African Fusion August 2018

AFRICAN AUGUST 2018

Journal of the Southern African Institute of Welding

A leading provider of complete welding solutions

www.esab.co.za

Contents

August 2018

FEATURES 4 SAIW support for the modern welding industry African Fusion talks to SAIW Technical Services manager, Riaan Loots, about some new services and the need for the welding industry to be open to modern technology. 10 H-ESC: A high-speed innovation in electro slag strip cladding This paper from the IIW 2018 International Conference details a hybrid electro slag strip cladding (H-ESC) process that can achieve undiluted single layer surface chemistry for nickel and stainless steel alloys. 16 TOPTIG offers TIG quality with MIG productivity This article introduces TOPTIG, which incorporates an integrated wire feeder and a novel torch design to enable welding speeds associated with MIG/MAG with the typical quality of a TIG weld. 18 Lasting connections: filler materials for welding pipelines Robert Bischof of voestalpine Böhler Welding discusses specially developed welding consumable selections customised for pipeline use. 20 Welding automation solutions: essential for growth African Fusion talks to Petrus Pretorius, general manager of Cosmo Industrial, about the wide variety of Lincoln Electric automation solutions nowavailable throughCosmo Automation Solutions. 23 Calibration essential for accurate, safe and traceable NDT Yvette Volschenk of H. Rohloff highlights the importance of calibrating NDT equipment to achieve the full safety and traceability benefits of the technology. 24 Automotive success for second generation CMT process Automotive industry supplier, voestalpine, was the first company to choose Fronius’ second generation TPS/i ‘cold arc’ advanced CMT welding system for use in series production. 26 Resource screening centre maximises on-site efficiency Launched less than a year ago, Babcock’s new resource screening centre is proving its value in matching skilled labour resources to specific on-site job requirements. 29 Fabcon: turnkey solutions for diverse applications Structural and reinforcing steel supplier Fabcon Steel continues to expand its service offering, while targeting growth opportunities beyond the construction sector. 31 Thermaspray’s Plasma coatings for sticky situations Thermaspray sales engineer, Johan Squara, describes the Plasma coating process, which offers the benefits of wear resistance with non-stick properties. REGULARS 3 Sean’s comment 6 SAIW bulletin board 8 Front cover story: Premium welding products enable rapid growth 33 Welding and cutting forum 40 Today’s technology: Arc Torchology: a most powerful TIG torch range

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Bedfordview 2008 Tel: (011) 622 4770 Fax: (011) 615 6108

Editor: Peter Middleton E-mail: peterm@crown.co.za Advertising: Helen Couvaras E-mail: helencou@crown.co.za Publisher: Karen Grant

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Deputy publisher: Wilhelm du Plessis Production & layout: Darryl James Circulation: Brenda Grossmann Printed by: Tandym Print, Cape

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African Fusion talks to ESAB South Af- rica’s MD, Chris Eibl, about premium products and the advantages of fo- cusingon the costs of depositedweld metal rather than the cost per kg of a consumable or the comparative costs of a quality welding solution.

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www.africanfusionmagazine.co.za

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SAIW: Sean's comment

SAIW and SAIW Certification

SAIW Governing Board President: Morris Maroga – Eskom S Blake – SAIW L Breckenridge – CEA G Joubert – SAISI A Koursaris – Metforensics DJ Olivier – Olivier Survey Group A Paterson – University of the Witwatersrand T Rice – Personal member J Tarboton – SASSDA JR Williamson – Wilconsult J Zinyana – New Age Welding Solutions SAIW Certification Governing Board Chairperson: G Joubert – ArcelorMittal B Beetge – Sentinel Inspection Services P Bruwer – Sasol Synfuels F Buys – TUV S Blake – SAIW G Buitenbos – Steinmüller G Joubert – SAISI A Koursaris – Metforensics D Olivier – Olivier Survey Group H Potgieter – SAIW Certification P Pistorius – University of Pretoria R Williamson – Wilconsult J Zinyana – New Age Welding Solutions M Maroga – Eskom S Moodley – SAPREF

O ur SAIW Annual Dinner on September 7 is a very special one because we will be celebrating our 70 th Anniversary. The symbol for a 70-yearmarriage is platinum, which is a particularly appropriate representa- tion of the durability and national value of the SAIW.

