Magnetic Properties of Steels after Quenching and Tempering. I. General. Carbon Steels

The publication is composed of three parts. The first describes characteristics that are used in nondestructive tests of ferromagnetic components and assemblies, and the classification of these characteristics with structure- and phase-sensitive ones. Physical processes during quenching and tempering of carbon and low-alloyed steels are discussed, alongside their effect on the coercive force, saturation magnetization, electric resistivity, and hardness of the 30Kh3MFA, 40KhFA, and ShKh15 steels. These parameters are given as functions of the heating temperature in the processes of quenching and tempering of these steels.     

Functional Possibilities of SM-401 Magnetic Structuroscope

The possibilities of nondestructive testing the quality of product hardening using an SM-401 magnetic structuroscope with an H-shaped attached electromagnet are shown with references for ShKh15 and EI928 steels. Possibilities of the device for testing the quality of tempering products made from 40KhN2MA and wheel-tire steels are demonstrated.     

Possibility of Nondestructive Testing of Operational Heating of Contact Surfaces of Rolling Bearings

The coupling between variation of parameters of nondestructive testing and heating of rolling bearings associated with their operation regime in a helicopter reduction gear is demonstrated. The coercive force method and the eddy-current method of testing outer bearing rings made from ShKh15 steel are considered.     

Utilization of electromagnetic acoustic conversion to estimate microstress in steels

Results of studies on the influence of microstress on the parameters of electromagnetic-acoustic transduction (EMAT) in thermally treated and cold-worked steels are presented. It is shown that in thermally treated steels, except high-alloy corrosion-resistant austenite-martensite steel 1Kh15N5AM3Sh, the amplitude of the EMAT signal decreases linearly with an increase in the microstress. In this situation, the propagation velocity of normal elastic waves also decreases monotonously; this is also the case for 1Kh15N5AM3Sh steel. In pearlitic steel that is cold-worked by drawing, the dependences of the EMAT amplitude and the propagation velocity are linear only at the initial stage of deformation. After that, the parameters of the EMAT are affected most strongly by the phenomena that occur during the drawing: the turning of ferrite and carbide plates and the decrease in the dispersion angle of the axial crystallographic structure.Translated from Defektoskopiya, Vol. 40, No. 7, 2004, pp. 26–33.Original Russian Text Copyright © 2004 by Gorkunov, Zadvorkin, Solomein.     

Multipurpose Use of Magnetic Properties of Steels in Nondestructive Testing of the Quality of Heat-Treated Workpieces

The paper is devoted to calculation of expressions relating the hardness both of a series of low-alloyed steels and of high-chromium steels 14Kh17N2A, 20Kh13, 30Kh13, and 40Kh13 with their magnetic properties after quenching and subsequent tempering over a wide temperature range. Expressions relating the hardness of 60S2A, 50G, and U8 steels with reading of a MS-2 magnetic structuroscope are also calculated. A table containing tempering temperature intervals on which the coercive force, the relaxation magnetization, and the magnetic susceptibility vary monotonically is given for a series of steel grades. Limits of variation of the above-mentioned quantities and the hardness are also given.     

Effect of ion-beam nitriding on structure, phase state, and tribological behavior of efficient thermal spray coatings deposited from various classes of rod steels

Thermal spray coatings produced by the hypersonic spraying of ferritic (Sv-08G2S), martensitic (40Kh13), and austenitic (06Kh19N9T) rod steels and treated by intensive nitrogen ion flows were studied. Metallographic and X-ray diffraction structural analyses of modified coatings were carried out, as well as their microhardness and tribological characteristics were determined. It has been shown that ion-beam treatment leads to an increase in the wear resistance of coatings from the ferritic steel by 2–80 times, those from the martensitic steel by 2–13 times, and those from the austenitic steel by 10–35 times. Based on the results obtained, temperature conditions for ion-beam nitriding that ensure the best tribological characteristics of the coatings deposited from various classes of rod steels have been selected.     

A comparative analysis of radiation-thermal forming for reflectors of reactors BN-600 and BN-800 by results of numerical simulation

The results of numerical simulation of radiation-thermal forming for bearing shells of reflectors for reactors BN-600 and BN-800, made of various austenitic steels, with the help of parameters of models for radiation swelling, radiation creep, and plasticity, are presented. Based on an analysis of the results, we show that the radiation change in basic dimensions, which characterizes the efficiency of the reactor BN-800 reflector made from austenitic steel Kh16N11M3, is significantly lower than changes for similar sizes for the reactor BN-600 reflector made from steel Kh18N9.     

