首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 46 毫秒
1.
1.  An optimum combination of mechanical properties for the VNL-3 steel grade composition is achieved by a double heat treatment: heating to 1100°C (1 h) with air cooling, annealing at 600°C for 1/2 h plus quenching from 970°C, cold treatment at –50 to –70°C and annealing at 450°C. This heat treatment system can be recommended for obtaining high strength, although in order to secure better ductility, a strengthening heat treatment is carried out as follows: quenching from 970°C, annealing at 450°C and cold treatment at –50 to –70°C.
2.  The heating temperature for the second heat-treatment stage is increased to 1100°C in order to correct casting defects (carburization). This yields B 1000 N/mm2, 18%, and a1=90–110 J/cm2.
3.  Heating of the VNL-3 steel should be carried out in a shielding atmosphere or in a vacuum. The component surface can also be protected by applying the ÉVT-10 enamel.
Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 9–10, March, 1992.  相似文献   

2.
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°.
  相似文献   

3.
1.  The cooling capacity of UZSP-1 polymeric quenching medium is determined by the molecular mass (MM) of the copolymer.
2.  With concentrations of more than 1.5% for the UZSP-1 solutions, their cooling capacity is virtually constant for a constant MM and temperature (<80°c).>
3.  To eliminate the rigorous effect of the temperature of the medium on its cooling capacity in both cases where HMW and LMW polymners are used, it is expedient to heat-treat the components in solutions with temperatures of 20–60°C; in this case, the LMW concentration of the UZSP-1 should be no less than 1.5%.
4.  The HMW solutions of UZSP-1 are subject to "thermal shock;" in this connection, it is more perferable to use low-molecular-weight UZSP-1 to avoid frequent regeneration of the quenching bath.
Scientific-Production Union NIITavtoprom, Moscow. NIIMSK. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 17–20, April, 1991.  相似文献   

4.
1.  A mechanism was suggested for separating the melt thus ensuring its high cooling rate in obtaining fine metal fibers from the alloy Fe–Ni–B.
2.  Increased quenching speed of the melt entails a tendency toward a rise of the vitrification temperature of the alloy Fe–Ni–B whereas its crystallization temperature remains almost unchanged.
3.  Crystallization of the amorphous alloy Fe–Ni–B during isothermal annealing proceeds by the mechanism of cutectic crystallization.
4.  The microhardness of the amorphous alloy Fe–Ni–B during annealing has two maxima. The first maximum (at about 280°C) is associated with the special traits of the vitreous state near the vitrification temperature, the second maximum at 360°C) with the appearance of the bride phase at the stage of cyrstallization.
5.  In the temperature range 15–23 K the electrical resisitivity of the amorphous alloy decreases abruptly.
Gomel' Polytechnic Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 21–24, September, 1992.  相似文献   

5.
1.  Rolling of steel at 1100° and higher leads to austenite grain growth after annealing.
2.  A recrystallization threshold appears with plastic deformation at temperatures up to 1100°, the range of the recrystallization threshold broadening as the temperature of the preceding plastic deformation decreases. Plastic deformation =20% at 1150° always leads to a jump of austenite grain growth with repeated quenching, and for steel rolled at 1150 and 1200° the region of austenite grain growth broadens to =30–40%.
3.  At all degrees of deformation at different temperatures the average diameter of austenite grains decreases with decreasing preliminary rolling temperatures and increasing degrees of repeated plastic deformation. This undoubtedly affects the consistency of the properties inherited by high-speed steel during subsequent high-temperature plastic deformation.
  相似文献   

6.
1.  Inequigranulaity in series-produced rings with shaped profile of alloy ÉI437BVD develops on account of nonuniform deformation and nonuniform distribution of secondary carbides.
2.  Heat treatment in the regime: annealing at 1000°C 3h, cooling in air, air hardening from 1080°C (8 h), aging at 750°C 16 h ensures the formation of a uniform granular structure almost in all zones of expanded rings with shaped profile, and in consequence it enhances and stabilizes the mechanical properties.
All-Unin Institute of Light Alloys. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 34–37, June, 1993.  相似文献   

7.
1.  In the temperature range with which deformation does not cause formation of -phase for Fe-Ni-Co alloys, a reduction is observed in the thermal linear expansion nature is evidently connected with the Invar anomaly.
2.  In alloy 29NK at –70°C as a result of extension -phase occurs (30% in the overall volume and 59% at the area of a break).
3.  Alloy 32N14K showed high stability towards -transformation with deformation over the whole cryogenic temperature range down to –269°C. Precipitation of -phase is only observed in the area of a specimen break at temperatures below –196°C where the degree of deformation =55%. This alloy may be used for articles operating under load at temperatures down to –269°C.
I. P. Bardin Central Scientific-Research Institute of Ferrous Metallurgy. "Élektrostal'" Factory. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 34–37, February, 1988.  相似文献   