Back in 1948 when the SAIW was established by Afrox’s Harvey Shacklock, whowouldhavebelieved that this small non-profit Institute would become the leading welding organisation on the African Con- tinent: a founder member of the IIW; the Continent’s most respected training facility for welding related personnel; and its champion of welding quality standards and certification. The key to remaining successful for this length of time, I believe, is twofold. Firstwehavealways strived tobe relevant to thewelding indus- try at large. The SAIW serves industry and it can only do so successfully by using the skills and experience of members from industry. All of our training courses and examinations, for example, have been developed on behalf of and using input fromwelding specialists actively involved in thewelding industry, specialistswho knowwhat is requiredof young graduates for them to have long and successful careers. Second is our obsessionwith excellence and continuous improve- ment. Thewelding industry has changed significantly since the SAIW’s establishment in 1948 as a voluntary industry association. Then in 1977, Phil Santilhano joined as the Institute’s technical director to offer technical support to members. In response to our industry’s increasing needs for personnel, the SAIW developed and began to run training courses in the early 80s. In the early 2000s, we began to offer IIW qualifications and in 2003 we became an Authorised National Body (ANB) of the IIW. Our relation- ship with the IIWhas gone from strength to strength and today we run the IIWWelding Inspection programmes, with graduates receiving IIW diplomas that are valid internationally. And we continue to improve our training offerings: with the intro- duction of modern NDT techniques such as phased array UT, eddy- current testing and digital radiography, for example. The SAIW is now accredited by the Quality Council for Trades and Occupations (QCTO) as per the recently introduced South African Na- tional ArtisanWelder programme. Inpartnershipwith ArcelorMittal, we are now introducing the SAIW QCTO Artisan Training for a group of 15 apprenticeswhowill be funded fromthe SAIWFoundationProgramme. The QCTO programme is alignedwith the IIW International Welder, andgraduates fromtheSAIWFoundationwill receive internationally rec- ognised IIWqualifications on topof their National ArtisanQualification. We are also in the process of establishing our Future Welder Train- ing Centre, which will focus on advanced and automated welding processes, which are becoming increasingly important in industry. Welding has long been a process governed by welding codes, but the international welding industry has been on a path of increasing professionalism, driven by the development and implementation of ISO quality systems and standards. Most notable for us is the ISO 3834 standard for fusion welding of metallic materials. We are particularly proud to have introduced this standard into South Africa along with the associated SAIW Welding Fabricator Cer- tification Scheme. To date, SAIW Certification has certified over 160 welding companies in South Africa against ISO 3834. In recognition of the importance of ISO 3834, we have introduced two additional awards, whichwill be first presented at our 70 th Annual Dinner: theBest ISO3834Welding FabricationCompany Award; and the Best Welding Co-ordinator Award. Selecting winners will not be easy. We have a lot to celebrate at our Platinum Anniversary and I look forward to reminiscing with you all about 70 years of SAIW successes. Sean Blake

SAIW Foundation Board Chairperson: M Maroga - Eskom S Blake - SAIW P Pistorius - University of Pretoria P Venter – ArcelorMittal J Pieterse- Afrox

SAIW and SAIW Certification representatives

Executive director Sean Blake Tel: (011) 298 2101 sean.blake@saiw.co.za

Training services manager Shelton Zichawo Tel: (011) 298 2148 shelton.zichawo@saiw.co.za

SAIW Certification manager Herman Potgieter Tel: (011) 298 2149 herman.potgieter@saiw.co.za

NDT training manager Mark Digby Tel: (011) 298 2169 mark.digby@saiw.co.za

Executive secretary Dimitra Kreouzi

Technical services manager Riaan Loots Tel: (011) 298 2144 riaan.loots@saiw.co.za

Tel: (011) 298 2102 Fax: (011) 836 6014 dimitra.kreouzi@saiw.co.za Finance and administration manager Michelle Warmback Tel: (011) 298 2125 michelle.warmbank@saiw.co.za Cape Town branch manager Liz Berry Tel: (021) 555 2535 liz.berry@saiw.co.za SAIW regional representatives

KZN branch manager George Walker Tel: (087) 351 6568 george.walker@saiw.co.za

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SAIW: Modern technical services

African Fusion talks to SAIW Technical Services manager, Riaan Loots, about some new services nowavailable fromThe Institute and the need for the welding industry to be open to modern technology. SAIW support for the modern welding industry

“ T he role of Technical Ser- vices at SAIW has not re- ally changed,” begins Loots. “Supported by our Materials testing laboratory, which is accreditedbySANAS to ISO 17025, we still offer consultancy services in five key areas, investigating and preventing failure; establishing new and better welding and cutting procedures; quality assurance and qual- ity systems requirements – ISO 3834, EN 15085 and ISO 14731, for example; materials support and testing; and col- laborative research and development programmes. “Our consultants are constantly busy helping companies with welding procedure specifications and welder performance qualifications and advis- ing on all welding related issues that arise: this supported by our laboratory services that do the mechanical and materials testing required for approvals

and investigations,” he continues. AccordingtoLoots,newtechnologies and changes in thewaymodernwelding equipment is able tocontrol andmonitor the welding arc, however, are changing thewelding industry, whilebringingnew challenges and opportunities. “Modernweldingmachines are now mostly inverter drivenandoffer sophisti- catedwaveformcontrol: pulsed current; pulse-on-pulse; ac/dc wave balance, cold-metal and surface tension transfer, and more. What people should be look- ing for is how these machines can be effectively used to improve productivity and weld quality. We can help users of these machines to make the transition – and there are important differences that need to be borne in mind: how to calculate the arc energy/heat input, for example,” he tells African Fusion . There is a standard dealing with this – ISO/TR 18491: 2015; Welding and allied processes; Guidelines for measur- ing welding energies – which gives ad- ditional formulas for calculating the arc energy/heat input for different types of power sources. “Power sources featuring fast chang- ing or pulsing current and voltagewave- form control are effectively delivering the arc energy in pulses too. So the resulting effective arc energy can no longer be accurately calculated using traditional volts×amps/travel speed formulas,” he suggests. ISO/TR 18491 describes three differ- ent formulas available to help welding engineers and supervisors to get the arc energy calculation right for conventional andwaveform-controlmachines: one for non-waveform controlled machines; a second for non-waveform controlled machines but using instantaneous en- ergy or power; and a third formula for calculating the instantaneous energy or power for waveform-control machines,” Loots explains. Heat input/arc energy is a critical weld variables stipulated in ISO 15614,

