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1.
| 1. | After standard heat treatment (quenching and tempering at 550°) the wear resistance of steel 30KhGSA is higher than that of steel 40KhNMA. |
| 2. | HTMT has no effect on the wear resistance of these steels. The wear resistance of steel 30KhGSA is 40% higher than that of steel 40KhNMA after HTMT and tempering at 550°. |
| 3. | The wear resistance of these steels increases considerably after treatment I (HTMT+normalization+quenching and tempering at 550°), which is explained by the more homogeneous fine structure. |
2.
V. I. Murav’ev 《Metal Science and Heat Treatment》2000,42(2):70-73
Conclusions
Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 23–26, February, 2000. 相似文献
| 1. | Intermediate annealing after stamping large preforms of steel 30KhGSNMA-VD can be accompanied by temper brittleness of kind II, which causes the formation of brittle cracks in subsequent grinding and quenching. |
| 2. | In order to prevent the formation of brittle cracks in stamped preforms, they should be subjected to sandblasting after grinding and decelerated heating for quenching in the final treatment. |
3.
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. |
4.
E. A. Pudov S. F. Kuvshinov N. V. Golomazova O. A. Kushmanova A. Ya. Zaslavskii 《Metal Science and Heat Treatment》1999,41(1):22-24
Conclusions
Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 20–22, January, 1999. 相似文献
| 1. | All tested silicon steels with a carbon content of 0.3–0.4% harden to a depth of 10 mm in water quenching without formation of quenching cracks. |
| 2. | The strongest effect on the strength and spring properties of railroad washers is exerted by the content of carbon and silicon in the composition. |
| 3. | Washers made of steels 30S1, 30S2, 35S1, and 35S2 with less than 0.38% C do not provide the requisite spring properties. These steels have a low resistance to tempering, and therefore an increase in the tempering temperature for increasing the ductility of the product causes a considerable decrease in their hardness. |
| 4. | Steel 40S2A is recommended for commercial production of railroad washers. |
5.
I. N. Bogachev L. G. Korshunov A. A. Rudakov V. V. Istomin 《Metal Science and Heat Treatment》1976,18(1):42-46
| 1. | Martensite—carbide structure does not ensure high resistance to thermal wear of steel 9Kh18, which is due to the low resistance of martensite to dynamic tempering in the process of friction. |
| 2. | A substantial amount of unstable austenite in the structure of steel with a high capacity for hardening and high heat resistance increases the wear resistance of the steel under severe conditions. To increase the wear resistance of steel 9Kh18 under conditions of thermal seizing it is necessary to increase the amount of retained austenite in the structure and also its stability, which can be achieved by raising the quenching temperature. |
6.
| 1. | The optimal combination of mechanical properties and damping capacity of structural steels of elevated and high strength can be obtained by quenching from 880° and tempering at 650° For carbon steel VSt 3 sp this heat treatment is useless — the damping capacity after heat treatment is the same as in the original condition. |
| 2. | The damping capacity after quenching+tempering at 650° is highest for steel 15KhG2SFR, followed by steels 14KhGS and 15KhG2SFMR, while the remaining steels have almost identical damping capacities. For structures subject to vibrations and dynamic loads we recommend the use of steels with a high damping capacity. |
| 3. | The damping capacity of the structural steels investigated consists of two components — damping due to the magnetic nature of the material and damping of nonmagnetic origin. The damping capacity is affected mainly (about 90%) by magnetomechanical phenomena. |
7.
| 1. | Hardening without tempering of low-alloy, low-carbon steel with microadditions of boron may provide a satisfactory combination of strength, ductility, and impact strength. |
| 2. | The high level of mechanical properties of the test steel with the strengthening treatment used was achieved with presence in its structure as the main component of acicular ferrite with a high dislocation density within laths and with a high level of ferrite grain fragmentation. |
8.
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. |
9.
