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Issue Eight of Weld Purging World - December 2019

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Published by Huntingdon Fusion Techniques HFT®, 2019-12-10 04:27:31

Weld Purging World - December 2019

Issue Eight of Weld Purging World - December 2019

ISSUE 8 December 2019

Merry Christmas on our 45th Anniversary in 2020
& a Happy New Year

In December’s Issue: Feliz Navidad
Próspero Año Nuevo
• Year end message!
Joyeux Noël
• Ask the Expert: Chairman Ron Sewell Bonne Année

• Product News: PurgEye® 200, Purge Film and

• Technical Article: Dairy and Food Pipe Welding

Buon Natale Frohe Weihnachten
Felice Anno Nuovo Ein Gutes Neues Jahr

Prettige Kerstdagen
Gelukkig Nieuwjaar



Huntingdon Fusion Techniques HFT® are proud members of:



Year End Message from CEO Georgia 3

HFT® News 4 - 6

Product News 7 - 8

Technical Paper: Dairy & Food Pipe Welding 9 - 11


Dear Reader,

Welcome to December’s Weld Purging World.

It’s the final issue of 2019 and we’ve had some great feedback on the magazine. It is definitely
a huge step up from our old Newsletter style. Something we hope to grow even further in 2020.

This month, HFT CEO Georgia sums up 2019 and delivers
her year end message. Chairman Ron Sewell is featured
our as ‘Ask the Expert’ and we feature our latest Technical
Paper, Dairy and Food Pipe Welding.

We’d love to hear from you in 2020!

Are you using our products? Do you have a question to
feature in our Ask the Expert feature? If so, contact me!

Wishing you all a fantastic Christmas and New Year.

Thank you for reading!

Best wishes,

Marketing and Social Media Manager
[email protected]

FABTECH 2019 3


Wow! What another fantastic year it has been here at Huntingdon Fusion Techniques. One of my
personal highlights has to be winning Manufacturer of the Year at the Made in Wales Awards in
October. Broadcaster Sian Lloyd hosted the night, with speeches made from Faheen Khan. It was
an amazing night, with an overwhelming sense of pride and achievement in the room. We are also
entered into the 2020 UK Awards, which takes place in June, this time in Liverpool.
We’ve had a busy November, taking part in two major
Industry Exhibitions, Adipec in Abu Dhabi and Fabtech in
Chicago where we support our Exclusive Distributor COB
Industries. Here we showcased our full product range,
including our Flexible Welding Enclosures with a robot cell
inside, perfect for Additive Manufacturing. We also had on
display our new PurgeNet™ accessory – the Dewpoint
Sensor – details on that to follow shortly.
2020 looks set to be another busy year kicking off with a
Distributor Training Course at HQ in January and an open
day to show off our new conference facility. We have two
overseas trade missions to China and Vietnam and three
major industry exhibitions in USA, UAE and Germany.
This is in addition to our usual visits across our network
supporting Distributors with sales visits, demonstrations
and training.
I read an interesting passage in Michael Caine’s book
‘Blowing the Bloody Doors off’. He said: “Success comes
from doing. The best way to keep doing enough of the
right things is to keep doing a lot of things. Even if some
of those things end up as flops, you’ll be building up your
experience, building relationships, building confidence,
opening up opportunities, keeping life fresh and learning
your craft. So long as enough of them are good enough,
you will be allowed to keep going.” Of course Michael was talking about his acting career but we can
apply the same thought process to business.
Despite modern technology nobody will really notice us if we sit comfortable and warm in our offices.
It’s about getting out there. Doing it.
I recently gave a speech at a Welsh Government networking evening in the UAE and mentioned
Michael’s comment. It provoked a lot of thought in the room and several people afterwards said it
had spurred them on to try again where previously they had failed. Hope it has the same effect for
Hope you all have a wonderful Christmas with your families and loved ones.



Chairman - Ron Sewell

In this month’s Weld Purging World, we continue to take your
questions to our experts! We ask Chairman Ron Sewell some
questions about our QuickPurge Tube and Pipe Purging
Q. How can Argweld® QuickPurge® help me?
QuickPurge® dramatically reduces weld purging times thereby
saving the costs of waiting time, in addition to which there is a
large saving in the cost of argon.
For example, with home made dams using cardboard, foam or
rubber discs, a 36” (900 mm) stainless steel or titanium pipe
joint might take 4 – 8 hours to prepare and purge correctly. Using QuickPurge®, the joint will be
ready in 30 minutes with a fraction of the Argon cost.
Q. Are Argweld® QuickPurge® Systems re-usable?
Yes, QuickPurge® is rugged and can be used for multiple welds..

Q. Are Argweld® QuickPurge® Systems resistant to
Yes, QuickPurge® is resistant to the heat of all typical arc
welding processes. Special heat-protected purge systems
called Argweld® HotPurge® are available to accommodate
pre-weld and post-weld heat-treated joints.
Got a question you’d like one of our experts to answer?
Then get in touch! We might feature the question in an up
and coming issue to share with others.


