Size stability and strength of multiphase metastable materials

The changes in the clearances (interferences) caused by the differences in the temperature coefficients of linear expansion (TCLE) of joined materials are considered. In operation and long-term storage of precision parts made of high-strength steels these changes can exceed the admissible ranges due to the instability of the phase composition even when the parameters of the heat-treatment process correspond to the existing technological recommendations. A study of the nature of the size instability of high-strength corrosion-resistant steel 25Kh17N2B-Sh allowed the authors to recommend regimes for its final heat treatment that provide maximum size stability at the specified level of mechanical properties. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 12–16, May, 1998.     

Structure and hardness of corrosion-resistant ferritic steels subjected to high-temperature nitriding

A comparative study of the effect of high-temperature internal nitriding (at above 1000°C) on the structure formation and hardening of thin-sheet samples of 08Kh17T (0.06% C-17.0% Cr-0.5% Ti) and 15Kh25T (0.10% C-25.0% Cr-0.5% Ti) steels was performed. The high-temperature internal nitriding of the 08Kh17T steel leads to the formation of martensite structure with Cr₂N precipitates. The nitriding of 15Kh25T steel results in the formation of a layered structure; in this case, individual layers consist of a mixture of the α and γ phases and Cr₂N particles, which are present in different proportions. It was shown that the internal nitriding of both steels with their subsequent annealing leads to their substantial uniform hardening.     

Structural Inheritance of Cast Steels for Road Tools

Mechanical properties and special features of structure of cast high-strength steel 23Kh3N2GFL used for the production of blades and dippers of road machines are considered. It is shown that castings from this steel have low impact toughness and ductility due to the structural inheritance that occurs in heating for quenching. It is suggested that steel 23Kh3N2GFL should be replaced by new grades of steel with a diminished nickel content, which possess high mechanical properties and are not susceptible to structural inheritance.     

Steel 08Kh17N6T for compressor blades

Steel 08Kh17N6T in recent years has become widely used for manufacturing parts for pumps and gas turbines in connection with its better mechanical properties and corrosion resistance, compared with the chromium steel 20Kh13 used previously for this purpose. In this paper, we present the results of an investigation of the longterm and fatigue strength and the corrosion resistance of steel 08Kh17N6T, and also data on the effectiveness of using it to manufacture compressors.I. I. Polzunov Central Scientific Research, Planning, and Design Institute of Boilers and Turbines (Scientific-Industrial Association). Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 25–26, November 1994.     

Structure of chromium-nickel steel 14KH17N2 after high-temperature tempering

The structure of steel 14Kh17N2 after quenching exhibits -phase (ferrite alloyed with chromium and nickel), which causes the formation of streaks, filaments, and other defects in the metal during rolling and hot pressure treatment. The properties of the microstructure of this steel can be judged by the state of the carbide phase segregating on phase interfaces and inside grains. A complex analysis of the changes in the state of the carbide phase M₂₃C₆ in the process of high-temperature tempering of steel 14Kh17N2 (for example, at 700°C is of practical interest. The results of this analysis make it possible to make recommendations on improvement of the properties of the steel and to refine the optimum chemical and phase compositions.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5 , pp. 36–38, May, 1995.     

Acoustic detection of stress-corrosion cracking of nitrogen austenitic steels

Structural changes and resistance to the stress-corrosion cracking of the nitrogen-bearing austenitic steels 04Kh20N6G11M2AFB and 09Kh20N6G11M2AFB (with 0.04 and 0.09 wt % C, respectively) after different treatments, including thermomechanical action, quenching from 1200°C, and aging at 700°C for 2 and 10 h, have been studied. It has been shown that aging at 700°C of the air-melted austenitic steel 09Kh20N6G11M2AFB leads to a decrease in the strength of samples with an induced crack upon the cantilever bending in air and in a 3.5% aqueous solution of NaCl as compared to the strength of the steel 04Kh20N6G11M2AFB-EShP with a smaller carbon content after high-temperature mechanical treatment or quenching from 1200°C. The smallest resistance to stress-corrosion cracking is observed in the samples of 09Kh20N6G11M2AFB steel after 10 h of aging, which is accompanied by the most intense acoustic emission and by brittle intergranular fracture. This is explained by the high rate of the anodic dissolution of the metal near chromium-depleted grain boundaries due to the formation of continuous chains of grain-boundary chromium-containing precipitates of carbides and nitrides.     