Wear resistance of cast Fe–Cr–C steels with various combinations of structural constituents at high velocities of sliding

The positive effect of the additional alloying of cast Fe–Cr–C steels on the formation of a secondary structure in the steels and their tribological characteristics under boundary friction has been shown. This effect leads to a decrease in the wear rate of the cast steel 1.2–5.2 times compared to that of the commercial 95Kh18 steel depending on the alloying system of the steels.     

Using Kelvin probe force microscopy for controlling the phase composition of austenite–martensite chromium–nickel steel

The effectiveness of Kelvin probe force microscopy, which is one of the scanning probe techniques, is demonstrated for assessing plastic-deformation induced changes in the phase composition of 08Kh21N6M2T austenite–martensite chromium–nickel steel. Changes in the numerical values of surface potentials of different phase components of two- and three-phase stainless steels versus sample deformation extent have been established. Dependence of surface electric potentials as measured with Kelvin probe force microscopy on the presence and amount of newly formed deformationmartensite phase has been discovered.     

Study of the surface layers of high-alloyed steels in braking

Specimens of high-alloyed steels for use in the brake-disk crowns of high-speed railway cars are subjected to tribotests. The surface-layer structure of a disk from steel 20Kh13 is studied. The wear-resistance features and temperature distribution in high-alloyed steels are described during braking. It is shown that within the range of moderate sliding velocities, alloyed high-chrome steels containing manganese and nickel are more wear-resistant and possess a lower friction coefficient, while in the range of fast sliding velocities steels free of alloying elements possess the maximum wear resistance.     

Developing techniques for testing magnetic properties of electric steels. I. Epstein’s apparatus (Review article)

The review briefly describes the history of development of techniques measuring magnetic parameters of one of the materials which are of vital importance for energy generation, electric engineering, radio engineering, and other branches of industry, i.e., electric steel, whose quality determines operational characteristics of numerous devices, such as generators, transformers, electric motors, magnetic conductors of relay switches in various automated systems, etc. The development of techniques for measuring its magnetic parameters is reviewed starting with the advent of Epstein’s apparatus, which was designed at the turn of the century [1] and has remained an instrument used in resolving controversies between suppliers and consumers of electric steels, and ending on contemporary methods of testing roll steels using complex electronic circuits incorporated in automatic control systems of factories. In connection with the spread of magnetic parameters of electric steels (in sheets, rolls, and batches), the issues of standardization and selection of measures for more reliable characterization of steels are discussed. Instruments and facilities for classification and distribution of steels in batches with uniform characteristics are also described. Sheet-testing instruments for measuring steel parameters, which are designed to replace Epstein’s apparatus, are described. Problems of on-line testing of electric steel in rolls and instruments for such tests developed by this time are discussed. In this connection, the issues of steel tests based on indirect characteristics [those not specified in GOSTs (State Standards)], which could be more easily conducted on production lines, alongside the methods and facilities for nondestructive measurements of magnetic parameters are broached. Part I of the review is dedicated to conditions of magnetic measurements using Epstein’s apparatus, and this paper was written exactly one hundred years after its invention in 1900.     

Tribotechnical properties of thin-film coatings obtained by the tribomodifcation of crankshaft pins for ship diesel engines

The tribotechnical properties of thin-film coatings obtained as a result of the tribomodification of 40Kh steel by various organic-inorganic tribotechnical materials (natural inorganic and synthetic polymers), as well as the compositions and composites created based on vermiculite are considered in the work. Comparative tribotechnical tests have made it possible to establish that the most promising materials for the tribomodification of the friction surfaces of steels are nanostructured composites based on vermiculite, which make it possible to get the minimum coefficient of friction and high wear resistance of the conjugation under the friction condition at boundary lubrication.     

Structure and wear resistance of electron-beam nitrous coatings

The paper deals with the study of the tribological properties of nitrogen-containing austenite coatings deposited by electron-beam facing during abrasive wear and the sliding friction of a VK6 hard alloy indentor. The abrasive wear resistance of the nitrous coatings deposited by the electron-beam facing of steel 60Kh24AG16 powder in quartz sand is lower than that of the steel 65G coatings after hardening; it increases with increasing mass share of the filler. At contents of nitrided ferrovanadium of 10?C30 wt % the abrasive wear rate increases by 30?C50%, respectively. It is found that under a certain load applied to the VK6 ball indentor the friction coefficient and the shear resistance of the surface layer diminish. It is shown that under heavy specific loads applied to the ball indentor the nitrous coating faced from steel 60Kh24AG16 powder and composite nitrous coatings have wear resistance exceeding that of steels 110G13 and Kh18N10 by more than two and seven times, respectively. Based on the results of structural studies an explanation of the observed behavior of the nitrous coatings is proposed.     

