INVESTIGATION OF REASONS FOR A DECREASE IN THE IMPACT STRENGTH OF PIPELINE COMPONENTS MADE OF STEEL 10G2FBY
DOI:
https://doi.org/10.14529/met200304Keywords:
impact strength, pipeline components, pipe steel, transcrystalline fracture, intercrystalline rupture, cleavage facet, dimple ruptureAbstract
Testing of mechanical properties of products is one of the most important production stages because they, most objectively, allow determining whether products manufactured by a certain technological process meet the necessary requirements. Impact strength is the most important parameter in assessing the mechanical characteristics of tubular steel products, impact values at low temperatures are especially important. Brittle fracture is very dangerous, since it proceeds at a high speed and with a load much less than with viscous fracture.
This characteristic depends on many factors, including: the number, size and nature of the distribution of non-metallic inclusions, grain size, the presence of reinforcing particles, the uniformity of their distribution, and much more. Impact strength is strictly controlled during testing of pipeline components operating at elevated pressures and freezing temperatures; transition to brittle fracture can provoke disruption of the entire pipeline.
The task of determining the causes of a local decrease in impact strength remains relevant due to the many individual factors acting on it, or even a complex of factors. Due to the fact that the probability of a defect contributing to brittle fracture, because of the relatively small crosssectional area of impact samples, is not high, it is necessary to test several samples from the same area of the product to average the results.
The aim of this work was to determine the causes of reduced viscosity when testing pipeline components made of 10G2FBY steel by comparing fractures and sample structures with reduced and required impact strengths.
References
GOST 19281–2014. Prokat povyshennoy prochnosti [State Standard 19281–2014. High strength rolled metal]. Moscow, Standartinform Publ., 2016. 50 p.
Malinov L.S. [Ways to improve the properties of 10G2FB steel, ensuring its use for a new purpose and energy saving]. Novi materialy i tekhnolohiyi v metalurhiyi ta mashynobuduvanni, 2017, no. 2, pp. 71–75. (in Russ.)
Gol’dshteyn M.I., Grachev S.V., Veksler Yu.G. Spetsial'nye stali [Special steels]. Moscow, MISiS Publ., 1999. 408 p.
GOST 9454–78. Metally. Metod ispytaniya na udarnyy izgib pri ponizhennykh, komnatnoy i povyshennykh temperaturakh [State Standard 9454–78. Metals. Impact bending test method at low, room and elevated temperatures]. Izdatel'stvo standartov Publ., 1994. 12 p.
Beckert M., Klemm H. Handbuch der metallographichen Atzverfahren, 1988. 400 p. (Russ. ed.: Beckert M., Klemm H. Sposoby metallograficheskogo travleniya [Methods of metallographic etching]; Spravochnoe izdanie. 2nd ed., revised and updated. translation from German. Moscow, Metallurgiya Publ., 1988. 400 p.
Khil'chevskiy V.V. Nadezhnost' truboprovodnoy pnevmogidroarmatury [Reliability of pipeline pneumohydro valves]. Moscow, Mashinostroenie Publ., 1989. 208 p.
Zaynullin R.S. Sertifikatsiya neftegazokhimicheskogo oborudovaniya po parametram ispytaniy [Certification of petrochemical equipment according to test parameters]. Morozova E.M. (Ed.). Moscow, Nedra Publ., 1998. 446 p.
Gerasimova L.P. Izlomy konstruktsionnykh staley: spravochnik [Structural Steel Breaks: A Guide]. Moscow, Metallurgiya Publ., 1987. 272 p.
Zorin E.E., Lanchakov G.A., Stepanenko A.I., Shibnev A.V. Rabotosposobnost’ truboprovodov. V 3 ch. Ch. 1: Raschetnaya i ekspluatatsionnaya nadezhnost’ [Pipeline operability. Design and operational reliability]. Moscow, Nedra Publ., 2000. 244 p.
Goritskiy V.M. Diagnostika metallov [Diagnostics of metals]. Moscow, Metallurgizdat Publ., 2004. 408 p.
Gulyaev A. P. Metallovedenie: uchebnik dlya vuzov [Metallurgy. Textbook for high schools]. Moscow, Metallurgiya Publ., 1986. 544 p.
Engel' L. Rastrovaya elektronnaya mikroskopiya. Razrushenie: spravochnik [Scanning electron microscopy. Destruction: A Guide]. Moscow, Metallurgiya Publ., 1986. 232 p.
GOST 1778–70. Stal'. Metallograficheskie metody opredeleniya nemetallicheskie vklyucheniy [State Standard 1778–70. Steel. Metallographic methods for the determination of nonmetallic inclusions]. Moscow, Standartinform Publ., 2011. 25 p.
Salikhov T.Sh. Faktory neodnorodnosti kachestva listovykh staley i metody ikh otsenki. Dokt. diss. [Factors of heterogeneity in the quality of sheet steels and methods for their assessment. Dokt. Diss.]. Moscow, 2009. 121 p.
Goritskiy V.M. Ustalost' i vyazkost' razrusheniya metallov [Fatigue and fracture toughness of metals]. Moscow, Nauka Publ., 1974, pp. 148–161.
