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

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish
Pages (from-to)128-142
Number of pages15
JournalBulletin of the Tomsk Polytechnic University, Geo Assets Engineering
Volume329
Issue number10
Publication statusPublished - 1 Jan 2018

Fingerprint

brittle fracture
residual stress
Brittle fracture
Residual stresses
Stress relaxation
crack
Cracks
Microhardness
Welds
Superheaters
Electric furnaces
Steel
Diffractometers
Thermal cycling
Crack initiation
Dosimetry
Loads (forces)
Microscopes
Aging of materials
research method

Keywords

  • Crack formation.
  • Heat cycling
  • Internal stresses
  • Microhardness
  • Thermal relaxation
  • Weldaffected zone
  • Welding heataffected zone
  • Weldment

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

Cite this

@article{fa5cf0c877f54f729e90b10d5f13f931,
title = "Influence of residual stresses on resistance to brittle fracture in weldment zones",
abstract = "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.",
keywords = "Crack formation., Heat cycling, Internal stresses, Microhardness, Thermal relaxation, Weldaffected zone, Welding heataffected zone, Weldment",
author = "Zavorin, {Alexander S.} and Lyubimova, {Lyudmila L.} and Buvakov, {Konstantin V.} and Kulesh, {Aygul S.} and Tashlykov, {Alexander A.} and Kulesh, {Roman N.}",
year = "2018",
month = "1",
day = "1",
language = "English",
volume = "329",
pages = "128--142",
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TY - JOUR

T1 - Influence of residual stresses on resistance to brittle fracture in weldment zones

AU - Zavorin, Alexander S.

AU - Lyubimova, Lyudmila L.

AU - Buvakov, Konstantin V.

AU - Kulesh, Aygul S.

AU - Tashlykov, Alexander A.

AU - Kulesh, Roman N.

PY - 2018/1/1

Y1 - 2018/1/1

N2 - 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.

AB - 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.

KW - Crack formation.

KW - Heat cycling

KW - Internal stresses

KW - Microhardness

KW - Thermal relaxation

KW - Weldaffected zone

KW - Welding heataffected zone

KW - Weldment

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M3 - Article

VL - 329

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EP - 142

JO - Bulletin of the Tomsk Polytechnic University, Geo Assets Engineering

JF - Bulletin of the Tomsk Polytechnic University, Geo Assets Engineering

SN - 2500-1019

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