scholarly journals Effect of Tool Rotational Speed on the Microstructure and Mechanical Properties of Bobbin Tool Friction Stir Welded 6082-T6 Aluminum Alloy

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 894 ◽  
Author(s):  
Yupeng Li ◽  
Daqian Sun ◽  
Wenbiao Gong
Keyword(s):  
Aluminum Alloy ◽  
Cross Section ◽  
Heat Affected Zone ◽  
Rotational Speed ◽  
Maximum Temperature ◽  
Friction Stir ◽  
Fracture Location ◽  
Microhardness Distribution ◽  
Average Grain Size ◽  
The Cross

Samples of 6082-T6 aluminum alloy were welded by bobbin tool friction stir welding at different rotational speeds. The thermal cycles, microstructure, microhardness, and tensile properties of the specimens were investigated. The results show that the maximum temperature at the joint increases first and then decreases with increasing rotational speed, and the maximum temperature is 509 °C at 1000 r/min. The macromorphology of the cross-section of the joint is rectangular, and an ‘’S” line and gray-white texture can be observed. The stirred zone had much smaller equiaxed recrystallized grains. With increasing welding speed, the average grain size in the stirred zone region decreases. The microhardness distribution of the cross-section of all joints is W-shaped. When the rotational speed increases, the hardness of the heat-affected zone decreases gradually, and the hardness of the stirred zone increases. At 600 r/min, the strength is the lowest. The fracture location is between the stirred zone and the thermomechanically affected zone. When the rotational speed is increased, the fracture location is entirely located in the heat affected zone, and the fracture surface is dimple-like; the strength significantly increases and reaches a maximum at 800 r/min.

CHANGES IN THE MICROSTRUCTURE AND MICROHARDNESS OF 65G STEEL AFTER THERMAL HARDENING AND SURFACING WITH A LOW-CARBON ELECTRODE

2021 ◽  
Vol 1 (142) ◽  
pp. 107-114
Author(s):  
Aleksandr Mikhal’chenkov ◽  
◽  
Sergey Fes’kov ◽  
Irina Kozarez ◽  
Elena Slezko
Keyword(s):  
Wear Resistance ◽  
Fusion Zone ◽  
Cross Section ◽  
Surface Friction ◽  
Research Purpose ◽  
Low Carbon ◽  
Thermal Hardening ◽  
Microhardness Distribution ◽  
The Cross ◽  
Shock Zone

When reinforcing the surfaces of the working bodies of tillage tools, they are surfaced with electrodes with a low-carbon rod. The surface in contact with the soil is not subjected to heat treatment. Recently, thermal hardening of local parts has been used. (Research purpose) The research purpose is in studying the transformation of the microstructure of 65G heat-strengthened steel deposited by an electrode with a low-carbon rod, as well as the specifics of the microhardness distribution in this section. (Materials and methods) Investigated in the cross-section of the structure of the deposited area by the standard method, consisting in the preparation of microsections, etching and directly microanalysis. (Results and discussion) The transformation of the microstructure of heat-strengthened steel 65G deposited by an electrode with a low-carbon rod is complex due to the specificity and versatility of the phase transformations that occur during its formation. The microhardness distribution plot in the cross-section of the surfacing area has a complex configuration, determined by the variety of structural components, the presence of deformation processes during crystallization and solidification, and the presence of preliminary thermal hardening of the base metal. (Conclusions) Increased values of the hardness of individual areas contribute to an increase in the abrasive wear resistance of the part. The presence of the fusion zone ensures the resistance of the deposited area to cracking. The zone of thermal influence has four clearly distinguishable areas: the drop in microhardness; the stable values according to the Vickers method; the near-shock zone; the fusion zone. The microhardness of the weld surface of the cushion is 410 Vickers or 42 Rockwell, which creates conditions for increasing the wear resistance of the surface friction. The use of electrodes with a low-carbon rod is advisable when conducting surfacing reinforcement of heat-strengthened steels.

A Study of Texture Component Distribution Over the Cross Section of an Aluminum Alloy 8011 Billet with Hot Rolling in a Four-Stand Continuous Group

2019 ◽  
Vol 61 (5-6) ◽  
pp. 300-304
Author(s):  
V. V. Yashin ◽  
E. V. Aryshenskii ◽  
S. V. Konovalov ◽  
V. Yu. Aryshenskii ◽  
I. A. Latushkin
Keyword(s):  
Aluminum Alloy ◽  
Cross Section ◽  
Texture Component ◽  
Hot Rolling ◽  
Continuous Group ◽  
Component Distribution ◽  
The Cross

The structure of Ti-Ta welded joint and microhardness distribution over the cross section

