This document provides an overview of hydroforming, including: 1. Hydroforming is a process that shapes sheet metal or tubes using high-pressure fluid inside a die to form complex shapes. It offers benefits like lower tooling costs and better part properties compared to stamping. 2. There are two main types - tube hydroforming and sheet hydroforming. Tube hydroforming uses pressure inside a tube held in a die to form it, while sheet hydroforming forms sheets using fluid counter-pressure. 3. Hydroforming allows complex shapes to be formed and improves strength to weight ratio of parts at lower cost than individual stamped pieces. It sees use in automotive and other industries for parts like structural components.

1. MAHARISHI MARKANDESHWAR UNIVERSITY
SADOPUR, AMBALA
A
Seminar Report
on
HYDROFORMING
Department of Mechanical Engineering
SUBMITTED TO: SUBMITTED BY:
Miss. Preeti Saini Pawan Kumar
B. Tech. (Mech.)
7th Semester
75144028

2. CONTENTS
SR. NO. PARTICULARS PAGE NO.
01. Abstract 01
02. Introduction 02
03. Methods of Hydroforming 03
04. Hydroforming process control 06
05. Benefits of Hydroforming 08
06. Forming limit diagram 11
07. Application 11
08. Factors affecting the Hydroforming 12
09. Advances in hydroforming 13
10. New conceptin SheetHydroforming 22
11. Conclusion 24
12.
References
25

3. ~ 1 ~
ABSTRACT
Until recently hydro forming of sheet and tube was not considered for automotive manufacturing due
its high cycle time. However, advances in hydraulics and intelligent press design over the time have
reduced cycle time considerably making it attractive for automotive manufacturing. In addition, hydro
forming of sheet and tube offers benefits such as a) low tooling cost, b) better properties (dent
resistance and energy absorption) of part after forming, c) ability to form complex shapes and
integrated structures (hydro formed tube may replace an assembly from several stampings). These
reduce assembly cost and time thereby represents an attractive alternative to stamping in the current
market trend towards smaller batch size of new models. It is broadly classified into sheet and tube
hydro forming depending on the input pre form. Further, sheet hydro forming is classified into hydro
mechanical deep drawing and high pressure sheet hydro forming depending on the male or the female
die that has the shape/impression to be formed. High pressure sheet hydro forming is further classified
into hydro forming of single blank and double blank depending on number of blanks being used in the
forming process. This paper provides an overview on the advances in press (machines) & tools, tests
for material and lubrication selection and strategies for process design through FE simulation in all the
areas of sheet and tube hydro forming.

4. ~ 2 ~
INTRODUCTION
Hydro forming is a high-pressure deformation process that shapes metal sheets or tubes into a
predefined geometry by using a fluid under high pressure. Hydro forming is similar to the
conventional deep-drawing technique with a counter-mould. The specific difference from the
conventional method is that a fluid is used instead of a die to forming into final shape. This
deformation process requires application of fluid pressures up to 4000 bars depending on the size of
the component.
As the automobile industry strives to make car lighter, stronger and more fuel efficient, it will
continue to drive hydro forming applications. Some automobile parts such as structural chassis,
instrument panel beam, engine cradles and radiator closures are becoming standard hydro formed
parts.
Recently hydro forming was used for manufacturing of clad pipe used in oil and chemical industry.
The capability of hydro forming can be more fully used to create complicated parts. Using a single
hydro formed item to replace several individual parts eliminate welding, holes, punching etc.
Hydroforming simplifies assembly and reduce inventory.
The process is quite simple - a blank with a closed-form, such as a cylinder, is internally pressurized
using fluid. The fluid is frequently water. The applied pressure is usually in the range 80-450 MPa. Its
resultant plastic expansion is confined in a die of the desired shape.
Hydroforming is a cost-effective way of shaping malleable metals such as aluminum or brass into
structurally stiff and strong pieces. One of the largest applications of hydro forming is the
automotive industry, which makes use of the complex shapes possible by hydro forming to produce
stronger, lighter, and more rigid body structures for vehicles. This technique is particularly popular
with the high-end sports car industry and is also frequently employed in the shaping of aluminum
tubes for bicycle frames.
Hydro forming allows complex shapes with concavities to be formed, which would be difficult
standard solid die stamping. Hydro formed parts can often be made with a higher stiffness to weight
ratio and at a lower per unit cost.
This process is based on the 1950s patent for hydra molding by Fred Leuthesser. It was originally used
in producing kitchen spouts. This was done because in addition to the strengthening of the metal,
hydramolding also produced less "grainy" parts, allowing for easier metal finishing.

