scholarly journals Fracture Assessment of Cracked Welded Structures Considering the Heterogeneity of Welded Joints

2014 ◽  
Vol 3 ◽  
pp. 556-561 ◽  
Author(s):  
Egor Moskvichev
Keyword(s):  
Welded Joints ◽  
Welded Structures ◽  
Fracture Assessment

Fracture assessment of cold-press-formed square hollow sections at welded joints

2012 ◽  
pp. 773-777
Author(s):  
M Arita ◽  
Y Kayamori ◽  
Y Suzuki ◽  
K Hanya ◽  
T Suzuki ◽  
...  
Keyword(s):  
Welded Joints ◽  
Cold Press ◽  
Fracture Assessment

FEATURES OF REPAIR OF WELDED STRUCTURES OF LARGE THICKNESSES FROM TITANIUM ALLOY VT6ch.

2021 ◽  
pp. 34-43
Author(s):  
A.V. Sviridov ◽  
◽  
М.S. Gribkov ◽  
Keyword(s):  
Titanium Alloy ◽  
Residual Stresses ◽  
Elemental Composition ◽  
Welded Joints ◽  
Mechanical Characteristics ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Vacuum Annealing ◽  
Base Material ◽  
Welded Structures

The technology of electron-beam welding (EBW) of structures of large thickness made of titanium alloy Ti–6Al–4V has been developed. A complex of metallographic studies of welded samples has been carried out. Tests to determine the mechanical characteristics of repair welded joints, that these joints made by EBW are equal in strength to the base material. The analysis of the level of residual stresses in various parts of the welded joint after repeated repair passes has been carried out. It was found that the subsequent vacuum annealing reduces the level of residual stresses in welded joints to 50 %. The analysis of the elemental composition showed that the elemental composition of the samples from the center of the weld to the base metal practically does not change for welding with the number of repeated passes up to 3.

Investigation of Welded Joints Made of Construction Steel by the Barkhausen Noise Method

2020 ◽  
Vol 992 ◽  
pp. 957-963
Author(s):  
E. Nikolaeva ◽  
A. Nikolaev
Keyword(s):  
Stress State ◽  
Residual Stresses ◽  
Welded Joints ◽  
Arc Welding ◽  
Barkhausen Noise ◽  
Low Carbon ◽  
Butt Weld ◽  
Welded Structures ◽  
The Relationship ◽  
Weld Seams

Steel weld seams are characterized by heterogeneity of their microstructure. Microstructure affects the nature of the distribution, sign and magnitude of residual stresses. In combination with unfavorable factors (low temperature, metal hypoductility and an unsuccessful joint form) residual stresses lead to a decrease of load carrying capacity of a whole structure. In a weld seam residual stresses are distributed in a complex way and can affect the build quality of heavy section welded structures. Monitoring of residual stresses remains a big problem. Residual stresses in welds are often evaluated only by modeling. Unfortunately, all mathematical models describe the stress state of the welded material with low accuracy. Simple quality control, the results of which can be easy interpreted, is necessary. Welded joints made by manual arc welding and by automatic submerged arc welding were investigated. Butt seams of steel sheets of different thickness have been welded. Steel was low-carbon and low-alloyed. It is often used in welded structures for various purposes, including construction, and for pipelines manufacture. The temperature range of welded structures operation is very large – from-70 to 450С. The authors studied the structure of butt weld seams by the Barkhausen noise method, which is interesting as it represents an alternative to the known methods, which characterizes the structure and stress state of material. The relationship between the weld microstructure and magnetic noise is shown. Studies have allowed us to establish the relationship between the structure and magnetic properties and to evaluate the feasibility of applying the Barkhausen noise method to welded structures.

Fatigue Life of Multi-Spot Welded Structures

2007 ◽  
Vol 348-349 ◽  
pp. 249-252
Author(s):  
Pietro Salvini ◽  
Francesco Vivio ◽  
Vincenzo Vullo
Keyword(s):  
Fatigue Life ◽  
Numerical Solution ◽  
Welded Joints ◽  
Structural Model ◽  
Fatigue Behaviour ◽  
Progressive Damage ◽  
Welded Structures ◽  
Accumulated Damage ◽  
Fatigue Data ◽  
Spot Welded

A procedure that makes use of a conventional stress value (ERS) is applied to spot welded joints. The ERS can be evaluated for every spot weld of the structural model. Through the use of ERS-N curves, fatigue data performed on different joint geometries can be successfully mixed together. One of the main aspects is that progressive damage deeply influences fatigue behaviour, so that a simple numerical solution neglecting accumulated damage is unable to foresee the whole fatigue life. In the present paper the method has been applied to many experimental results: it is shown that a unique criterion is able to deal with several different structures and materials.

scholarly journals Evaluation of Crack Occurrence Probability of T-Shape Welded Structures

2011 ◽  
Vol 27 (2) ◽  
pp. 279-286
Author(s):  
Y. Hsu ◽  
W.-F. Wu ◽  
H.-T. Kuo
Keyword(s):  
Residual Stress ◽  
Chemical Composition ◽  
Hydrogen Content ◽  
Welded Joints ◽  
Occurrence Probability ◽  
Diffusible Hydrogen ◽  
Element Analysis ◽  
Welded Structures ◽  
Welded Structure ◽  
Major Factors

