This document discusses capacitor resistance welding and its advantages over traditional resistance welding. Capacitor resistance welding uses charged capacitors to quickly deliver a high peak weld power that establishes a maximum interface temperature, followed by a rapid decline, improving weld quality. It describes traditional resistance welding and factors that affect it like welding current, pressure, and time. It also discusses how capacitor resistance welding defines the relationship between current and temperature using a thermocouple to measure temperature during welding. This allows determining the maximum required current for efficient welding without destructive testing.

1. Capacitor resistance welding
Time and temperature relationship
Denishkumar P. Vachhani
Mechanical engineering department
Lukhdheerji engineering college
Morbi-363642, India
vachhanidenish4962@gmail.com
Gopal M. Sonagra,
Mechanical engineering department
Lukhdheerji engineering college
Morbi-363642, India
sonagragopal60800@yahoo.com
AsstProf. Hardik N. Jani
Mechanical engineering department,
Lukhdheerji engineering college,
Morbi-363642, India.
HN.jani1982@gmail.com
Abstract—This paper is including the review of resistance welding
and capacitive resistance welding. By this new developed welding
one conclusion can be get which is defining the relationship of
current and temperature. This can define the quality of welding.
Index : introduction, resistance welding, capacitor resistance
welding, relationship of current and temperature, conclusion,
references.
Introduction:
Welding is define as “A localized coalescence of
metals, wherein coalescence is obtained by heating to suitable
temperature, with or without the applications of pressure and
with or without use of filler metal.”
Many welding processes are now available in market
as per use of weld element and properties of welding elements
there are different type of welding can be used. List of
welding processes are as follows:
I. Pressure Welding
II. Fusion welding
III. Morden/miscellaneous welding Techniques
Our interest of welding technology is resistance
electric welding. This technology is very time and power
consuming. So for replacing this technology or to decrease the
power consumption capacitor resistance technology is
introduced.[I]
Resistance welding:
It is the method of uniting two pieces of metal by the
passage of a heavy electric current while the surfaces are
pressed together. The fusion temperature is obtained by
placing the surfaces to be joined in contact with one another,
And passing a current of two to eight volts, at a high ampere
through them.
The heat is developed around the point to which they
touch, forcing them together and at the same time switching
off the current, completes the weld.
 Sensible factors which is affecting to the resistance
welding :
I. Welding current
II. Welding pressure. [II]
III. Time of the application(cycle time)
Weld times, squeeze time, Hold time,
Off time
IV. Contact area of electrodes.
 Electrode :
The electrode s in resistance welding should have
higher electrical conductivity as well as higher hardness.
Generally, copper cadmium and copper chromium alloys are
used as electrodes. Currents usually range from 3000A to
40,000A , depending on the materials being welded and their
thickness. The bulk resistance and contact resistance value of
work piece ,electrode and their interface both are cause and
affect the amount of heat generated. Exaggerated cross-
section of two pieces of metal indicates formation of metallic
bridges that result in high current density. Subsequent melting
and the formation of new bridges allow the weld to be
formed.[IV]
Factors which are affecting to resistance welding:
 Heat Affected Zone (HAZ)

2. It is the volume of material at or near the weld which
properties have been altered due to the weld heat. Since the
resistance welding process relies on heating two parts, some
amount of HAZ is inevitable. The material within the HAZ
undergoes a change, which may or may not be beneficial to
the welded joint. In general, the goal in good resistance
welding is to minimize the HAZ.
 Material properties which affect the welding process :
 Thermal conductivity
 Thermal expansion
 Oxide contamination
 Plastic temperature range
 Hardness and strength
 Polarity
 Surface roughness
 Projection
 Heat imbalance
 Weld affected zone:
It is the major affecting factor which is reason of the
heat loss. Factor are as follow
 weld metal zone
 heat affected zone
 unaffected zone[II]
Capacitor resistance welding :
A capacitive discharge welding method is used for joining
firing tips, such as those made from various precious metals,
to spark plug electrodes. In one embodiment, charged
capacitors or other energy storage devices coupled to welding
electrodes quickly release stored energy so that a peak weld
power and maximum interface temperature is quickly
established, followed by a rapid decline in weld power and
interface temperature.
The resulting capacitive discharge weld joint may include
solidified molten material from both the firing tip and the
electrode and possess a number of other desirable qualities.
 For checking the weld quality some tests are done on
welded substance.
 Pretesting while selecting material:
weld ability testing :
 Theoretical weld ability test
 A simulated test
 Actual welding test
Fabrication weld ability, Service weld
ability
 Conclusion of testing give information about:
 Process selection
 Preheat
 Energy input

Joint design
To avoid these all steps this welding technology is modifying.
For thin sheet metal welding new welding technology is
introduced. Which is capacitor resistance welding.[III]
 Relationship between current and temperature:
When two dissimilar metals are joined at two points a
thermocouple circuit is formed. When these two
junctions are at different temperatures, an
electromotive force (emf) develops, causing an
electric current to flow through the circuit. The
magnitude of this emf is proportional to the
temperature difference between the two junctions.
reference temperature (Tref) while the other is
positioned for temperature measurement. The
temperature to be measured (T) is converted from
thermoelectric voltage V according to:
T= Tref + (V/α)
Where V is the measured voltage in the thermocouple
circuit and a is the voltage/temperature
proportionality constant (V8C21). Voltage can be
measured with a potentiometer or a high-impedance
solid-state digital voltmeter . The value of constant a
depends on the type of wires used to make the
thermocouple.[V]
At the time of welding, thermocouple are fitted in the
Electrode. This thermocouple produce emf by which the gain
temperature can find which is generated by current. Formula
of the couple is as follows:
e = K (T1 – T2)
e means emf which is known so temperature can be define.
Here we are using revers phenomenon. By the material
property, resistance of metal can be gain. By that desire
temperature which is required for welding can decide. So for
the efficient welding required current flow can be determined.
After the welding, some test are done on the joint in the
present scenario. But after this calculation maximum required
current can be determined. So time of the testing is eliminated
by the calculation. And destructive test is not required so
wastage of the material is also prevented.
REFERENCES
I. “R.K.jain”,khanna publication,page no-
273,9.1 introduction.
II. “R.K jain”,khanna publication,page no-
281,9.15 Resistance welding.
III. Frederick J. Quitmeyer, Rochester Hills,
MI (US),”Patent Application Publication”,
Pub. No.: US 2014/0239796 A1
IV. Doebelin, E.O. Measurement Systems
Application and Design; Mcgraw-Hill Book
Company: New York, 1983.
V. Amada Miyachi America.INC,
www.amadamiyachi.com