Effect of warm extrusion on structure and properties of steel 20Kh

Conclusion Warm extrusion of steel 20Kh at 600–800° makes it possible to obtain a structure with high strength and ductile characteristics: _0.2=40–50 kg/mm², _b=50–60 kg/mm², =60–75%.Voroshilovgrad Machine Construction Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 56–57, March, 1976.     

Effect of nitrogen and chromium on the mechanical properties of austenitic steels at −196°C

Conclusion Nitrogen lowers and chromium raises (with >3% N) the strength (_b0.2), ductility (, ), and fracture toughness of austenitic stainless steel of the Kh(18-24)N20 type in the aged condition. The effect of chromium on the properties is due to a change in the solubility of nitrides.I. P. Bardin Central Scientific-Research Institute of Ferrous Metallurgy. Translated from Metallovedenie Termicheskaya Obrabotka Metallov, No. 8, pp. 6–8, August, 1979.     

Influence of original structure and heating rate on the properties of steel after hardening from the intercritical range

Conclusions The original condition and heating rate determine the mechanical properties of the steel after hardening from the intercritical range. The best properties, particularly ductility, _t=1600 MPa, _0.2=1250 MPa, =14%, anda _n=0.9 MJ/m², are obtained after preliminary hardening from 930°C, tempering at 200°C, a second hardening from 800°C (5% ferrite), and tempering at 200°C. Full hardening from 930°C with subsequent tempering at 200°C (without preliminary hardening) makes it possible to obtain _t=1550 MPa, _0.2=1200 MPa, =9%, anda _n=0.9 MJ/m².Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 52–56, May, 1981.     

Austenitic stainless steels strengthened by phase strain hardening and aging

Conclusions Nonmagnetic stainless steels of the Kh12N12T3 and Kh12N14T3 type have good mechanical properties after phase strain hardening and aging (_0.2 = 685 - 785 MPa, _b = 1275 MPa, 20%) as compared with the properties of Fe-Ni-Ti austenitic steels with 26–30% Ni. After phase strain hardening and aging the stability of these steels is high with respect to the transformation during cold treatment.IFM UNTs AN SSSR. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 57–60, June, 1981.     

Analysis of fatigue curves for alloy 36NKhTYu in the quenched and annealed conditions

Conclusion The limiting cycle amplitude in alloys is determined by friction stress which hinders dislocation movement, and in the region of stresses satisfying the condition _m + _{m f} it does not depend on the magnitude of the static component of the stress cycle.Novosibirsk Pedagogical Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 21–23, March, 1991     

Effect of differences in grain size on the mechanical properties of steel 18Kh2N4MA

Conclusions A difference in grain sizes has a negative effect on the ductile characteristics of steel. The ductile characteristics (T₅₀,ap) of the steel with differing grain sizes (grades 1 and 8) are slightly better than those of the coarse-grained steel (grade 1). A difference in grain size mainly lowers the resistance to ductile (ap) and brittle (T₅₀) fracture. The strength characteristics (b, _0.2), hardness (HRC), and ductility (, ) of the quenched and tempered steel do not depend greatly on the original austenite grain size. With ductile fracture the negative effect of a difference in grain size is more evident after high-temperature tempering. A difference in grain size has the same negative effect on the ductile-brittle transition temperature (resistance to brittle fracture) after tempering at both low and high temperatures.I. P. Bardin Central Scientific-Research Institute of Ferrous Metallurgy. Translated from Metallodenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 2–5, April, 1977.     

Effect of lamellar structure parameters on the properties of titanium alloy VT3-1

Conclusion An increase in the ultimate breaking strength, stress-rupture strength, and fatigue limit of alloy VT3-1 with a lamellar structure may be achieved as a result of refining any parameter of the structure, particularly -phase platelet thickness, and increasing the volume fraction of secondary -phase. An increase in ductility characteristics, toughness, and creep resistance may be provided by increasing the dimensions of -colonies and primary -phase particles (up to 2.5–3.5 m) and reducing the volume fraction and dispersivity of secondary -phase lamellar precipitates. Coarsening of -grains leads to an increase in a_c, k_Q, and refinement leads to an increase in and a_n.Qualitative dependences for mechanical properties of alloy VT3-1 on lamellar structure parameters made it possible to isolate those structural parameters which have the most marked effect on properties.The properties of alloys with a finely lamellar structure (d25 m, b_{I, II}<2 m) are most sensitive to structure. In this case a change in -colony size by 10 m and -platelet thickness by 1 m affects the properties 3–20 times more strongly than a change in -grain size by 100 m. The effect of finely dispersed secondary -phase precipitates is greater, the coarser the primary -phase structure. Refinement of primary -phase structure with an increase in secondary phase platelet thickness to 1 m or more reduces the sensitivity of alloy mechanical properties to the effect of secondary -phase.With coarsening of the intragranular structure (d>25 m, b_{I, II}2 m) the effect of structural parameters d and b on properties is markedly weakened: on strength properties (_f, ₁₀₀ ⁴⁵⁰ ) by a factor of 100, on ductility (, ), by a factor of 10 to 20, and on impact strength and fracture toughness (a_n, a_c, K_Q) by a factor of five.The qualitative relationships obtained between structure and mechanical properties of alloy VT3-1 are fundamental for controlling the structure of semifinished titanium alloy products.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 52–55, July, 1986.     

