Weld Purging World - January 2021

2021 ISSUE 01: JANUARY

IN THIS ISSUE:

WISHING YOU ALL A
SAFE AND HEALTHY 2021

UPDATE FROM OUR UK HQ
TECHNICAL ARTICLE: DAIRY AND FOOD PIPE WELDING

WELD PURGING PRODUCTS
INNOVATORS, MANUFACTURERS AND
INTERNATIONALLY RENOWNED SPECIALISTS
MADE IN WALES ‘MANUFACTURER OF THE YEAR’ &
WELSH BUSINESS AWARDS – EXPORTER OF THE YEAR

WWW.HUNTINGDONFUSION.COM

2 CONTENT

WHAT’S IN THIS MONTH’S ISSUE

New Year Message from CEO 3-4
HFT® News 5-6
Product News 7-9
10 - 11
Technical Paper: Dairy and Food
Pipe Welding

A WELCOME FROM THE EDITOR

Dear Reader,

Welcome to the first issue of Weld Purging World for 2021 and Happy New Year.

In this month’s issue CEO Managing Director Georgia Gascoyne reflects on a challenging 2020
and takes a look at what 2021 has in-store for HFT®.

Technical Sales Manager Luke Keane gives an update on
the recent activity at our UK HQ and we feature our Technical
Paper on Dairy and Food Pipe Welding.

If you have any information that you would like to be
featured in future issues of this publication, please contact
me. Perhaps a photograph of a special weld that you have
made, a product that you find of interest or a question of
some kind?

From everyone here at HFT®, thank you for reading and
stay safe!

Best wishes,
Michaela - Marketing and Social Media Manager
[email protected]

HFT® NEWS 3

HAPPY NEW YEAR

A message from our CEO Managing Director,
Georgia Gascoyne.
Hi everyone and a very Happy New Year to you all.
I don’t think any of us will forget 2020 in a hurry, it was
an extremely challenging year on both a business
and personal level.
I am very proud of everybody at HFT for how they
have coped with the ongoing pandemic. We continue
to make a collective decision on the morning following
any lockdown announcement to carry on and be here
for our worldwide Distributors and customers.
At the beginning we quickly worked out a new, safe office layout, put up the necessary markers and
signs and stocked up on hand sanitiser, which has meant that HFT hasn’t lost one business day to
the virus and we haven’t furloughed any of our staff.
Foresight on behalf of our Purchasing Team prior to the virus taking a grip in the UK meant that we
were already stockpiling raw material and components well before the initial lockdown and because
we manufacture the majority of our products in the UK, we weren’t beholden to matters beyond our
control.
Of course, it hasn’t been easy and logistics plays a large part in our business and this is an area
many of us have found particularly challenging.
Despite it all, we have had many highlights this year:
45th Anniversary
In 2020, HFT celebrated 45 years in business! Our dedication to product development, land-standing
industry experience and a loyal Distributor network are key elements to our success.
Export Business of the Year
In March, we were named winners of the Export Business of the Year 2019 and I scooped the very
prestigious President’s Award. We had an incredible night and what an achievement it was for us.
Supplier to Spacex
In May, Spacex launched its first private spacecraft into orbit and HFT supported them throughout
the build of the spacecraft as one of their suppliers.
New Products
In 2020, we launched two new products, the PurgeNet™ Dew Point Purging Gas Moisture Sensor™
for eliminating porosity during welding and the Rubber PetroChem Stoppers, which have many
applications including the sealing of scupper ports on boats and Super Yachts.

4 HFT® NEWS

HAPPY NEW YEAR

Sizewell C Consortium
We were delighted to be included in the Sizewell C Consortium, a group of businesses that are
behind getting Sizewell C constructed, lobbying the government and ensuring that the majority
of services, goods, supplies are procured from UK businesses.
Non-executive Director of the TWI
I was also delighted to be appointed as a non-executive Director of The Welding Institute (TWI).
A look ahead….
So, what’s next? We have already started off 2021 with our exit from the EU and within days
another announcement from Boris Johnson of tougher lockdown measures for at least 6 weeks.
Once again, we pull together and carry on jumping the hurdles as they are placed in front of us.
We’ve a lot to look forward to this year:
Canadian Virtual Trade Mission – Nuclear Sector
The first of its kind taking place at the end of January bringing OCNI members and Welsh
businesses together to form collaborations in order to supply products or services into each
nation’s nuclear sector.
Product Enhancements and Improvements
There are some exciting developments taking place
including a more robust casing for the handheld
PurgEye® 200 Weld Purge Monitor®.
New Packaging
We have used the lockdown period to assess our
packaging and labelling in order to eliminate unnecessary
waste, which includes changes to the Weld Backing
Tape® packaging from this month.
Industry Shows
We hope to be heading back to Fabtech and Adipec at the end of the year where we can finally
see some of our loyal Distributors and Customers face to face. Both industry shows, along with
many others were sadly cancelled during 2020.
From all of us here at HFT, we wish you a safe and healthy 2021.
Georgia

HFT® NEWS 5

UPDATE FROM OUR UK HQ

Technical Sales Manager Luke Keane gives us an update on recent activity from our UK HQ.

