Experimental and Numerical Evaluation of Fracture Toughness on Electron Beam Welded Joint in Al6061-T6

2016 ◽  
Author(s):  
W. Rekik ◽  
O. Ancelet ◽  
C. Gardin ◽  
F. Hamon
Keyword(s):  
Electron Beam ◽  
Mechanical Behavior ◽  
Yield Stress ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Material Behavior ◽  
Failure Assessment ◽  
Tearing Resistance ◽  
Alloy 6061

In order to ensure the integrity of structures, failure assessment is required. In this context, the fracture behavior of an electron beam (EB) welded joint on thick plate of aluminum alloy 6061-T6 used for structural components of experimental nuclear reactors was investigated. In the particular case of welded structures, the tearing resistance is strongly dependent on the mismatch of the welded joint and the local behavior of each metallurgical zone. For a reliable analysis, the tensile mechanical behavior of each position of the welded joint was precisely determined by the use of a new measurement prototype. The toughness behavior under different configurations was then evaluated on CT specimens. From these experimental results a mechanical behavior contrast was highlighted. In fact, the fusion zone presents the lowest yield stress and a gradient is observed in the heat affected zone until the material behavior reaches of the base metal yield stress. On the contrary, the toughness of the welded zone is the highest and decreases strongly in the heat affected zone according to an exponential function until the base metal toughness is reached.

scholarly journals MODELING THE WORK OF THE HEAD OF A HYDROMECHANICAL EXPANDER FOR WELDED PIPES OF A LARGE DIAMETER

2020 ◽  
pp. 35-42
Author(s):  
L. M. Gurevich ◽  
V. F. Danenko ◽  
A. A. Istrati ◽  
V. A. Sonnova
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Internal Pressure ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Large Diameter ◽  
Design Parameters ◽  
Maximum Stresses ◽  
Distribution Of Stresses

Finite element simulates of changing stresses and strains under loading by gradually increasing internal pressure of cylindrical welded vessels was carried out. The vessels had an annular mechanically inhomogeneous welded joint with different mechanical properties of the joint, heat-affected zone, and base metal. Maximum stresses developed in the caps of the vessels, and the annular joint are lightly loaded. The distribution of stresses and strains in joint at various design parameters of the vessels is investigated.

Forming Process during Electron Beam Surfi-SculptTM on Ti-6Al-4V Alloy

2019 ◽  
Vol 813 ◽  
pp. 25-30
Author(s):  
Kai Li ◽  
Peng Fei Fu ◽  
Zhen Yun Tang ◽  
Bo Zhang ◽  
Yan Long Ma ◽  
...  
Keyword(s):  
Electron Beam ◽  
Fusion Zone ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Surface Region ◽  
Martensite Phase ◽  
Treatment Technique ◽  
Layer By Layer ◽  
Forming Process ◽  
Near Surface

Electron beam Surfi-SculptTM is a novel surface treatment technique applied to produce high level performance Composite-Metal-Weld (ComeldTM) joints. Investigation on forming process during electron beam Surfi-SculptTM on Ti-6Al-4V alloy showed protrusions were formed via a layer-by-layer mode like additive manufacturing process. The near-surface region of electron beam Surfi-Sculpted Ti-6Al-4V alloy was occupied by fusion zone, heat-affected zone and base metal from the outermost surface to the underlying bulk alloy. The microstructure of fusion zone was characterized by a high density of fine acicular martensite phase, leading to a higher micro-hardness. A heat-affected zone was sandwiched between fusion zone and the underlying base metal, with different microstructural features compared to both fusion zone and the base metal.

Microstructural and mechanical characterization of the effect of the welding process on creep behavior of welded joint and base metal specimens of Inconel 600

MRS Advances ◽  
2020 ◽  
Vol 5 (59-60) ◽  
pp. 3003-3014
Author(s):  
Lourdes Y. Herrera-Chávez ◽  
Alberto Ruiz ◽  
Víctor H. López-Morelos ◽  
Carlos Rubio-González ◽  
Martín R. Barajas-Álvarez ◽  
...  
Keyword(s):  
Base Metal ◽  
Creep Behavior ◽  
Heat Affected Zone ◽  
Structural Integrity ◽  
Welded Joint ◽  
Welding Process ◽  
Creep Tests ◽  
Inconel 600 ◽  
Two Temperatures

AbstractIn this study, plates of Inconel 600 superalloy were gas metal arc welded to investigate the effects of the welding process on the creep behavior of the welded samples and compare it to the creep behavior of samples in the as-received condition. Creep tests were performed at two temperatures (600 and 650 °C) with different stress levels. During the welding process, three distinctive microstructural zones are generated, i.e. welded material, heat affected zone, and base metal that may affect the properties of the welded joint. Microstructural, elemental analysis of samples was conducted using Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The experimental results show that creep rupture preferentially occurs in the heat-affected zone of the base metal at 4 mm from the fusion line and that the creep behavior of welded samples is different from that of the base metal. These results can be used in the design of structural components to assure their structural integrity.

