372595901

ANALYSIS, TESTING

JPRS-UMS-92-003 16 March 1992

Computer-Aided MTI-3M Complex for Measuring Microhardness of Materials and Coats

927D0081N Moscow ZA VODSKA YA LABORA TORIYA in Russian Vol 57 No 12, Dec 91 pp 55-57

[Article by V.N. Skvortsov, R.M. Matvcyevskiy, V.A. Borodkin, Institute of Science of Machines imeni A.A. Blagonravov at the USSR Academy of Sciences, Moscow]

UDC 620.178.15.65.011.56

[Abstract] The MTI-3M computer-aided complex intended for investigating the micromechanical proper-ties of products and samples from various materials by forcing the indenter into the specimen and automatically recording the indentation diagram in the force-indentation depth coordinates is described. Two microhardness testing procedures specified by GOST and COMECON standards are outlined and the conclusion is drawn that the method based on the depth of indentation is the most promising, objective, and reproducible. The use of the MTI-3M system for plotting the kinematic diagram of indentation and its advantages are outlined and a typical indentation diagram obtained by the new system is cited. In addition to the indenter and sensors, the new complex contains an IBM PC microcomputer and an RS/232 interface; the specifications of the indenter are cited. The proposed complex may be useful in physical metallurgy, mechanical engineering, metal-lurgy, fracture mechanics, mineralogy, and tribology. Figures 2; tables 1; references 3.

Computer-Aided Collection and Processing System for Experimental Data on Physical and Mechanical Properties of Metal

927D0081M Moscow ZA VODSKA YA LABORATORIYA in Russian Vol 57 No 12, Dec 91 pp 53-55

[Article by A.A. Pcrfilov, Ye.D. Panov, S.N. Kabuzenko, M.V. Pirusskiy, Central Scientific Research Institute of Ferrous Metallurgy imeni I.P. Bardin]

UDC 620.172.224.65.011.56

[Abstract] A computer-aided system of mechanical ten-sile tests which is capable of collecting, Processing, and storing experimental data as well as printing the results in the form of a test log, displaying them graphically on a color screen, and sending them to a graphics plotter is described. The system is developed at the Central Scientific Research Institute of Ferrous Metallurgy imeni I.P. Bardin and is characterized in that it can automatically identify the type of the diagram of conditional or physical yield strength and calculate the metaTs strength parameters. The system is aimed at using conventional CAMAC, SM 1420, MERA 660, MERA 1300, and PC XT/AT computers and an ICHAC interface or a built-in interface board. The hardware components, system architecture, and software are described in detail and an examplc of a tensile diagram is cited. The development of the system madę it possible to automate the tedious and skill-demanding task of obtaining and Processing experimcntal data on the physical and mechanical char-acteristics of metals, eliminate the subjective factor, increase the data reliability, and eliminate manuał data entry. Figures 2.

Crack Resistance Characteristics of Welded Joints: Assessment, Design, and Statistical Analysis

927D0081L Moscow ZAVODSKAYA LABORATORIYA in Russian Vol 57 No 12, Dec 91 pp 48-51

[Article by A.M. Lepikhin, V.V. Moskvichev, Computer Center of the Siberian Department of the USSR Academy of Sciences, Krasnoyarsk]

UDC 620.192.46:621.791.052

[Abstract] The role of incipient and propagating cracks in the mechanics of fracture necessitates a study of the characteristics of crack resistance and such specific fac-tors as the notch sensitivity index and critical crack apex divergence. In determining the crack resistance of welded joints, it is necessary to take into account the mechanical inhomogeneity of the joints due to the local character of thermal and mechanical metal “excitation” during the welding process which leads to the develop-ment of residual stress and strain, a change in the phase composition and structure, and the development of micro- and macrodefects. The results of mechanical tests of 3 mm-diameter samples and templates of welded joints from Steel lOKhSND demonstrating the behavior of mechanical properties are examined: the ultimate strength, conditional yield strength, percentage reduc-tion in area, and elongation and changes in the grain size and microhardness. As a result, the crack resistance behavior in the welded joint cross section, the depcn-dence of crack resistance on the testing temperaturę, and the crack resistance distribution function in the welded joint are plotted. A study of the effect of structural and mechanical nonuniformity of welded joints on the crack resistance characteristics and the statistical pattems of their behavior as well as the possibilities of their simu-lation can be used in designing welded joints and ana-lyzing their crack resistance and reliability on the basis of failure criteria. Figures 6; tables 1; references 20: 17 Russian; 3 Western.

Crack Growth Criterion Under Creep Conditions

927D0081K Moscow ZAYODSKAYA LABORATORIYA in Russian Vol 57 No 12, Dec 91 pp 42-45

[Article by S.I. Olkin, Central Aerohydrodynamic Institute imeni N.Ye. Zhukovskiy, Zhukovskiy, Moscow oblast]