HFT®’s Technical Sales Manager Luke flew out to Chicago in
November to join Exclusive Partner Cob Industries to exhibit
and one of the biggest industry shows, Fabtech.

Luke said: “It was another fantastic opportunity for us to

showcase our full product range, from the latest in Weld Purge

Monitoring, to

Tube and Pipe

Purging and

even a Flexible

Welding Enclosure with a robot cell inside for Additive


Thank you to everyone who came along and we look
forward to joining Cob at the 2020 show in Las Vegas.



We were delighted to attend Adipec on a trade mission
with the Welsh Government in November and to
support our Middle East Distributor PCT. We had quite
a high profile at the event and were featured some
local Newspapers including Al Littihad and Al Bayan.

Adipec was attended by a lot of professionals in the Oil and Gas Industry including COO of Petrofac,
John Pearson and Head of Business Development Alex Haynes (pictured).

Thank you again to the Welsh Government for the continued support and opportunity to attend a
fantastic event.


17 - 20 March 2020 30 March - 3 April 2020
TechniShow Tube
Utrecht, Netherlands Düsseldorf, Germany

9 - 12 November 2020 18 - 20 November 2020
Adipec Fabtech
Abu Dhabi, UAE Las Vegas, USA


1. Weld Purge Monitor for On-Site Conditions


The simple addition of a Weld Trailing
Shield® will ensure titanium alloy and
stainless steel tubes, pipes and flat sheet
will remain under a protective inert gas
coverage for longer, allowing the weld to
cool and come into contact with oxygen,
preventing it from oxidising on contact with

A simple comparison shows the benefits of
using a quality Trailing Shield. On the right
of the image, shows the benefits of using
a genuine Argweld® Trailing Shield with
the clean weld below, while the pictures to
the left shows an alternative shield with the
oxidised weld below.

The Trailing Shield® is connected to the inert gas supply,
diffusing gas without turbulence through multi layers of
stainless steel mesh built into the body of the shield.
At each side, replaceable silicone rubber side shields
provide a barrier to prevent the gas escaping sideways.
As the welding torch is moved forward, the weld remains
under an inert gas shield until the welded metal has cooled
below its oxidation temperature.

You can be sure you are using a genuine HFT® Shield by looking for our registered nameARGWELD®.


After Luke attended Fabtech, he
travelled to Canada to meet up
with our Exclusive Distributor,

Luke said: “It was a great
opportunity to visit Justram and
during the course of the week
we provided updated training on
the recent Weld Purge Monitor®
updates and new additions to our
family of products.”



Measuring the oxygen level during Pipe Purging is crucial. Stainless
steel has to be monitored down to at least 100 ppm, however alloys
such as titanium and zirconium may need to be monitored down to as
low as 10 ppm.

Pipe Purging Experts Huntingdon Fusion Techniques HFT®’s
PurgEye® 200 Weld Purge Monitor® will ensure zero colour, non-
oxidised welds are achieved every time, with accurate readings down
to 10 ppm.

The PurgEye® 200 is a portable, hand held monitor, specifically
developed and designed for use when welding titanium, zirconium, high specification stainless steel
and nickel alloy joints, so that the user can produce metallurgically sound and oxide-free welds
every time.

Luke Keane, Technical Sales Manager for HFT® said: “We’ve recently updated our Range of
Weld Purge Monitors and most of which now include PurgeNet™, a networking device that allows
accessories to be connected. These include an automatic welding machine interface so that the
oxygen level in the vicinity of the weld can be continuously monitored and the welding machine can
be switched on or off according to pre-set oxygen levels, an external audible and visual warning
devices and a dew point monitor.”



Weld Purging is the act of removing oxygen from the vicinity of a joint before, during and after
welding. Metals that require weld purging include stainless steels, titanium and zirconium.

Weld Purging various sizes of tubes and pipes can be challenging as well as expensive, which is
why many welders today continue to construct their own dams to cut costs. Homemade dams made
from material such as foam, sponge or paper can often lead to loss of welds when they leak or slip
from position thus flooding the welding zone with air.

Leaders in Weld Purging Technology, Huntingdon Fusion Techniques
HFT® offer low cost Weld Purge Film® Kits which can be cut to
each pipe size.

Luke Keane, Technical Sales Manager for HFT® said: “Weld Purge
Film is great for when mechanical purging devices cannot be
retrieved. The Film can be used to create an impermeable barrier, but can be easily washed away
after use without leaving any residue.”

These affordable Kits will save operators high costs by minimising gas usage dramatically reducing
purge time and eliminating the need to clean or even a failed weld. Weld Purge Film® Kits have
been designed and developed by HFT®, containing product accessories needed to manufacture
dams that will not come loose during welding.


Dramatic savings can be achieved when welding stainless and chromium steels and also titanium
alloy tube and pipes with the use of an Inflatable Pipe Purging System.