5. ~ 3 ~
Hydro formed handle bar Hydro formed T-junction
METHODS OF HYDRO FORMING
1. Tube hydroforming
2. Sheet hydroforming
1. Tube hydroforming
In tube hydroforming (THF) there are two major practices: high pressure and low pressure. With the
high pressure process the tube is fully enclosed in a die prior to pressurization of the tube. In low
pressure the tube is slightly pressurized to a fixed volume during the closing of the die (this used to be
called the Variform process). It is mostly used in the automotive sector, where many industrial
applications can be found. It is also a method of choice for several tubular members of bicycles. In
tube hydroforming pressure is applied to the inside of a tube that is held by dies with the desired cross
sections and forms. When the dies are closed, the tube ends are sealed by axial punches and the tube is
filled with hydraulic fluid. The internal pressure can go up to a few thousand bars and it causes the
tube to calibrate against the dies. The fluid is injected into the tube through one of the two axial
punches. Axial punches are movable and their action is required to provide axial compression and to
feed material towards the center of the bulging tube. Transverse counterpunches may also be
incorporated in the forming die in order to form protrusions with small diameter/length ratio.
Transverse counter punches may also be used to punch holes in the work piece at the end of the
forming process.

6. ~ 4 ~
HOW CAN TUBE HYDRO FORMING BENEFIT THE AUTO
MANUFACTURER
 Increased strength to weight ratios
 Multiple cross – section reshaping or section modules increase
 Improved stiffness torsion and bending rigidly
 Improvement in NHV Factor

7. ~ 5 ~
 Incorporation of hole punching, slot making, embosses swing hydro forming process.
 Reduction in number of manufacturing stages, hence tooling.
 Reduction in welding, hence distortion and subsequent heat treatment.
2. Sheet Hydro Forming
Sheet hydro forming involves forming of sheet with application of fluid pressure. A sheet metal blank
informed by hydraulic counter pressure generated by punch drawing sheet into pressurized water
chambers. The water pressure effectively punches the sheet firmly against punch to form required
shape.
The major advantage of fluid forming is increased drawing ratio. The process tale place in two stages
performed during one press stroke. The sheet in performed by applying low fluid pressure while it is in
clamped firmly by a blank holder pressure. Performing achieves on evenly distributed strengthening in
the component center. In next step fluid pressure in gradually increased and blank holder pressure in
controlled relative to sheet reformation.

8. ~ 6 ~
Advantages of sheethydroforming
1. Requires fewer operations to make certain part geometries.
2. Does not require lower or upper draw punch or cavity.
3. Uses water, a widely available resource.
4. Forces material to distribute stretch or strain more evenly
5. Reduces springback
6. Reduces material consumption
7. Forms higher strength materials Inexpensive tooling costs and reduced set-up time.
8. Reduced development costs.
9. Shock lines, draw marks, wrinkling, and tearing associated with matched dieforming are
eliminated.
10.Material thinout is minimized
11.Low Work-Hardening
12.Multiple conventional draw operations can be replaced by one cycle in a hydroforming press.
13.Ideal for complex shapes and irregular contours.
14.Materials and blank thickness specifications can be optimized to achieve cost savings.
Disadvantages of sheet hydroforming
1. Requires expensive equipment
2. Cycle times are generally poor
3. Operators often get wet
HYDRO FORMING PROCESS CONTROL
A typical hydroforming system would include a press capable of developing necessary forces to clamp
the die valves together when internal pressure acts on fluid; a high pressure water system to intensify
water pressure for forming component, looking including aerial cylinder and punches, depending on
component and a control system for process monitoring.