the standard for welding procedure specifications (WPSs). It is also increas- ingly important when using modern high-strength steels, particularly those used in the power and petrochemical industries. With these steels, the weld thermal cycle can alter the condition of the base metal being welded, that is, themicrostructure is affected, which di- rectly affects themechanical properties. “So if there is a calculation differ- ence for determining arc energy based on the power source being used for welding, then the welding industry needs to become more aware of it. We at Technical Services can help people to better employ this new equipment to give them a competitive edge, par- ticularly when competing with global players,” Loots assures. “Inthelaboratory,whenweareasked to develop a welding procedure speci- fication, we now need to know which welding technology and, sometimes, which machine will be used to fabricate the product. And this relates also to the increase incomplexityof thenewmateri- als available for use,” he continues. “For common structural steels such as S355, the materials are well known and fabrication shops know exactly how to weld them using their existing fleet of machines. But when it comes to the P91/92 type steels used for power stations, much more care has to be adopted to prevent the properties of the steel from being impaired during welding. And this is increasingly true as lightweighting in design becomes more prevalent, which relies on stronger and thinner material sections with more complicated microstructures. “Duplex stainless steel is another example where arc energy is important, and for joining dissimilarmaterials. In all these cases, the real heat input values and the associated thermal cycle will play an important role in the quality of the final product,” Loots notes.

Lincoln Electric’s True Energy module is able to measure instantaneous arc energy values and use them, along with arc-on time and weld length, to determine an accurate value for heat input for machines that use waveform control technology.

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SAIW: Modern technical services

The material specifiers may give guidance on how to weld these new materials, and the welding equipment OEMs may offer guidance on how to use their machines and to calculate arc en- ergy. “But to get the best out of both the material and themachine, developing a WPS that properlymatches thematerial and the welding equipment to the qual- ity specifications of the product has got to be the way to go,” Loots advises. In addition, Loots cites the increas- ing use of automation technology as influencing change in the welding industry. In the automotive industry, for ex- ample, the trend is to use thinner and thinner plate to keep vehicles as light as possible. So new ‘colder’ welding processes have to be applied to reduce arc energy and minimise distortion. For higher welding speeds, better quality and tighter heat input control, robot cells are typically used and car- makerswill try to use thewelding equip- ment’s waveform control capability to full effect to meet the requirements in the fastest possible time. “Operators can take advantage of the consistency of the new digital automation technologies to prevent burn through, eliminate distortion and reduce reject rates drastically. But to do so, they also need to develop properly researched welding procedures, which are equipment-specific. In the past, SAIW has been very fo- cused on arc welding, “but we are now starting to lookat different technologies, such as brazing and additive manu- facturing (3D printing), which will be increasingly important in the factories of the future. “Metal additive manufacturing or 3D printing was a big new focus of the IIWAnnual Assembly in Bali last month. Industry 4.0 is coming fast and we at SAIW will be moving in that direction, too. By engaging and learning from our international IIW colleagues, we aim to start bringing best-practice modern approaches to shop floors in South Africa,” he says. Modern welding equipment from OEMs such ESAB, Lincoln Electric and Fronius all now comes with data moni- toring capabilities built in. This enables advanced data tracking capabilities, al- lowing many of the critical parameters specified inweldingprocedure specifica- tions to be tracked and deviations re- corded and time stamped, for example.

Systems such as Lincoln Electric’s Production Monitor allow many of the critical parameters specified in welding procedure specifications to be tracked and deviations recorded and time stamped, for example.

ity and documentation right. “People are starting to understand that, these days, it is possible to control welding andweld quality if fabricators all look to work within a welding quality manage- ment system,” he says, adding that it is no longer acceptable to simply produce goodwelds. A qualitymanagement sys- tem such as ISO 3834 is now becoming a requirement for doing business at all levels of complexity. “Smaller fabricators, however, often struggle to justify employing their own responsible welding coordination per- sonnel. SAIW Technical Services is in a position to provide these services on a contract basis, which means that small component level fabrication shops can also comply with ISO 3834 certification requirements without the burden of employing high-level technical staff. We canoffer IWT- or IWE-qualifiedpersonnel to take that role, checking that theweld- ing qualitymanagement system is being implemented via regular site visits. “Neither advanced technology nor quality management certification need be a barrier to welding success, no matter how small the fabricator,” Loots concludes.

The machine OEMs are also cur- rently working on making this data live and connected to the Internet. “So the instantaneous heat input, for example, will soon be able to be tracked while welding proceeds, and alerts sent to the welder and the welding supervisor while the welder is still busy welding,” Loots predicts. In ten years’ time, these features might be standard on all welding equip- ment and the data collected may well be shared with the welding inspectors to alert them to likely defect locations. All of this technology is fast becom- ing available and, if properly used, it is sure to reduceweld repair rates, improve weld quality and reduce costs. It could also significantly improve welder skills, because welders can be held accountable for every metre of welding they do throughweldmaps and traceability. “All of this is already part of the ISO3834 quality requirements for fusion welding. Potentially, following research into the practical applications of In- dustry 4.0 and the Industrial Internet of Things (IIoT), it is not inconceivable that welding data mining may also

become incorporated into our welding quality system standards,” Loots argues. ISO 3834 remains the cornerstone of quality in welding and Loots sees more and more people wanting to get their qual-

“Operators can take advantage of the consistency of the new digital automation technologies to prevent burn through, eliminate distortion and reduce reject rates drastically. But to do so, they also need to develop properly researched welding procedures, which are equipment-specific.”