Phase and structural transformations in deformation and heat treatment of 08Kh15N5D2T steel tubing

Conclusion Annealing in the intercritical area of the -transformation or hardening from a continuous furnace with subsequent tempering in the -transformation range included in the production plan for cold-rolled 08Kh15N5D2T tubing do not restore the original workability of the steel since the residual austenite is stabilized toward the -transformation in deformation. Annealing at 650°C does not lead to complete recrystallization and detexturing of the metal. To obtain this it is recommended that rapid electric heating for hardening with subsequent tempering be introduced into the production plan for rolling of tubing.Ural Polytechnic Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 7–11, August, 1990.     

Effects of the composition and low-temperature thermomechanical treatment on the mechanical properties of structural steels

Conclusions The investigation of the effect of thermomechanical treatment on the mechanical properties of steels with different compositions makes it possible to put in evidence the effect of alloyed elements. The addition of up to 1.2–1.5% Si (particularly with vanadium) makes it possible to increase the tempering temperature to 350°C without significantly decreasing the strengthening effect of low-temperature thermomechanical treatment. An increase of the concentration of chromium from 1.5 to 3–5% also increases the resistance of the steel. In steel containing 3–5% Cr and also molybdenum, vanadium, and tungsten, the effect of low-temperature thermomechanical treatment is retained after tempering at temperatures up to 500°C, the plasticity remaining rather high. Low-temperature thermomechnical treatment of batches 8 and 10 followed by tempering at 500°C resulted in the following mechanical characteristics: _b=240–255 kg/mm² when =10–13% and =30–35%; after tempering at 350°C _b=255–265 kg/mm², ₅=8–12%, and =28–36%.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 36–40, April, 1963     

Resistance of 1201 aluminum alloy to plastic deformation at various strain rates

Conclusion With an increase in the rate of plastic strain there is a change in the resistance of 1201 alloy to plastic deformation, which is revealed in a nontraditional decrease in _0.2 and increase in , and A_p. The characteristics _k and _t increase nonlinearally.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 56–61, August, 1989.     

Thermal straightening of tubes made from martensiteaging steels

Conclusion Two-stage thermal straightening of martensite-aging N18K12M5T steel tubes manufactured according to the All-Union State Standard (GOST) 9567-75, with an accuracy of ±0.45 mm, permits the manufacture of tubes in accordance with the 2nd accuracy class (±0.015 mm) and with high mechanical characteristics: _ult MPa, _0.2 MPa.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 46–47, October, 1985.     

Anisotropy of the ductility of steel 14Kh17N2

Conclusion In commercial forgings of steel 14Kh17N2 (containing 0.35% nonmetallic inclusions) with a proportional change in the geometric parameters of the section at 20–300° the anisotropy of the ductility increases, coefficient R decreases, and the difference in the absolute values of the reduction in cross-sectional area increases with increasing forging reduction ratios due not only to an increase in the deformability of nonmetallic inclusions but also to an increase in the deformability of soft ferrite in the solid solution of martensite. At the forging reduction ratios investigated the distribution of nonmetallic inclusions and inclusions of ferrite leads to anisotropy of the ductility in the temperature range investigated.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 58–59, October, 1976.     

Control of the phase composition and nitrogen content in the nitride layer in the nitriding of the steel 38Kh2MYuA

It is known that in order to obtain a high-hardness, wear- and corrosion-resistant article a nitrided layer of nitride (+)-phases should be formed on its surface. However, in some cases, for example, in nitriding high-speed die steels and steel 38Kh2MYuA, the formation of brittle nitride surface layers should be eliminated and only a zone of internal nitriding (a+ + MN) should be formed in order to provide the requisite hardness and wear resistance. The article concerns preparation of nitrided layers with different compositions on the widely used 38Kh2MYuA nitralloy.     