8.
1.  When preliminarily hardened high speed steel, tempered at 350–560°C, is treated by a continuous CO2-laser with energy density J=34±3 MJ/m2, a strengthened layer with maximal thickness and hardness forms.
2.  Accelerated heating by laser beam to temperatures in the range between Ac3 and Tpl and practically instantaneous cooling to normal temperature at rates of more than 104°C/sec give rise to a highly disperse (in melting) and fine-grained structure recrystallized by precipitation hardening (in quenching in the solid state) and consisting of martensite, residual austenite (in increased amount), and carbides (in a small amount). The intense dissolution of ledeburitic carbides type M6C in the laser-hardened zone causes additional alloying of the solid solution, increased stability of the residual austenite, and super-sautration of the finely accular martensite.
3.  The decomposition of residual austenite and the intense dispersion hardening in the process of tempering at 560–600°C 1 h increase the hardness of the laser-hardened layer of high speed steel R6M5 by 2–4 HRCe, and resistance to tempering by 40–50°C compared with conventional heat treatment. The absence of coarse carbide particles in the hardened layer reduced the probability of brittle failure by chipping in operation of the cutting tool.
Moscow Institute of Steel and Alloys. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 7–12, October, 1989.  相似文献   

9.
1.  Preparation in plate steel 09G2S with water quenching and tempering at 600–680°C of a structure of temper sorbite and polygonal ferrite provides compared with normalizing (ferrite + pearlite) a marked increase in its strength properties and resistance to brittle failure.
2.  The greatest cold resistance and specific work for ductile crack propagation of plate steel 09G2S occurs after quenching and tempering at 630±20°C.
3.  With the aim of improving the reliability of blast furnace jackets against formation of extended brittle cracks it is desirable to use steel 09G2S for the uncooled zone of the bottom in the temper hardened condition, which exhibits improved strength and cold resistance compared with normalized steel.
Central Scientific-Research and Planning Institute of Metal Building Structures. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 2–5, December, 1990.  相似文献   

10.
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.
  相似文献   

11.
1.  Stainless steels containing 14% Cr, 0.15% N, and 14\2-22% Mn, which are austenitic with cooling to \t-253\dg, undergo the martensitic transformation during deformation, with formation of \ga\t" and \ge\t" phases. The addition of 3% Ni to the steel with 18% Mn suppresses the martensitic transformation, and the steel remains austenitic with deformation at temperatures down to –253°.  相似文献   

12.
1.  To eliminate zonal nonuniformity of the structural constituents in casting of plain bearings the bearing shell temperature must be not less than 280°C and the cooling rate not more than 200°C/min.
2.  To obtain a more favorable structure of the babbitt lining the use of brass or bronze is recommended as the material of the bearing shell.
3.  To reduce zonal nonuniformity the temperature of the B83 babbitt case must not exceed 520°C.
4.  The optimum cooling rate providing a fine-grained structure of the structure constituents of the babbit lining is 180–200°C/min, which is obtained by the use of air or airwater-cooling with a low water content.
Kaliningrad Technical Institute for the Fishing Industry. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 50–53, September, 1990.  相似文献   

13.
1.  The proposed regime for heat treating high-speed steels (TDH) increases their mechanical properties and decreases distortion in tools manufactured from them. It also decreases the treatment time.
2.  The TDH process specifies cooling of the tool from the hardening temperature to a temperature lower than MI but higher than 20°C. This is followed by heating to 600–630°C (in order to obtain the greatest increase, in mechanical properties) or to 500°C (in order to obtain the least amount of distortion) followed by air cooling. After TDH only one temper at 560°C for 1 h is necessary.
3.  The proposed thermal treatment process is based on the intense emission of alloying elements and carbon from the residual austenite during its recrystallization.
4.  The TDH process is most effective for cutting tools of small size, and also for dies of complex shape.
Moscow Machine Tool Institute, I. P. Bardin TsNIIChERMET. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 24–29, May, 1989.  相似文献   

14.
1.  For technological titanium containing 0.025% H after hardening causing the transition of hydrogen to a solid solution, are characteristic two plasticity minima, at +20 and –80°C. The biggest decrease of relative contraction is observed at –80°C. After aging for a year hydrogen changes to hydrides. Here the plasticity of the commercial titanium decreases with falling temperature but its value remains higher than the minimum plasticity of hardened specimens at corresponding temperatures.
2.  For VT3-1 +-alloy containing 0.03% H alongside with the minimum of in the range of 0 to –20°C is observed its sharp decrease at –60 to –80°C. At lower temperatures increases.
3.  In the VT15 -alloy hydrogen embrittlement appears at temperatures of 0 and –40°C.
Leningrad Naval Engineering College. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 48–50, July, 1990.  相似文献   

15.
1.  Good elastic and elinvar properties (low TCF) of steels based on N23K9M5T containing 22–24% Ni and 1.0–1.8% Ti are attained by heating them to temperatures of the biphase (+)-region.
2.  Preliminary cold forming (rolling) with =30–50% and subsequent aging lead to a considerable increase of the elastic limit (0.005=300–400 N/mm2) but have practically no effect on the TCF.
3.  Steels N23K9M5T1 (1.1% Ti) and N24K9M5T2 (1.8% Ti) have an optimal complex of elastic and elinvar properties after deformation with =50%, cold treatment at –196°C, and aging at 560–575°C 3 h: 0.005=1400–1450 N/mm2, TCF20–100=±(10–20)·10–6 l/deg.
Deceased.  相似文献   

