CERTIFICATE
This is to certify that the Seminar Report entitled ‘Tube Expansion’ submitted
by Mr. Naveen. D. Unde, Examination No. B2210872 for the partial
fulfillment for the award of the degree of B.E. (Mechanical Engineering) of
university of Pune, Pune, is approved.
(Prof. Pradeep A Patil) (Prof. V.N.Phadkule)
Guide, Head of the Deptt.
Mechanical Engineering Deptt.., Mechanical Engineering,
A.I..S.S.M’S COE, A.I.S.S.M.S’, C.O.E.,
Pune Pune
Date: Date:
2

ACKNOWLEDGEMENT
I pay my profound gratefulness and express my sincere gratitude to
Prof. Pradeep A Patil , Department of Mechanical Engineering,
A.I.S.S.M.S.’s, C.O.E., PUNE for providing me very useful and valuable
information, for providing guidance and extending their co-operation in
writing this report.
3

CONTENTS
DEFINATION OF TUBE EXPANSION 05
TUBE SHEET PREPARATION 06
PROCEDURE FOR EXPANSION 07
EXPANSION LIMIT FOR TUBE EXPANSION 13
TIPS FOR GOOD EXPANSION 15
TUBE EXPANDER 16
TUBE PULLER 21
TUBE REMOVAL 23
CONCLUSION 25
4

Abstract:-
Tube expansion means elimination of diameter differences between two
pipe end and are joint with welding .The process is carried out to prevent stress
induced in the tubes due to expansion and contraction. The process is also useful to
avoid misalignment.
In this process tension is created between tube and tube sheet to make the
joint leak proof. In some cases buckling and bends are induced in the tubes, which
are minimized by tube expansion.
Tube expansion has minimum distortion of tube sheet and has high
reliability and reduces stress corrosion.
5

TUBE EXPANSION
· Definition: elimination of diameter difference between the two pipe ends to be
joined with welding (girth weld).
·
·
·
Fig.1
Measures:
· outside diameter of the pipe to be expanded, D1 [mm];
· wall thickness of the pipe to be expanded, t1 [mm];
· expansion length, L [mm].
· Possible cause of origin:
· pipe installation (laying);
· repair.
6

TUBE SHEET PREPARATION
Procedure for the preparation of tube sheet :
The sizes of the plates vary from 12.5 mm to 25 mm depending on the size
and capacity of the chiller. Normally the chiller with a lower capacity has a plate of a
small thickness and vice versa.
The preparation of tube plate start from the plate cutting shop where the plate
is cut into the required shape on the laser cutting machine. This machine is basically
a Linde cutting machine incorporated with a CNC control.
Once the plates are cut they are welded with small hooks which facilitate in
the lifting of the tube plate. These plates are then sent to the Parkerizing where all
the foreign particles (oil, grease etc.) present on the surface are made cleaned.
After the cleaning procedure is complete then the plate are then sent to the
machine shop where the operation of drilling, remaining and deburring are carried
out.
Normally the drilling operation is carried out with the help of a delta drill which
is little less in size than the actual hole to be drill. For example in case of copper
tube of size 16.25 mm a delta drill of 16.00 mm is drilled. After the delta drilling
operation is complete a groove is made in the hole which helps the tube to sit firm
inside the hole and also it prevent the loctite from flowing inside the chiller and
causing contamination of the liquids present inside the chiller and also the groove
also provide additional strength to the joint between the tube sheet and tube.
After the grooving operation is complete the plate are moved to the deburring
area where the entire burr present on the surface of the plates is removed with a
help of a deburring tool.
After carrying out all the operation on the tube plate the plates are then
shifted to the assembly shop where they are welded as the lower shell tube plates
and the upper shell tube plate. During this operation care must be taken that the
plates are aligned parallel to each other.
After the set up is complete the tube are instead and the tube expansion is
carried out as explained before.
7