Region-Specified Ratcheting Behavior of API X80 Welded Joint Under Uniaxial Cyclic Loading

2016 ◽  
Author(s):  
Hongsheng Lu ◽  
Yonghe Yang ◽  
Gang Chen ◽  
Xu Chen ◽  
Xin Wang
Keyword(s):  
Weld Metal ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Pipeline Steel ◽  
Coarse Grained ◽  
Strain Accumulation ◽  
Lower Strength ◽  
Fine Grained ◽  
Ratcheting Strain

Evaluation of mechanical performance of different regions can be difficult by using standard size samples due to the size limitation of weld metal and heat-affected zone (HAZ). At first, the microstructure of different regions was characterized and quantified by Scanning Electron Microscope, which indicate that the pipeline steel is a typical acicular ferrite steel. In this study the deformation behavior of different regions (base metal, weld metal and heat affected zone) in a welded joint of API X80 pipeline steel were studied by conducting uniaxial loading tests on miniature specimens with the cross section of 2×0.5mm and gauge length of 9mm. From the results of uniaxial tension in base metal and weld metal it is shown that the welding is overmatching. Compared to the base metal, the coarse grained HAZ exhibits a lower strength, while the fine grained HAZ exhibits a higher strength. Under near zero-to-tension cyclic stress loading, all regions of the welded joints exhibit progressive accumulation of plastic strain. Under the same stress level, the base metal shows the fastest ratcheting strain accumulation, which is the result of lower strength than other regions. This fact may indicate that the ratcheting behavior of the overall welded joint is highly dependence on that of base metal for the present case. But when under the same normalized stress level (σ = σ/σYS), the fine grained HAZ has the highest ratcheting strain accumulation, while the coarse grained HAZ has the lowest ratcheting strain accumulation, which reveals that the intrinsic resistance to ratcheting is yield strength dependent.

Research on Microstructure and Properties of Welded Joint of 2205 Steel with FCAW

2011 ◽  
Vol 391-392 ◽  
pp. 763-767
Author(s):  
Li Yang ◽  
Na Zhang
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
High Strength ◽  
Two Phase ◽  
Flux Cored Arc Welding ◽  
Mechanical Properties And Corrosion

On the basis of the analysis of composition, microstructure, properties and weldability of 2205 duplex stainless steel, the flux cored arc welding (FCAW) process is made. Then the microstructure, mechanical properties and corrosion resistance of welded joint were analyzed. The results shows using FCAW process, in order to obtain high strength, perfect impact toughness and overall and partial resistance to stress corrosion in welded joint, the Ni content of duplex stainless steel welding material should be 2% to 4% higher than that of base metal, multi-layer and multi-channel welding is adopted with the strict control of energy input less than or equal to 0.926KJ/mm, layer temperature is less than 120 °C, thus the appropriate proportion of two-phase structure in the welded joint can be got. Using a reasonable welding procedure, the microstructure in weld beam is austenite (A) + ferrite (F), and in heat affected zone is ferrite (F) + austenite (A) + a small amount of third phase, the content of austenite in weld beam and heat affected zone is higher than that of the base metal. Tensile strength of the welded joint is up to 854.5MPa and the fracture occurs in the base metal and the heat affected zone. The welded joint has high strength, good plasticity, toughness and corrosion resistance.

scholarly journals Influence of Welded Pores on Very Long-Life Fatigue Failure of the Electron Beam Welding Joint of TC17 Titanium Alloy

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1825 ◽  
Author(s):  
Fulin Liu ◽  
Hong Zhang ◽  
Hanqing Liu ◽  
Yao Chen ◽  
Khan Muhammad Kashif ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Fatigue Life ◽  
Base Metal ◽  
Fatigue Failure ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Fatigue Cracks ◽  
Failure Behavior ◽  
Long Life

