Weld Purging World - January 2020

ISSUE 1 JANUARY 2020

In January’s Issue:

• #Weld of The Month
• What is Weld Purging?
• Ask the Expert - Pipe Freezing
• Product News: PurgEye® Nano & Inflatable Stoppers
• Technical Article: WAAM for Marine Propellers and Aircraft

Structures

WELD PURGING PRODUCTS
INNOVATORS, MANUFACTURERS and
INTERNATIONALLY RENOWNED SPECIALIST

Huntingdon Fusion Techniques HFT® are proud members of:

www.huntingdonfusion.com

2 CONTENT

WHAT’S IN THIS MONTH’S ISSUE

#Weld of the Month & 3
2020 Industry Events
HFT® News 4-6
Product News 7-8
Technical Paper: WAAM 9 - 11

A WELCOME FROM THE EDITOR

Dear Reader,

Welcome to January’s Weld Purging World.

Happy New Year! We hope you all had a wonderful Christmas and have entered 2020 feeling fresh
and ready for the year ahead.

2020 has more big plans for HFT®. We have some exciting
products in development, attending some fantastic Trade
Shows and working on more interesting technical articles.

Next month, we are launching our Welding Knowledge Series,
aimed at explaining in engineering terms the principles of arc
welding, the properties of materials, the need for pre- and
post- weld heating and other related issues. Look out for the
first publication titled The Principal Arc Welding Processes in
February’s Weld Purging World.

I’m always on the look out for more exciting content for Weld
Purging World, so if you have any news or would like to be
featured in our magazine, then please get in touch.

Thank you for reading!

Best wishes,
Michaela

Marketing and Social Media Manager
[email protected]

HFT® NEWS 3

# WELD OF THE MONTH

What a great way to start the year, with these fantastic welds from Diogo Faustino (@faustino.fpw)
who has been welding with our PurgEye® 100.

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.

1.

CALENDAR: EVENTS IN THE INDUSTRY

Distributor Exhibiting! Distributor Exhibiting!

Nuclear Power Plants Expo WIN Eurasia
Stand No. D12 HALL 12 A160
4 - 5 March 2020 12 - 15 March 2020
Istanbul, Turkey İstanbul, Turkey

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

Fabtech Mexico Fabtech Canada
12 - 14 May 2020 16 - 18 June 2020
Mexico City, Mexico Toronto, Canada

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

4 HFT® NEWS

HFT® NEWS 5

ASK THE EXPERT - PIPE FREEZING

Pipe freezing is fast becoming one of the most efficient ways to make pipe repairs or to carry out
pipeline maintenance. By creating an ice plug, fluids inside the pipe can remain present, rather than
having to drain down the entire system.
Here are some of our frequently asked questions regarding the Pipe Freezing System, Accu-
Freeze™.
Q. What applications is Accu-Freeze™
designed for?
Accu-Freeze™ utilises liquid nitrogen to create
the cryogenic temperature necessary to form
ice plugs. Freeze sealing is most often used
to isolate a section of a piping system where
no other ready means of isolation (such as
valving) is available. Freeze sealing refers to
the process of applying an external refrigerant
to a point in a process in order to cause the
formation of a solid internal plug from the frozen
process fluid contained in the pipe.
Q. What size pipes is Accu-Freeze™ suitable
for?
The Accu-Freeze® insulating jacket
accommodates pipe sizes from 6 – 12″ (150 – 305 mm). Copper coil is used for the smaller sizes.
Aluminium clam shells are available for 2” – 16” (50 mm – 400 mm).
Q. Can I freeze contents that are moving within a pipe?
No, the liquid contents of the pipe have to be stationary and non-vibrating
Q. Can I freeze liquids other than water?
Yes, milk and beer are all examples of other liquids that can be frozen. Some liquids containing
refrigerants can be frozen too, just check with our Technical Team on the type and % content.
Q. Can I do a freeze either side of the repair joint?
Yes, this is called a double freeze and necessary accessories can be purchased along with the
Accu-Freeze™ kit. A double freeze is required when a valve needs replacing for example.
Q. What kind of pipes can Accu-Freeze™ be used on?
Accu-Freeze™ can be used on iron, lead, steel and copper pipes. It is also applicable to plastic
pipes, but these will take up to three times longer.