ABSTRACTWelded structures are vulnerable to fracture due to cracks, especially at the welds. To investigate the safety of T-Shape welded structures used in some construction sites, a method is proposed in this paper to evaluate the crack occurrence probabilities of the structures. Three major factors that affect the crack occurrence are taken into consideration. They are residual stress, diffusible hydrogen content and chemical composition of the weld metal. In the analysis, finite element analysis is performed to find the residual stress distribution of the structures. The uncertainties of diffusible hydrogen content and chemical composition are treated as random variables. The critical cooling time is found and utilized for evaluating the crack occurrence probability of the welded structure. Numerical results indicate that T-shape welded joints lead to higher residual stresses and higher crack occurrence probabilities in comparison with the traditional butt joints. Therefore, more attention should be paid to this kind of welded joints when they are used.

scholarly journals Bending Strength of Welded Joints in TMCP Steel Square Tubular Profiles “T” Connexions

2016 ◽  
Vol 5 (3) ◽  
pp. 70
Author(s):  
Rafael Luciano Dalcin ◽  
Ivan Guerra Machado ◽  
Arnaldo Ruben Gonzalez ◽  
Cintia Cristiane Petry Mazzaferro
Keyword(s):  
Tensile Strength ◽  
Welded Joints ◽  
Bending Strength ◽  
Mechanical Efficiency ◽  
Structural Steels ◽  
Detailed Data ◽  
Welded Structures ◽  
Longitudinal Joints ◽  
Longitudinal Welds ◽  
Loading Axis

The use of DOMEX 700 MCTM steel weldments is still little explored, due to some concern of the validity of the rules imposed by several standards and Codes for this class of steel. This material has low ductility and consequently the relation between tensile strength and yield strength is significantly lower than ordinary structural steels. For this reason, the instability phenomena are more critical than the instability phenomena of ordinary structural steels. Therefore, the aim of this study was to obtain detailed data on the mechanical efficiency of joints welded by GMAW. Six different heat inputs were used on square tubular profiles of TMCP steel. The tubular profiles were placed as a column/beam weldment with transverse and longitudinal welds positioned in relation to the loading axis. Twelve welded structures were instrumented with extensometer and tested in simple bending. Comparing the obtained data, it was verified that longitudinal welded joints presented higher bending strength than transversal welded joints. In the case of longitudinal joints, two weld beads were subjected to bending efforts, and in the case of transverse joints, only one weld bead resisted bending forces.

Quality control of steel for large-sized welded structures of Arctic shelf. Application of Russian and foreign requirements

2019 ◽  
pp. 136-153
Author(s):  
V. Yu. Filin
Keyword(s):  
Quality Control ◽  
Scale Development ◽  
Welded Joints ◽  
Low Temperatures ◽  
Large Scale ◽  
Arctic Shelf ◽  
Marine Structures ◽  
Welded Structures ◽  
International Projects ◽  
The Difference

Future large-scale development of Arctic inevitably requires marine structures both of Russian and foreign manufacturers and, correspondingly, applying of domestic and foreign steels. So, it is expedient to compare Russian and foreign systems of standard requirements for steel products and welded joints’ metal applied at low temperatures. The paper analyzes their theoretical and experimental grounding as it is extremely important because the difference in requirements serves an instrument to drive out Russian steel manufacturers from international projects.

scholarly journals Fracture Assessment of Weld Joints of High-Strength Steel in Pre-Strained Condition

2019 ◽  
Vol 9 (7) ◽  
pp. 1306
Author(s):  
Gyubaek An ◽  
Jeongung Park ◽  
Mituru Ohata ◽  
Fumiyoshi Minami
Keyword(s):  
Fracture Toughness ◽  
Welded Joints ◽  
Steel Structures ◽  
Great Earthquake ◽  
Small Scale ◽  
Ship Structures ◽  
Strained Condition ◽  
Critical Fracture ◽  
Fracture Assessment ◽  
Unstable Fractures

Unstable fractures tend to occur after ductile crack initiation or propagation. In most collapsed steel structures, a maximum 15% pre-strain was recorded, at the steel structural connections, during the great earthquake of 1995, in Japan. Almost-unstable fractures were observed in the beam-to-column connections, where geometrical discontinuities existed. Structural collapse and unstable failure occurred after large-scale plastic deformations. Ship structures can also suffer from unstable fractures in the welded joints. The fracture resistance of butt-welded joints subjected to tension in the pre-strained condition was estimated by considering the toughness deterioration, due to pre-strain and toughness correction for constraint loss in a tension specimen. The target specimen for this fracture assessment was a double-edged, through-thickness crack panel, with a crack in the weld joint (heat-affected zone (HAZ)). The critical fracture toughness value (crack tip opening displacement (CTOD)) of a large structure with pre-strain, which was applied to the HAZ region, was estimated from a small-scale, pre-stained, three-point bend specimen. Fracture toughness values, evaluated by a CTOD test, were recently mandated for shipbuilding steel plates. The critical fracture toughness value is a very useful parameter to evaluate the safety of huge ship structures.

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