Effect of softening heat treatment on mechanical properties of maraging high-strength corrosion-resistant steel

It has been shown in many investigations that the corrosion-resistant maraging steel 03Kh1 IN I0M2T (BHC 17) has high plasticity and the lowest deformation resistance after softening heat treatment (annealing, quenching, or aging at 650°C). However, the available data are insufficient for the development of a technology for producing parts by cold plastic deformation. In this case it is important to know the effect of different kinds and regimes of softening heat treatment not only on the mechanical properties and the structure of the steel but also on its deformation behavior and sensitivity in the stress state. The sensitivity to dynamic loads is very important. The present work is devoted to the investigation of these problems.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 29–32, August. 1995.     

Effect of Periodic High-Voltage Discharge in a Flow of Liquid on the Surface Layers of Structural Steels and Titanium Alloys

Results of a study of the effect of electric pulse treatment with the use of high-voltage periodic discharge in a flow of water on the structure and hardness of surface layers of specimens of steels 45KhN2MFA, 30Kh3NMAF, 12Kh18N10T and titanium alloys OT4-1 and VT6 are described. It is shown that the structure and properties of the surface in the zone of the action of electric discharge change due to the rapid fusion, crystallization, and rapid hardening of microvolumes of specimens subjected to the highly concentrated energy action. The microhardness of the surface of specimens of pearlitic steels after such a treatment is higher than after volume quenching. The microhardness of the surface layers of specimens of austenitic steel 12Kh18N10T decreases. Hardening of the surface layers of titanium alloys under the action of high-voltage discharge is substantially higher than in the case of quenching, which seems to be connected with their saturation with oxygen and nitrogen from the ionized ambient. Some regular features of the influence of the conditions of periodic discharge on the structure and properties of surface layers of the studied materials are described.     

Low-temperature nitriding of austenitic steel in a vibrofluidized bed

The prospects for use of a vibrofluidized bed (VFB) for low-temperature nitrogen saturation of high-strength austenitic steel based on Cr−Ni−Mn (12Kh17N8G2S2MF) are considered. The positive effect of preliminary plastic deformation on the intensity of nitriding is described. The temperature and time parameters of nitriding in a VFB for strain-aging austenitic steel 12Kh17N8G2S2MF are shown to be adequate for the regimes of the final heat-treatment operation of aging. This creates the possibility of combining the operations of surface alloying and strain aging into a single cycle. This combined treatment increases substantially the resistance of the steel to cyclic loads while preserving the strength parameters. It is shown that the presented method of low-temperature nitriding in a VFB is expedient for improving the service characteristics of austenitic steel 12Kh17N8G2S2MF used for production of force springs of automobile brake systems. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 6–10, November, 1999.     

The Influence of High-Pressure Gas Nitriding on the Properties of Martensitic Steels

Metal Science and Heat Treatment - The influence of high-pressure gas nitriding on the structure and properties of martensitic steels VKS-5, VKS-7, 20Kh3N3MFB, and 25Kh5M is investigated. It is...     

Effect of the quenching technique on the structure of steel Kh12M

Results of a study of the structure and phase composition of steel Kh12M after quenching by various regimes are presented. It is shown that the favorable combination of mechanical and service properties of steel Kh12M attained after a two-stage quenching is caused by the presence of finely disperse special carbides uniformly distributed in the matrix. Translated from Metallovedenic i Termicheskaya Obrabotka Metallov, No. 12, pp. 12–15, December, 1999.     

Red hardness of hard-facings of different materials

Conclusions In the reduction of the red hardness of facing layers and the reduction of the hardness after tempering at high temperatures the materials investigated can be placed in the following order: U30Kh25N4SV8, U25Kh23N4S3G, 3Kh2V8, Kh12VF, U20Kh17T1, U20Kh17T, 5Kh4V3FT, 5Kh4V3FTs, and 5Kh4V3F.Gipronisélektroshakht, Makeevskii Metallurgical Plant. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 56–58, December, 1966.     