By restricting weld purging zones, Inflatable Pipe Purging Systems achieve a huge saving in time
waiting for pipes to be completely filled with argon, purged down
to a low enough oxygen level to start welding safely and also the
cost of using a large amount of inert gas.

To avoid such risks and to see that the inert gas being delivered
to the pipe purging system is controlled, Huntingdon Fusion
Techniques HFT® have designed and developed PurgeGate®, a unique valve which regulates the
pressure and flow of gas that is passed through the system, ensuring that it will not burst regardless
of the pressure and flow rate.

Ron Sewell, Chairman for HFT® said: “Purging larger diameter pipes has never been easier.
PurgeGate® has found valuable applications in the welding industry where inflatable devices are
used for weld purging of tubes and pipes. Setting flow rates and pressures on gas regulators can
be interfered with. The pressure inside a purge system can also rise dramatically during a welding
sequence, to create a burst. If inflatable devices burst during a tube or pipe weld sequence then the
loss of protective gas can result in a highly expensive and extremely inconvenient weld repair.”



Most industries using stainless steel pipes do so because of their corrosion resistance.
The dairy and food sectors are major users since the end products must be contamination free. Pipe
and tube joints inevitably contain crevices and any build-up of contaminants here present a potential
problem. Large facilities manufactured by major producers such as Alfa Laval AB in Sweden can
contain not metres but kilometres of pipes and joints.
Welded joints are common. Well made, they offer a smooth transition from one section to another,
high strength and are cosmetically attractive. However, the welding process itself can lead to
significant loss of corrosion resistance in the joint area and a reduction in mechanical properties
unless precautions are taken to prevent oxidation.

Fig 1 Complex pipework in typical dairy processing plant
Welds carried out on most metals without adequate inert gas coverage oxidise. The effect is even
noticeable with many stainless steels. To some, the discolouration due to oxidation is an inconvenient
feature that can be removed after welding, but this may be difficult and costly, especially if access is
restricted. Unfortunately, any oxidation can result directly in a reduction in corrosion resistance and in
some cases loss of mechanical strength. This is significant in dairy and food pipe applications where
stainless steels are employed principally for their corrosion resistance and mechanical properties.
It will come as a surprise to many that oxygen contents as low as 50 ppm (0.005%) in the protective
gas can produce discolouration or ‘heat tint’.


Fig 1a The result of unprotected underbead in welded austenitic stainless steel

Fig 1b To ensure no discolouration occurs the oxygen content needs
to be reduced to 20 ppm (0.002%).

The Mechanism of Corrosion
Stainless steels owe their resistance to corrosion to the formation of a very thin (10-5 mm), transparent
surface layer of chromium oxide. This provides a passive film that acts as a barrier to penetration
by an invasive environment. When heated to a high temperature in the presence of oxygen this
film increases in thickness until it becomes visible – the colour becomes darker with increasing film
At a critical film thickness the film becomes unstable and begins to break down. The fractured zones
created offer sites for localised corrosion.
Protection is thus essential and this is achieved by surrounding the joint with an inert gas such as
argon or helium. The gas shield associated with a GTAW torch will protect the upper surface of the
joint but the inside of pipes and tubes needs special attention. To meet the need for total internal
protection, called weld purging, dedicated equipment has evolved over the past 25 years.
Pipe and tube purging
Systems for weld root protection are based on sealing the inside of a pipe on either side of the weld
zone then displacing air with an inert gas. The seals must be reliable and leak tight, effective and
easy to insert and remove.


Residual oxygen measurement instruments
Any effective weld purge process needs to be supported by suitable oxygen detecting equipment.
Weld purge monitors have now been developed to meet the need for reliable, robust and sensitive
For reactive and refractory alloy welding these must be capable of measuring oxygen levels down
to 10 ppm.
As an example, the PurgEye® 600 instrument manufactured by Huntingdon Fusion Techniques
reads down to 10 ppm with extreme accuracy and has a display range from 1,000 to 10 ppm.

The entire Argweld product range is supported by an extensive library of publications including
Technical Notes, White Papers, Conference Proceedings and peer-reviewed International Articles.
These are available on-line by application to Huntingdon Fusion Techniques Ltd.
Microbiologically influenced corrosion of stainless steel, 2nd symposium on orbital welding in high
purity industries, La Baule, France
Effects of purge gas purity and Chelant passivation on the corrosion resistance of orbitally welded
316L stainless steel tubing, Pharmaceutical Engineering. Vol 17 Nos 1 & 2 1997
Considerations for Orbital Welding of Corrosion Resistant Materials to the ASME Bioprocessing
Equipment Standard, Stainless Steel America conference 2008
Heat Tint Poses Corrosion Hazard in Stainless Steel, Welding Journal December 2014
ASM International. Corrosion in Weldments. 2006
Author: Michael Fletcher
Dr M J Fletcher is a qualified metallurgist with extensive experience in welding and non-destructive
He works as an independent consultant, providing support to a wide range of manufacturing industry
on a global basis.

Backing Tape®

Resistant to very high temperatures
so fully compliant with

GTAW, GMAW and PAW processes



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