Q. What about bursting or fracturing pipes?
Pipe fractures are not caused by the ice plug or the freezing
process. They are caused by a failure to allow enough space
between the ice plug and closed connections. This is due
to the increase in pressure that is caused by water that
is displaced by the ice plug as it grows that can create a
‘hydraulic ram’ if enough space is not allowed.
Q. Can I freeze on a weld?
It is not ideal to freeze on a weld unless the weld has been
x-rayed.

6 HFT® NEWS

1. Weld Purge Monitor for On-Site Conditions

LAUNCH OF ‘WELDING KNOWLEDGE’ SERIES

Whilst welders generally are highly skilled in their own disciplines, there are some aspects of metal
joining where a clear understanding is limited.
Metals and the effects of welding on their properties, the importance of cleaning and protection
against oxidation are only some examples where additional knowledge is often required.
With this in mind, we are launching a series of short publications titled Welding Knowledge, aimed
at explaining in engineering terms the principles of arc welding, the properties of materials, the need
for pre- and post- weld heating and other related issues.
The first publication titled The Principal Arc Welding Processes will be featured in February’s Weld
Purging World. HFT® Chairman Ron Sewell, has welcomed the series saying: “Availability of this
type of information is long overdue and we have therefore commissioned the preparation of Welding
Knowledge from our independent engineering consultants.”
Technical Sales Manager at HFT, Luke Keane said: “Our customers often request clarification on
the use of our welding products and Welding Knowledge will satisfy the evident need for more
information.”
Look out for Issue One in February’s Weld Purging World!
If you would be interested in publishing HFT®’s ‘Welding Knowledge’ Series, please get in touch.

PRODUCT NEWS 7

MONITOR YOUR TITANIUM WELDS FOR HIGH QUALITY RESULTS

Preventing oxidation when welding tubes and pipes can be
achieved by purging the inside with an inert gas. This simple
procedure saves both time and cost. By knowing the exact
level of oxygen inside the pipe at all times, the welder knows
when to start welding for high quality results.
With restricted budgets in mind, the basic-entry level
PurgEye® Nano, designed and developed by Weld Purging
Experts Huntingdon Fusion Techniques HFT®, will show
oxygen levels down to 1 ppm (accurate to 10 ppm), which
can be used to monitor the oxygen content when welding
titanium, zirconium and all other reactive alloys.
A customer recently said: “The PurgEye® Nano is really easy
to use, with excellent results. Previously, each welder would
let argon flow as much as possible before starting to weld, to
be sure that purging was sufficient. Now, they know when to
reduce it prior to welding and in such a way they save good
amount of argon. There is no guessing and welders and their
assistants can use it after only a few minutes of instruction.”
The PurgEye® Nano has been developed for weld purging where data logging, alarms and machine
control are not necessarily required. The monitor has been developed with a unique long life sensor
that has a warm up time under 60 seconds.

With leak-tight connectors for weld purge hoses, the
lightweight PurgEye® Nano can be used with optional
accessory hand pump and gas sampling probe. It can
be used to check purge gas quality from the main
source and at the exhaust end of a purging system,
as well as to find air leaks in purging hose connections
anywhere in a system. The monitor can also be used
to check the quality of the gas source to ensure that
no contamination is present.
HFT® has a Family Range of PurgEye® Weld Purge
Monitors® for every application. The range includes
hand held, battery operated monitors and mains powered monitors, which can read oxygen levels
from atmospheric level of 20.94%, right down to 1 ppm.
Ron Sewell, Chairman for HFT® said: “All of Huntingdon Fusion Techniques HFT®’s Weld Purge
Monitors® and Inflatable Tube, Pipe and Pipeline Weld Purging Systems as well as our inflatable
welding enclosures are manufactured in the UK. We do not sacrifice on quality. We guarantee to
help welders achieve zero colour welds, time and time again.”

8 PRODUCT NEWS

FLOW STOPPING SOLUTIONS FOR ALL APPLICATIONS

Flow and line stopping equipment gives the user the opportunity to isolate a section of pipeline to
carry out repair and maintenance work.

The Pipestoppers® Division from Huntingdon Fusion Techniques HFT® design and manufacture
a Range of standard and non-standard Inflatable Stoppers for tanks, chambers, tubes, pipes and
pipework fabrications, offering a range of pipe stopping and blocking requirements.

