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.

Influence of Residual Stresses on the Weld Metal Hardness of 5V Titanium Alloy

2021 ◽  
Vol 410 ◽  
pp. 359-365
Author(s):  
Egor V. Terentyev ◽  
Artem Yu. Marchenkov ◽  
Ksenia T. Borodavkina
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Residual Stresses ◽  
Weld Metal ◽  
Welded Joints ◽  
Arc Welding ◽  
Electron Beam Welding ◽  
The Difference ◽  
Metal Hardness ◽  
Hardness Values

Influence of residual welding stresses on the hardness values of the weld metal is studied. The investigations were carried out on 5V titanium alloy welded joints, obtained by electron-beam welding and argon-arc welding (TIG-welding). It is shown that the nature of the residual stresses distribution depends on the parameters of welding and affects the hardness values of the weld metal. It is shown, that the difference between the hardness values of the metal after welding and the metal after partial relief of residual stresses on the investigated alloy is up to 90 MPa, which is about 3% of the weld metal hardness level.

Microstructural Characterization and Tensile Behavior of TA1 Titanium Alloy Sheet Welded by Electron Beam Welding

2021 ◽  
Vol 1027 ◽  
pp. 149-154
Author(s):  
Sen Dong Gu ◽  
Ji Peng Zhao ◽  
Rui Jie Ouyang ◽  
Yong Hong Zhang
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Fusion Zone ◽  
Heat Affected Zone ◽  
Electron Beam Welding ◽  
Base Material ◽  
Optical Microscope ◽  
Alloy Sheet ◽  
Tensile Behavior ◽  
Electron Backscattered Diffraction

In the present study, TA1 titanium alloy sheets with a thickness of 0.8mm were welded by electron beam welding. Microstructure of the welded region was investigated using optical microscope and electron backscattered diffraction. Then, the tensile test was conducted to analyse the tensile behavior of the welded sheets as well as the fractography of the fracture surfaces. It is shown that the mean grain size in the heat-affected zone is smaller than that in the fusion zone and base material. The strength of the base metal is lower than that of the fusion zone and heat-affected zone. The average values of the yield strength, tensile strength and elongation of the tensile specimens are 224MPa, 335MPa and 35%, respectively. In addition, the tensile specimens of the welded sheets suffer both ductile and brittle deformation during the tensile tests.

Investigation on the microstructure and mechanical properties of Ti6Al4V titanium alloy electron beam welding joint

2022 ◽  
pp. 095440622110329
Author(s):  
Xilong Zhao ◽  
Xinhong Lu ◽  
Kun Wang ◽  
Feng He
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Electron Beam ◽  
Penetration Depth ◽  
Welding Speed ◽  
Welded Joints ◽  
Electron Beam Welding ◽  
Martensite Phase ◽  
Ti6al4v Titanium Alloy ◽  
Microstructure And Mechanical Properties

Electron beam welding (EBW) is a fusion joining process particularly suitable for welding titanium plates. In the present work, 2.5 mm thickness Ti6Al4V titanium alloy plates were butt-welded together with backing plates by EBW. The detailed procedures of experiments were used to investigate the microstructure and mechanical properties of welded joints. The optimum welding speed was determined by microstructure examinations, microhardness tests, X-Ray diffraction tests, shear punch tests (SPT) and stress simulation calculations. The results showed that all microstructure of welded metal (WM) was martensite phase under the different welding speeds. In the heat-affected zone (HAZ), the martensite phase gradually evolved to be small and equiaxed. It can be seen that the microstructure of each region in welded joints did not change significantly. When the welding speed is between 8 mm/s and 14 mm/s, it can be seen from the macroscopic appearance of the joints that there was no utterly fused penetration between the butt plate and substrate. Finite element simulation was carried out for the no-penetration depth under different welding conditions, and it was found that the stress suffered by the small no-penetration depth was the smallest. Using different welding parameters shows that the engineering stress in WM was higher than other areas, and BM was the lowest. As welding speed increases from 8 mm/s to 14 mm/s, the variation of microhardness distribution was not evident.

