OPERATIONAL RELIABILITY OF FORGED BOILER TUBES OF 15Cr1Mo1V STEEL PRODUCED BY NKMZ PJSC
DOI:
https://doi.org/10.30838/J.PMHTM.2413.260222.62.634Keywords:
forged boiler tubes, chemical composition, microstructure, short-term mechanical properties, high-temperature strength, long-term strengthAbstract
Purpose: To assess operational reliability of metal of forged boiler tubes of 15Cr1MoV steel manufactured by NKMZ PJSC (Kramatorsk) based on comprehensive studies of chemical composition, structure and properties, including high-temperature strength. Procedures. Modern methods and procedures of metallographic studies, chemical analysis, tests of short-term mechanical and high-temperature strength properties were used. Results. It has been shown that a distinctive feature of metal of forged tubes of 15Cr1MoV steel manufactured by NKMZ PJSC consists in unfavorable (from the point of view of ensuring high-temperature strength and working capacity) ratio of mass fraction of vanadium to mass fraction of carbon (V/С˂1.6). Metal structure is characterized by inhomogeneity in a relation to distribution of structural components across the wall thickness and along the length of tubes of all sizes under study. In metal of the tubes studied, along with a satisfactory microstructure, objectionable structures were found, which do not provide the level of long-term strength required by the normative documents. Necessity of adjusting chemical composition and conditions of heat treatment of forged boiler tubes made of 15Cr1MoV steel at NKMZ PJSC to ensure a satisfactory structure and required level of service properties in metal of a wide range of tubes was shown. A need to develop a new specification for forged boiler tubes of 15Cr1MoV steel in a wide product range, including requirements for microstructure and conditions of thermal treatment instead of outdated Technical Specification 923 not applied currently in Ukraine, has been established. Scientific novelty. Chemical composition and structure of forged 15Cr1MoV steel tubes produced by NKMZ PJSC in a wide product range and their effect on long-term strength were established for the first time. Practical value. The obtained study results will serve as a basis for improving technology of production of boiler tubes at NKMZ PJSC and will make it possible to meet the demand of Ukrainian power engineering industry in 620 mm and more diameter 15Cr1MoV Ф steel tubes having high operational reliability.
References
TU 14-3-460/TU U 27.2-05757883-207. Truby stalevi bezshovni dlia parovyh kotliv i tryboprovodiv [Seamless steel pipes for steam boilers and piplines]. Dnipro : SE “SRTI”, 2009, 50 р. (in Ukraine). (Technical Conditions).
TU3-923. Truby stalnye bezshovnye mehanicheski obrabotannye iz konstrykcionnoi marki stali [Seamless mechanical machined boiler tubes from a structural grade of steel]. Volhohrad : Plant “Barrikady” Publ., 1975, 10 p. (in Russian). (Technical Conditions).
Zlepko V.F., Perevezentseva T.V. and Novikov S.V. O nekotoryh osobennostiah strukturnogo sostoianiia metalla tsentrobezhnolityh paroprovodnyh trub iz stali 15H1MF [About some features of the structural state of metal of centrifugally cast steam pipes made of steel 15Cr1Mo1V]. Elektricheskie stantsii [Power stations]. Moscow, 1991, no. 3, рр. 12−17. (in Russian).
Opryshko L.V., Goloviak T.V., Malenik A.O. and Kozminskii A.N. Osobennosti struktury i svoist metalla trub iz stali 15H1MF-Sh, izgotovlennyh metodom elektroshlakovoi vyplavki [Features of the structure and properties of metal pipes made of steel 15Cr1Mo1V-Sl, produced by electroslag smelting]. Metallurgicheskaia i gornorudnaia promyshlennost [Metallurgical and Mining Industry]. Dnipro, 2014, no. 2, рр. 43−47. (in Ukraine).
Antikain P.A. Metally i raschety na prochnost kotlov i truboprovodov [Metals and calculation for the strength of boilers and piping : monograph]. Мoscow : Energoizdat Publ., 1990, 386 р. (in Russian).
Krutasova E.I. Nadozhnost metalla energeticheskogo oborudovania [Reliability of metal power equipment]. Мoscow : Energoizdat, 1981, 240 р. (in Russian).
Bugai N.V., Berezina T.G. аnd Trunin I.I. Rabotosposobnost i dolgovechnost energeticheskogo oborudovaniа [Performance and durability of metal power equipment: monograph]. Мoscow : Energoatomizdat Publ., 1994, 272 р. (in Russian).
Kumanin V.I., Kovaliova V.I. аnd Alekseev S.V. Dolgovechnost metalla v usloviyah polzuchesti [Creep durability] : monograph. Мoscow : Metallurgy Publ., 1998, 224 р. (in Russian).
Lanskaia K.A. Zharoprochnost stali [Heat resistance steel: monograph]. Мoscow : Metallurgy Publ., 1969, 247 р. (in Russian).
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