Friction Stir Welding of High-Strength Steels

2019 ◽  
pp. 139-158
Author(s):  
R. Ramesh ◽  
I. Dinaharan ◽  
E. T. Akinlabi
Keyword(s):  
Friction Stir Welding ◽  
High Strength Steels ◽  
High Strength ◽  
Friction Stir

The Backing Bar Role in Heat Transfer on Aluminium Alloys Friction Stir Welding

2010 ◽  
Vol 636-637 ◽  
pp. 459-464 ◽  
Author(s):  
M.J.C. Rosales ◽  
N.G. Alcantara ◽  
Jorge Santos ◽  
R. Zettler
Keyword(s):  
Heat Transfer ◽  
Friction Stir Welding ◽  
Aluminium Alloys ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced Materials ◽  
Mechanical Degradation ◽  
Great Effort ◽  
Friction Stir ◽  
Advanced High Strength Steels

Although new structural and advanced materials have been used in the automotive and aircraft industries, especially lightweight alloys and advanced high strength steels, the successful introduction of such materials depends on the availability of proven joining technologies that can provide high quality and performance joints. Solid-state joining techniques such as Friction Stir Welding (FSW) are a natural choice since their welds are produced at low temperatures, so the low heat input provides limited, slight distortion, microstructural and mechanical degradation. Great effort has currently been devoted to the joining of Al-Cu-Mg and the Al-Mg-Si alloys because of their high strength, improved formability, and application in airframe structures. FSW is a continuous, hot shear, autogenous process involving a non-consumable and rotating tool plunged between two abutting workpieces. The backing bar plays an important role in heat transfer from stir zone (SZ), which can influence the weld microstructure as well as the consolidation of material in the root of the join. This study aims at investigating issues concerning heat generation, within the SZ of friction stir welded aircraft aluminium alloys.

scholarly journals Comprehensive Analysis of the Microstructure and Mechanical Properties of Friction-Stir-Welded Low-Carbon High-Strength Steels with Tensile Strengths Ranging from 590 MPa to 1.5 GPa

2021 ◽  
Vol 11 (12) ◽  
pp. 5728
Author(s):  
HyeonJeong You ◽  
Minjung Kang ◽  
Sung Yi ◽  
Soongkeun Hyun ◽  
Cheolhee Kim
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Joint Strength ◽  
Solid Phase ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Low Carbon ◽  
Friction Stir ◽  
Welding Processes

High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive steels.

Study of the Key Issues of Friction Stir Welding of Titanium Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 1185-1190 ◽  
Author(s):  
Hui Jie Liu ◽  
Li Zhou ◽  
Yong Xian Huang ◽  
Qi Wei Liu
Keyword(s):  
Titanium Alloy ◽  
Friction Stir Welding ◽  
Melting Point ◽  
Titanium Alloys ◽  
Welding Process ◽  
High Strength ◽  
Liquid Cooling ◽  
Friction Stir ◽  
Key Issues ◽  
Aluminum And Magnesium Alloys

As a new solid-state welding process, friction stir welding (FSW) has been successfully used for joining low melting point materials such as aluminum and magnesium alloys, but the FSW of high melting point materials such as steels and titanium alloys is still difficult to carry out because of their strict requirements for the FSW tool. Especially for the FSW of titanium alloys, some key technological issues need to solve further. In order to accomplish the FSW of titanium alloys, a specially designed tool system was made. The system was composed of W-Re pin tool, liquid cooling holder and shielding gas shroud. Prior to FSW, the Ti-6Al-4V alloy plates were thermo-hydrogen processed to reduce the deformation resistance and tool wear during the FSW. Based on this, the thermo-hydrogen processed Ti-6Al-4V alloy with different hydrogen content was friction stir welded, and the microstructural characterizations and mechanical properties of the joints were studied. Experimental results showed that the designed tool system can fulfill the requirements of the FSW of titanium alloys, and excellent weld formation and high-strength joint have been obtained from the titanium alloy plates.