PROCEDURE FOR EXPANSION OF THE TUBE OF HIGH TEMPERATURE
GENERATORS:
In case of high temperature generators where the temperature of the liquid is
about 187 degree Celsius more care is to be taken as with the expansion of the
tubes inside the high temperature internal stresses are introduced in the generators
and hence a special process is implemented for the expansion of these tubes.
In this case one of the sides of the tubes of the generators are expanded
before with a help of a four roller tube expansion tool with the torque kept at about 4
ampere. during this operation the other sides of the tube are kept free. After this is
complete special type of expansion procedure is used for the expansion which
involves the use of steam.
The steam is made to pass through the tube to be expanded from the side
already expanded, when steam is made to pass through the tube which have
sagged due to the self weight of the tube become straight and the projects outside,
due to the expansion due to longitudinal expansion of the tube. Now the expansion
is carried out on the other side. After this the ends of the tube are trimmed to close
tolerances.
There are three main critical factors that have to be taken care of during this
process :
1) The pressure of the steam which is been used in the process : Normally the
pressure of the steam us only about 5 Kg/meter square that means the pressure
is very less but at the same time it is very critical.
2) The thickness of the tube and the tube sheet.
3) The torque which is being used in the process : Normally more the torque more
is the expansion and more is the percentage reduction in the thickness if the
tube. In some cases the tubes normally crack due to over expansion.
8

COPPER Expansion Loops:
Copper tube, like all piping materials, expands and contracts with temperature
changes. Therefore, in a copper tube system subjected to excessive temperature
changes, a long line tends to buckle or bend when it expands unless compensation
is built into the system. Severe stresses on the joints may also occur.
Such stresses, buckles or bends are prevented by the use of expansion joints or by
installing offsets, "U" bends, coil loops or similar arrangements in the tube assembly.
These specially shaped tube segments take up expansion and contraction without
excessive stress. The expansion of a length of copper tube may be calculated from
the formula:
Temperature Rise (degrees F)
x Length (feet)
x 12 (inches per foot)
x Expansion Coefficient (inches per
inch per degree F)
= Expansion (inches)
Calculation for expansion and contraction should be based on the average
coefficient of expansion of copper which is 0.0000094 inch per inch per degree F,
between 70 F and 212 F.
For example, the expansion of each 100 feet of length of any size tube heated from
room temperature (70 F) to 170 F (a 100 F rise) is 1.128 inches.
100 F x 100 ft x 12 in./ft. x 0.0000094 in./in./°F = 1.128 in.
. Alternatively, the necessary length of tube in an expansion loop or offset can be
calculated using the formula:
where:
9

L = developed length in the expansion loop or offset (in feet), as shown in
E = modulus of elasticity of copper (in psi)
P = design allowable fiber stress of material in flexure (in psi)
do = outside diameter of pipe (in inches)
e = amount of expansion to be absorbed (in inches)
For annealed copper tube:
E = 17,000,000 psi
P = 6,000 psi
Thus, the developed length L is simply:
Hydro Expansion
Fig2
Advantages of the Airmo’s Model 222 Hydro Expansion System
Fast - Expansion operation of 2 to 5 seconds per tube Portable - You can bring the
expander to the coil Consistent - Normal wall thickness tolerances have no effect on
the expanded diameter result Flexible - Coil size and shape are of no concern Safe -
Operator is exposed to no moving parts Compact - Machine requires 10 square feet
of floor space Efficient - Very low power consumption Environmentally safe -
10

Expander uses ordinary tap water as the hydraulic expansion medium Economical -
Less expensive to purchase and maintain than mechanical expansion systems
Hydro expansion is a method of tube expansion, which fills the tube (either straight
length or hairpin tubes) with water. Once filled, the water is pressurized past the
yield point of the tube thereby providing expansion. This method is used extensively
in baseboard header assemblies and in air conditioning coil production for bonding
tubes to fin assemblies.
The hydro expansion system utilizes high-speed PLC control and pressure sensors
to produce an exact expansion. This is achieved by matching a preset pressure
value (operator entered) with actual line pressure or expansion pressure. When the
actual line pressure reaches the preset value, the expansion system instantly dumps
pressure providing a fast constant expansion and fin bond.
Hydro-Pel (is Hydro Mechanical) Expansion
Fig.3
Fast
Repeatable
Compact size
Hand held tooling
Low maintenance
11

Ball tube expansion
Ball insertion systems and tooling
Tube end bell systems and tooling
Hydrostatic test systems and tooling
Fig.4 Fig.5
Airmo, Inc. offers unique systems and tooling designed for full length, mechanical
tube expansion.
Hydro-Pel is a method of tube expansion which places a projectile, usually a ball,
into a tube with water pressure forcing the ball through the tube. Generally, the
amount of expansion is a function of the ball diameter and the tube wall thickness.
This method is suggested where straight length tubes are used with one operator
performing the expansion.
Airmo offers two Hydro-Pel expansion methods:
For applications in which tube belling is performed as a standard operation,
conventional ball expansion methods are used. With the tube pre-belled or
preexpanded, the operator places a ball into the tube and places an expanding tool
over the tube end and starts the system pressure cycle. High pressure water is
directed behind the ball, forcing it down the tube. If the tube is not in a prebelIed
condition, ball insertion can be done with the Airmo ball insert tool.
12