9. ~ 7 ~
Since the entire process of operation takes place inside a closed die, one cannot see what actually
happens during forming. Therefore the controller plays a vital role in displaying, monitoring and
controlling the different parameters of forming in real time.

10. ~ 8 ~
BENEFITS OF HYDRO FORMING
 Better degree of deformation of the formed part
By applying a uniform force to the metal sheet, the fluid shapes it into the form of the tool. In this
process, a uniform distribution of sheet thicknesses is achieved, which allows for maximum degrees of
deformation. Abrupt changes in stress are avoided – a factor that ensures high dimensional accuracy
and reduces the tendency of the material to return to its original size and shape when the applied load
is removed.
Conventional deep-drawing Hydroformed with the FB25
 strong local thinning of the material
 inhomogeneous distribution of material
thicknesses
 less internal stress of the formed part
 less internal stress and less tendency to
return to its original shape
 homogeneous strength and less amount of
waste
 high dimensional accuracy
Stresses in Hydroformed component
 Good Surface Finish
Since the metal sheet is deformed using a pressurized fluid instead of a conventional deep-drawing die,
the surface is not in direct contact with any tool that may lead to surface damage. In the hydroforming
process, the metal sheet only comes into contact with the tool when the maximum required forming
pressure is reached. This results in excellent surface finish of the formed parts.

11. ~ 9 ~
 Use of Various Engineering Materials
The hydroforming process allows you to use the complete spectrum of all ductile and malleable
materials. No matter if you are using steel sheets, stainless steel, special alloys, aluminium, copper,
brass or titan: for all of them, optimum degrees of deformation can be achieved. Metal sheet
thicknesses range from 0.05 to 6 mm. specifically for very thin metal sheets, the possibilities of
hydroforming are far superior to those of conventional forming techniques.
 Savings in tooling costs up to 80%
Low tooling costs are a great advantage of the hydroforming process using the Form Balancer. Tooling
costs are reduced to 50% by the fact alone that only the negative moulding tool is needed. Further
savings are generated by no longer needing hold-down devices and guide way systems. Due to the
possibilities of forming complex geometries with only one tool, upstream machining operations can
often be omitted, which in most cases reduces tooling costs to only 20% compared to those of
conventional deep-drawing tools.
 Reduction in weight
Automakers continuously strive to reduce motor vehicle mass, mainly for efficiency and
environmental reasons such as improving fuel efficiency and reducing emissions. However, as they
reduce vehicle weight, they must try to avoid compromising other important criteria, such as strength
and energy management. They look for technologies, techniques, and processes that satisfy these
various needs, to which hydroforming are the answer. Also the process and functional characteristics
need to be maintained.

12. ~ 10 ~
Hydroformed versus Stamped Components
Much of a vehicle's weight is in the structural frame, and most frames are made from steel. The
exception is aluminium, which is used in some automobiles.
Concept
Mass
(kg)
Weld Length
(mm)
Performance Fore/Aft
Loading
Stamped 23.0 4,915
Red scale set to 1.0 x material
strength
Hydroformed 20.9 3,975
Red scale set to 1.0 x material
strength
Change -2.1 -940
Compared to a traditional stamped automotive part, a similar tubular
component has less mass and requires less welding. In this case, the
reductions were more than 9 percent mass and 19 percent in weld length.
 Nearly unlimited wall Thickness variations
The wall thickness can be adjusted anywhere along the part between some predetermined minimum
and maximum thickness, allowing a nearly infinite combination of thickness zones. This level of
design freedom enables design engineers to fine-tune the part to achieve a desired load response.
Variable-wall technology is not limited to round cross sections—it can be used to manufacture most
symmetric shapes without any post forming operations. Heat treatment adds even more versatility to
these structures, imparting properties that range from those of strip to fully cold-worked steel. Finally,
it can be beneficial in many nonautomotive applications as well.