Investigations on the Mechanical Properties and Formability of Friction Stir Welded Tailored Blanks

2007 ◽  
Vol 344 ◽  
pp. 143-150 ◽  
Author(s):  
Gianluca Buffa ◽  
Livan Fratini ◽  
Marion Merklein ◽  
Detlev Staud
Keyword(s):  
Mechanical Properties ◽  
Stress Condition ◽  
Research Effort ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Friction Stir ◽  
Tailored Blanks ◽  
Sheet Stamping ◽  
Wide Range

Tight competition characterizing automotive industries in the last decades has determined a strong research effort aimed to improve utilized processes and materials in sheet stamping. As far as the latter are regarded light weight alloys, high strength steels and tailored blanks have been increasingly utilized with the aim to reduce parts weight and fuel consumptions. In the paper the mechanical properties and formability of tailored welded blanks made of a precipitation hardenable aluminum alloy but with different sheet thicknesses, have been investigated: both laser welding and friction stir welding have been developed to obtain the tailored blanks. For both welding operations a wide range of the thickness ratios has been considered. The formability of the obtained blanks has been characterized through tensile tests and cup deep drawing tests, in order to show the formability in dependency of the stress condition; what is more mechanical and metallurgical investigations have been made on the welded joints.

Effect of plasma preheating on weld quality and tool life during friction stir welding of DH36 steel

2021 ◽  
pp. 095440542199013
Author(s):  
Avinish Tiwari ◽  
Pardeep Pankaj ◽  
Saurav Suman ◽  
Piyush Singh ◽  
Pankaj Biswas ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Tool Life ◽  
Force Measurement ◽  
Deep Understanding ◽  
High Strength ◽  
Microstructural Characterization ◽  
Stir Zone ◽  
Friction Stir ◽  
Allotriomorphic Ferrite ◽  
Fsw Parameters

Friction stir welding (FSW) of high strength materials is challenging due to high tool cost and low tool life. To address this issue, the present investigation deals with an alternative of plasma-assisted friction stir welding (PFSW) of DH36 steel with WC-10%Co tool. Plasma preheating current (13 A, 15 A, and 17 A) was varied by keeping other FSW parameters as constant. During the FSW and PFSW process, force measurement and thermal history aided in a deep understanding of the process, tool degradation mechanisms, accompanied by the mechanical and microstructural characterization of the welded joints. The stir zone hardness was increased from 140 HV0.5 to about 267 HV0.5. The yield and tensile strength of weld increased from 385 MPa and 514 MPa to about 391 MPa and 539 MPa, respectively. Weld joint elongation (%) was increased from ~10% of weld 1 to ~13.89% of weld 4. During PFSW, the process temperature was increased, the cooling rate was lowered, and the weld bead was widened. The results also revealed that the plasma-assisted weld resulted in polygonal ([Formula: see text]) and allotriomorphic ferrite as the major constituents in the stir zone. Pearlite dissolution and spheroidization were observed in the ICHAZ and SCHAZ, respectively. Additionally, the plasma preheating reduced the tungsten tool’s wear by 58% compared to FSW.

Metallurgical Study of Friction Stir Welded High Strength Steels for Shipbuilding

2014 ◽  
Vol 783-786 ◽  
pp. 2798-2803 ◽  
Author(s):  
Marion Allart ◽  
Alexandre Benoit ◽  
Pascal Paillard ◽  
Guillaume Rückert ◽  
Myriam Chargy
Keyword(s):  
Cubic Boron Nitride ◽  
High Strength Steels ◽  
High Strength ◽  
High Yield ◽  
Friction Stir ◽  
Polycrystalline Cubic Boron Nitride ◽  
Recent Developments ◽  
Metallurgical Study ◽  
Welding Processes ◽  
Pcbn Tools

Friction Stir Welding (FSW) is one of the most recent welding processes, invented in 1991 by The Welding Institute. Recent developments, mainly using polycrystalline cubic boron nitride (PCBN) tools, broaden the range of use of FSW to harder materials, like steels. Our study focused on the assembly of high yield strength steels for naval applications by FSW, and its consequences on the metallurgical properties. The main objectivewas to analyze the metallurgical transformations occurring during welding. Welding tests were conducted on three steels: 80HLES, S690QL and DH36. For each welded sample, macrographs, micrographs and micro-hardness maps were performed to characterize the variation of microstructures through the weld.

scholarly journals Design and Fabrication of Friction Stir Welding End-Effector for an ABB IRB1410 Robot

2016 ◽  
Vol 5 (2) ◽  
pp. 98
Author(s):  
Santosh Vanama
Keyword(s):  
Friction Stir Welding ◽  
High Strength ◽  
Fusion Welding ◽  
Fusion Temperature ◽  
End Effector ◽  
Friction Stir ◽  
Aluminum Sheets ◽  
Operation Pressure ◽  
Welding Processes ◽  
Tool Rotation