TITANIUM ROLLER EXPANSION:
The most commonly use method of making tube/tube sheet joints is roller
expansion.
Roller expansion procedures for titanium tubes into tube sheets are similar to those
used for other materials. For best results, the tube sheet holes should be within the
limits specified by TEMA (Tubular Exchanger Manufacturers Association) or within
the limits specified by HEI (Heat Exchange Institute)
There are three commonly used methods of determining the correct
amount of expansion:
1.Measuring wall reduction
2.Simulating wall reduction by interference
3.Pull-out strength versus torque curve
The above pull-out test is preferable.
The suggested wall reduction for titanium tubes is 10%. Thus, in a .028" tube or a .
020" tube, the required reduction is .0028" or .0020". A small error in measurement
can result in a large deficiency in pull-out strength.
Using the interference fit method, four measurements are required:
1. Tube I.D.
2. Tube wall thickness
3. Tube sheet hole diameter
4. Tube O.D.
13

RUBBER EXPANDTION
Fig.6
The Advantages
Of Rubber
Expansion Joints
and Flexible
Connectors
1. Prevents stress due
to expansion and
contractions
2. Insulates against the
transfer of noise
and vibration
3. Compensates for
misalignment
4. No electrolysis
5. Greater recovery
from movement
6. Freedom from
corrosion
7.7. Ease of installation
8. Small space
requirements
Expansion limit for expansion of tubes
Tube expansion can be compared to the cold rolling of steel sheets. The tube to be
expanded can also be equated with an endless steel sheet which, during the rolling
process, has been lengthened or enlarged to a point when the external diameter of
the tube equals the diameter of the tube sheet hole.
This first stage is called 'metal to metal contact'. Note that the expansion at this
stage is not yet leakproof.
Further rolling is necessary to increase the expansion and reach the point when the
material is deformed. This creates tension because of the compression between the
14

tube and the tube sheet. A leakproof expansion is assured if the pressure tension is
greater than the service pressure, which arises from the heating, the lengthening
and finally the tension of the medium. The difference of expansion between the
'contact' and the final expansion is called 'expansion limit'
This 'expansion limit' must never cause a rupture in the cohension of the molecules
of the tube material by an exaggerated deformation of the material. If this were the
case the tube material could become dammaged – it could crack or break – and this
would create the danger of explosions etc. when the tube comes under high
pressure.
It could then happen that, though the tests had turned out positive, the tube will
prove useless after a few days in service.
Example:
Tube dimension: 30 x 3 mm
Tube sheet hole: 30.4 mm
less 2x3mm tube wall thickness: - 6.0 mm
theor. internal dia. of the tube at 'metal to metal contact': 24.4 mm
plus expansion limit i.e. 20% of the tube wall thickness: + 0.6 mm
Theoritcal inner dia. of tube after having reached the expansion limit: 25.0 mm
Recommended expansion ranges:
Metal to metal contact: about 3 - 5% of tube wall thickness
Expansion limit: about 15 - 20% of tube wall thickness
:
· Listed below are the tips for proper tube expansion
15

· The tube plates must be shot blasted – parkerised – CNC drilled – vapour
degreased before fabrication.
· A groove must be provided for preventing the loctite entering the machine and
the groove must also contribute to the strength of joint between the tube and the
tube sheet.
· The tube hole should not have a prefect round shaped hole without any
longitudinal or helical scratches as they contribute to he leak path.
· Expander tool maintenance
 The grub screw should be made tight before the start of the shift.
 The roller should be changed after the expansion of ever 70 ends.
 The mandrel should be changed after the expansion of ever 1400 ends.
 The tube expander should be cleaned with the soap solution after completing
the four tube ends.
 All burr and loctite stick should be removed after ever hundred tube ends are
completed or even before.
· Under rolling may be preferred as it can be easily reworked but in case of over
rolling it is not accepted.
· In case of direct fired vapour absorption machine all gaps should be sealed in
order to prevent crevice corrosion.
· In case of titanium tubes which are used in conjunction with saline water a four
roller expander is normally recommended with low rpm. This is done in order to
prevent cracking of tubes.
· The expansion length should normally be about 2 mm less then the thickness of
the tube sheet.
· In case of stainless steel tubes steam is used to prevent elongation of the tubes
during expansion process.
· In case of special tubes always swage the ends always remove the tube from the
same side.
16