“We made a number of large systems in the run up to Christmas including this 102” Weld Purge Dam
(pictured above) manufactured to weld end caps onto a number of large vessel tanks.

As the product is inflatable, it allowed the system to be
removed from a smaller 30” vent after welding.
The Weld Purge Dam saved a massive volume of the tank
from being purged, keeping both the purge time and the
argon cost low.
We also manufactured 64” QuickPurge (pictured left) for
the Oil and Gas Industry and various sized Heat Resistant
Weld Purge Dams for a site in Europe, where the application
involved pre-heating up to 200ºC.

2021 has also started well for our new
design Weld Trailing Shields®. The first
batch of the New Year are now making
their way to various sites around the
World.
It’s been a fantastic end to 2020 and start
of 2021 and we look forward to another
successful year.
As always, if you need any technical
support, then please get in touch!”

6 HFT® NEWS

REPLACE FOAM DAMS WITH A QUALITY PURGING SYSTEM

Weld Purging dams are still fabricated on-site by welders to save money. They are often made from
unsuitable materials such as foam, wood, paper and even tape.
These types of Weld Purging dams can often leak, become displaced and even burst into flames.
Rework is then consequently necessary and in some cases welds have to be rejected. Displacing
the oxygen with an inert gas before, during and after welding helps to create welds that are free from
oxidation. However the Weld Purge dams should be made of materials that do not outgas water
vapour or any other undesirable gases.
There are many reasons for using quality designed and manufactured Pipe Weld Purge Systems
instead of homemade dams.
A customer of HFT® said: “I’ve seen many home-made devices. The rubber seal type always give
a better seal and are more durable to heat, however burning foam dams release fumes. These are
unhealthy and can contaminate the weld.
“More than once I’ve seen welders burn their hands whilst hurriedly removing a foam dam which had
caught fire. Masking tape used in their place can often start peeling off whilst the welder is oblivious.”
“Foam dams can fall out during welding – a real sickener when you lift your hood to inspect your
work.” Foam is also highly porous and will be full of voids containing air, water vapour and maybe
even hydrocarbons that will outgas as the dams become warm from the welding process.
HFT® manufacture a range of Tandem Weld Purging Systems in sizes 1” to 88” (25 to 2,235mm), a
reusable method of welding reactive metal tube and pipe joints to ensure a very fast weld purge time
and a very high quality weld root, free from oxidation, discolouration and coking.
Where Tandem Weld Purging Systems are unsuitable, Weld
Purge Dams are available for pipe diameters from 6 to 88”
(150 mm up to 2,235 mm) and offer a low-cost alternative to
foam or cardboard dams that are still frequently handmade
by welders on site.
Apart from the benefit of having a metallurgically sound weld,
the difficulties of cleaning an oxidised weld are eliminated,
saving vast amounts of money in labour and material costs
as well as the disposal costs when pickling acids are used.
Now there is no more reason to put welds at risk by using
cheaper unsuitable materials.

1. CALENDAR: EVENTS IN THE INDUSTRY

Fabtech WIN Eurasia
10 - 13 November 2021
13 - 16 September 2021 Istanbul, Turkey

Chicago, USA

Adipec TechniShow
March 2022
8 - 11 November 2021 Netherlands

Abu Dhabi, UAE

PRODUCT NEWS 7

UPDATED YOUTUBE VIDEOS

We recently added some demonstration videos
to our YouTube Channel including a PurgEye®
100 recalibration video.
The video is a step by step guide on how to
perform a zero calibration on a PurgEye® 100
Weld Purge Monitor®. Also featured in the video
is a step by step guide on how to perform a
sensor and battery replacement.
Visit our YouTube Channel to watch any of our
videos: www.youtube.com/huntingdonfusion

ELIMINATE POROSITY DURING WELDING WITH A DEW POINT SENSOR

The presence of moisture on the joint surface can create porosity in the weld metal. It is therefore
important that the dew point is monitored so that welders are made aware when moisture is likely
to be present.
Innovators in Weld Purging Huntingdon Fusion Techniques HFT® have recently developed the
PurgeNet™ Dew Point Purging Gas Moisture Sensor™, an important prediction instrument of when
water will form on metal surfaces in the welding environment.
Ron Sewell, Chairman for HFT® said: “Under arc conditions, water is broken down into hydrogen
and oxygen in atomic form which, when present in weld metal, cause porosity and are known to
create cracking in the weld joint. Water can form as moisture on metal surfaces while welding, so
it is crucial to be able to measure ‘Dew Point” while welding lengthy critical joints as conditions can
change during the welding process.”
“The PurgeNet™ Dew Point Purging Gas Moisture
Sensor™ accessory has been designed to integrate
with most of the Argweld® Weld Purge Monitors®
via the PurgeNet™ Smart Cable that is supplied with
them, thereby giving values and water present on the
same screen. In this way, the user is not forced into
the purchase of an expensive, separate Dew Point
Monitor that will give its reading elsewhere.”
The PurgeNet™ Dew Point Purging Gas Moisture
Sensor™ is designed to fit any of the Argweld® Weld
Purge Monitors® that read down to 1ppm, which includes the PurgEye® 200, PurgEye® Desk,
PurgEye® 600, PurgEye® 1000 and the PurgEye® Site.
Data is displayed on the OLED screen of the Weld Purge Monitor® in split format, so both oxygen
(02) and moisture (H20) content are shown as ppm value.