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.

scholarly journals Application of Dynamic Beam Positioning for Creating Specified Structures and Properties of Welded Joints in Electron-Beam Welding

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2233
Author(s):  
Tatyana Olshanskaya ◽  
Vladimir Belenkiy ◽  
Elena Fedoseeva ◽  
Elena Koleva ◽  
Dmitriy Trushnikov
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Weld Metal ◽  
Thermal Effect ◽  
Welded Joints ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Parent Metal ◽  
Cooling Rates ◽  
Structures And Properties

The application of electron beam sweep makes it possible to carry out multifocal and multi-beam welding, as well as combine the welding process with local heating or subsequent heat treatment, which is important when preparing products from thermally-hardened materials. This paper presents a method of electron beam welding (EBW) with dynamic beam positioning and its experimental-calculation results regarding the formation of structures and properties of heat-resistant steel welded joints (grade of steel 20Cr3MoWV). The application of electron beam oscillations in welding makes it possible to change the shape and dimensions of welding pool. It also affects the crystallization and formation of a primary structure. It has been established that EBW with dynamic beam positioning increases the weld metal residence time and the thermal effect zone above the critical A3 point, increases cooling time and considerably reduces instantaneous cooling rates as compared to welding without beam sweep. Also, the difference between cooling rates in the depth of a welded joint considerably reduces the degree of structural non-uniformity. A bainitic–martensitic structure is formed in the weld metal and the thermal effect zone throughout the whole depth of fusion. As a result of this structure, the level of mechanical properties of a welded joint produced from EBW with dynamic electron beam positioning approaches that of parent metal to a greater extent than in the case of welding by a static beam. As a consequence, welding of heat-resistant steels reduces the degree of non-uniformity of mechanical properties in the depth of welded joints, as well as decreases the level of hardening of a welded joint in relation to parent metal.

Stress State Simulation and Durability Evaluation of a Spot-Welded Joint in Case of Random Vibration

2017 ◽  
Vol 269 ◽  
pp. 51-59
Author(s):  
Aleksandr S. Sidorenko ◽  
Artem G. Rybaulin ◽  
Lev N. Rabinskiy ◽  
Elena L. Kuznetsova
Keyword(s):  
Stress State ◽  
Welded Joints ◽  
Random Vibration ◽  
Welded Joint ◽  
Base Material ◽  
Computational Studies ◽  
Random Loading ◽  
Local Zone ◽  
Vibration Strength ◽  
Detailed Simulation

In this paper the authors present the methodology and results of computational studies of the stress state and the evaluation of the construction durability with multipoint welded joints in the event of random vibration. A special feature of the technique is a detailed simulation of the stress state in the most stressed connection junctions, taking into account the change in the properties of the base material during welding. The empirical equations between the microhardness and the material yield point in the local zone of the welded point are used for this. The developed technique for numerical simulation of the dynamic stressed state of a construction with a point-welded joints can be used to assess the vibration strength of such constructions under conditions of random loading.

scholarly journals Effect of Laser Peening with a Microchip Laser on Fatigue Life in Butt-Welded High-Strength Steel

2021 ◽  
Vol 2 (4) ◽  
pp. 878-890
Author(s):  
Tomoharu Kato ◽  
Yoshihiro Sakino ◽  
Yuji Sano
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
High Strength Steel ◽  
Welded Joint ◽  
Base Material ◽  
High Strength ◽  
Microchip Laser ◽  
Laser Peening ◽  
Near Surface ◽  
Compressive Residual Stresses

Laser peening introduces compressive residual stresses on the surfaces of various materials and is effective in enhancing fatigue strength. Using a small microchip laser, with energies of 5, 10, and 15 mJ, the authors applied laser peening to the base material of an HT780 high-strength steel, and confirmed compressive residual stresses in the near-surface layer. Laser peening with a pulse energy of 15 mJ was then applied to fatigue samples of an HT780 butt-welded joint. It was confirmed that laser peening with the microchip laser prolonged the fatigue life of the welded joint samples to the same level as in previous studies with a conventional laser.

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