Formation of welded joints of magnesium alloys in pulse multipass electron beam welding

Electron beam welding process of AZ61 with 10mm thickness magnesium alloys was investigated. The influence of processing parameters including focusing current, welding beam current and welding speed was researched. The results show that an ideal weld bead can be formed by choosing processing parameters properly. Focusing current is main parameter that determines cross section shape. The beam current and welding speed are main parameters that determine the weld width and dimensions. The test results for typical welds indicate that the microhardness of the weld zone is better than that of the base meta1. A fine-grained weld region has been observed and no obvious heat-affected zone is found. The fusion zone mainly consists of small α-Mg phase and β-Mg17A112. The small grains and β phases in the joint are believed to play an important role in the increase of the strength of weld for AZ61 magnesium alloys.

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Relational analysis between parameters and defects for electron beam welding of AZ-series magnesium alloys

Vacuum ◽

10.1016/j.vacuum.2007.12.019 ◽

2008 ◽

Vol 82 (11) ◽

pp. 1177-1182 ◽

Cited By ~ 19

Author(s):

Chao-Ting Chi ◽

Chuen-Guang Chao ◽

Tzeng-Feng Liu ◽

Che-Chung Wang

Keyword(s):

Electron Beam ◽

Magnesium Alloys ◽

Electron Beam Welding ◽

Relational Analysis

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

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/09544062211032988 ◽

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.

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Influence of Electron Beam Technological Movements on Aluminium Alloy AW2099 Welded Joints Properties

Materials Science Forum ◽

10.4028/www.scientific.net/msf.994.36 ◽

2020 ◽

Vol 994 ◽

pp. 36-43

Author(s):

Ján Urminský ◽

Milan Marônek ◽

Jozef Bárta ◽

Michaela Lopatková ◽

Róbert Hrušecký

Keyword(s):

Electron Beam ◽

Welded Joints ◽

Electron Beam Welding ◽

Welding Current ◽

Welding Parameters ◽

Porosity Formation ◽

Surface Appearance ◽

Current Focusing ◽

Acceleration Voltage ◽

Beam Oscillation

The electron beam welding (EBW) parameters have significant influence on weld surface appearance and porosity formation. Besides basic welding parameters, such as acceleration voltage, welding current, focusing current and welding speed, the beam oscillation during EBW plays an important role in weld metal formation and directly impacts the final welded joints properties. The influence of technological movements during EBW on the properties of aluminium-lithium alloy welded joints was studied. The same frequency and different amplitude as well as same amplitude and different frequency were chosen. The other welding parameters were constant.

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

Materials ◽

10.3390/ma13102233 ◽

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.

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A Study of the Influence of Electron Beam Welding Defects on Fracture Processes in Titanium Alloys

Proceedings of Higher Educational Institutions Маchine Building ◽

10.18698/0536-1044-2020-3-23-34 ◽

2020 ◽

pp. 23-34

Author(s):

V.V. Grigoriev ◽

V.I. Muravyev ◽

P.V. Bakhmatov

Keyword(s):

Electron Beam ◽

Titanium Alloys ◽

Welded Joints ◽

Pore Formation ◽

Electron Beam Welding ◽

Strength Properties ◽

Technical Documentation ◽

Welding Defects ◽

Static And Dynamic Loads

The appearance of pores when welding titanium has been extensively studied by domestic and foreign researchers, but there has been no consensus on the causes and conditions of pore formation to date. An overview of advances in the studies of pore formation showed that the problem of formation of the macropores, reaching 0.1 mm was investigated by A.A. Erokhin, V.V. Frolov, G.D. Nikiforov, S.M. Gurevich, V.N. Locks, V.I. Muravyev, B.I. Dolotov, P.V. Bakhmatov et al. The advent of modern x-ray machines in the technological control of permanent joints made by electron beam welding has enabled researchers to detect a specific defect — the so-called dark bands, which make it difficult to assess the quality of permanent connections due to the absence of this defect in the normative and technical documentation. Determining the causes of specific defects and their effect on the properties of titanium alloy structures made by electron beam welding is an important task. This paper presents the results of studies investigating the effect of specific defects of electron beam welding of titanium alloys VT20, VT23 on the nature of destruction under static and dynamic loads and changes in the mechanical properties of the welded joints. It is established that specific defects occurred during electron beam welding have a significant impact on the strength properties of welded joints, as well as on the stages of their destruction. It is determined that the presence of such welding defects as lack of penetration, residual stresses and pores in the fusion zone, expulsion without bonding, etc. contribute to the formation of sub-micropores that lead to brittle destruction of welded joints. The presence of specific defects in permanent joints made by electron beam welding leads to decreased strength properties and to nearly complete absence of such characteristics as elongation and contraction. It is established that heat treatment improves the quality of welded joints.

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