D. A. Prokoshkin A. G. Vasil'eva V. V. Goryushin 《Metal Science and Heat Treatment》1976,18(2):140-142
| 1. | The character of the changes in the properties after HTTMT depends on the chromium content of the steel. Raising the chromium content in steel of the 40KhNMS type leads to an increase in strength that tends to be retained after tempering. |
| 2. | The increase in the strength of the steel with 1% Cr by deformation in the austenitic condition makes it possible to obtain approximately the same strength as for steel with 5% Cr after standard quenching, and better ductility and toughness. |
10.
I. I. Mints T. G. Berezina Z. I. Nenasheva K. A. Lanskaya 《Metal Science and Heat Treatment》1976,18(1):6-9
| 1. | Isothermal treatment of steel 12Kh1MF at 350–500°C leads to the formation of a structure consisting of upper and lower bainite. At 500° the structure consists primarily of upper bainite, and at 350° of lower bainite. |
| 2. | With tempering of the steel with a structure of upper and lower bainite at 730° for 3 h the dislocations undergo redistribution of the polygonization type within ferrite needles, with development of a cellular substructure. The acicular structure of the matrix is retained in this case. The density and evenness of the distribution of carbides is higher in upper bainite than in lower bainite. |
| 3. | Steel 12Kh1MF with a structure of upper bainite is more susceptible to recrystallization as compared with a structure of lower bainite, which is responsible for the higher heat resistance of the latter. |
11.
| 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. |
12.
M. A. Shumilov V. I. Bondar' L. N. Kudryavtseva K. N. Sokolov L. P. Tarasova 《Metal Science and Heat Treatment》1976,18(10):896-898
| 1. | The addition of 0.13% As to steels 16GS, 16G2SF, and 18G2SF increases the ferrite grain size and raises the critical points of steels 16GS and 16G2SF. |
| 2. | Alloying of ferrite with arsenic leads to an increase in the rate of grain boundary migration. |
13.
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. |
14.
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. |
15.
| 1. | Recrystallization of deformed ferrite in steel R6M5 commences at about 780°C and it continues to the maximum recrystallization temperatures for existence of -solid solution. The temperature ranges for recrystallization and superplasticity coincide. |
| 2. | Dynamic recrystallization of ferrite in steel R6M5 with rolling for one pass is incomplete with all degrees of deformation. |
| 3. | Static recrystallization occurs entirely with 50%. The recrystallized ferrite grain size is finer than the original by a factor of four to five. |
| 4. | Polygonization of deformed ferrite may markedly stabilize the structure and there-by make recrystallization difficult. |
16.
R. K. Guseinov 《Metal Science and Heat Treatment》1991,33(7):536-540
| 1. | The strength and ductile properties of steel 20KhSTTsR do not depend on its boron content. |
| 2. | The hardenability of steel 20KhSTTsR increases 1.5 times to twice when the boron content is increased to 0.005%, a further increase to 0.01% entails a decrease of hardenability to the level of steel without boron. |
| 3. | The resistance of steel to brittle (T50) and ductile (at) failure increases with boron content increasing to 0.005%; this is connected with the increased hardenability of steel to a martensitic-bainitic structure. |
17.
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). |
18.
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%. |
19.
L. R. Botvina T. V. Tetyueva T. D. Geikhman L. S. Kagan S. A. Artamoshkin 《Metal Science and Heat Treatment》1992,34(10):614-621
| 1. | Use of the relative length of a stable crackl c/b, where b is specimen width, is proposed for evaluation of the fracture resistance of a steel and determination of the critical defect size. |
| 2. | 09G2S steel has higher impact strength and crack resistance and a lower ductile-to-brittle transition temperature but a greater anisotropy of properties than 20 steel. |
| 3. | In fractures of specimens of 20 and 09G2S steels at temperatures of the ductile-to-brittle transition in impact bend and static tensile tests zones of drawing out ( 1) and of shear ( 2) and separation ( 3) fracture were observed. Their total is the zone of stable crack growth (l c). The ductile-to-brittle transition temperature of 20 steel determined from the fibrous constituent in the fracture (F=50%) is practically independent of notch sharpness of the specimens used. |
20.
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. |