2018 ◽  
Author(s):  
Aleksandr A. Fomin ◽  
Vladimir Koshuro ◽  
Ivan Egorov ◽  
Andrey Shelkunov ◽  
Andrey Zakharevich ◽  
...  
Keyword(s):  
Cross Section ◽  
Welded Joint ◽  
Microhardness Distribution ◽  
The Cross

scholarly journals Metallurgical and Mechanical Characterization of High-Speed Friction Stir Welded AA 6082-T6 Aluminum Alloy

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4211 ◽  
Author(s):  
Anton Naumov ◽  
Iuliia Morozova ◽  
Evgenii Rylkov ◽  
Aleksei Obrosov ◽  
Fedor Isupov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Welding Speed ◽  
Welded Joints ◽  
High Speed ◽  
Structural Characteristics ◽  
Tensile Fracture ◽  
Friction Stir ◽  
Microhardness Distribution ◽  
Aluminum Sheets

The objective of this study was to investigate the effect of the high welding speed on the mechanical properties and their relations to microstructural characteristics of butt friction stir welded joints with the use of 6082-T6 aluminum alloy. The aluminum sheets of 2.0 mm thick were friction stir welded at low (conventional FSW) and high welding speeds (HSFSW) of 200 and 2500 mm/min, respectively. The grain size in the nugget zone (NZ) was decreased; the width of the softened region was narrowed down as well as the lowest microhardness value located in the heat-affected zone (HAZ) was enhanced by HSFSW. The increasing welding speed resulted in the higher ultimate tensile strength and lower elongation, but it had a slight influence on the yield strength. The differences in mechanical properties were explained by analysis of microstructural changes and tensile fracture surfaces of the welded joints, supported by the results of the numerical simulation of the temperature distribution and material flow. The fracture of the conventional FSW joint occurred in the HAZ, the weakest weld region, while all HSFSW joints raptured in the NZ. This demonstrated that both structural characteristics and microhardness distribution influenced the actual fracture locations.

Casting of Thin Bare Wire Using Wheel Caster Equipped with Rotating Side-Dam Plates

2020 ◽  
Vol 846 ◽  
pp. 152-156
Author(s):  
Toshio Haga ◽  
Kirito Itou ◽  
Hisaki Watari ◽  
Shinichi Nishida
Keyword(s):  
Aluminum Alloy ◽  
Mild Steel ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Side Surface ◽  
Fabrication Process ◽  
The Cross

A simple twin-wheel caster is proposed for casting thin bare wire. An unequal diameter twin wheel caster equipped with rotating side-dam plates is proposed for casting a thin bare wire of aluminum alloy to shorten the fabrication process. The rotating side-dam plate was made of mild steel. Al-10%Mg bare wire with a rectangular cross section could be cast at wheel speeds of 3 and 4 m/min. Area of the bare wire was less than 100 mm2 at these wheel speeds. The side surface of the bare wire was made flat by the rotating side-dam plates. The rotating side-dam plates prevent the cross section of the bare wire from becoming concave.

Study on the Precipitation Behavior of Precipitates of 7075 Aluminum Alloy Friction Stir Welding Joint

2020 ◽  
Vol 1003 ◽  
pp. 37-46
Author(s):  
Hao Zhu ◽  
Shao Kang Dong ◽  
Ze Ming Ma ◽  
Jun Wang
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Strain Hardening ◽  
Strengthening Effect ◽  
7075 Aluminum Alloy ◽  
Friction Stir ◽  
Microhardness Distribution ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Precipitated Phases

In this work, the microhardness of 7075 aluminum alloy friction stir welding (FSW) joint was measured by a micro vickers hardness tester, the microstructure of the joints was characterised by microscope, the precipitated phases among the welding nugget zone (WNZ), thermal mechanical affected zone (TMAZ), heat affected zone (HAZ) were affirmed by X-ray diffractometer (XRD) and the lattice fringe of transmission electron microscopy (TEM) high resolution image. Based on this, the precipition behavior of precipitated phases was studied. The results show that the microhardness distribution of the 7075 aluminium alloy FSW joints is heterogeneous in comparison with the base metal (BM). The precipitates in the joint mainly include MgZn rod shape and AlCuMg in elliptical shape. In the WNZ, the main precipitate is AlCuMg, and the fine grain strengthening effect is better, so the microhardness in this zone is relatively high. In the TMAZ, the quantity of AlCuMg decreased while the MgZn2 increased relatively in comparison with the WNZ. At the same time, the effect of the fine grain strengthening was weakened, though the strain hardening increased. Therefore, the microhardness in the TMAZ still decreased. In the HAZ, the quantity of MgZn2 increased furtherly, and there is no strain hardening and fine grain strengthening, so the microhardness of the HAZ was the lowest among the FSW joints. Besides, through comparative tests, the optimal process parameters of friction stir welding of 7075 aluminum alloy were obtained.

scholarly journals Experimental Investigation of Friction Stir Welding on 6061-T6 Aluminum Alloy using Taguchi-Based GRA

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1480
Author(s):  
Assefa Asmare ◽  
Raheem Al-Sabur ◽  
Eyob Messele
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Process Parameters ◽  
Rotational Speed ◽  
Weight Ratio ◽  
Welding Process ◽  
Quality Criteria ◽  
Alloy Sheet ◽  
Friction Stir ◽  
Weld Joints

The use of aluminum alloys, nowadays, is swiftly growing from the prerequisite of producing higher strength to weight ratio. Lightweight components are crucial interest in most manufacturing sectors, especially in transportation, aviation, maritime, automotive, and others. Traditional available joining methods have an adverse effect on joining these lightweight engineering materials, increasing needs for new environmentally friendly joining methods. Hence, friction stir welding (FSW) is introduced. Friction stir welding is a relatively new welding process that can produce high-quality weld joints with a lightweight and low joining cost with no waste. This paper endeavors to deals with optimizing process parameters for quality criteria on tensile and hardness strengths. Samples were taken from a 5 mm 6061-T6 aluminum alloy sheet with butt joint configuration. Controlled process parameters tool profile, rotational speed and transverse speed were utilized. The process parameters are optimized making use of the combination of Grey relation analysis method and L9 orthogonal array. Mechanical properties of the weld joints are examined through tensile, hardness, and liquid penetrant tests at room temperature. From this research, rotational speed and traverse speed become significant parameters at a 99% confidence interval, and the joint efficiency reached 91.3%.

Experimental Study on Friction Stir Welding of Dissimilar Al 6061 to Trip 780/800 Steel

2014 ◽  
Author(s):  
Xun Liu ◽  
Shuhuai Lan ◽  
Jun Ni
Keyword(s):  
Friction Stir Welding ◽  
Cross Sections ◽  
Welding Speed ◽  
Rotational Speed ◽  
Maximum Temperature ◽  
Friction Stir ◽  
Al 6061 ◽  
Tool Axis ◽  
Edge Temperature ◽  
Welding Force

Friction stir welding (FSW) of dissimilar Al 6061 and TRIP 780/800 steel has been performed under different process parameters, including tool rotational speed, welding speed as well as the relative position of the tool axis to the abutting edge. Temperature and mechanical welding force was recorded during the process. Welding speed has an insignificant effect on either the maximum temperature or welding force. However, it can directly change the length of high temperature duration, which will accordingly influence temperature distribution in the weld and the microstructure. Higher rotational speed can effectively elevate weld temperature through greater amount of heat input. Metallurgical observations on weld cross sections perpendicular to the joint line was performed using both optical and scanning electron microscope. Microstructure evolution was analyzed and related to the force and temperature measurement results during the FSW process.

scholarly journals Aging Behavior of Aluminum Alloy 6082 Subjected to Friction Stir Processing

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 337 ◽  
Author(s):  
Khaled Al-Fadhalah ◽  
Fahad Asi
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Aging Time ◽  
Friction Stir Processing ◽  
Aging Temperature ◽  
Friction Stir ◽  
Average Grain Size ◽  
Different Temperatures ◽  
Equiaxed Grains ◽  
Electron Back Scattered Diffraction

The present work examined the effect of artificial aging on the microstructure, texture, and hardness homogeneity in aluminum alloy AA6082 subjected to friction stir processing (FSP). Aging was applied to FSP samples at three different temperatures (150 °C, 175 °C, and 200 °C) for a period of 1 h, 6 h, and 12 h. Microstructure analysis using optical Microscopy (OM) and Electron Back-Scattered Diffraction (EBSD) indicated that FSP produced fine equiaxed grains, with an average grain size of 6.5 μm, in the stir zone (SZ) due to dynamic recrystallization. Aging was shown to result in additional grain refinement in the SZ due to the occurrence of recovery and recrystallization with either increasing aging temperature and/or aging time. An optimum average grain size of 3–4 μm was obtained in the SZ by applying aging at 175 °C. This was accompanied by an increase in the fraction of high-angle grain boundaries. FSP provided a simple shear texture with a major component of B fiber. Increasing aging temperature and/or time resulted in the formation of recrystallization texture of a Cube orientation. In addition, Vickers microhardness was evaluated for the FSP sample, indicating a softening in the SZ due to the dissolution of the hardening precipitates. Compared to other aging temperatures, aging at 175 °C resulted in maximum hardness recovery (90 Hv) to the initial value of base metal (92.5 Hv). The hardness recovery is most likely attributed to the uniform distribution of fine hardening precipitates in the SZ when increasing the aging time to 12 h.

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