The electron beam welding process is widely used in the connection among titanium alloy material parts of aero-engines. Its mechanical properties need to meet the requirements of long life and high reliability. In this paper, the static strength and the fatigue failure behavior of the electron beam weldments of TC17 titanium alloy were investigated experimentally under low amplitude high frequency (20 kHz), and the mechanical response and failure mechanism under different external loading conditions were analyzed. In summary, the samples were found to have anisotropic microstructure. The tensile strength of the PWHT of TC17 EBW joint was ~4.5% lower than that of the base metal. Meanwhile, compared with the base metal, the fatigue strength was reduced by 45.5% at 109 cycles of fatigue life. The fracture analysis showed that the fatigue failure of the welded joint of TC17 alloy was caused by the welded pores and the fatigue cracks initiated from the welded pores. A fine granular area (FGA) was observed around the crack initiation region. The existence of pores caused the stress intensity factor of the fine granular area (KFGA) to be inversely proportional to the fatigue life. The KFGA calculation formula was modified and the fatigue crack propagation threshold of the welded joint of TC17 alloy was calculated (3.62 MPa·m1/2). Moreover, the influences of the effective size and the relative depth of the pores on the very long fatigue life of the electron beam welded joint of TC17 titanium alloy were discussed.

Quantification of Creep Cavitation in Welded Joint and Evaluation of Material Characteristics of Simulated Heat-Affected Zone in X 20 CrMoV 12 1 Steel

2000 ◽  
Vol 123 (1) ◽  
pp. 112-117 ◽  
Author(s):  
Yong-Keun Chung ◽  
Cheol-Hong Joo ◽  
Jong-Jin Park ◽  
Ik-Man Park ◽  
Hyo-Jin Kim
Keyword(s):  
Base Metal ◽  
Heat Affected Zone ◽  
Power Plants ◽  
Welded Joint ◽  
Charpy Impact ◽  
Creep Damage ◽  
Average Diameter ◽  
Damage Mechanism ◽  
Creep Rupture ◽  
Creep Cavitation

X 20 CrMoV 12 1(DIN 17 175) steel has been used for components subjected to high temperature in power plants and chemical and petroleum industries. Therefore, extensive studies have been made on this steel. However, these studies focused mainly on the base metal, and few studies on the welded joint have been reported. Actually, a large number of failures have occurred at the welded joint, so there is increasing need to investigate the characteristics of X 20 CrMoV 12 1 weldment. In this study, the interrupted and creep rupture tests were carried out and quantification of the creep damage was attempted for the X 20 CrMoV 12 1 welded joint. The interrupted and creep rupture tests were performed at four conditions\M650-60, 600-100, 600-120, and 575-150(|SDC-MPa)\Mon the X 20 CrMoV 12 1 welded joint specimens, respectively. It was revealed from the experimental results that creep damage mechanism of a welded joint was mainly creep cavitation, and that the intensively damaged area by creep cavitations was the transition region from fine-grained heat-affected zone (HAZ) to unaffected base metal, namely intercritical HAZ. For both the interrupted and ruptured specimens, quantification of creep damage was attempted by evaluating cavitated area fraction, average diameter, and the number of cavities with creep life fraction. In addition, on the basis of the heat input during the welding, microstructure, microhardness, and grain size of the actual intercritical HAZ, simulated HAZ was made in order to evaluate its material properties. For the simulated HAZ specimens, tensile, charpy impact, and creep rupture tests were carried out. As a result, yield, tensile strength, and elongation of simulated HAZ were similar to those of base metal, respectively, and impact property of simulated HAZ was slightly above base metal. Also, it was found that creep strength of simulated HAZ was inferior to that of the base metal.