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SAIW bulletin board

SAIW establishes Future Welder Training Centre

T he old adage ‘The future is not what it used to be’ is no more evident than at the SAIW with the in- troduction of its Fu- ture Welder Training Centre, which will use augmented or virtual reality welder training techniques. Augmentedwelder training, in essence, al- lows students to work with real 3D objects combined with virtual computer-generated

designed curricula; trade theory; simulated practice; andwork experience, whichare all tightly interwoven. All studentswill nowget practical training andwork experiencewith employers selecting and managing their own apprentices. In the latest project, ArcelorMittal S.A. (AMSA) has committed to appointing 15 apprentices and to signing an MOU with the SAIWthat will provide all the theoretical and practical training over the next three years. AMSAwill supply all workplace learn- ing while Nell will oversee overall quality assurance. industry feel that there hasn’t been suffi- cient change in the past 50 years in theway welding is taught. This, they say, may have led to a negative image of the profession and the consequent shortage of welders worldwide. “Many other industries are ahead in the useofmodern technologies for trainingpur- poses and its time that thewelding industry caught up. We hope that the SAIW will be able to show the way in Africa,” he says. The first machines that will be used in the new SAIW Future Welding Training Centre are the Lincoln Electric REALWELD® and ClassMate™ Robotic Welding Trainer systems and the Soldamatic Augmented Reality Welding Simulator. With the REALWELD Trainer, students can practise stick, MIG and flux-cored arc welding, while receiving audio coaching and weld performance tracking on five key parameters. It’s like having a teacher’s assistant right in the booth helping to advance every student along his or her career path. The Lincoln ClassMate is a complete ro- botic training solutiondesigned tomeet the

Lourens Hand has been appointed as a Welding Instructor to run the new SAIW Future Welder Training Centre. “I am excited about making our centre an ex- ample of excellence for the rest of the continent.”

Lincoln Electric’s ClassMate™ Robotic

Theoretical and Practical sections of the training will be funded by the SAIW FoundationandAMSAhas agreed todonate all the steel required for the project. Nell says that this is a pilot project and that the SAIW is looking for other compa- nies that would be interested in this new and exciting way of training welders. “This new systemwill certainly make a palpable difference to the quality of graduates and of the welding industry as a whole. I urge other companies to take a leaf out of AMSA’s book and initiate training in thismanner in conjunction with the SAIW,” he says. need for advancedmanufacturing training. Instructors can teach robotic concepts in the classroom and quickly move to the lab for welding practice. Students can perform offline programming and then test their skills at amanufacturing-ready robotic cell. Lourens Hand, a long-time staff mem- ber of the SAIW, has been appointed as a Welding Instructor to run the new Future Welder Training Centre. Welding Trainer system enables programming to be taught in the classroom before moving through to the welding lab for robotic welding.

images to give them the most realistic welding experience possible,” says SAIW executive director, Sean Blake. “They can repeatedly practise techniques, at no extra cost, and the system can be networked and controlled by the tutor, for optimal teaching.” He adds that augmented welder train- ing could possibly revolutionise the way welding is taught. “Many people in the T he SAIW Foundation, an NGO that the SAIW started as a public benefit organisation to provide training to disad- vantaged individuals in a wide range of areas including: welding and inspection; the training of trainers for welding and re- lated technologies; andmore, is changing with the times. In the past, learners recruited by the SAIWFoundationwereplaced inan Interna- tional Institute of Welding (IIW) programme with the aim of equipping them with IIW International welder diplomas. “This has been very successful,” says SAIW’s Etienne Nell, “but with the advent of the dual training QCTO system, a Depart- ment of Higher Education and Training ini- tiative,wearechanging the training format.” In essence, explains Nell, future SAIW Foundation trainingwill align itself with the Quality Council for Trades andOccupations (QCTO) ArtisanWelder Curriculum, which is aimed at producing: a skilled and capable welding workforce to support economic growth; an increased availability of inter- mediatewelding skills andan increasedde- livery of properly qualified artisanwelders. This system, unlike the old one, reflects occupational competence; new, industry-

SAIW Foundation students to enter SAIW/AMSA QTCO programme

Successful SAIW Foundation Students show off their IIW International Welder Diplomas.

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SAIW bulletin board

South African women change the Arc Cup

O f the five MerSeta/SAIW-sponsored welders that recently participated in the third edition of the Arc Cup, three of competitors were females. “This shook up the competition organisers in terms of rec- ognising thepower ofwomen in thewelding industry, with the result that a dedicated Arc Cup for women is on the agenda for all future competitions,” says SAIW’s Etienne Nell whose participation on the Arc Cup organising committee was an essential ingredient in this innovative move. This years’ South African team, which comprised Zelda Khumalo, Rose Mfabane, Princess Mpembe, Michael Ross and Chandle Cloete acquitted themselves well, gaining a bronze medal in the team com- petition, which comprised 36 countries. All three female competitors came from the SAIW Foundation – an NGO that provides bursaries for young welders. The Arc Cup, which is regarded as the second most prestigious international welding competition after the interna- tional WorldSkills event, was originally the Chinese national welding competition for the selection of the Chinese WorldSkills participants.