Ron Sewell, Chairman for HFT® said: “These versatile Inflatable
Stoppers are used to service a wide variety of industrial
applications. As “overnight stoppers” they provide a strong
barrier in pipeline activities, to prevent foreign bodies entering
the line during downtime.”

“In machining applications, they can be inserted below a
horizontal flange on a vertical pipe, to prevent machining fluid,
swarf and tools from falling into expensive machinery such as pumps and turbines etc.”

“When welding large tanks and vessels, stoppers inflated with air can dramatically reduce the volume
inside, so that the argon purging process takes little time and uses the minimum of expensive
gas. The stoppers can pay for themselves in one weld or application and can be used multiple
times. Other applications include leak testing of pipework systems, whether commercial, domestic
or industrial, in pipes made of any materials.”

All Inflatable Stoppers are manufactured with a strong internal latex balloon covered in a waterproof
polyurethane coated nylon bag for low friction and to prevent the production of static electricity or
accidental sparking.

Inflatable Stoppers are particularly useful when one or
more can be inserted into a small opening close to a work
location, rather than at the end of the pipe, tank or vessel.
No high-pressure equipment is needed for inflation.

The standard range of Inflatable Stoppers is available for
immediate delivery in Cylindrical or Spherical formats with
sizes ranging from 1 to 96” (25 to 2,440 mm).

Inflatable Stoppers are available with heat resistant covers to protect them against high temperatures.
HFT® also has a range of Rubber Inflatable Stoppers that are suitable for petrochemical applications
and are resistant to all hydrocarbon fluids and gases.

TECHNICAL ARTICLE - WAAM 9

WAAM FOR MARINE PROPELLERS AND AIRCRAFT STRUCTURES

Since 3D printing was introduced over 30 years ago
there have been a number of significant developments.
Various melting techniques have been used to achieve
this aim including electron beams and lasers, but one
being most actively pursued currently is Wire and Arc
Additive Manufacture (WAAM) using a GTAW (TIG)
power source. To be specific, additive manufacturing
is not the same as 3D printing!
The recent use of fusion welding as a deposition
source has opened up wide ranging possibilities in
manufacturing. The process is one in which metal is
deposited layer-by-layer under computer control to
form a three dimensional shape.
No longer is it necessary to keep an inventory of high value generic stock: parts can be customised
and manufactured on demand. A recognition that components can be fabricated using WAAM
technology has spawned a new industry to exploit a wide range of exciting opportunities.
Two outstanding examples showing how engineers have exploited the potential of WAAM to achieve
major cost savings are the production of ship propellers and the fabrication of airframe components.
The Damen Shipyards Group entered a cooperative consortium with RAMLAB, Promarin, Autodesk
and Bureau Veritas to develop first class approved marine propellers. Damen’s involvement in the
project began as a result of one of its in-house student research programmes. Three students from
Delft Technical University were investigating the potential of WAAM technology and they introduced
Damen to the other members of the consortium. Kees Custers, Project Engineer in Damen’s
Research & Development department commented, “What is quite unique about this group of five
companies is that, while we have joint interests, we also have individual aims. This leads to a very
productive and cooperative atmosphere in what is a very exciting project.”
The early work terminated in the production of the world’s first WAAM manufactured propeller in
2017. It is based on a Promarin design typically found on a Damen Stan Tug type 1606 (Fig 1).

Fig 1. 1300mm diameter
propeller produced by Damen
Shipyards Group. It weighs
approximately 180kg. The
WAAM product has been
fabricated from a bronze alloy
using the GTAW process.

10 TECHNICAL ARTICLE - WAAM

Researchers at Cranfield University in the UK have developed the WAAM process to examine the
use of Inconel, titanium, aluminium and various nickel alloys. The focus is currently directed towards
airframe components.
Although “laser and powder methods” are useful for certain applications such as rapid prototyping
or for small highly complex parts, this technology is limited by its speed and the size of component it
can accurately manufacture. In contrast, the processes being developed at Cranfield are designed
for high deposition rates.
The programme began in 2007 with funding from both the University’s Innovative Manufacturing
Research Centre and 15 industry partners. The idea is to simplify the process of complete product
within a single one-hit additive manufacturing system incorporating a fully integrated robot. The
Centre is currently targeting a deposition rate of 10kg an hour for titanium, compared with a typical
0.1 kg using laser + powder methods. WAAM systems are also capable of producing parts several
metres in size and simplify the process of producing single piece linear intersections.
Fig 2. This main structural element of an aircraft wing was
produced using WAAM technology. Traditionally this type of
component would be manufactured by machining from a solid
block of metal. Over 50% of the original stock is lost as swar.