Identification of the Gradient of Mechanical Properties in Electron Beam Welded Joints of Thick Al6061-T6 Plate

2016 ◽  
Author(s):  
W. Rekik ◽  
O. Ancelet ◽  
C. Gardin
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Tensile Test ◽  
Weld Joint ◽  
Heat Affected Zone ◽  
Welded Joint ◽  
Tensile Tests ◽  
Tensile Specimen ◽  
Experimental Methodology

In this paper, the mechanical behavior of the different metallurgical zones of the Electron Beam welded joint of thick Aluminum alloy 6061-T6 plates was identified by means of a single tensile test on round specimen oriented transversely to the fusion line. Commonly, the analysis of tensile tests allows a global characterization of the weld joint behavior. However, in this work, specific post processing of results was developed in order to determine in addition to standard findings, the local behavior on each position of the weld joint. The identified behavior laws are then simplified using the Hollomon analytical model. Hence, an evolution of the Hollomon parameters (n, K) along the weld joint is proposed. To validate the experimental methodology and the analytical approach, the experimental tensile test on crossed tensile specimen was numerically modeled. Experimental results and numerical simulations were in a good agreement which denotes of the reliability of the identified gradient model. In a second step, for more accurate characterization of the electron beam welded joint, an optimized geometry of tensile specimen was numerically dimensioned and tested. From these analyses, a relatively large heat affected zone with significant gradients of mechanical properties was highlighted. The fusion zone was qualified as the softest metallurgical zone but with a high strain hardening effect in contrary with the heat affected zone where the fracture occurs.

Electron Beam Welding of Ti-24Al-17Nb-0.5Mo Alloy

2005 ◽  
Vol 475-479 ◽  
pp. 821-824
Author(s):  
J.Y. Zou ◽  
Yu You Cui ◽  
Rui Yang
Keyword(s):  
Electron Beam ◽  
Base Metal ◽  
Room Temperature ◽  
Electron Beam Welding ◽  
Welded Joint ◽  
Weld Zone ◽  
Welding Parameters ◽  
Eb Welding ◽  
Phase Combination ◽  
Postweld Heat

Electron beam (EB) welding of Ti-24Al-17Nb-0.5Mo (at.%) alloy and the effects of postweld heat treatments (PWHT) were studied. Through optimizing the welding parameters, defect-free welding joint was obtained. For the as-welded joint, the fusion zone (FZ) consisted of predominant β and occasional α2 within β grains. Microhardness of FZ was higher than that of the base metal (BM) and that of the heat affected zone (HAZ) was between that of BM and FZ. PWHTs greatly modified the microstructures and mechanical properties of the weld zone. PWHTs at both 820oC and 900oC yielded fine acicular laths in FZ leading to severe brittleness of the weld. Appropriate microstructures and phase combination were obtained by PWHT at 1000oC for 2 h, and room-temperature tensile strength reached the value of the base metal after the same thermal cycle.

Study of wear resistance of railway rails welded joint

2020 ◽  
Vol 76 (8) ◽  
pp. 818-825
Author(s):  
N. A. Kozyrev ◽  
R. A. Shevchenko ◽  
A. A. Usol'tsev ◽  
R. E. Kryukov ◽  
A. R. Mikhno
Keyword(s):  
Wear Resistance ◽  
Thermal Treatment ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Welded Joint ◽  
Welding Method ◽  
Welded Seam ◽  
Short Time ◽  
Metal Hardness

Welding joints of rails are a weak point of a jointless railway line, which stipulates actuality of studies on increasing their operational resistance. Microstructures of welded joints made by existing at present welding technology and by a new one were compared. Existing (base) technology comprises further thermal treatment of the welded joint, while the new technology comprises welding followed by a short-time electric current impact during the rail joint cooling. To study the microstructures of welded joints, samples were cut out the welded seam zone and heat affected zone, as well as out of the base metal. The study was carried out in the depth of 5 mm from the surface, after thin section etching by 4% solution of nitric acid in alcohol. In the macro-structure of the metal of welded joint, made by the base technology, an uneven heat affected zone was detected. The zone had the following dimensions: 51 mm – in the head, from 45 mm to 62 mm – in the neck and 64 mm – in the bottom (by each of the seal side). In the longitudinal mac- ro-template of sample Б (the new welding method), the heat affected zone was even and along the whole joint had the width of 22 mm (in each of the joint side). It was shown, that the new welding method of railway rails enables to decrease the extension of zone with sorbitic and granular pearlite at various stage of coagulation. A short-time impact of electric current during rail joint cooling ensures obtaining a zone with a decreased hardness of 15 mm extension and decrease of welded seam metal hardness relatively the lower border of base metal hardness by less than 15%. Application an additional local thermal treatment by a separate induction heating during base technology results in forming zones of 30 mm extension in the area of welded joint, which wear resistance is 4.5 times lower comparing with wear resistance of the rail base metal. At the new welding method application, the extension of the abovementioned zone does not exceed 10 mm and wear resistance was decreased by less than 2 times.

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