ENCOR 4010 - Friction Welding: Processes, Applications, Advantages

This literature review provides a comprehensive overview of friction welding, a solid-state welding technique widely used in industries like aerospace and automotive. It details the process, advantages, and disadvantages of friction welding, highlighting its speed and versatility in joining dissimilar metals while noting limitations such as its primary use on round bars. The review covers various industrial applications, including marine, aerospace, and railway industries, and explores different types of friction welding such as inertial, continuous induction, linear, and friction surfacing. It also discusses process parameters and numerical simulations related to specific alloys, offering a thorough understanding of friction welding's principles and practical implementations. Desklib provides access to this document along with numerous other solved assignments to aid students in their studies.

Running head: FRICTION WELDING 1
FRICTION WELDING
Name of Student
Institution Affiliation

FRICTION WELDING 2
Abstract
Friction welding is a solid state welding technique with high automation and good quality.it
has been broadly applied in various industries especially in aerospace and automobile
industries. Because of high level of automation and less process parameters, the inertial
friction is common in many fields. There are many merits which are associated with the use
of friction welding in production such as, it is fast method of welding as compared to other
welding techniques. Even though there are many benefits which are associated with it, there
are also some drawbacks such as, is mainly used in round bars which have the same cross
section.
Table of Contents

FRICTION WELDING 3
1.0 Introduction..........................................................................................................................3
2.0 Background..........................................................................................................................3
3.0 Principle...............................................................................................................................3
4.0 Advantages and disadvantages of friction welding..............................................................4
4.1 Advantages of friction welding...................................................................................4
4.2 Disadvantages of friction welding...............................................................................5
5.0 Industrial applications of friction welding...........................................................................5
5.1 Marine and shipbuilding industries.............................................................................6
5.2 Aerospace industry......................................................................................................6
5.3 Railway industry..........................................................................................................6
5.4 Other industries include...............................................................................................7
6.0 Types of friction welding.....................................................................................................7
6.1 Inertial friction welding...............................................................................................7
6.2 Continuous induction method......................................................................................8
6.3 Linear friction welding................................................................................................8
6.32 Process parameters...........................................................................................11
6.31 Numerical simulation of inertia friction welding process of gh4169 alloy.....11
6.4 Friction surfacing.......................................................................................................16
7.0 Conclusion..........................................................................................................................16
References................................................................................................................................18
1.0 Introduction

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Friction welding is defined as Solid state or a simply forge whereby the welding process
occurs between two mating surfaces of metals through the application of friction between
them. The welding technique has been adopted by well-known international companies in in
America and Europe such as American Manufacturing Foundry and Rockwell international to
manufacture their machines.
Friction welding is considered to be very essential in the production industry, by adopting
this welding method the high overhead costs which the companies will undergo to have this
technique in place will be balanced with the high production rates and lower labour
requirements.
The friction welding technique has many dimensional and hardware which are easily
adjustable making it to be very significant in the production of very small parts and
components. There are many industrial applications where friction welding can be applied
such as the machine and spare part production.
2.0 Background.
The process of friction welding was first discovered in the late 1920s, however during that
time there was very little data which was recorded about its use. A detailed discussion about
friction welding was recorded in the USSR in the early 1960s, but that time it was described
as ‘very doubtful, as a production technique due to the challenges in generating reciprocating
linear motion. The fist well-structured industrial research into friction welding took place in
the 1980s at TWI, UK, while the first ever research academic to be to be recorded took place
at Ohio State University, and the University Of Bristol, UK.
3.0 working Principle
The friction welding technique works on the basic principle of friction. In the process of
welding, friction is used to create heat at the interfaces surfaces (Anderson, 2016). The heat is

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used to join the two work pieces through the application of the external pressure at the work
pieces surfaces. In friction welding, the friction is applied until the plastic forming
temperature is reached which is usually900-1300oc for steel. After the heating process,
pressure which is uniformly increasing is applied to both of the metal work pieces until they
make a permanent joint.
4.0 Advantages and disadvantages of friction welding
4.1 Advantages of friction welding
There are many merits which are associated with the use of friction we in production. Some
of the merits include:
 It easier and convenient to join metals which are not similar and some of which are
considered to be unweldabl or incompatible.
 Friction welding is very fast method of welding as compared to other welding
techniques (Granjon, 2014).
 Due to their versatility the friction welders are able to join a wide range of materials,
shapes and sizes without any challenge.
 In this friction welding joint preparation is not of great importance since, saw cut,
machine and even the sheared surfaces are weldabl.
 The resulting joints are of forged quality, with up to 100% butt joint weld through the
contact area.
 Human error are eliminated by machine controlled process, and the quality of the
weld is independent of the operator skill.
 It is environmental friendly as there is no objectionable fumes, gases or smoke that
are generated which needs to be exhausted.

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 In friction welding there are no consumable that are required, no filler material, flux
or shielding gases.
 The power requirements for friction welding as low as 20% of that which is required
for conventional welding processes.
 Since there is no melting which occurs there is no solidification defects such as gas
porosity, slag or segregation inclusions.
4.2 Disadvantages of friction welding
Even though there are many benefits which are associated with friction welding it has also
some drawbacks such as:
 This technique of welding is mainly used in round bars which have the same cross
section. Due to that the bars which are not of the same cross section cannot be welded. In
some industries welding of metals which are not round in shape is very common the
application pf friction welding for such cases is limited (Sahin, 2016).
 There are exist holes left when the tools are withdrawn. Most of the metal bars which are
to be joined together are held by strong tools which drills holes through them.
 Friction welding requires extensive clamping
 Needs special backing support
 The cost of setting up a friction welding facility are very high. The equipment and
machines which are used for friction welding are very expensive to acquire. This makes a
lot of people to move to the convention welding which is much easier and cheaper.
 The design of the joints is very limited.
 It involves critical preparations of work pieces (Welding InstituteElsevier Science &
Technology, 2010).