16.
1.  The level of crack resistance of cast hypereutectoid steels is determined by the size of the inclusions of eutectic cementite which depends solely on the amount of carbon contained in the steel. Alloying with 0.86–1.72% Cr, 0.9–1.32% Ni and 0.16–0.3% Mo does not affect the amount of eutectic cementite, and has practically no effect on the level of crack resistance when the steel contains 0.90–1.00% C; it decreases somwhat when the carbon concentration increases to 1.80–1.90%.
2.  Heat treatment (quenching in air from 920°C, tempering at 550°C) raises the level of crack resistance of chrome-molybdenum and chrome-nickel-molybdenum steels. The effect manifests itself the more strongly, the higher the degree of alloying of the steel with carbide forming elements is (with 0.9–1% C).
3.  The optimal combination of hardness and dynamic crack resistance after heat treatment of specimens is attained in hypereutecoid alloy steels when the carbon content is slightly higher than the eutectoid concentration. This has to do with the complete dissolution of excess cementite and the formation of special globular carbides. The same combination of properties can be ensured in steels with higher carbon content by raising the degree of alloying of the steel with carbide forming elements.
Ukrainian Research Institute of Metallurgy. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 21–24, April, 1990.  相似文献   

17.
1.  Characteristics of the mechanical properties of titanium alloy VT22 are found to be nonlinearly dependent on the heat-treatment parameters. As a rule, the strength increases, and the plasticity decreases with increasing temperature of the first step, the heating temperature for quenching, and the cooling rate, and with decreasing aging temperature.
2.  Effects of the paired interaction between the heat-treatment parameters under investigation, i.e., the dependence of the effect of each of the parameters in vestigated on the level of the other parameters, are characteristic for alloy VT22.
3.  Alloy VT22 is hardened during heat treatment at low cooling rates (but no lower than 3.5°C/min).
4.  Computational equations are proposed for adjustment of the aging temperature during the heat treatment of welded subassemblies.
Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 46–49, March, 1990.  相似文献   

18.
1.  Carbonitriding at 700°C in atmospheres of ammonia and carbon-containing components (endogas or natural gas) makes it possible to obtain a high-quality carbonitride (oxycarbonitride) case containing 3–4% N in the dense zone and 0.5–1% in the porous zone 0.5–1.0% C, and up to 3.5% 0, an austenitic-martensitic sublayer containing 1.0–0.6% N and C and 0 at the level of the matrix, and a lower-lying layer of a solid solution of nitrogen in -Fe.
2.  Carbonitriding at 700°C promotes a significant increase in wear resistance of constructional steels. In this case the coefficient of sliding fraction in tests without lubricant was 0.20–0.23, the fatigue limit in bending increases by 1.7 times in comparison with the normalized condition, and the corrosion resistance increases by an average of 10 times.
Moscow Automobile Road Institute. All-Union Scientific Research Institute for Machine Building Technology Scientific and Production Union. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 26–27, July, 1991.  相似文献   

19.
1.  Diffusion of the elements of heat-resistant coating based on nickel monoaluminide with additions of Cr, W, Si, C into the nickel alloy ZhS6K causes a substantial change of its composition and structure at a considerable depth: after facing at 1200°C 10 min up to 35–50 m, after additional holding at 1100°C 160 and 500 h to 250–350 and 400–500 m, respectively.
2.  Additional holding at 1100°C and diffusion of elements of the coating into the alloy are factors impairing the composition and structure of the protected alloy. Additional holding leads to the segregation of acicular secondary phases throughout the bulk of the alloy (the volume fraction is 2.5% beyond the diffusion zone). Diffusion of elements of the coating into the alloy intensifies the segregation of secondary phases(near the coating their volume fraction increases to 7.5%).
3.  Silicon that diffused from the coating into the alloy does not concentrate in the matrix of the alloy where its mass fraction remains almost unchanged (0.25–0.4%) but in the acicular phase in which, after additional holding at 1100°C 160 and 500 h, the mass fraction of Si near the coating attains 2.0 and 3.2%, respectively.
Institute of Silicate Chemistry, Academy of Sciences of the USSR. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 24–25, September, 1991.  相似文献   

20.
1.  Heating the KhN56MBYuD alloy before quenching at 980–1180°C for 0.5–2 h helps dissolve the eutectic, increase the volume fraction of the sulfide (compared to the as-received state), coagulate the carbonitride, and significantly grow the grains of the solid solution.
2.  The most homogeneous structure with a low content of nonmetallic inclusions, uniform distribution of the carbonitride, and grain size of the solid solution of less than 600 m were found in the KhN56MBYuD (ESM) alloy after holding at 1130°C for 2 h.
3.  The short-term mechanical properties of a cast, tubular billet after heat treatment under the optimum conditions are a little bit higher than the properties obtained in hot-deformed rods. This leads us to recommend the KhN56MBYuD alloy for cast massive objects which are not possible to produce by hot-deformation techniques.
MVMI, NIKIÉT. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 19–22, March, 1993.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号