Effect of High-Density Electric Current on Wear and Average Temperature of Steel/Steel Triboelectric Contact

In this paper, we presented studies of the sliding friction without lubrication of Hadfield steel, ShKh15 bearing steel, and AISI steel 1020 against AISI steel 1045 upon applying an electric current with a contact density higher 100 A/cm². We showed that the intensity of the surface layer deterioration increased with increasing current density. The catastrophic wear of materials begins at different values of the current density and at close values of the wear energy intensity. The dependences of the average contact temperatures on the current have been determined. The major conclusion is that it is impractical to harden the primary structure by alloys to achieve a low wear rate.     

Ion beam processing of austenite steels: Tribotechnical and corrosion properties

This article presents data on wear and corrosion resistance of 10Kh17N13M2T and 55Kh20G9AN4 austenite steels processed by nitrogen ions. It has been demonstrated that the temperature of ion beam nitrogenation significantly influences structure and phase transformations and properties of materials. The obtained values of electron work function agree with the data of tribotechnical and corrosion tests.     

High-temperature friction and wear behaviour of different tool steels during sliding against Al–Si-coated high-strength steel

The recent years have witnessed an increasing usage of high-strength steels as structural reinforcements and in energy-absorbing systems in automobile applications due to their favourable high-strength-to-weight ratios. Owing to poor formability, complex-shaped high-strength steel components are invariably produced through hot-metal forming. The high-strength steel sheets are in some instances used with an Al–Si-coating with a view to prevent scaling of components during hot-metal forming. However, friction and wear characteristics of Al–Si-coated high-strength steel during interaction with different tool steels have not yet been investigated. With this in view, friction and wear behaviours of different tool steels sliding against Al–Si-coated high-strength steel at elevated temperatures have been investigated by using a high-temperature version of the Optimol SRV reciprocating friction and wear tester at temperatures of 40, 400 and 800 °C. In these studies both temperature ramp tests with continuously increasing temperature from 40 to 800 °C and constant temperature tests at 40, 400 and 800 °C, have been conducted. The results have shown that both the friction and wear of tool steel/Al–Si-coated high-strength steel pairs are temperature dependent. Friction decreased with increasing temperature whereas wear of the tool steel increased with temperature. On the other hand, the Al–Si-coated high-strength steel showed significantly lower wear rates at 800 °C as compared to those at 40 and 400 °C. The Al–Si-coated surface undergoes some interesting morphological changes when exposed to elevated temperatures and these changes may affect the friction and wear characteristics. The mechanisms of these changes and their influence on the tribological process are unclear and further studies are necessary to fully explain these mechanisms.     

Friction of PM ferritic stainless steels at temperatures up to 300 °C

Two ferritic stainless steels (409Nb and 434L) manufactured through powder metallurgical techniques were wear tested at different temperature conditions (up to 300 °C). Two sliding speeds were used, and tests were carried out against a wrought austenitic stainless steel. Materials’ wear performance was characterized through friction coefficients and analysis of wear tracks was carried out through scanning electron microscopy. Results have shown an adhesive wear mechanism. Oxidized ferrite particles have also been found on wear tracks.     

Triboengineering characteristics of unicomponent PVD coatings

In order to explore the opportunities of using vacuum coatings in tribounits, the triboengineering characteristics of unicomponent PVD coatings were studied based on titanium, zirconium, chrome, tungsten and aluminum in sliding friction interfaced with ShKh15 steel GOST 801-78. The study has revealed coatings with the optimal combination of properties, such as the friction coefficient, the wear resistance, the time of running-in, and the wear ability with respect to the counterbody.     

Coercive force measurements in nondestructive testing

The paper considers applications of coercive force meters with external electromagnets to nondestructive measurements of strength, plastic, and viscous properties of rolled high-carbon and low-alloyed steels, characterization of annealed high-carbon, predominantly chromium-doped, steels, testing of the quality of quenched and tempered steels, measurements of the depth and hardness of surface hardened layers on metallic components, and their use in sorting out different steels.     

Characterization of microstructure of H13 tool steel using ultrasonic measurements

This study presents nondestructive characterization of microstructure of AISI H13 hot work tool steel. Heat treatments were carried out in order to obtain different microstructural phases in the tool steel specimens. The microstructural phases were characterized by metallographic examinations and hardness measurements. Velocities of ultrasonic longitudinal and transverse waves were measured by means of pulse-echo method using contact type normal beam probes. Ultrasonic apparent attenuation also determined in the steel specimens having different microstructural phases. A lower value of ultrasonic velocity was observed for the martensite compared to the other microstructures, while the opposite was observed in ultrasonic attenuation. Results show that the use of ultrasonic measurements in order to correlate them with the microstructures is fast and reliable, permitting nondestructive characterization of microstructure in steels.