Mechanical properties of steel 30KhGSA with grains of different sizes

Conclusions Grains of different sizes impair the ductile characteristics of steel. This is manifest in a reduction of the resistance to brittle fracture, which is particularly notable for samples tempered at high temperature and brittle samples. The strength characteristics (_b, _0.2, HRC) and ductility (, ) of quenched and tempered steel vary negligibly with the grain size, and therefore static tests of smooth samples are inadequate to determine the service life of such materials.I. P. Bardin Central Scientific-Research Institute of Ferrous Metallurgy. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 52–53, December, 1977.     

General laws governing variation in properties of cast alloys of the Al-Zn-Mg system

Among existing high-strength corrosion-resistant aluminum alloys, those of the Al-Mn-Zn system are most promising. They have a different phase composition, depending on the content of magnesium and Zinc: + (Al₃Mg₂), + + T(Al₂Mg₃Zn₃), + T, + T + (MgZn2) and + The majority of industrial Al-Mg-Zn alloys correspond to the phase regions + T and + T + with respect to composition. A high level of strength and satisfactory overall corrosion resistance are characteristic for these alloys. Al-Mg-Zn alloys may, however, tend to the most dangerous form of corrosion - stress-induced corrosion cracking. Using methods of experiment planning in the study, we investigated Al-Zn-Mg alloys of various compositions for the purpose of selecting alloy compositions with a high level of mechanical properties and stress-induced corrosion cracking.All-Union Scientific-Research Institute of Aviation Materials. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 24–28, December, 1994.     

Effect of the tempering temperature and time on the structure and phase composition of the AMg6 alloy

Conclusions It was determined that the decomposition of the solid solution in the AMg6 alloy begins at the grain boundaries. After a certain time interval the plate-like -phase precipitates within the grains. After a longer tempering time the platelets coagulate and take on a rounded form.At temperatures of 200 and 250°C the metastable -phase is not completely converted into the -phase, and even after a very long tempering time there is still a considerable amount of the -phase in the structure.At a temperature of 150°C or lower, only the metastable -phase occurs in the alloy even after tempering as long as 9 months.Translated from Metallovedenie i Termichesakaya Obrabotka Metallov, No. 9, pp. 59–61, September, 1966.     

Oxidation Behavior of Two-Phase γ + σ Nb-Ti-Al Alloys

The oxidation behavior of a series of single-and two-phase Nb-Ti-Al alloys, selected from the sameextended + tie-line, was investigated at1200°C in air. The single-phase alloy suffered from extensive internal oxidation andoxidized at a much higher rate than the single-phase alloy. In a two-phase + microstructure, the phase was preferentiallyattacked to form internal alumina andTi-rich nitride. This preferential attack of limited the extent to which the phase wasinternally oxidized, but also interrupted the formationof a continuous alumina scale. The single-phase alloyalso did not form a continuous alumina scale. Theinability of the phase to form continuousalumina was attributed to a combination of nitrideformation and internal oxidation. The oxidation behaviorof the two-phase + Nb-Ti-Al alloys isdiscussed in terms of mechanisms developed for theoxidation of binary, two-phase alloys.     

Formation of a Rhenium-Base Coating on a Nb-Base Alloy

To protect Nb–5Mo–15W alloy against high-temperature oxidation a novel coating was developed involving electroplating of a Re–Ni film, followed by pack cementation with Cr and Al. The coating consisted of a duplex-layer structure, an inner (Re–Cr) or Re(Cr) layer and an outer Cr(Al) or NiAl layer. The Re–Ni film containing more than 70at.%Re, developed in the present investigation, is more useful than the conventional low Re–Ni film. The inner (Re–Cr) and Re(Cr) layer acts as a diffusion barrier between the Nb–5Mo–15W alloy substrate and the outer -Cr(Al) or -NiAl layer, which forms a protective -Al₂O₃ scale. The coated Nb–5Mo–15W alloy was oxidized in air at 1373K for up to 360ks, showing very good oxidation resistance.     

Heat-treatment with induction heating of pipes within the pipe welding mill

Conclusion Induction heat treatment of corrosion-resistant steel pipes in the line of an argon-arc welding mill produces a fine-grain structure of the base metal and weld, ensures the mechanical properties of pipes as specified in GOST 11068-81: _t 560 N/mm²; ₅ 36%. and also makes possible the oxidation of the metal by 0.33%, reduces the time and consuption of the etching solution during chemical processing, and saves power.Dnepropetrovsk, Moscow Pipe Works. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 26–29, August, 1987.