Nell sayshewaspleasedwith the team’s results this year andhoped that future SAIW teams will do even better. “The Arc Cup is excellent experience for our welders to get used to international competition and hopefully, we will be at the top of the pile in this competition and in the international WorldSkills competitions,” he says.

The three South African Arc Cup women helping to change the nature of the competition. From left: Princess Mpembe, Rose Mfabane and Zelda Khumalo.

SAIW to celebrate its 70 th at Annual Dinner T his year the SAIW is 70-years old and will celebrate one of the great success stories in South African industry. “Back in 1948 the SAIW was founded and simulta- neously became a founder member of the world’s most important welding body, the International Institute of Welding (IIW),” says executive director Sean Blake.

for years to come,” he says. The SAIW has been an Authorised National Body (ANB) of the IIW since 2003, offering the full range of IIW qualifications – Engineer, Technologist, Specialist, Prac- titioner, Welder and Inspector. “Our teaching staff, like our students, represent the full gamut of South African society and are dedicated to making a difference in South Africa by providing our youth and more experienced personnel in the industry an opportunity to get ahead in life,” says Blake “In short, over 70 years, the SAIW has become the foremost welding training and standards watchdog in Africa. This is cause for real celebration,” he concludes.

“Out 70 th Anniversary is indeed a mo- mentous occasion for the SAIW and the culmination of this celebration is at our Annual Dinner on 7 September,” adds SAIW President, MorrisMaroga. “This is anoppor- tunity for ourmembers andmembers of the welding industry to participate and make this moment a truly great one. I urge you all to make our 70 th year live on in memory

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Cover story: ESAB South Africa

Premium welding products enable rapid growth African Fusion talks to ESAB South Africa’s MD, Chris Eibl, about premium products and the advantages of focusing on the costs of deposited weld metal rather than the cost per kg of a con- sumable or the comparative costs of a qualitywelding solution.

“ E SAB South Africa has made massive strides in regaining lost market share and we are well on our way to getting back towhere we were prior to the dissolution of ESAB AfricaWelding and Cutting,” begins Eibl. “We are striving to regainourmarket leading position in cutting-edgewelding and cutting technology and more and more customers are moving over to ESABbecause of our ability to offer com- plete welding and cutting solutions,” he adds, citing a new relationship with Air Liquide as a national distributor for the entire ESAB product range. “The ESABbrand is back towherewe want it to be. In the last six months we haveexperienced25%growthcompared to the same period in 2017, and that in a declining economy, which we think is remarkable,” Eibl tells African Fusion . How has this been achieved? “Many of our competitors have introduced cheaper products to try to retainmarket share, but we have taken the opposite approach. Low cost products tend to increase costs in the long term, so we have chosen to offer real value to clients instead. Our strategy is to target the total cost of ownership of welding and cut- ting operations, which directly affects fabrication profitability. Some believe that a lower R/kg for consumables will do this, but this is seldom the case. At

the end of the day, a customer needs to be successful in all aspect of fabrication, by reducing all of the input costs at the same time,” Eibl argues. By way of a demonstration, ESAB ran a comparison between its premium AristoRod ASC (Advanced Surface Char- acteristic) weldingwire and a lower-cost alterative. “Even at double the price of the cheaper wire, we still managed to achieve a 10% reduction in the total cost of the fabrication,” Eibl reports. How? “Through improved ef- ficiency of the whole welding process. There is less downtime associated with our premium quality copper-free ASC wire: less stopping to clean liners and feed discs and labour. In short, the arc-on time is higher when using AristoRod ASC wire, leading tomuch lower total costs,” he explains. “So a fabrication shop with 20 bays can reduce to 18, simply by switching to this premium quality wire, and as a bo- nus, the fume generationwill be reduced to a third of what it was. This makes the process more environmentally friendly, and has the added benefit of reduc- ing the risk of non-welding personnel suffering from arc-eye, which is often rollers cloggedwith copper; and significantly less spatter, which saves on clean up time, grinding

Some of ESAB’s WeldCloud- enabled welding power sources. The top-of-the range Aristo® Mig 4004i Pulse welding machine (second from left) will be the flagship product on show at Electra Mining.

hydrogen (LH) OK 55.00 with AWS clas- sification of E7018-1 H4R electrode as an example. “The key benefit of this product is that it has a recovery of 125%, whichmeans every kg of corewire in the consumable canproduce around1.25 kg of deposited weld metal. Our nearest competitor can only deliver 1.1 kg due to them having only 110% recovery, which means that our LH consumables are over 13%more efficient with respect to deposition than the best of the rest,” Eibl calculates. “Once again, this benefits custom- ers through improved productivity and more arc on time. Total costs are not only about the price per kg paid for consumables, but about the cost of the material deposited – andmore arc time along with reduced clean-up and lower reject rates all make using a premium electrode such as our OK 55.00 themost cost-effective option,” he points out. ESAB’s OK 55.00 consumables also features lowmoisture absorption (LMA) coating technology, “which is now incorporated into all of our basic LH, stainless and low- and high-alloy elec- trode ranges. This effectively means

caused by reflected light offwelding fume,” he says. “So as well as reducing total fabrica- tion costs, the use of ESAB’s AristoRod ASC results in better health and safety and a more welder-friendly work- place.” A similar premium quality consumable strategy has been ap- plied to ESAB’s OK MMA electrode range. Eibl lifts out the low

In 80% humidity at 28 °C, the moisture of most LH electrodes will reach 1.0 % within 24 hours. In the same 24 h period, exposed ESAB LMA electrodes remain very close to the 0.2% level.