8 PRODUCT NEWS

PIPE PURGING WITH WATER-SOLUBLE WELD PURGE FILM®

When it comes to pipe purging, it is not desirable,
nor cost effective to simply pour inert gas into the
pipe assembly in the hope that a good purge is
achieved. A tough, leak tight purging barrier is
required.
To keep purging costs down, Weld Purging
Experts, Huntingdon Fusion Techniques HFT®
have designed and developed Weld Purge Film®,
a water-soluble polyvinyl acetate purging barrier
for a variety of pipe sizes.
Luke Keane, Technical Sales Manager for
Huntingdon Fusion Techniques HFT® said: “It is
so easy to cut a circle of water-soluble film and
place it a short distance away from the root gap before welding, pasting in place with the Argweld®
Water Soluble Super Adhesive® to ensure a tough leak tight barrier, keeping the purging volume to
the barest minimum. Argweld® Weld Purge Film® offers users the opportunity to make significant
economies by minimising gas usage and cutting down dramatically on time taken to make a purge,
whilst at the same time, achieving a desirably low oxygen level.”
After welding, the water-soluble film can be dissolved and washed away by simply flushing the pipe
interior. Previously, pipe welders might have used water-soluble paper, but as paper contains a high
percentage of water which undesirable to have near a weld, the Argweld® Weld Purge Film® is a
tremendous new benefit for weld purging.
These affordable kits will save operators high costs by minimising gas usage, reducing purge time
and eliminating the need for cleaning. Weld Purge Film® Kits have been designed and developed
by HFT®, as a complete accessory to manufacture dams that offer effective shielding and stability.

RELIABLE OXYGEN MONITOR FOR TITANIUM WELDING IN AEROSPACE APPLICATIONS
Prior to welding of titanium, widely practiced in the aerospace Industry, the oxygen content of the
purge gas must be reduced to a level below 50 ppm.
Engine components such as discs, blades, shafts and
casings, from the front fan to the rear of the engine, and
fasteners, airframe components and landing gear are all
examples where titanium is used. Further examples are
fuel tanks for satellites and military jets. Components
such as wing spars have also been made recently out
of titanium using the Wire Arc Additive Manufacturing
(WAAM) process.
The innovative PurgEye® Desk, a new monitor designed
and manufactured by weld purging experts Huntingdon
Fusion Techniques HFT®, is leading the way in inert gas
weld purging technology by reading oxygen levels from
1,000 ppm, right down to levels as low as 1ppm (highly accurate to 10 ppm), ensuring welders
achieve perfect oxide free, zero colour welds time and time again.

PRODUCT NEWS 9

PurgEye® 200 Weld Purge Monitor®

with PurgeNet™
Pipe Purging accurately down to 10 ppm

Scientific Developers of
Weld Purging Technology and

Manufacturers of
Weld Purging Products since 1975
Celebrating our 45th Anniversary

www.huntingdonfusion.com

10 TECHNICAL ARTICLE - DAIRY AND FOOD PIPE WELDING

TECHNICAL ARTICLE - DAIRY AND FOOD PIPE WELDING

Most industries using stainless steel tubes 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 tubes 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.
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%).

TECHNICAL ARTICLE - DAIRY AND FOOD PIPE WELDING 11

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
thickness.

At a critical film thickness it 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
measurements.

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 1 ppm with extreme accuracy and
has a display range from 1,000 to 1 ppm (accurate
to 10 ppm) shown on the OLED display.

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.

References
1. Microbiologically influenced corrosion of stainless steel, 2nd symposium on orbital welding in high purity industries,
La Baule, France
2. 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
3. Considerations for Orbital Welding of Corrosion Resistant Materials to the ASME Bioprocessing Equipment Standard,
Stainless Steel America conference 2008
4. Heat Tint Poses Corrosion Hazard in Stainless Steel, Welding Journal December 2014
5. ASM International. Corrosion in Weldments. 2006
6. www.huntingdonfusion.com

Author: Michael Fletcher
Dr M J Fletcher is a qualified metallurgist with extensive experience in welding and non-destructive testing.

Weld Backing Tape®

Supporting Weld Roots

Scientific Developers of
Weld Purging Technology and

Manufacturers of
Weld Purging Products since 1975
Celebrating our 45th Anniversary

www.huntingdonfusion.com