FSW welding at LORTEK
- 12/01/2020
Friction Stir Welding (FSW)
Friction Stir Welding (FSW) technology is a solid state welding process where a non-consumable rotating tool (normally comprised of a shoulder and a probe) is pressed against the materials to be welded. The friction and deformation produced between the tool and the base materials increase the temperature, leading to a softening of the materials to be welded. The tool is traversed along the joint line so that, due to its rotation and specific design, it generates a plasticized material flow, producing a mixture that consolidates the joint in the solid state.
FSW welding is a mature technology, particularly for low melting point alloys (aluminium, magnesium, lead, etc.). FSW welding of aluminium alloys is governed by the ISO25239 standard. LORTEK has participated in the development of this standard as a nationally-acknowledged expert.
The main characteristics of FSW welding are:
Friction Stir Spot Welding (FSSW)
This is the spot welding variant of FSW welding. The image below shows a sketch of the basic principles of the process:
The main characteristics of FSSW welding are:
FSSW welding is a mature technology, particularly for low melting point alloys (aluminium, magnesium, lead, etc.). FSSW welding of aluminium alloys is governed by the ISO18785 standard. LORTEK has participated in the development of this standard as a nationally-acknowledged expert.
Rotary friction welding technology is a solid-state welding process where a rotating part is pressed against a static part. The friction generated at the interface of the parts raises the temperature until the material is softened and plasticized. The rotation of the rotating part is stopped, and the pressure increased, so the two parts are forged together, producing the joint in the solid state.
The main characteristics of rotary friction welding are:
LORTEK also has experience and collaborations in other technologies, such as:
Industrial implementation of FSW to replace arc welding and flame welding.
Ad-Hoc FSW equipment, including development of controller with process data recording and monitoring capabilities, FSW tools, process parameters and ISO25239-based qualification, clamping and positioning fixtures, etc. Improvement of welded joint quality. Reduction of cycle time by approximately 80%. Reduction of manufacturing and energy consumption costs. Improvement of work environment and health of operators. LORTEK’s own control system (Copyright “SOFTWARE DE CONTROL FSW” - TXu 2-023-714).
Reduce distortions in reinforced structures manufactured in aluminium by arc welding (MIG).
FSW welding in T-joints, including development of FSW tools, process parameters, clamping and positioning fixtures, etc. Up to 90% reduction of distortions; reduction of manufacturing times and costs.
Need to lighten the weight of structures by welding aluminium and steel components.
Design of structure to be manufactured by means of explosion welded, arc welded and FSW bimetallic materials. Development of FSW welding process, including FSW tools, process parameters, etc.
Work carried out in collaboration with CAF R&D in the BIMETAL project. Publication of co-patent “METHOD FOR WELDING TOGETHER DISSIMILAR PARTS” (EP 3 178 600 A1).
Need to measure maximum temperatures reached during FSW processes.
Development of wireless temperature measurement system by means of thermocouples placed into the actual FSW rotating tool, with maximum temperature measurement capacity during the FSW process at the interface between the FSW tool and welded material. Patent publication application “Sistema para la medición de temperaturas en un procedimiento de soldadura por fricción – agitación” (PCT/ES2017/070807). Patent Publication Application: "System for the measurement of temperatures in a friction-agitation welding procedure" (PCT / ES2017 / 070807).
System developed in cooperation with the University of Bordeaux within the framework of the MONITEMP project.
Need to optimize the FSW process control software for robotic equipment.
Control software developed with high-speed FSW welding process data acquisition and monitoring capacities. Improvement of stability and repetitiveness of FSW welding process in KUKA KR500-3MT robotic equipment.
Software developed in cooperation with ACTEMIUM and optimized by LORTEK within the framework of the MALGUROB project.
Need to lighten the weight of structures for transport vehicles (automobile, aircraft, railway).
Development of FSW and FSSW processes for manufacturing stiffened structures with extrusions and rolled sheets welded in the overlap configuration. Improvement of dimensional quality (reduction of distortions compared with other welding processes) and structure stiffness/weight ratio. Reduction of manufacturing times and costs.
Technologies currently under development within the framework of the ecoTECH project, in collaboration with Hellenic Aerospace Industry (HAI), Israel Aerospace Industries (IAI), AeroMagnesium (AM), AkzoNobel, NLR, ALTRAN, etc.
Need for high speed FSW (>3m/min), complying with the quality demands to respond to the manufacturing cycle times of the automobile sector (e-mobility).
High-speed FSW (up to 4 m/min) complying with quality requirements established by the ISO25239 standard, including development of FSW tools, process parameters, clamping and positioning fixtures, etc. Significant reduction of distortions and manufacturing costs compared with other welding processes.
Challenges to be faced in the coming years: