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Weld Purging Best Practices Issue 1-May 2019

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Published by Huntingdon Fusion Techniques HFT®, 2019-05-09 10:11:06

Weld Purging Best Practices Issue 1-May 2019

Weld Purging Best Practices Issue 1-May 2019

ISSUE One: May 2019

In May’s Issue:

• Focus on Distributor Australia
• TWI UK Welding & Joining Exhibition
• 2nd Annual High School Welding Competition
• Product News
• Technical Article: Liquid Nitrogen Freezing Solves Pipe Cutting

• 2019 Calender of Exhibitions and Events


Huntingon Fusion Techniques HFT® are proud members of:



Weld of the Month and Distributor Feature 3
TWI UK Welding and Joining Exhibition 4
Industry News 5
HFT / Product News 6-7
Technical Paper 8-9


Dear Reader,

Welcome to the 1st Weld Purging Best Practices Magazine.

My name is Michaela, I’m the Marketing Manager for HFT® and Editor of Weld Purging Best
Practices. I’m delighted to announce the move from our old Newsletter style monthly news to
this new look magazine.

Although the magazine will predominantly feature news about Huntingdon Fusion Techniques,
we’d be happy to feature any welding or weld purging related news.

In this issue read about the up and coming TWI UK Welding and Joining Exhibition that we
will be attending. We have our White Paper 308: Liquid Nitrogen Freezing Solves Pipe Cutting
Problems featured.

If you have any news or would like to be
featured in our magazine, then please
get in touch.

I hope you enjoy our new look magazine.

Best wishes,

[email protected]


Weld of the Month goes to one of our MultiStrike®
Tungsten Electrode users Johannes (@tig_happens)
for this incredible weld! Head over to his page to see
more of his work.
If you are using our products and would like to enter
to have your weld featured as Weld of the Month, tag
us in your weld photos. We will try and repost them on
our Instagram page too. Extra points if you can get our
product in the photo too...@huntingdon_fusion


Exclusive Distributor in Australia: Smenco
Smenco knows welding and has experienced
people to service & support what we sell.
That’s what makes Smenco one of Australia’s
leading distributors of welding equipment,
consumables and associated welding
Smenco is the agent for Fronius welding
equipment and Castolin Eutectic both
recognised as leaders in Welding Technology
and Wear Solutions.

With offices in Melbourne, Sydney, Brisbane and
Perth, Smenco experienced field staff are backed by
a national Distributor Network to provide customers
with first class service that’s never far away.
Our Technical Sales Manager Luke (pictured) visited
Smenco in April to support with training and on-site

If any of our Distributors would like to feature here, then please get in touch!



WHEN: 22ND MAY 2019



TWI is partnering with equipment and consumable manufacturers
to help you identify opportunities to reach your productivity and quality targets at this free Exhibition.

Discover what’s new, optimise your existing processes and technology, identify potential benefits,
and understand risks of introducing new welding technology, and discuss your challenges with TWI
and industry experts first-hand.

Huntingdon Fusion Techniques will be at the UK Welding and Joining Exhibition.

Come along and see our Range of Weld Purge Monitors® measuring from atmospheric down to 1
ppm (accurate to 10 pm). We have a Weld Purge Monitor for all budgets and applications. From the
low cost, entry level PurgEye® Nano, the PurgEye® Desk for Chamber and Enclosure Welding and
even the PurgEye® 1000 for long distance monitoring.

Our Range of Tube and Pipe Welding Purging Products are designed to achieve oxide free tube and
pipe welds from 1” right up to 88’. These high quality purging systems will help make extra significant
savings in time and inert gas costs within the first weld.

We have Weld Purging Accessories including our Weld
Trailing Shield®, which was recently featured on Weld
Tube’s Titanium Tutorial video. Our flat and curved shields
are designed to provide additional inert gas coverage
during stainless steel or titanium welding.

For welding parts that need to be completely surrounded
by an inert gas, our Flexible Welding Enclosures® are
the solution! They are just a fraction of the cost of a rigid
chamber and will maintain a low level of oxygen throughout
the welding cycle.

We promote safer welding with our thoria-free Tungsten Electrodes that will also strike 10 times the
number of arcs as a red tipped thoriated tungsten electrode when tested under identical conditions.

Our Pipestoppers® Range and Pipe Freezing also make stopping, blocking, purging and freezing

HFT® pride ourselves on our first class Worldwide customer support, innovative technology and
quality products. Our aim is to save you time and money whilst achieving outstanding welds.

We will be carrying out demonstrations all day and we look forward to seeing you there.



South Coast Welding Academy and Weld Tube held
their 2nd Annual High School Welding Competition
at the end of April and what an event it was. Some
big names attended the event including Jimmy
McKnight from Arc Junkies Podcast, Travis Field,
Bob Moffatt from Weld.Com, Jacob Schofield just
to name a few!