13. ~ 11 ~
FORMING LIMIT DIAGRAM
During hydro forming process failure occurs due to thinning, this is due to the excessive
deformation in a given region. A quick and economic analysis of deformation in a forged part is
analyzed from forming limit diagram. The sheet is deformed, converting circles in to ellipse, and the
distorted pattern is then measured and evaluated. Regions where the area has expanded are locations
of sheet thinning Regions where area has contracted have undergone sheet thickening. Using the
ellipse on the deformed grid, the major (Strains in the direction of larger radius) and associated
minor strains (Strains perpendicular to the major) can be determined for variety of locations and
values can be plotted on the forming limit diagram. If both major and minor strains are positive
deformation is known as stretching, and thinning will possible.
APPLICATIONS
Almost any industry can benefit from the advantages of the hydroforming process. Again and again
companies are faced with the challenge of simultaneously achieving both lower operating costs and
innovative solutions for evolutionary advances of their products. Our high-pressure forming
technology offers attractive possibilities in terms of price-performance ratio and manufacturing time.
Hydroforming finds its application in following industries:

14. ~ 12 ~
 Automotive industry
 Aerospace industry
 Medicine technology
 Electronic appliances
 Heating & air conditioning
 Agriculture industry
FACTORS AFFECTING THE HYDRO FORMING PROCESS
As hydro forming becomes more widely used, several issues must be addressed to increase the
implementation of this technology in the stamping industry. These issues include:
1. Preparation of tubes, which involves material selection and quality of the incoming tube.
2. Pre form design and production method.
3. Part design for hydro forming.
4. Welding and assembly of hydro formed components that is, fixturing and joining.
5. Crush performance and joint stiffness.
6. Selection of a lubricant that does not break down at high pressures.
7. Rapid process development.

15. ~ 13 ~
ADVANCES IN HYDROFORMING
In recent years hydroforming has become a commonly used method of tube expansion for many
applications, such as automotive chassis frames, exhaust manifold piping connectors, and air-
conditioning system components. Because hydroforming uses water under high pressure to expand the
tube or pipe from the inside, and water can take any shape, it’s a versatile process and is suitable for
forming complex, single-piece components.
During the last decade, industry has seen dawn of hydroforming as an alternative for stamping and
various forming the reason for this are its advantages and the unprecedented research work done in
improving the techniques of hydroforming. Some of the new techniques are:
 Variform process or Pressure sequencing
 Hammering
 Pre-Pressurizing
 Manufacturing of Clad Pipes
1. Variform process or Pressure Sequencing
Pressure Sequence Hydroforming (PSH) is a patented tube hydroforming process that utilizes low
internal fluid pressure to support the tube while the die closes. Once closed the majority of the part
profile has been formed. At this point the internal pressure is increased to lock in the form and provide
backup for punching holes.
Hole size can range from as small as 2 times material thickness to as large as 50 mm X 200 mm. Holes
can be extruded or clean pierced, and practically any shape including round, slot, square, hexagon, or
rectangular. The resulting material slug is typically pushed back out of the way and left attached inside
the tube, though there are techniques available to remove them when required.
Pressure Sequence Hydroforming (PSH) is compatible with most metals; if it can be made into a tube
PSH can form it. The process that normally establishes the required material elongation is the
prebending operation. PSH has proven process compatibility with High Strength steel up to 960 MPa

16. ~ 14 ~
UTS, Dual Phase, and TRIP steels. In addition to carbon steel the PSH process has been used to form
both 5000 and 6000 series aluminium, and numerous grades of stainless steel.
Pressure Sequence Hydroforming (PSH) reshapes the tube cross section into the required profile
without stretching the material. The tube material thickness distribution found after hydroforming is
the same as that present in the bent tube. Pressure Sequence Hydroforming (PSH) reshapes the tube
while the die closes. Once the die is completely closed the tube has been forced to take the shape of the
die cavity without requiring the material to expand. High Pressure Hydroforming first closes the die on
an undersized tube and then utilizes high internal fluid pressure to expand the tube to fill the die cavity.
The part to part or floor to floor cycle time for Pressure Sequence Hydroforming is in the range of 17
seconds for a small part such as an Instrument Panel Beam to 24 seconds for a large part such as a roof
rail or structural member.
The Pressure Sequence Hydroform (PSH) process uses a completely different mechanism than HPH to
form the corners. In the PSH process, the tool stops before it is completely closed on the tube, this is
referred to as the prefill height. The tool dwells at this point as the tube is then filled with fluid and
lightly pressurized. The die is then fully closed while the tube is supported by the prepressure. Using
this support PSH forms the cross section corners while the die is closing under prepressure.
Pressure Sequence Hydroforming is a dimensionally stable and robust process. Product features that
are produced in the hydroform tool are typically very stable as the entire part profile and all piercing is
completed in a single cavity.
Sequencing the pressure prevents pinching the material in the die. As part complexity continues to
increase, in order to minimize part, containing the tubular blank inside the die cavity becomes more
difficult. An improperly contained blank can easily become pinched between the die halves, leading to
an improper fill and perhaps rupture. It also eliminates the need for posthydroforming processes such
as annealing and washing. Using the PSH process, tube corner radii are formed in the bending mode
beyond the yield limit of the base material, rather than in the tensile mode reached during conventional
high-pressure hydroforming.