Effect of Overheating on the Mechanical Properties of Roll-Foundry and Die Steels

The effect of overheating on the properties and structure of roll steels 9Kh2, 9Kh2MF, and 9Kh2SVF and steel 5KhNV used for the production of heavy-duty forging dies is studied. It is shown that the elevation of the heating temperature changes the fracture behavior of roll steels. The temperature of overheating of roll steels is established. It is shown that the consequences of the overheating can be removed by means of subsequent quenching from conventional temperatures (860 – 890°C). The overheating is shown to have a weak effect on the properties of steel 5KhNV, which can be removed by single heating to a temperature of 890°C.     

Effect of low-temperature quenching on the microstructure and capacity for corrosion cracking of steel 03Kh11N10M2T-VD

Conclusions Low-temperature quenching (from 800°C) of steel 03Kh11N10M2T-VD promotes a noticeable increase in the ultimate rupture strength and the resistance to corrosion cracking after aging at 520°C. We established a tendency toward an increase in the resistance to corrosion cracking after quenching from 800°C and a provoking aging at 500°C. This behavior of the steel seems to be connected with the formation of a finer martensite with a disperse intermetallic phase with uniformly distributed grain size after low-temperature quenching. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 8–11, February, 2000.     

Effect of Preliminary Hardening on the Properties of Steel 15Kh16K5N2MVFAB

Modes of heat treatment of steel 15Kh16K5N2MVFAB used in commercial production of parts are considered. It is suggested to complement the process of heat treatment used by preliminary hardening and tempering. A comparative analysis of the mechanical properties, structure, and machinability of parts after the conventional and the suggested heat treatment variants is presented.     

Corrosion cracking of welded joints of pipelines from steel 08Kh18N10T in power units with RBMK-type reactors

The effect of coolant parameters (temperature, content of oxygen and chlorine ions, acidity parameter pH) and of residual stresses on the susceptibility of welded joints of pipelines from steel 08Kh18N10T at power units with RBMK-type reactors to intercrystalline corrosion cracking is studied. It is shown that the endurance of the pipelines depends on the heat treatment of welded joints and on the deaerated rise of the reactor to the operating conditions. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 36–42, February, 2007.     

Die steels for high-speed automatic hot die forging machines

Conclusions Steel 3Kh3M3F produced by ESR has the best combination of strength, hardness, and toughness, and also resistance to crazing. The life of punches made of this steel was double that of standard steel 3Kh2V8F and considerably higher than that of steels with a higher carbon content (0.4–0.5%).The life of 3Kh3M3F punches (ESR) was three to four thousand bearing races higher than that of the same steel melted in an open furnace.These data lead us to recommend that punches for high-speed water-cooled presses be manufactured from steel 3Kh3M3F (ESR) with the following chemical composition: 0.26–0.34% C, 2.8–3.3% Cr, 2.5–2.9% Mo, 0.40–0.60% V (ChMTU-1-963-70).The following heat treatment is recommended: preliminary heating in an electric furnace at 500–510°, salt bath at 850–860°, and salt bath at 1040±10°. The parts should be quenched in oil with a temperature of 120–150°. The first tempering after quenching should be conducted in a salt bath at 600° for 2 h, with cooling in air. The second tempering should be conducted in a salt bath at 560° for 2 h, with cooling in air. The hardness of the parts after heat treatment is HRC 49–51.All-Union Scientific-Research Institute of the Bearing Industry. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 20–25, November, 1973.     

Formation of nitrogen austenite in steel 08Kh15N5D2T due to quenching in closed volume

The process of high-temperature nitriding of low-carbon steel 08Kh15N5D2T in a medium of nitrogen contained in air is studied. The regular features of formation of nitrogen austenite after quenching in a closed volume are determined.     

Methods for raising the impact toughness of steel 14Kh17N2 in the direction transverse to deformation

Metal Science and Heat Treatment - The effect of heat treatment modes used to raise the impact toughness in the direction transverse to that of deformation on the structure of steel 14Kh17N2 is...     

Influence of high-temperature plastic deformation on the heat resistance of austenitic steel 3Kh19N9MVBT

Summary High-temperature plastic deformation and quenching can be used to strengthen very thick pleces of 3Kh19N9MVBT steel.TsNHTMASh. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 49–52, January, 1967.