in aggressive media. |
| 2. | For 07Kh16N6 steel heat treatment in a hydrogen atmosphere is ineffective. |
4.
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. |
5.
| 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. |
6.
V. P. Nikitin D. V. Shaburov A. P. Shlyamnev M. N. Shmatko G. E. Trusov 《Metal Science and Heat Treatment》1991,33(5):412-415
| 1. | Rolling of ferritic class steel strip at 1000°C and higher results in the formation of strips with various structures in their cross section and is accompanied by a decrease of impact strength. |
| 2. | A satisfactory impact strength of hot-rolled 08Kh18Tl type steel sheet is obtained at temperatures below 950°C. |
| 3. | Improvement of the impact strength of hot-rolled 15Kh25T steel sheet can be achieved by organizing in the production flow rapid cooling of metal in the temperature range of the onset of 475-degree brittleness. |
7.
| 1. | The application of a nickel coating on copper reduces the effect of the surface stages on the rate of hydrogen liberation and improves the reproducibility of measurements. |
| 2. | The role played by grain boundaries in copper specimens is similar to traps with an energy lower than the energy of dissolved hydrogen at regular interstitial sites of the lattice. |
8.
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. |
9.
T. S. Kuznetsova T. A. Chernyshova S. U. Myakisheva 《Metal Science and Heat Treatment》1993,35(5):278-282
| 1. | Embrittlement of the weld joints of the investigated chrome—manganese—nickel steels in the 350–500°C range is caused primarily by processes occurring in the -ferrite, 475° brittleness or precipitation of excess phases at the interphase boundaries and within the -ferrite grains. The level of plasticity is determined not by the quantily of -ferrite in the structure but by the density and quantity of excess phase precipitates in it. |
| 2. | Aging processes occur in the weld zone at lower temperatures than in the base metal. For weld joints of the experimental steels 05Kh18G2N5T and 05Kh18G10N5M3F the maximum operating temperature for long service is 300°C and for 05Kh18G10N5M3AF steel below 300°C. |
10.
S. M. Zakharov R. L. Mezhvinskii Yu. A. Polushkin V. R. Ryabov 《Metal Science and Heat Treatment》1989,31(12):885-887
| 1. | Presence of bcc phase in sheet steel 18Kh15N5AM3 gives rise to embrittlement after annealing at temperatures of about 400°C. The austenitic structure of the steel realized in wire provides a higher thermal stability of mechanical properties compared with the twophase condition. |
| 2. | Intense loss of strength for steel 18Kh15N5AM3 occurs after annealing at temperatures above 550°C. |
11.
N. M. Sytnik 《Metal Science and Heat Treatment》1989,31(9):702-704
| 1. | High cooling rates cause the formation in uninoculated iron of zones heterogeneous in structure which in character of disposition resemble polygonized boundaries. |
| 2. | Inoculation of cast iron with small additions of elements (formation of compact forms of graphite together with lamellar) leads to formation of polygonized boundaries (coarse secondary grains) and under certain conditions (an increase in cooling rate) cracks are formed at these boundaries. |
| 3. | With an increase in graphite of the compact form in the structure of cast iron the size of the secondary grains in the iron decreases. |
| 4. | In the presence of spheroidal graphite in the structure of the iron the polygonization process is not observed. |
12.
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. |
13.
É. N. Zhelikhovskaya A. S. Zavarov S. V. Grachev 《Metal Science and Heat Treatment》1989,31(6):422-424
| 1. | A preliminary anneal before hardening of carburized components permits one to obtain a surface layer containing finely dispersed carbides, and to regulate their size, volume, and distribution. |
| 2. | The optimum annealing temperatures are: for steel 20Kh –790°C and for steels 20KhN3A and 20Kh2N4A –760°C. The optimum holding time is 45–60 min. |
| 3. | The optimum annealing temperature of steel 20Kh is practically independent of the degree of carbon saturation in the case-hardened layer and is determined by the position of the critical point Ac 1 of the steel. In chrome-nickel steels 20KhN3A and 20Kh2N4A, as the degree of carbon saturation increases, this temperature somewhat decreases. |
14.
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. |
15.
G. G. Derkach O. N. Zheleznyak Yu. A. Pestov V. N. Semenov 《Metal Science and Heat Treatment》1999,41(10):446-450
Conclusions
Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 25–29, October, 1999. 相似文献
| 1. | The mechanical properties, the microstructure, and the phase composition of steel 07Kh16N6 with different contents of carbon after a heat treatment simulating the production process of a part from steel 07Kh16N6 and granulated nickel alloy éP741NP joined by the method of HIP fully recover the optimum values after the final heat treatment by a regime recommended for steel 07Kh16N6. The mechanical properties of alloy éP741NP do not worsen. |
| 2. | Counter diffusion of Fe, Cr, and C from the steel into the alloy and of Ti, Al, Nb, W, and Mo from the alloy into the steel is observed in the diffusion zone of the combined preform. A narrow (15–20 μm) carbide zone with an elevated concentration of titanium is formed due to the counter diffusion over granule boundaries of alloy éP741NP. The depth of iron diffusion into alloy éP741NP is 40–50 μm. |
| 3. | The mechanical properties of the combined preform at a temperature ranging from −196 to +650°C are close to the properties of steel 07Kh16N6; fracture occurs predominantly over the diffusion zone. |
| 4. | In order to raise the working capacity and reliability of units with rotating parts from alloy éP741NP joined permanently to a shaft from steel 07Kh16N6 by the method of HIP, the shaft should be coated with a nickel barrier layer that diminishes the possibility of the formation of titanium carbide on the surface of alloy éP741NP over granule boundaries. |
16.
| 1. | Presence in a welded joint of steel 08Kh18N10T of 2–2.5% -ferrite promotes an increase in the degree of first-order stress relaxation at 400–480°C without reducing strength properties and with retention of resistance to ICC. |
| 2. | A reduction in the relaxation resistance of an electroslag weld with an austenitic structure with a small amount of ferrite is due to the greater deformation capacity of ferite and microvolumes of austenite adjacent to it. |
17.
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. |
18.
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. |
19.
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. |
20.
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. |