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5.0 Industrial applications of friction welding
Many production industries all over the world are experiencing the high costs of energy due
to the amount of energy which is consumed during the production process’s adoption of
friction welding can greatly assist in solving this challenges (Yilbas, 2016). The friction
welding has been applied in various industrial applications as discussed below:
5.1 Marine and shipbuilding industries
The marine and shipbuilding are among the earliest industries to adopt friction welding for
commercial applications (Anderson, 2016). Friction welding is suitable for the following
applications:
 Panels for side, decks, floors and bulkhead.
 Superstructures and Hulls
 Aluminium extrusions
 Booms and Mast for example for sailing boat
5.2 Aerospace industry
Currently the aerospace industry is welding production parts and prototype by application of
friction welding. There exist opportunities to weld, ribs, spars and stringers for civilian and
military aircrafts (Vill', 2015). The friction welding process can be considered for the
following:
 Fuselage, empennages, wings
 In the case of space vehicle the friction welding can be considered for cryogenic fuel
tank
 Scientific and military rockets
 Aviation fuel tanks

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5.3 Railway industry
The commercial production of high speed trains which are made from aluminium extrusions
that can be joined through friction welding has been published and the applications include:
 Trams, underground undercarriages and the rolling stock of railways
 Good wagons and railway tankers
 Container bodies (American Welding Society. Committee on Friction Welding, 2012)
5.4 Other industries include
 Electric motor housing
 Kitchens and cooking equipment
 Gas cylinders and gas tanks
 Axle tube, gears, drive line, valves and other components are friction welded.
 Connecting rods, Gear levers, drill bits are friction welded
 It regularly used to replace casting or forging assembly
 Truck rollers, and hydraulic piston rods are friction welded
 In welding shafts and tubes
 In electrical industries it is used for welding aluminium and copper equipment
 In pumps friction welding is used to weld pump shafts (Singh, 2016).
6.0 Types of friction welding
There exists many variations in the process which work on the same principle, due to that
there are various types of friction welding as listed below:
1. Continuous induce friction welding
2. Linear friction welding
3. Spin welding/Inertial friction welding
4. Friction surfacing

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6.1 Inertial friction welding
Inertial Friction Welding refers to a variation of the friction welding in which the required
energy to make the weld is provided mainly by the stored rotational kinetic energy of the
welding machine (Blau, 2012). In the Inertial Friction welding, one of the two workpieces is
connected to a flywheel while the other is prevented from rotating. The flywheel is then
accelerated to a given rotational speed which is predetermined, storing the required energy.
The motor driver is disengages and then the work pieces are joined together by the friction
welding force. This makes the faying surfaces to rub to each other under pressure. The kinetic
energy which is stored in the rotating wheel is released as heat through friction at the
interface of the weld as the wheel speed decreases. A forge force might be applied before the
flywheel completely stops (Wang, 2013). After rotation has stopped the forge force is
maintained for a predetermined period.
6.2 Continuous induction method.
In this welding process, the rotor I connected together with band brake. When the plastic
temperatures are achieved, the band brake which was connected comes into action with the
main role being is to stop the rotor but at the same time the pressure which is applied
continue to increase until the two work pieces joints well and thus the weld is achieved
(Yilbas, 2016).
6.3 Linear friction welding
Linear Friction welding is a solid-sate joining process which works through oscillating one
workpiece relative to another while under a large compressive force as shown in fig 1 below.
The friction which exist between the oscillating surfaces generates heat that causes the
material of the interface to plasticise (Blaga, 2015). The material which is plasticised is then
expelled from the interface causing the workpiece to burn-off (shorten) in the compressive

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force direction. In the process of burn-off the interface contaminants such as foreign oxides
and particles that can affect the properties and possibly the service life of a weld are expelled.
Once the workpieces are free from contaminants the metal to metal contact occurs which
leads to formation of an integral bond (Vill', 2015). Linear friction welding unlike other
methods of friction welding it takes place in four phases as listed below:
I. Phase 1: Initial stage
II. Phase 2: transition stage
III. Phase 3: Transition stage
IV. Phase 4: Forging and Deceleration phase
Phase 1 ( Initial stage):in this stage contact exist between asperities on the two surfaces
which are to be joined, then heat is generated because of friction shown in the figure below
.
Fig 1 : contact exist between asperities on the two surfaces

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The asperities deforms after softening , thus increasing the true area of the work pieces which
is in contact.axial shortening in the direction of the applied force is observed even tough it is
neligible.
Phase 2 ( Transition stage):The interface materails palcticise because of friction thus
becoming visious as shown in the figure below (Kim, 2017).
Fig 2: Transition stage
This makes the true area of the contact between the work pieces to increase to 100% of the
cross sectional area. More materials are softened as the heat conducts away. Due to the
expulsion of the viscous materials form the interface the burning-off starts to occur
(Metallurgists, 2013).
Phase 3 (Transition stage): During this phase axial shortening occurs at a constant rate by
the rapid expulsion of the viscous interface material and a quasi-steady-state condition is
also achieved, forming the flash as shown in the figure below (Friction Welding Technical
Group, 2010).

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Figure 3: Transition stage
Phase 4 (Forging and Deceleration phase): In this phase the workpieces are aligned and the
relative motion is stpoed.in some cases an addition forge force may be applied to assist the
weld to consolidate well (Ellis, 2013).
6.32 Process parameters
During linear friction there are eight are six parameters which are used as listed below.
 Oscillation amplitude
 Oscillation frequency
 Ramp-up time
 Supplied force
 Normal force
 Axial shortening (American Welding Society. Committee on Friction Welding, 2012)