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that moisture pick up is dramatically reduced. “As well as having a lower initial moisture content, re-absorption of moisture is much slower with ESAB’s LMA coating than with normal basic electrodes. After six hours in 80% hu- midity at 28 °C, the moisture content of typical LH electrodes will double from just over 0.2% to 0.4% within six hours, and reaches 1.0%within 24 hours. In the same 24 h period, exposed ESAB’s LMA electrodes remain very close to the 0.2% level, which means that

even after 24 hours of exposure, they may not need tobe baked

ESAB’s entire LH, low alloy, stainless, cast iron and nickel alloy electrode range is available in vacuum packs, which totally eliminates the need for baking before welding and enables welders to use electrodes directly from stores. They include SLAM TM (shock limita- tion and absorption mechanism), which removes the possibility of the neck shearing off, which would transform the cylinder into a mis- sile that can cause serious injury or even death considering it can pass straight through a double brick wall,” notes Eibl, adding that EDGE regulators are also available for con- trolling welding shielding or purging gases – and they come pre-calibrated to suit the gas being used. To be launched at Electra Mining next month, ESAB’s WeldCloud TM is a secure, robust and scalable welding data man- agement platform that provides insight to facilitate continuous improvement in welding operations by efficiently track- ing key parameters for each weld seam produced. “As well as managing welding pro- cedures, WeldCloud-enabled welding machines to do self diagnostics and produce service alerts – and it can even alert welders andmanagers to potential weld defects, in real time,” says Eibl. “It is also now possible to establish awelding procedure specification (WPS) via aweld test in a laboratory anywhere in the world, and then to push the ap- proved welding parameters down to all of the welding machines required to do the work,” he adds. While many of ESAB’s machines are now available with WeldCloud built in, ESAB has taken a ‘top-box’ approach that ensures that any electronic weld- ing machines can be retrofitted with the technology. “And this also applies WeldCloud: ESAB’s online data management system

ESAB EDGE regulators with SLAM TM technology are not only easy to use, accurate and reliable; they are also robust and significantly safer. to non-ESAB machines. So a fabricator with machines from different OEMs can still manage all of its welding on the WeldCloud platform,” Eibl informs African Fusion . Particularly suited to track and trace applications, WeldCloud can collect and store data on every weld produced, making it ideal for meeting weld quality requirements. “It is also 100% scalable, which means that it can be used on one machine or a thousand: and new fea- tures and functionality are constantly being developed and updated on the platform,” he says, adding that ESAB’s CutCloudTM, is also under development tosupport andmonitor cuttingactivities. On the welding machine side, Eibl says that the top-of-the range Aristo® Mig 4004i Pulse welding machine will be the flagship product on show at Electra Mining. “Particularly suited to aluminium and stainless steel applica- tions, the new Aristo 4004i Pulse power source provides substantially improved arc welding performance. It is designed for high productivity and high qual- ity welding applications; it comes with WeldCloud TM and can be connected via Wi-Fi, mobile/cellular networks or via hard-wired Ethernet links. “These machines are brilliant for welding advanced materials where heat input needs to be reduced, for example, helping fabricators to achieve the best possible endweld quality,” Eibl concludes.

before use when there are no baking facilities available. “In addition, the H4 means that these electrodes are guaranteed to produce less than 4 mg of hydrogen per 100 g of deposited weld metal. In fact, we strive to produce only half of that, 2 mg/100g of hydrogen, which is only 25% of the hydrogen produced by standard H8 low-hydrogen electrodes,” Eibl tells African Fusion . “Our entire LH, low alloy, stain- less, cast iron and nickel alloy range is also available in vacuum packs, which totally eliminates the need for baking before welding and enables welders to use electrodes directly from stores. This saves on baking furnace electricity costs and significantly reduces delays, increases arc-on time and minimises the total costs of welding,” he argues. On the equipment side ESAB has also chosen to focus on premium prod- ucts, which can reduce the real costs of welding through improved safety, better deposit efficiencies, higher final weld quality and less rework. “Our EDGE regulators for oxy-acet- ylene cutting, for example, are not only easy to use, accurate and reliable, they are also robust and significantly safer.

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Hybrid electro slag cladding

This paper from the IIW 2018 International Conference of July 2018 held in Bali, Indonesia, details a hybrid electro slag strip cladding (H-ESC) process that better controls dilution lev- els to achieve clean undiluted single layer surface chemistry for all commonly used nickel and stainless steel alloys. H-ESC: A high-speed innovation in electro slag strip cladding Vincent van der Mee, Zhuyao Zhang and Pallav Chattopadhyay