· In case wherein the clearance between the tube and the tube sheet is very large
then the max tube expansion limit is in sufficient than trust collar butting tube is
used.
· The high temperature stainless steel tubes which are internal seam welded
should be ground to length of 60 mm and the projection should not exceed 0.3
mm.
· The best method of cleaning tubes and tube sheet is the use of vacuum pump
and not the use of compressed air.
· The holes of the tube sheet should be cleaned by the use of vapour degreasing
method. After this is done then the cleaning is done by the use of clean rag and
not with cotton waste.
· Gloves should be used while handling tubes.
· In case of a Sugino expansion machine with present torque – value the machine
may stop before the set limit due to error or at a set limit due to manual error or
at a set limit without any expansion due to a malpractice.
TUBE EXPANDER
113/123 Series
Fig.7
For Heat Exchangers and other Heat Transfer Units. The function of the series
113/123 heavy duty tube expander is to make a good mechanical seal between tube
and tube sheet.
Elliott expanders do this by means of a set of rotating, parallel-rolling and self-feeding
rolls which cold-work the tube joint metals until the tube ends fit tightly in the
17

holes in the sheet. This occurs because the forces built up in the tube sheet reach
inward toward the center of the hole, and those in the tube react outward.
Parallel-roll expanders roll tubes more uniformly than other types, thus developing
maximum strength in the joint. Elliott expanders have adjustable ball- bearing thrust
collars. A radius on the front of the rolls, prevents any sharp offsets inside the tube.
The rolls have also been given a feed angle that assures uniform expansion and
tightness of the tube in the tube sheet.
3300 Series:
Fig.8
For use in Fire and Water Tube Boilers, Air Coolers, Heaters
and Re-Rolled Flared or Welded Tubes
Series 3300 Elliott tube expanders are recommended for any requirement for
parallel rolling of tubes in tube sheets.
These tube expanders have a ball bearing thrust collar which reduces friction to a
minimum. They typically are used with torque controlled rolling motors for uniform
rolling of tubes.
DRE Series
Fig.9
Series DRE tube expanders for deep rolling and hard rolling of steam and mud
drums of high pressure boilers.
18

Series DRE tube expanders are furnished with a minimum reach of 3.5", maximum
reach of 10.50", and an effective roll length of 2-5/8".
The Series DRE and the Elliott Series 1500 make a great combination of boiler tube
erection or boiler tube replacement expanders
For High and Low Pressure Steam Boilers
Fig.10
Series 1500 Elliott tube expanders are self-feeding for power or hand use. Will roll
tube parallel and smooth in tube hole and flare projecting tube end at an angle of 20º
from center line in one operation.
These tube expanders are made for sheet or drum thicknesses from ½ to
3". The expanding rolls are sufficiently long to roll tubes 3/8" beyond sheet thickness
listed plus a generous radius to eliminate sharp offset within tubes ... enabling
erectors and boiler makers to roll tubes the desired distance beyond tube sheet,
drum or header wall.
3300 Series
Fig.11
For use in Fire and Water Tube Boilers, Air Coolers, Heaters
and Re-Rolled Flared or Welded Tubes
19

Series 3300 Elliott tube expanders are recommended for any requirement for
parallel rolling of tubes in tube sheets.
These tube expanders have a ball bearing thrust collar which reduces friction to a
minimum. They typically are used with torque controlled rolling motors for uniform
rolling of tubes
Universal Joint Drives:
Fig.12
Provides an effective operating range at angles up to 35°, designed especially for
use with tube expanders when rolling tubes where space is limited and where tubes
are not in direct line wit hand holes
SPECIAL TYPES OF TUBE EXPANDERS
Table:-1
Step By Step Tube Expander
This model expander is especially
designed for thick tube sheets
Automatic overlapping of the rolling in
stages.
For tubes 3/8" to 13/8"(9.5 mm to 34.9
mm) I.D. and tube sheet thickness 2 1/2"
to 27 1/2" (63.5 mm to 698.5 mm) .
Five Roll Expander
Model Ch800 and Ch 1200
A special line of Expanders to expand thin
wall tubes, titanium, stainless steel and
other high quality metals. Available with
special thrust collars, to eliminate the
possibility of the tube being drawn into the
trust collar.
20

