2 Fundamentals of Friction Stir Welding, Its Application, and Advancements
51
forces material into the concave cavity and pushes the existing material behind the
pin. It also increases the tool life by reducing locally generated stress during welding.
During welding, the material contained within the shoulder participates in the joint
formation as no material is lost in the form of flash [37]. The problem associated
with the convex surface is that it further displaces away from the plasticized material
from the weld center.
2.3.2 Tool Material
The tool material considered for FSW needs to be rigid and strong as compared to
the workpiece. Also, the mechanical property of the tool should be on the higher side
including its strength and thermal properties. These are the significant and important
factor for proper and uniform dissipation of the heat [38]. Tool materials used for
joining soft materials like aluminum and magnesium alloy are easy to fabricate with
required properties. High-speed steel, low carbon steel, and H13 tool steel are some
common commercially available tools for them. These are also effective material to
weld in different input process parameters [14]. The above tools perform well without
undergoing much wear and material loss. Tool steel H13 is a widely accepted material for the welding of aluminum and magnesium alloys ranging from 0.5 to 50 mm
thickness [39, 40]. A tool having a longer life and satisfactory weld properties has a
great demand for structural applications especially, in the defense sector, aerospace
industry, oil and gas companies, and heavy manufacturing industries. Tool materials
for harder alloys like steel and titanium alloys still need further research and development. A few advanced tool materials like tungsten carbide and polycrystalline cubic
Boron Nitride (PcBN) is widely used for welding of material having high strength
like steel, copper, and titanium. The tool needs to be cost-effective, durable, and
structurally sound for commercial FSW applications [32]. Material selection and
performance analysis of tools along with the quality of weld and cost is a major
concern.
2.3.3 Commonly Used Tool Materials
2.3.3.1 Tool Steel
Material like aluminum, magnesium, and other soft materials can be welded using
steel tools. H13 grade is mostly used in both lap and butt configuration [41]. Tool
steel is preferred for the welding of similar and dissimilar material. It maintains high
strength and a significant low wear rate during the service condition. The wear rate
increases with an increase in rotational speed and lowering travel speed. It is found
that steel tools wear slowly with threads in it and also produce a sound weld [33].
51
forces material into the concave cavity and pushes the existing material behind the
pin. It also increases the tool life by reducing locally generated stress during welding.
During welding, the material contained within the shoulder participates in the joint
formation as no material is lost in the form of flash [37]. The problem associated
with the convex surface is that it further displaces away from the plasticized material
from the weld center.
2.3.2 Tool Material
The tool material considered for FSW needs to be rigid and strong as compared to
the workpiece. Also, the mechanical property of the tool should be on the higher side
including its strength and thermal properties. These are the significant and important
factor for proper and uniform dissipation of the heat [38]. Tool materials used for
joining soft materials like aluminum and magnesium alloy are easy to fabricate with
required properties. High-speed steel, low carbon steel, and H13 tool steel are some
common commercially available tools for them. These are also effective material to
weld in different input process parameters [14]. The above tools perform well without
undergoing much wear and material loss. Tool steel H13 is a widely accepted material for the welding of aluminum and magnesium alloys ranging from 0.5 to 50 mm
thickness [39, 40]. A tool having a longer life and satisfactory weld properties has a
great demand for structural applications especially, in the defense sector, aerospace
industry, oil and gas companies, and heavy manufacturing industries. Tool materials
for harder alloys like steel and titanium alloys still need further research and development. A few advanced tool materials like tungsten carbide and polycrystalline cubic
Boron Nitride (PcBN) is widely used for welding of material having high strength
like steel, copper, and titanium. The tool needs to be cost-effective, durable, and
structurally sound for commercial FSW applications [32]. Material selection and
performance analysis of tools along with the quality of weld and cost is a major
concern.
2.3.3 Commonly Used Tool Materials
2.3.3.1 Tool Steel
Material like aluminum, magnesium, and other soft materials can be welded using
steel tools. H13 grade is mostly used in both lap and butt configuration [41]. Tool
steel is preferred for the welding of similar and dissimilar material. It maintains high
strength and a significant low wear rate during the service condition. The wear rate
increases with an increase in rotational speed and lowering travel speed. It is found
that steel tools wear slowly with threads in it and also produce a sound weld [33].