T he application of strip cladding using the electro slag welding (ESW) process to cover large surface areas of vessels for the oil and gas industries has been com- mon over the last few decades. There has been continuous development by welding consumable suppliers to improve this method further, through introduction of high speed ESW flux and specially designed over-alloyed welding strips to achieve required weld metal chemistry in a single layer for some specific alloys. The conventional method, however, had limitations in achieving the desired chemistry in a single layer, among which, the Ni-625 alloy with maximum 5% Fe dilution limit is most notable. A newvariant of electro slag cladding called hybrid electro slag cladding or H-ESC has successfully been introduced into the market by Lincoln Electric, wherein a 3 rd dimension has been added to the conventional ESWstrip cladding technique, in the form of the addition of multiple hot metal cored wires into the molten electro slag weld pool. The addition of mul- tiple hot coredwires in a particular proportion into themolten weld pool by a uniquely designed digital weld control system helps in controlling the dilution level, thereby achieving clean undiluted cladding chemistry coupledwith at least 50%higher welding speed and nearly double the weld deposition rate as compared to conventional ESW cladding techniques. In this newhigh-speed single layer cladding technique that uses neutral flux, it is possible to achieve an Fe content of less than5%forNi-625clad layersandgreater than40%Ni inasingle Ni-825 clad layer. Similarly, this new technique offers unique solutions in case of high speed single layer austenitic stainless steel cladding, wherein only one standard stainless steel strip type is usedalongwithneutral flux to easily achieve thedesired AWS clean weld metal chemistry for SS 308L, SS 316L, SS 347 andSS317L layersbyusing suitablydesignedmetal coredwires.

Table 1: Comparisons of deposition rates for different weld cladding processes. Such solutions help fabricators immensely in minimising working capital and for receiving faster deliveries of weld con- sumables, in addition to reaching desired 3.0mmof undiluted weld metal chemistry while using a high-speed, single layer clad layer of only 3.5 mm thick. On the industrial applications’ side, Walter Tosto SpA – Italy supported Lincoln Electric as a partner in successfully implementing this new technique for the first time in theworld by applying single layer high speed SS 347 cladding using 60×0.5 mm and 90×0.5 mm wide consumable strips on Cr-Mo vessels. Introduction In the oil and gas industries for vessels dealing with highly corrosive service fluids, applying a protective layer is manda- tory. This protective layer is called cladding. There are various methods of applying clad materials to protect the substrate. Weld overlay is the most commonly used method as it offers high reliability to plant owners as well as high degree of flex- ibility for fabricators (Figure1). The process of cladding is very sensitive and can take up to months under precise controlled quality procedures. The weld overlay process, therefore, has been through an evolu- tion over the past decades to make the process more reliable andmore productive. It has been, for example, a long pending wish fromcritical process equipment (CPE) fabricators around the world to reach Ni-625 chemistry in single layer of cladding with a maximum Fe content of 5% without having to use an alloyed flux. Cladding Cladding is applied across the whole spectrum of industries, from nuclear, oil and gas and petrochemical to the steelmak- ing industry. Cladding is required on the process side of high pressure CPE to provide corrosion resistance against severely

Figure 1: An internal view of a typical vessel that requires protective weld cladding.

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Figure 2: Dilution in weld cladding, where A is the area above the plate and B is the area penetrated in the plate thickness.

 

  × 100

B A B +

(%) =

D

Welding process

Typical dilution (%)

SMAW FCAW

25-30 20-25

Figure 3: Evolution of strip cladding.

corrosive service fluids. While C-Mn, low-alloy steels and other material substrates provide strength and other mechanical properties, cladding provides the desired corrosion and wear resistance. The result is fabrication flexibility and cost savings. There are many ways to apply this corrosion-resistant layer – either by using roll-bonded or explosive-bonded clad plates or by applying more flexible weld cladding on a C-Mn or low alloy steel substrate. In the field of weld cladding, fabricators always look for solutions that will help themto achieve desired clean chemical and other properties of the clad material in least number of layers at faster speeds and higher deposition rates. To realise the above goals, welding consumable manu- facturers have come up with continuous upgrades in welding techniques. Over time, the more productive electro slag weld cladding (ESW) process was introduced as an alternative to standard submerged-arc (SAW) strip cladding. With the intro- duction of the ESW process, it was possible to offer a single layer cladding solution instead of the traditional two-layer cladding technique. As a further improvement to the process, newly designed high-speed fluxes were developed to substan- tially increasewelding speed in ESWcladding, froma standard speed of 16 to 19 cm/min to 25 to 40 cm/min. The latest innovation in the welding technique, H-ESC, is nowcapable of single layer high-speedandhighly-productivity cladding for Ni-625, which meets the maximum 5% Fe con- tent and the process is also suitable for other Ni-based and stainless steel alloys. This is achieved by introducing in a 3rd dimension to the ESW process in the form of added hot metal cored wires (MCWs). Weld cladding Typical CPE is large in size and vessels that require internal cladding on all the internal surfaces can involve the deposi- tion of five and 30 Mt of weldmetal. As a result, fabricators are always looking for weld cladding processes that can provide highest possible deposition rateswithminimumpossible dilu- tion, so that the desired undiluted cladding chemistry could be achieved by the thinnest possible thickness. While most of the existing arc and electro slag welding processes canbe utilised for weld-cladding, strip claddingwith submerged arc and electro slag welding process are the most attractive choices due to substantially higher deposition rates and, more importantly, higher surface area coverage rates. Table 1 shows a comparison of deposition rates for the most 25-35 SAW strip: 60×0.5 mm 18-20 ESW strip: 60×0.5 mm 7-12 Table 2: A comparison of the dilution percentages for different welding processes. SAW wire