17. ~ 15 ~
Part made using Variform Process
2. Hammering
Hammering uses two alternating pressures. It reduces the drag force, which is the friction that develops
between the work piece and the die. As the internal pressure increases, the work expansion force
increases the drag force, or friction, between the work piece and the die. Also, the internal pressure
becomes a force that pushes back against the hydraulic system. The combination of work expansion
force and internal pressure is the reaction force.
As the reaction force increases, it becomes difficult to force the material to flow into all of the contours
and recesses of the die. The hammering method cycles between a high and low pressure. The repeated
pressure drops reduce the drag force, allowing the material to flow further in the die. It also prevents
thinning at the expansion areas and improves the process capability.
The hammering process is driven by a pump that varies the pressure it develops, such as a direct drive
volume (DDV) control pump, a high-pressure generator that uses a hydraulic servo pump. The DDV is
a hybrid of an AC servomotor and reversible-piston pump. The pulsations are generated by controlling
the forward and reverse rotation of the AC servomotor at high speed.
The time from start-up time to shutdown time (including hold time) is one cycle. The frequency is the
number of cycles that elapse in one second and is measured in hertz (Hz). Results from hydroforming
trials have shown that the optimal hammering frequency range is between 1 and 3 Hz. Frequencies
higher than 3 Hz make it physically impossible for the pressure to reach the intended high and low
points. In other words, reversing the pressure more than 3 times per second doesn’t give the hydraulic
system enough time to achieve the programmed pressures. The optimal pressure range is between 725
and 4,350 pounds per square inch (PSI), or 5 to 30 MPa.

18. ~ 16 ~
Setup for Hammering
Above figure shows the actual setup used for Hammering. The complete system uses three DDV
pumps. One generates the pulsating pressure that forms the tube; the others are multipurpose pumps
used to raise and lower the press’s upper die at high speed. When the upper die is completely closed,
the DDV seals and presses in both ends of the tube work piece. The DDV’s AC servomotor is
regulated by a CNC. This controls the hammering frequency and pressure increase rate.
The pulse frequency and pressure on the secondary side is controlled by the reversible AC servomotor
of the DDV pump and pulsing the primary side of the oil and water boosting cylinder at a ratio of 1-to-
10. The shape that can be formed in one cycle of tube expansion is determined by the maximum water
capacity in the high-pressure cylinder.

19. ~ 17 ~
Hammering Cycle
The Hammering method cycles between a high and low pressure, so Hammering has more variables
than in conventional hydroforming. Instead of one pressure, hammering uses two alternating pressures.
Also, in this case, the last two cycles as can be seen in above figure have a brief hold time of 0.2
second at the points of minimum and maximum pressure. Hammering allows the user to vary the
difference between the high and low pressure (10MPa in this case), the cycle time and also the hold
time.
The two main problems faced while forming are rupturing and buckling. Rupturing is usually the result
of setting the internal pressure too high or the expansion force too low. This causes the material to
stretch and become too thin in the expansion area, ultimately causing a rupture. This is why it is
critical to balance the internal pressure and initial expansion force. Using an initial pressure that is too
high also can cause the pipe to expand too quickly, causing the material at the axis sealing area to pull
away. This, in turn, causes the fluid to leak, so the pressure does not rise to the set value and the
processing can’t start.
Buckling usually is caused by setting the internal pressure too low or the expansion force too high.
Using a processing time that is too fast also may contribute to buckling.
Hammering eliminates these problems as it uses two alternating pressures which balances initial
pressure & expansion force. As we can see the part made by conventional hydroforming process