Hjalmar Aguilo host of Weld Tube said:
“Congratulations to the winners of our 2nd annual national high school welding competition. We had
such a blast and seen some impressive welders and they didn’t make it easy at all for us. I want
to thank all the competitors that came out from all over the United States and locally as well. This
competition will definitely be down for the books, all thanks to everyone that supports Weld Tube
and South Coast Welding Academy.

Head over to Weld Tube’s Instagram for more!


Exhibiting! 4 – 7 June
22 May: ITM Poland Mach/Tool
UK Welding and Joining Exhibition Poznan, Poland
The Granta Centre, TWI, Cambridge, UK
Stand No. 13 Exhibiting!
11 - 14 November
16 – 21 September Adipec
EMO Hannover Adnec, Abu Dhabi
Hannover, Germany
26 - 28th November
Exhibiting! Stainless Steel World
11 - 14 November MECC Maastricht, The Netherlands
McCormick Place, Chicago, IL, USA

Distributor Exhibiting!
27 - 28 November
Ifema, Madrid, Spain



The use of home made sponge foam purge dams for pipe weld purging
is still very familiar throughout the welding industry. However, operators
are unaware as to how the use of sponge foam can adversely influence
the metallurgical strength of a joint.

When sponge foam starts to warm up from the heat of the weld, the
foam starts to outgas the harmful elements that exist throughout the
foam (oxygen, nitrogen and water vapour). If the operator is unable to use a high quality Weld Purge
Dam and wishes to use a low cost alternative, Huntingdon Fusion Techniques HFT® manufacture
water-soluble Weld Purge Film®, ensuring all welders can achieve a great purge every time, at a
reduced cost and without the introduction of harmful gases to the weld.

Ron Sewell, Chairman for HFT® said: “Making a dam with Argweld® Weld Purge Film® is much
easier than all of the complex cutting and shaving that goes into the self fabrication of a sponge dam.
Simply cut off a length of film from the roll, greater than the diameter of the pipe and stick the surplus
film to the water-soluble adhesive that is applied to the pipe beforehand.”

“Cut costs, but don’t use inferior products such as paper or sponge, use superior ones like Argweld®
Water Soluble Weld Purge Film®. 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, oxidising the weld and
causing unnecessary rework.”


Titanium is the metal of choice in a variety of industries due to its excellent corrosion resistance to
acids, chlorides and salt. Titanium has a wide continuous service temperature range, from liquid
nitrogen (-322°F) to 1,100°F and the highest strength-to-weight ratio of any metal.

Titanium is a reactive metal, so when heated it will react with surrounding
oxygen, discolour and lose its corrosion resistance properties. In
critical welding applications, it is therefore crucial that the oxygen level
surrounding the weld is purged of oxygen to 50 ppm or lower.

The innovative PurgEye® Desk, a new Weld Purge Monitor® designed and manufactured by weld
purging experts Huntingdon Fusion Techniques HFT®, is leading the way in inert gas purging
technology by reading oxygen levels from 1,000 ppm, right down to levels as low as 1ppm (highly
accurate to 10 ppm), ensuring titanium welders achieve perfect oxide free, zero colour welds time
and time again.

Ron Sewell, Chairman for HFT® said: “Titanium parts are often welded inside a welding enclosure,
where the entire atmosphere surrounding the weld can be kept at a controlled level of oxygen. The
PurgEye® Desk is ideal for use with Welding Chambers, cabinets and flexible enclosures, as well as
with Orbital Welding Machines and other Automatic Welding Systems.”



Titanium is a reactive metal. When it is heated during welding it will react with oxygen that surrounds
it, forming oxidised welds, which will lead to loss of corrosion resistance properties. In many industries
today, this is no longer acceptable. Oxidised welds will be rejected, causing unnecessary rework.

At least three major elements are crucial in Weld Purging Technology to make successful titanium

1. A good source of Weld Purge Gas

Welding gas suppliers all have special high quality grades of argon, which is the most widely
recommended gas for back purging titanium. Typical grades are 99.9995% which is 5 parts per
million of impurities, including oxygen.

2. Use a Weld Purge Monitor®

Initially, use your Weld Purge Monitor® to check your argon or helium gas supply to ensure that the
oxygen content is lower than 10 ppm.