commonly used weld cladding processes. From Table 1 it is clear that ESW is the most productive welding process for cladding applications and therefore the most preferred option for fabricators across the world. Since corrosion-resistant cladding material such as Ni- based alloys or stainless steel are appliedon ferritic C-Mn steel, low alloy steel or other types of base material, there is always the issue of dilution with the base material that needs to be considered as an important factor when selecting the correct weld cladding process. Typically, dilution (D%) is calculated as shown in the equa- tionand its associated schematicdiagrampresented inFigure2 from which it is clear that the lower the dilution percentage, the easier it is to achieve the desired weld cladding chemistry. In simple terms, it is only possible to achieve desired cladding chemistry in fewer layers if the dilution percentage is low. Table 2 provides a comparison of the typical dilution per- centages for different welding processes. Interestingly, traditional ESW is the most attractive clad- dingprocess fromadilutionperspectiveaswell, hence itswide- spread application claddingwork for oil and gas applications. Strip cladding processes The strip cladding process has been evolving ever since its introduction (Figure 3). The target has always been to achieve chemical and mechanical requirement of the surface alloy in a single layer and at high speed. There are two conventional strip cladding processes – submerged arc (SAW) and electro slag (ESW) strip cladding. Submerged arc (SAW) strip cladding This process (Figure 4) utilises an arc that runs back and forth at high speed along the strip, depositing weld metal onto the base material. Because this is an arc welding process, there will be penetration into the basematerial resulting in dilution levels of around 20%. Deposition rates are in the region of 12 to 14 kg/hr for 60×0.5 mm consumable strip.

Figure 4: The conventional SAW strip cladding process.

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Hybrid electro slag cladding

The process is restricted by the amount of current that can be applied without increasing dilution. Care must be taken for the overlap area as any residual slag will not be re-melted and may result in lack of fusion. For this reason, it is often not recommended for lane closures of rolled clad plate in the area where the roll cladding meets the base material. Since the dilution percentage is higher in SAW strip clad- ding, it is always necessary to apply a buffer or barrier layer in this process using strips of richer chemistry before applying second and subsequent layers using a strip that matches final required chemistry. Due to higher levels of dilution, this pro- cess always involves a minimum two or more layers to reach desired undiluted surface cladding material chemistry and it is, therefore, a costlier option. This process utilises a conductive flux and is an arcless process (Figure 5). The process initiates with an arc between continu- ously fed filler strip and the basemetal, which results in initial melting of high fluoride (CaF 2 ) containing flux. The molten slag, which is electro-conductive in nature due to the presence of special ingredients in the flux, supports current carrying at lower voltages, resulting in the arc being extinguished. The heat, which is required tomelt the strip and continue the process, is generated via the Joules heating effect (H = I 2 R) where I is the welding current and R is the electrical resistance generated in the electro-conductivemolten slag as a result of the high current flowing through it. Since the concentrated arc force is absent in this process, there is no deep penetration (digging) effect on the base ma- terial. As a result, the process is inherently characterised by low dilution level (7 to 12%). The ESW process, therefore, has significant advantages over its SAW counterpart. Using this process, cladding in single layer is a very com- mon practice due to the relatively low dilution levels. Single layer cladding is achieved either by using over-alloyed strip or by using a combination of over-alloyed strip coupled with alloyed flux. The former of these two options is more popular, however, since use of alloyed flux is not permitted by many process licensors. Table 3 provides a comparison between cladding using ESW and SAW processes. While conventional ESW strip clad- ding enjoys significant benefits over SAW strip cladding, this technique still has limitations in meeting the expectation of fabricators when there is a need to: (I) Deposit Ni-625 cladding to achieve <5% Fe in single layer using neutral flux. Electro slag strip cladding (ESW) Conventional ESW technique

Figure 5: The conventional electro-slag (ESW) strip cladding process.

Figure 6: The H-ESC electro-slag strip cladding technique.

(II) Achieve guaranteed >40% Ni in a single layer Ni-825 de- posit using neutral flux. These limitations encouraged Lincoln Electric to develop and introduce an innovative solution (ESW using the H-ESC tech- nique) into the market as described below. Hybrid electro-slag strip cladding (H-ESC) H-ESC is a new variant of ESW process developed and first in- troduced in 2016. In addition to the consumable strip and flux being used in the conventional ESW strip cladding processes, H-ESC adds multiple hot metal cored welding wires (MCWs) to the molten pool as a third constituent in this technique (Figure 6). Only neutral flux need be used in this technique. The role of the additional multiple hot metal-cored wires to the molten pool include: • Metal-cored wire offers a higher current density as com- pared to solidwire, therefore requiring lessmelting energy. TheMCWabsorbs the balance energy required for melting from the molten pool, thereby controlling heat input and reducing the dilution of the base material. Over-alloyed MCW wire can also compensate for the loss of alloying elements. This technique can achieve desired chemistry

Parameter Flux feeding Heat source

SAW strip cladding Both Front & Rear side

ESW strip cladding

Only Front side

Joule/resistance heating: H = I 2 R

Arc Energy

Flux consumption

High: typically 1:1.3

Low: typically 1:0.6

Dilution (%)

18-20 10-14 12-14

7-12

Welding speed (cm/min)

15-18 / 24-35

Deposition rate (kg/hr) 60×0.5 mm strip

22-30

content in weld metal

Cleaner chemistry with lower O 2

content

Weld metal quality

Higher O 2

Number of layers required to achieve undiluted surface chemistry

Minimum two layers

Single or two layers

Table 3: A comparison between SAW and ESW cladding processes.

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