20. ~ 18 ~
shown in the diagram below is ruptured, whereas the part at the bottom made by Hammering did not
get ruptured.
Part made by Hammering
3. Pre-pressurizing
In pre-pressurizing method a metal tube is placed in lower mold with the ends sticking out from it
and injects a pressurizing fluid into the metal tube through the inside of a seal punch and gradually
presses the seal punches against the tube ends, in the state with internal pressure and pressing force
applied the upper mold is lowered so as to deform the tube and end the processing with the tube
ends sticking out from the mold and further boosting the internal pressure in metal tube after closing
the mold and ending the forming operation and a hydroformed product having a flange across the
entire length in longitudinal section is formed.
As shown in Fig.1. the conventional hydroforming method relates to placing a metal tube shorter in
length than the mold in a mold so that the tube ends of the metal tube are positioned inside the end
faces of mold, then upper mold is lowered to close the mold and clamp the tube between upper and
lower molds. After that seal punches advance and water is inserted as a pressurizing fluid from one
of the seals, the pressure inside the tube is raised to obtain predetermined shape.
In this new technique of pre-pressurization a metal tube is placed in the lower mold with its tube
ends sticking out of the mold, injecting pressurized fluid into the metal tube through an inside of a
seal punch while pressing seal punches against the tube ends, filling the inside of metal tube with a
pressurized fluid to apply internal pressure, then the upper mold is lowered so as to close the mold,

21. ~ 19 ~
deforming the tube to the predetermined shape with the tube ends sticking out of the mold. The
process is shown in Fig.2.
Conventional Method of Hydroforming

22. ~ 20 ~
Pre-Pressurizing Method of Hydroforming

23. ~ 21 ~
4. Manufacturing of Clad pipes
The energy sector is hot right now, and so is pipe production. Pipe for transporting crude oil and
crude gas must meet several criteria. The material must have sufficient durability, corrosion
resistance, and strength, and the size must be large enough to transport the desired volume.
Corrosion resistance is necessary to prevent erosion damage from pollutants in the oil or gas, which
include hydrogen sulfide, chlorides, and water. Finding the optimum material for making pipe for
this industry is tricky. Low-alloy carbon steels tend to be strong, but lack corrosion resistance.
Stainless steels resist corrosion but lack strength. Cladding low-alloy carbon steel with a thin layer
of a corrosion-resistant alloy is a suitable process.
An alternative is to produce clad pipe that makes the best use of corrosion-resistant alloys and low-
alloy steels. Such pipe typically is made from strong, low-alloy carbon steel and lined with a sleeve
made from a corrosion-resistant material approximately 0.19 inch thick. The simplest mechanically
clad pipe consists of a corrosion-resistant liner inserted into a low-alloy external carbon steel pipe.
A more sophisticated mechanically clad pipe is produced by shrinking the external pipe or rolling
one pipe inside the other. The nature of the mechanical bond depends on the process. Regardless of
the method, the bond is purely mechanical. The two distinct materials remain two distinct materials
they do not fuse together to become a single mass as metallurgically bonded pipes do.
A process was devised which used hydraulic pressure on the inner pipe and induction heating on the
outer pipe. The hydraulic pressure caused the inner pipe to expand; removing the heat caused the outer
pipe to shrink as it cooled.
A modern improvement to this process uses a hydraulic pipe calibration and lining machine equipped
with an additional water system as well as sophisticated controls. It uses a process similar to
automotive parts hydroforming machines to attain a high degree of compressive contact between the
two pipes. The corrosion-resistant pipe is inserted into the outer low-alloy carbon steel pipe in a semi-
automated operation and is then placed into the calibration machine's open tool form. The tool closes
and axial cylinders seal each of the pipe ends. Hydraulic fluid under high pressure expands the inner
tube. A firm compressive contact is achieved by the elastic and plastic behaviors of the outer pipe and
the inner pipe. The elastic spring back of the outer pipe is greater than the plastic expansion of the
inner pipe; the resulting residual pressure stress of the inner pipe is in the region of 7,250 to 14,500
pounds per square inch (PSI). This provides a homogenous contact along the pipe's entire length.
One of the chief advantages of using a hydroforming process to manufacture mechanically clad pipe is
simple economics. Compared to producing a non-clad or a metallurgically clad pipe, manufacturing
clad pipe with this method represents a significant cost reduction. Potential cost reduction is in