<p>The paper propose modelling and fabrication of friction stir welding end-effector for ABB IRB1410 robot. A dynamically developing version of pressure welding processes, join material without reaching the fusion temperature called friction stir welding. As friction stir welding occurs in solid state, no solidification structures are created thereby eliminating the brittle and eutectic phase’s common to fusion welding of high strength aluminium alloys. In this paper, Friction stir welding is applied to aluminum sheets of 2 mm thickness. A prototype setup is developed to monitor the evolution of main forces and tool temperature during the operation. Pressure of a gripper plays a major role for tool rotation and developing torque.  Fabrication of the tool has done. Force calculations are done by placing the sensors on the outer surface of gripper. Methods of evaluating weld quality are surveyed as well.</p>

On the problem of tool destruction when obtaining fixed joints of thick-walled aluminum alloy blanks by friction welding with mixing

2021 ◽  
Vol 23 (3) ◽  
pp. 72-83
Author(s):  
Kirill Kalashnikov ◽  
◽  
Andrey Chumaevskii ◽  
Tatiana Kalashnikova ◽  
Aleksey Ivanov ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Friction Welding ◽  
Welding Process ◽  
High Strength ◽  
Heterogeneous Structure ◽  
Adhesive Interaction ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Electric Erosion

Introduction. Among the technologies for manufacturing rocket and aircraft bodies, marine vessels, and vehicles, currently, more and more attention is paid to the technology of friction stir welding (FSW). First of all, the use of this technology is necessary where it is required to produce fixed joints of high-strength aluminum alloys. In this case, special attention should be paid to welding thick-walled blanks, as fixed joints with a thickness of 30.0 mm or more are the target products in the rocket-space and aviation industries. At the same time, it is most prone to the formation of defects due to uneven heat distribution throughout the height of the blank. It can lead to a violation of the adhesive interaction between the weld metal and the tool and can even lead to a destruction of the welding tool. The purpose of this work is to reveal regularities of welding tool destruction depending on parameters of friction stir welding process of aluminum alloy AA5056 fixed joints with a thickness of 35.0 mm. Following research methods were used in the work: the obtaining of fixed joints was carried out by friction welding with mixing, the production of samples for research was carried out by electric erosion cutting, the study of samples was carried out using optical metallography methods. Results and discussion. As a result of performed studies, it is revealed that samples of aluminum alloy with a thickness of 35.0 mm have a heterogeneous structure through the height of weld. There are the tool shoulder effect zone and the pin effect zone, in which certain whirling of weld material caused by the presence of grooves on tool surface is distinctly distinguished. It is shown that the zone of shoulders effect is the most exposed to the formation of tunnel-type defects because of low loading force and high welding speeds. It is revealed that tool destruction occurs tangentially to the surface of the tool grooves due to the high tool load and high welding speeds.

Control of Material Flow During Friction Stir Welding Between Aluminum and Steel by Welding Tool Shape

2020 ◽  
Author(s):  
Toshiaki Yasui ◽  
Yuki Ogura ◽  
Xu Huilin ◽  
F. Farrah Najwa ◽  
Daichi Sugimoto ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Simulation Experiment ◽  
Low Cost ◽  
Flow Analysis ◽  
Material Flow Analysis ◽  
High Strength ◽  
Friction Stir ◽  
Tool Shape ◽  
Computational Fluid Dynamics Cfd

Abstract For the Friction stir welding (FSW) between aluminum and steel is important to fabricate vehicles with light weight and high strength for safety at low cost. For the fabrication of sound weld, it is necessary to control the material flow during FSW. In this study, the material flow during FSW was elucidated by numerical simulation by computational fluid dynamics (CFD) analysis and simulation experiment by transparent Poly-vinyle chloride (PVC) as simulant of aluminum and tracer material. Based on this material flow analysis, several shapes of welding tool were examined for control of material flow during FSW. Scroll shoulder is effective for enhancement of stirring zone by increasing material velocity around the probe. Flute and fine screw probe promote the material flow in depth and horizontal direction. The welding tool with scroll shoulder and flute and fine screw probe achieved sound weld with highest tensile strength of 120.4 MPa.

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