A common problem facing any arc welding fabricator, particularly when welding stainless steels,
nickel alloys and titanium, is the need to protect the weld and immediate metal from oxidation
during the welding process. For sheet and plate applications the hot zone can be protected to some
extent by the inert gas from the welding torch. With complex weld geometry and three dimensional
structures such as those witnessed in WAAM applications this becomes much more difficult. Inert
gas coverage is likely to be disrupted by the variations in profile and changes from the laminar
flow in the torch to a more turbulent flow at the joint. This leads directly to entrapment of air and
subsequent oxidation of the weld.
Overcoming the problem of oxygen contamination during WAAM
One solution is to undertake operations inside a steel chamber filled with inert gas. With the electron
beam process for example, protection is assured since operations are carried out in a vacuum.
Nevertheless this is an expensive alternative to arc welding.
Huntingdon Fusion Techniques, HFT® in the UK has resolved the issue of adequate protection by
providing some WAAM users, such as teams at Cranfield and the Welding Institute, with Flexible
Enclosures®.
The company has been developing these enclosures for many years by exploiting the opportunities
offered by advanced engineering polymers. The innovative products offer significant attractions over
both vacuum and glove box alternatives; a significant reduction in cost, very small floor footprint and
availability of a range of sizes up to 27 cu m. Since that time the HFT® product has been developed
and is rapidly becoming the preferred alternative enclosure.

Fig 3. Flexible Enclosure manufactured for a sports
car manufacturer.It illustrates some singular features
of flexible enclosures such as multiple operator and
equipment access points and the available size
range: this model is 4.0 x 1.6 x 1.6 metres.

TECHNICAL ARTICLE - WAAM 11

Fig 4. Low volume enclosure coupled with
robot operating through a flexible uper seal for
demonstration work and the production of small
components. For larger scale manufacture
flexible enlosures can be made large enough to
accommodate the entire work, welding equipment

The largest facility supplied to Cranfield has a volume of 27 cu m, adequate to accommodate all
work pieces, welding equipment and even a programmable robotic system.
Oxygen content of the enclosure gas can be monitored continuously with instruments developed
specifically for the welding industry. These are capable of measuring residual oxygen down to 10
ppm, well below the acceptance level required for high quality deposits of sensitive materials such
as titanium alloys.
Software is available for data acquisition and logging where traceability is vital. A high/low feature
allows the operator to control deposition between set oxygen levels. Relay contacts can be used to
operate warning lights, alarms or even switch welding power supplies on and off if levels exceed set
limits.
Flexible Enclosure® concept
Technical Specification: Ultra violet stabilised translucent or optically clear engineering polymers are
used with a material thickness typically 0.5 mm.
Principle large access zips are fitted and additional entry points can be provided for operators’
gloves, welding torches and for electrical leads and cooling water supplies. A purge gas entry port
and an exhaust valve to vent displaced gas to atmosphere are incorporated. A port is also provided
for gas sampling with a weld purge monitor.
Cost: Size for size the HFT® range costs less than 10% of a metal glove box and only 2% that of a
vacuum system.
Flexibility: Size and shape can be made to meet customer requirements. Standard models from 0.3
to 3.0 cubic metres are available. Weight is very low and the enclosures occupy little space – the
collapsed volume of a 1.25 metre diameter system is less than 0.2 cubic metres and weighs only 8
kg. They can thus be moved easily and stored efficiently so floor footprint is minimised.
Welding sources: The enclosures are suitable for use with Tig/GTAW welding and plasma/Paw arc
welding techniques and laser beam welding.
Author: Michael Fletcher
Dr M J Fletcher is a qualified metallurgist with extensive experience in welding and non-destructive
testing. He works as an independent consultant, providing support to a wide range of manufacturing
industry on a global basis.
REFERENCES
Zelinski P. Additive Manufacturing April 2017
Design for Wire and Arc Additive Layer Manufacture. J. Mehnen et al. 20th CIRP Design Conference, Nantes
April 2010
RAMLAB focuses on accelerating 3D printing. Bridget Butler Millsaps. Nov 30, 2016. 3D Printing, Business,
Robotics
World’s first class approved 3D printed propeller. International Institute of Marine Surveying May 2017