Part of the correct weld purging procedure is to ensure that the oxygen level in the exiting/exhausting
weld purge gas is held at 50 parts per million or lower and maintained throughout the weld.
This is best achieved by using a Weld Purge Monitor® that can measure down to at least 50 parts
per million and one that preferably can switch the weld set off or send out a warning signal in the
event of oxygen levels rising too high.
The titanium welding process should not begin until the oxygen level in the exiting/exhausting weld
purge gas is shown accurately to be about 10 ppm.
The titanium joint being welded must continue to be purged after welding has finished until the
temperature drops below 420ºC (800°F) approximately.
3. Protect your weld
Use a Trailing Shield or use an Enclosure and in the case of
pipework, use a properly designed and manufactured inflatable
pipe purging system.
It is important to protect your weld from oxygen. For small parts, it
is best to weld inside a properly designed and manufactured low
cost Flexible Welding Enclosure. This will guarantee the oxygen
level surrounding the weld can be purged out to a sufficiently low
For the outside of titanium tube and pipe welds, even the largest of gas cups are not large enough
to stop the weld from oxidising. The addition of a Weld Trailing Shield® will ensure the weld is kept
under an additional coverage of inert gas while the weld is cooling.


Huntingdon Fusion Techniques HFT®”s USA Partner has recently helped solve a major environmental
problem in a remote area of Oregon. Construction of a new access to the Willamette River was
necessary, as part of a plan to replenish a salmon hatchery1 but this necessitated removal of part of
a 10-inch (254 mm) pipeline that was causing an obstruction.

The pipeline had been isolated and abandoned previously and filled with water that had probably
become polluted. Simply cutting the pipeline would release over 1 million 300 thousand gallons
(5,000 m3) of contaminated water into surrounding land lying within a sensitive, environmentally
protected area. A decision was made to use liquid nitrogen to create ice plugs and isolate the
small section of pipe causing the obstruction. The pipe could then be cut, releasing only limited
contaminated water and this could be contained and removed from the site.

Pits were excavated on either side of the access exposing the pipe and the anti- corrosion coating
was removed. Freezing commenced in the early morning in record high temperatures combined
with little to no shade in the area.

Excavation of pipe in progress

The pipe was cut on both sides and the remaining contaminated water drained to disposal containers
for removal. Welders quickly capped the open ends. The freeze equipment was shut down and
the ice plugs allowed to thaw naturally. The proposed river access refurbishment was allowed to
continue the following week bringing life back to a vital natural habitat.

The equipment employed for the freezing operation was an Accu-Freeze™ System. The procedure
creates an in-line ice plug capable of withstanding 140 bar in pipes up to 12-inch (305 mm) diameter
and can be modified using available options to handle even larger diameters.

A specially designed insulated aluminium jacket is placed around the required section of pipe to be
frozen. An advanced temperature-monitoring unit controls the surface wall temperature of the pipe
to accurately and safely create a short ice plug that does not extend outside the jacket.

Accu-Freeze™ is automatic and can be remotely operated making it attractive for use in nuclear
applications and other locations where engineer access has to be restricted. Freezing using liquid
nitrogen is effective down to -184ºF (-120ºC) so is suitable for isolating sections of pipe carrying
petrochemicals so that valves and other control devices can be removed without the expense and
delays involved in draining the system.


The concept of isolation using liquid nitrogen had been
used in the past to resolve major problems with a NASA
launch vehicle and inside large chemical plant2.

With the space shuttle Atlantis on the launch pad ready Accu-Freeze™ Clam Shell on Pipe
to go on mission ST-101 a last-minute system check
revealed a fault in the power drive unit. The PDU is an
hydraulic power pump which controls the shuttles’ rear
rudder or air brake so failure of this unit during flight could
be catastrophic.

Repairing this sensitive system conventionally meant suspending the launch, rolling the shuttle back
to the vehicle assembly building and draining out the hydraulic lines to undertake repairs. This would
delay the launch for several weeks and be extremely costly.

The solution was to use liquid nitrogen to freeze six 16 mm hydraulic fluid lines either side of the
faulty PDU and then remove and replace it. There were demanding requirements. The lines were
nested in the base of the tail of the shuttle and physical access was restricted and Shuttle engineers
needed to be able to monitor and control the temperature of the pipes in order to ensure that the
freeze was being safely and consistently controlled.


Pipe freezer technology allows fluids to be frozen below
-238ºF (-150ºC) using liquid nitrogen. Specially designed
insulation and feeder hoses are used to deliver coolants and
continuous temperature control during the freeze operation
can be incorporated.

The use of freeze technology affords the opportunity to Accu-Freeze™ Clam Shell on Pipe
isolate sections of pipework for maintenance, repair and
replacement of valves, couplings and instrumentation and
thus obviates any need to drain the system. There is no
need to disrupt production beyond the time needed to
freeze and undertake changes.


2. White Paper from Huntingdon Fusion Techniques Ltd, reference HFT/WP 51.

Note for editor; The HFT® White Paper, referenced above, has been prepared for internal use and
not previously published. It contains an extended version of the NASA project and a separate case
study using liquid carbon dioxide as the freeze medium. We could submit this to you for possible
future publication

PurgEye® 500 Desk

with PurgeNet™

Suitable for use with Welding Chambers
and Enclosures as well as Orbital and other

Automatic Welding Systems


www.hfuonltliongwdounsfuosinon: .com

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