24. ~ 22 ~
welding, because clad pipe has thinner walls than homogenous pipe, and so requires less welding time.
In this scenario, the clad pipes are 0.39 in. thick, whereas the homogenous pipe is 0.59 in. thick, a 13
percent difference.
NEW CONCEPT IN SHEET HYDRO FORMING
 Double Sheet Hydro Forming
Structural component with closed components are formed by this process. Some advantages of this
process are:-
1. Integration of more parts, further reduction of components & thus steps.
2. Stiffness increase and reduction in overall spring back due to closed box section & continuous
weld section.
3. A complete component is made in one single hydroforming step, with only top and bottom die.
 Tailored Blank
By this method, the need for additional forming / joining operation is unnecessary. It is used in areas
where sound insulation and vibration damping is required & where high degree of energy absorption

25. ~ 23 ~
during crash in needed. The additional or path sheet could be of same or different material or different
thickness from parent material.
 Hydro Joining
Usually after hydro forming, additional joining operations are required to form assemblies. To reduce
manufacturing time and number of process steps, joining operation are being integrated into hydro
forming process. This also reduces tool cost. Two approaches to hydro joining are punch riveting
hydro clinching.
In punch riveting, pressurized fluid acts on one sheet while a moving punch acts on other sheets from
opposite sheet. Punch is moved against rivet and under the fluid counter pressure it spreads to form a
solid, visually attractive joint.
In hydro clinching, high pressure fluid actions the punch. The prescribed fluid presses the material to
be hydro formed part through a note in sheet to be joined.

26. ~ 24 ~
CONCLUSION
In this seminar report recent developments in hydroforming are discussed systematically. After
discussing these we conclude that:
1. Hydroforming has wide application in many industries like automobile, aerospace, electronic
goods, sanitary fittings, etc. Many benefits offered – Good surface finish, Use of almost all
ductile and malleable material, Better deformation, High dimensional accuracy, Savings up to
80% in post forming processes. Because of so many benefits offered Hydroforming is
considered as an effective method to meet the demands of ever evolving manufacturing
sector.
2. Due to introduction of hydroforming it is now possible to use lightweight aluminium
structural frame instead of the conventional heavy weight steel frame in automobiles.
Resulting in reduction of weight by more than 9 percent and weld length by 19%.
3. Hydroforming facilitates manufacturing of a single large complex component instead of
many small components, reducing the tooling costs by 50%. For example: operations like
piercing can be done during hydroforming itself. There is no need of finishing the surface
after hydroforming as hydrofomred component has a high grade of surface finish.
4. Of the above discussed recent techniques Pressure sequencing and Hammering are the most
useful methods. Using these methods we can hydroform any malleable metal ranging from
copper to high grade stainless steel. By reducing the drag force Hammering eliminates the
two major problems faced in forming namely rupturing and buckling.
Thus adopting these new techniques there is better utilization of material. The day will not be far away
when hydroforming will completely replace the conventional stamping and forming processes.

27. ~ 25 ~
REFERENCES
 https://www.google.co.in/
 https://en.wikipedia.org/wiki/Hydroforming
 http://www.jmpforming.com/hyrdroforming/hydroforming-process.htm
 https://www.schulergroup.com/major/us/technologien/grundlagen_hydroforming/index.html
 http://www.americanhydroformers.com/what-is-hydroforming/
 https://www.phase-trans.msm.cam.ac.uk/2006/hydroforming.html