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The article provides a substantiation for the use of the wear resistance criterion NF determined by the number of loading cycles before the separation of large wear particles and taking into account the indicators of fracture toughness, yield strength, friction coefficient, and also taking into account the dimensional characteristics of the initial cracks to predict the contact endurance of heavy-loaded friction pairs hardened by induction surfacing with powder hard alloys. It is shown that the use of this criterion can be extended for various types of loading, including combined ones. A method of experimental confirmation of analytical dependences for determining NF is described, the scheme of the test rig and the results of experiments for powder surfacing materials of various grades are presented. [ABSTRACT FROM AUTHOR]

Results are provided for determining standard mechanical properties, cold resistance, and crack resistance properties of base metal and a heat-affected zone, and corrosion-mechanical strength of new cold-resistant steels with yield strength of at least 420, 460, 890 and 960 MPa. Results are given for studying ferritic-bainitic and bainitic-martensitic parameters of the structure of sheets from low- and sparingly-alloyed high-strength steels of various thicknesses. The low-alloy steel developed with a yield strength of at least 420 and 460 MPa with the code Arc may be used for any components of marine Arctic structures without restriction at operating temperatures down to –40°C. The high-strength steel with a yield strength of at least 890 and 960 MPa is recommended as a promising material for constructing underwater mining complexes and deep-water marine equipment. [ABSTRACT FROM AUTHOR]

The contemporary state of oil and gas complex development gives rise high consumer specifications for the quality and reliability of pipe products. Continuous growth of recovery volumes, including the development of new fields and new industrial production regions, severe climatic conditions when the air temperature reaches minus 40-60 °С, the demand for cost efficiency of new pipeline construction, an increase in operating pressure up to 8.4-15 MPa, as well as ensuring corrosion resistance and reliability of main pipelines, all constantly raise the level of specifications requirements for pipe quality. Connected with this are new trends in the requests and needs of companies for extraction and transportation of hydrocarbon energy sources. Today these companies wish to obtain not only pipes that meet world quality standards, but also products suitable for the temperature conditions of oil production and transportation and the characteristics of extracted raw material chemical composition, and with a reduction in pipe product customer expenditure. [ABSTRACT FROM AUTHOR]

The available methods for identifying the type of failure of a 15-20 MPa gas pipeline used to evaluate the crack resistance of X90, X100, and Х110 high-strength steels cannot reliably predict the arrest of a main crack over the length of two or three pipes. Ductile fracture mechanics is used to determine the length of the plastic zone, the stress state, rate and degree of strain, and damage of the metal at the front of a growing macrocrack. A new fracture criterion based on plasticity diagram is proposed. The new approach to the evaluation of the crack resistance of steel reduces the growth rate of the main crack to less than the decompression rate of a gas pipeline after breakage and arrest of the main crack. [ABSTRACT FROM AUTHOR]

Results obtained at the Mariupol Metallurgical Combine with a new technology for reconditioning the steel work rolls of hot-rolling mills are presented. The technology is based on hard-facing of the rolls with strip electrodes made of steels 20Kh4MFB, 15kp, and 08kp. Rolls hard-faced with a composite consisting of alternating strong and ductile layers are shown to have good fracture toughness. The service life of the rolls is increased, their wear is made more uniform, and the amount of metal removed in regrindings is reduced thanks to differentiation of the composition and properties of the metal along the body of the rolls. Reconditioning rolls with the hard-facing materials made by the Mariupol combine increases productivity per 1 mm of roll wear and makes the reconditioning operation more profitable. [ABSTRACT FROM AUTHOR]

A comprehensive study is provided for the effect of a ferrite-pearlite microstructure with a pearlite content from 0 to 100% on the main operating properties of structural steel, including fracture toughness and ductility, brittle failure resistance, and crack resistance. It is found that an increase in carbon content is accompanied by rapid ferrite grain refinement. It is confirmed that an increase in pearlite content in a microstructure, especially above 20% has a marked, but not always favorable effect on all steel deformation and failure characteristics. [ABSTRACT FROM AUTHOR]

A new energy-saving, low-waste technology is proposed for conducting hydraulic tests. The technology was developed with consideration of the processes that take place in the metal of piping that has undergone long use. The method that has been developed to choose the test pressure for piping systems is based on an equation that links the stresses in the wall of a pipe with the pipe’s geometry, corrosion rate, test pressure, length of service, and operating conditions. [ABSTRACT FROM AUTHOR]