Influence of residual stresses on resistance to brittle fracture in weldment zones

Результат исследований: Материалы для журналаСтатья

Аннотация

The relevance of the research in the field of welded joints strength and failure is associated with the necessity of ensuring high opera tional reliability and safety running hazardous production facilities. Internal stresses and their relaxation as an independent cause of des truction are widely recognized nowadays. The final form of the maximum permissible state is cracks appearance, however the signs of the appeared maximum permissible state of the node or structure are not clearly defined. The aim of the research is to establish the signs of weld zone prefracture and fracture under redistribution conditions of internal stres ses during thermal relaxation. The subject of the research is welded superheater units made of dissimilar steels. Research methods: physical modeling of operating conditions by thermal cycling of samples in the MIMP10UE electric furnace, Xray dosimetry of the samples, internal structural stresses evaluation on DRON type Xray diffractometers, morphological analysis using the «Resource S7» metallographic analyzer, including an inverted Olympus GF41 microscope with the SIAMS Photolab software, cracks morphology with a PEN SCKOPE microanalyzer, microhardness analysis using a PMT3 microhardness tester. Results. According to the hypothesis of crack formation correlation with internal stress relaxation, crack appearance and growth and stress relaxation are interrelated processes. As a result of thermal fluctuation relaxation, the same qualitative regularities (which lead to destruction) for a singlephase and twophase system are found. Natural aging processes occurring in the sample with an initial crack in the absence of external loads and deformations are controlled only by internal stresses that activate all mechanisms of destruction, inc luding phase decay. Under the conditions of internal stresses thermofluctuation relaxation, the temperature limit of the stress state re gion is set, which determines the reliable operating temperature.

Язык оригиналаАнглийский
Страницы (с-по)128-142
Число страниц15
ЖурналBulletin of the Tomsk Polytechnic University, Geo Assets Engineering
Том329
Номер выпуска10
СостояниеОпубликовано - 1 янв 2018

ASJC Scopus subject areas

  • Materials Science (miscellaneous)
  • Fuel Technology
  • Geotechnical Engineering and Engineering Geology
  • Waste Management and Disposal
  • Economic Geology
  • Management, Monitoring, Policy and Law

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