We
offer orbital welding services as a turn key job or labor
jobs anywhere in India and abroad for orbital welding. We
are having state of the art orbital welding machines for welding
tubes of diameter upto 2” and thickness upto 3.5 mm.
We are a team of very expert and experienced engineers in
the field of piping.
Orbital
welding is Automatic Tungsten inert gas welding. It eliminates
chances of manual errors in welding. It produces identical
welds for hundred of times hence accuracy in welding.
Orbital
welding was first used in the 1960's when the aerospace industry
recognized the need for a superior joining technique for aerospace
hydraulic lines. A mechanism was developed in which the arc
from a tungsten electrode was rotated around the tubing weld
joint. The arc welding current was regulated with a control
system thus automating the entire process. The result was
a more precision and reliable method than the manual welding
method it replaced.
Orbital
welding became practical for many industries in the early
1980's when combination power supply / control systems were
developed that operated from 110 V AC and were physically
small enough to be carried from place to place on a construction
site for multiple in-place welds. Modern day orbital welding
systems offer computer control where welding parameters for
a variety of applications can be stored in memory and called
up when needed for a specific application. The skills of a
certified welder are thus built into the welding system, producing
enormous numbers of identical welds and leaving significantly
less room for error or defects.
Orbital Welding Equipment
In
the orbital welding process, tubes / pipes are clamped in
place and an orbital weld head rotates an electrode and electric
arc around the weld joint to make the required weld. An orbital
welding system consists of a power supply and an orbital weld
head.
Power
Supply: The power supply / control system supplies and controls
the welding parameters according to the specific weld program
created or recalled from memory. The power supply provides
the control parameters, the arc welding current, the power
to drive the motor in the weld head and switches the shield
gas (es) on / off as necessary.
Weld
Head: Orbital weld heads are normally of the enclosed type
and provide an inert atmosphere chamber that surrounds the
weld joint. Standard enclosed orbital weld heads are practical
in welding tube sizes from 1/16 inch (1.6mm) to 6 inches (152mm)
with wall thickness' of up to 0.154 inches (3.9mm) Larger
diameters and wall thickness' can be accommodated with open
style weld heads.
The Physics of the GTAW Process
The
orbital welding process uses the Gas Tungsten Arc Welding
process (GTAW) as the source of the electric arc that melts
the base material and forms the weld. In the GTAW process
(also referred to as the Tungsten Inert Gas process - TIG)
an electric arc is established between a Tungsten electrode
and the part to be welded. To start the arc, an RF or high
voltage signal (usually 3.5 to 7 KV) is used to break down
(ionize) the insulating properties of the shield gas and make
it electrically conductive in order to pass through a tiny
amount of current. A capacitor dumps current into this electrical
path, which reduces the arc voltage to a level where the power
supply can then supply current for the arc. The power supply
responds to the demand and provides weld current to keep the
arc established. The metal to be welded is melted by the intense
heat of the arc and fuses together.
Reasons
for Using Orbital Welding Equipment
There
are many reasons for using orbital welding equipment. The
ability to make high quality, consistent welds repeatedly
at a speed close to the maximum weld speed offer many benefits
to the user:
•
Productivity. An orbital welding system will
drastically outperform manual welders, many times paying for
the cost of the orbital equipment in a single job.
•
Quality. The quality of a weld created by
an orbital welding system with the correct weld program will
be superior to that of manual welding. In applications such
as semiconductor or pharmaceutical tube welding, orbital welding
is the only means to reach the weld quality requirements.
•
Consistency. Once a weld program has been
established an orbital welding system can repeatedly perform
the same weld hundreds of times, eliminating the normal variability,
inconsistencies, errors and defects of manual welding.
•
Orbital welding may be used in applications
where a tube or pipe to be welded cannot be rotated or where
rotation of the part is not practical.
•
Orbital welding may be used in applications
where access space restrictions limit the physical size of
the welding device. Weld heads may be used in rows of boiler
tubing where it would be difficult for a manual welder to
use a welding torch or view the weld joint.
•
Many other reasons exist for the use of orbital equipment
over manual welding. Examples are applications
where inspection of the internal weld is not practical for
each weld created. By making a sample weld coupon that passes
certification, the logic holds that if the sample weld is
acceptable, that successive welds created by an automatic
machine with the same input parameters should also be sound.
Industries
and Applications for Orbital Welding
Aerospace:
As noted earlier, the aerospace industry was the first industry
to recognize the requirement for orbital welding. The high-pressure
systems of a single plane can have over 1,500 welded joints,
all automatically created with orbital equipment.
Boiler Tube: Boiler tube installation and
repairs offer a perfect application for orbital welding. Compact
orbital weld heads can be clamped in place between rows of
heat exchanger tubing where a manual welder would experience
severe difficulty making repeatable welds.
Food, Dairy and Beverage Industries: The food, dairy and beverage
industries require consistent full penetration welds on all
weld joints. Most of these tubing / piping systems have schedules
for cleaning and sterilization in place. For maximum piping
system efficiency the tubing must be as smooth as possible.
Any pit, crevice, crack or incomplete weld joint can form
a place for the fluid inside the tubing to be trapped and
form a bacteria harbor.
Nuclear Piping: The nuclear industry with
its severe operating environment and associated specifications
for a high quality weld has long been an advocate of orbital
welding.
Offshore Applications: Sub-sea hydraulic
lines use materials whose properties can be altered during
the thermal changes that are normal with a weld cycle. Hydraulic
joints welded with orbital equipment offer superior corrosion
resistance and mechanical properties.
Pharmaceutical Industry: Pharmaceutical process
lines and piping systems deliver high quality water to their
processes. This requires high quality welds to ensure a source
of water from the tubes that is uncontaminated by bacteria,
rust or other contaminant. Orbital welding ensures full penetration
welds with no overheating occurring that could undermine the
corrosion resistance of the final weld zone.
Semiconductor Industry: The semiconductor
industry requires piping systems with extremely smooth internal
surface finish in order to prevent contaminant buildup on
the tubing walls or weld joints. Once large enough, a build
up of particulate, moisture or contaminant could release and
ruin the batch process.
Tube/Pipe
Fittings, Valves and Regulators: Hydraulic lines and liquid
and gas delivery systems all require tubing with connector
fittings. Orbital systems provide a means to ensure high productivity
of welding and improved weld quality. Sometimes the tubing
may be welded in place to a valve or regulator body. Here
the orbital weld head provides the ability to produce high
quality welds in applications with restricted access to the
weld joint.
A
manual weld taken from an operating plant.
This weld has defects that include lack-of- penetration, misalignment,
a huge crevice, and discoloration due to poor ID purge. This
weld would be considered unacceptable by any standard
An orbital weld on 316L-electropolished stainless steel. The
weld is fully penetrated with a uniform crevice-free inner
weld bead with good alignment. The ID was purged with argon,
which resulted in slight discoloration of the HAZ.
|