Tube Expanders Model: SR
Ideally suited for tube rolling with
minimum travel of mandrel. Expander
mandrel is retained at rear to shorten
mandrel length and to allow use near tube
bends or I.D. fixed tubes
Table :-2
STESB Series
Top plate tube expansion in pans, juice heaters with
sugar mills. Sizes range from 38.1mm (1 1/2") to
114.3mm (4 1/2").
STE CSB Series
Bottom plate tube expansion in pans, juice heaters
within the sugar mill. Tube sizes from 44.5mm (1 3/4")
to 101.4mm (4") O.D
STE114 Series
The STE114 series is a "general purpose"
expander for expanding and flaring boiler tubes,
waterwall, downcomer, economiser, riser and
airheater tubes. Tube sizes from 50.8mm (2") to
114.3mm (4 1/2") O.D. - Tube Sheet 12.7mm
(1/2") to 66.7mm (2 5/8")
21

1)Collet-Type Tube Puller
#M5360-00
Fig.13
Some customers say they can pull tubes in less than ten seconds, light-wall tubes in
five. Heavy wall tubes in thick tube sheets require more time to allow pump to
develop the needed pressure.
Features
· For pulling 1/2" through 1-1/2" O.D. tubes in seconds.
· Automatically sets teeth to the same preset pressure every time.
· Powerful 2 HP, 110 Volt industrial rated motor.
22

· 17 Ton Pulling capacity.
· 4000 PSI 20 ft. hydraulic hose connects the pump to the tube pulling cylinder
assembly
· Model M5733-00 for 230/1/50 electric applications.
:
2)Collet-Type Tube Puller Accessories
Collet and drawbar look like this before entering tube
Fig.14
Drawbar retracts by hydraulic pressure, setting collet teeth to fit tube I.D. Tube I.D.
will often vary, but the collet adjusts automatically to each tube and sets the collet to
a preset pressure for pulling
Fig.15
3)Cyclegrip
M5630-00
Fig.16
23

Continuous Tube Puller for maximum operating efficiency
Features:
· Extracts ferrous and non-ferrous tubes from ½" through 1"- O.D. Adapts to
these diameters without additional tooling.
· Grippers exert 2 tons of force at 4,000 PSIG
· Continuous 5 inch stroke operation as long as the pendant switch is
depressed.
· Comfortable "D" handle grip reduces operator fatique
· In continuous operation, a pulling rate of 120"/min. is produced
· Small profile permits extraction of tubes close to the water jacket
· Quick connect control cable and single hydraulic supply hose
· Weight 16 lbs
PROCEDURE FOR TUBE REMOVAL OF THE TUBES
24

After the tubes are placed in the tube sheet expanded they are checked for leaks
between the tube sheet and the tubes. The normally procedure for the leak detection
is nitrogen testing which is well known as soap test or bubble test, which is
explained in the following steps below :
1) The unit is cleaned with a vacuum pump and the adapter is welded to the unit.
2) After the welding operation is completed nitrogen is filled in the unit to a pressure
of about 1.3 Kg/m2. Then soap solution is sprayed on the entire surface and
checked for bubbles.
3) The places with leaks are indicated by the formation of bubbles. Once the tubes
with expansion leaks are detected they are marked.
4) After the detection of leaks in the tubes joints one end of the tubes is crushed
(collapsed) with the help of a tube crusher, care should be taken that during the
collapsing operation no damage is made to the surface of the tube sheet hole.
5) After the above operation, a Tube Puller with tapes is inserted on the other side
and the tube is puller out by the hammering operation. And a new tube is
inserted and expanded by the same standard procedure.
CONCLUSION:
25

Tube expansion is a faster and most reliable method of obtaining a perfect joint
between the tube sheet and the tube for the heat exchanger and high temperature
generator
The cost of tube expansion equipment work to economical at compared to any other
tube to tube sheet joint. To avoid this loss in some cases stresses are induced in
bends so it may causes a leakage in the joints so to avoid this, tube expansion
process is carried out.
Tube expansion is used to provide proper mechanical seal between tube and tube
sheet and to minimized friction.
Tube expansion process is having minimum distortion between tube and tube sheet
so to have proper leakproof joint.
REERENCES:
26

WWW.GOOGLE.COM
WWW.ALTAVISTA.COM
Tips for good expansion.THERMAX LTD INDIA
27

Tube Expansion Seminar Report Summary

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