scholarly journals Influence of the welding parameters on the weld metal mechanical heterogeneity of EP517 (Fe12Cr2NiMoWVNb) steel and 36NKhTYu (Fe36Ni12Cr3TiAl) alloy dissimilar welded joints

2021 ◽  
Vol 2077 (1) ◽  
pp. 012001
Author(s):  
K T Borodavkina ◽  
E V Terentyev ◽  
A P Sliva ◽  
A Yu Marchenkov ◽  
I E Zhmurko ◽  
...  

Abstract The article presents the results of assessing the effect of the welding speed and the displacement of the electron beam relative to the joint on the mechanical heterogeneity of the weld metal of dissimilar welded joints of EP517 (Fe12Cr2NiMoWVNb) steel and 36NKhTYu (Fe36Ni12Cr3TiAl) alloy. Aging curves are plotted for the weld metal of welded joints made at electron beam welding (EBW) speeds of 30 m/h and 120 m/h, as well as for the weld metal of the welded joint made at a speed of 30 m/h with various electron beam displacements. An assessment of the change in the mechanical heterogeneity of the weld metal was carried out by the change in the standard deviation of the hardness values, and metallographic studies were also carried out. It was found that a decrease in the EBW speed leads to a decrease in the standard deviation of the results of measuring the hardness of the weld metal after aging from 45 to 14 HV5 or from 18% to 6%. It was also found that an increase in the displacement of the electron beam to alloy 36NKhTYu (Fe36Ni12Cr3TiAl) to 60% leads to an increase in the hardness of the weld metal from 225 to 305 HV5 (by 35%).

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2233
Author(s):  
Tatyana Olshanskaya ◽  
Vladimir Belenkiy ◽  
Elena Fedoseeva ◽  
Elena Koleva ◽  
Dmitriy Trushnikov

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.


2021 ◽  
Vol 410 ◽  
pp. 359-365
Author(s):  
Egor V. Terentyev ◽  
Artem Yu. Marchenkov ◽  
Ksenia T. Borodavkina

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.


2020 ◽  
Vol 994 ◽  
pp. 36-43
Author(s):  
Ján Urminský ◽  
Milan Marônek ◽  
Jozef Bárta ◽  
Michaela Lopatková ◽  
Róbert Hrušecký

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.


2013 ◽  
Vol 753-755 ◽  
pp. 367-371
Author(s):  
Xin Liu ◽  
Zhi Yong Mao

Hydrogen distributions of TC4 electron beam welded joints with different hydrogen contents were measured by hydrogen oxygen analyzer. Microstructures of electron beam welded joints for TC4 titanium alloy with different hydrogen contents were observed and analyzed by optical microscope and TEM. And the influence of hydrogen on microstructure of the joints was investigated. The results show that the hydrogen content of weld HAZ is higher than other zones in the electron beam welded joints, while the hydrogen content of fusion zone is lower than other zones in the electron beam welded joints. The microstructure of the weld metal is fine lamellar α + β phase after hydrogen charging. In the range of hydrogen contents discussed in this study (from 0 to 0.101 wt. %), with the increase of hydrogen content, there is little change in the appearance of the microstructure of the weld metal. There are stacking fault and dislocation in the microstructure of TC4 electron beam welded joints with different hydrogen contents after hydrogen charging. The presence of hydrogen can promote the formation of twins in electron beam welded joints. With the increase of hydrogen content, the number of twins is increased.


2011 ◽  
Vol 287-290 ◽  
pp. 2393-2396 ◽  
Author(s):  
Xin Liu ◽  
Zhi Yong Mao ◽  
Yong Ping Lei

Microstructures of electron beam welded joints for TA15 titanium alloy with different hydrogen contents were observed and analyzed by SEM and TEM. And the influence of hydrogen on microstructure of the joints was investigated. The results show that the microstructure of the weld metal is lamellar α+β phase after hydrogen charging. In the range of hydrogen contents discussed in this study (from 0 to 0.101 wt%), With the increase of hydrogen content, there is little change in the appearance of the microstructure of the weld metal. The presence of hydrogen can promote the growth of twins in electron beam welded joints. With the increase of hydrogen content, the number of twins is increased. When hydrogen content reaches to a certainty level, hydrides are found in TA15 electron beam welded joints.


Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 522 ◽  
Author(s):  
Petro Loboda ◽  
Constantine Zvorykin ◽  
Volodymyr Zvorykin ◽  
Eduard Vrzhyzhevskyi ◽  
Tatjana Taranova ◽  
...  

In this article, structural features of Ti-TiB and (α+β) Ti alloys in the initial state, in the weld and in the heat-affected zone of electron beam welds were investigated. The influences of welding parameters, such as influence of the electron beam velocity, preheating of the welded alloys and the subsequent annealing of the welded joint on the its microstructure, and the mechanical strength and ductility of the critical elements of the joint were studied by scanning electron microscopy using microprobe Auger spectral and X-ray diffraction analysis and tensile tests. It has been shown that the conditions for rapid crystallization of the material from the melt of the weld contribute to refining of reinforcing fibers of TiB and its hardening in comparison with the starting material Ti-TiB. Besides that, influences of the preferential orientation of TiB reinforcing microfibers (along and across the welded butt joint) on the mechanical properties of the welded joint were investigated bz tensile testing. Using the methods of fractographic analysis, the effect of the boron-containing phase on the fracture character of Ti-TiB welded joints was established. It was shown that, along with the strengthening effect, TiB fibers cause embrittlement of the material.


2005 ◽  
Vol 475-479 ◽  
pp. 821-824
Author(s):  
J.Y. Zou ◽  
Yu You Cui ◽  
Rui Yang

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.


2011 ◽  
Vol 287-290 ◽  
pp. 2181-2184
Author(s):  
Bing Wu ◽  
Zhi Yong Mao ◽  
Jian Xun Zhang

Fatigue test of AF1410 steel and two thickness of electron beam have been done, and fatigue properties of the base metal and EB-welded joints have been studied. The results showed that fatigue limit of electron beam welded joints was close to that of base metal under this test conditions, and the welded thickness has little effect on S-N curves of electron beam welded samples under this test conditions. From SEM fracture morphology, it can be seen that fracture morphology of the welded samples was not obvious different form base metal. In the instant-off area of electron beam welded sample, there was dimple-like morphology showing good ductility.


2019 ◽  
Vol 269 ◽  
pp. 02010 ◽  
Author(s):  
Jozef Bárta ◽  
Beáta Simeková ◽  
Milan Marônek ◽  
Mária Dománková

The paper deals with the welding of AW 2099-T83 aluminium lithium alloy being used for construction of lower wing stringers. The thickness of AW 2099-T83 aluminium lithium alloy was 25.4 mm. Electron beam welding with the accelerating voltage of 55 kV was used for production of welded joints. Welded joints were inspected by computer tomography, macroscopic and microscopic analysis, tensile strength test and microhardness measurement. Welded joints exhibited good weld joint formation, typical to electron beam welding. Weld metal was structure was dendritic formed by α solid solution. Decrease of microhardness was observed mainly in the centre of weld metal due to dissolution of precipitates. The fracture occurred in the weld metal during tensile strength test. Further research will focus on post-heat treatment of welded joints in order to improve mechanical properties of weld metal.


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