TPi July 2021

ISSN: 1755-7216

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The trade magazine for tube and pipe products

July 2021

More than pipes BUTTING is one of the leading processors of stainless steels. Our core competences are in forming and welding techniques and in materials engineering. Take advantage of our know-how and contact us. www.butting.com

Business & market news

Severstal completes first delivery of large-diameter pipes to South America

PAO Severstal, a vertically integrated steel and steel-related mining company, has delivered an order of large-diameter pipes to Peru, in the company’s first ever shipment to South America. The products were produced at Severstal’s Izhora Pipe Plant, located in St Petersburg, Russia. Pipes were manufactured in line with API 5L PSL 1 steel production standards, grade X52, diameter 762mm, thickness

9.53mm and shipped directly from St Petersburg port to the port of Ilo, in southern Peru. The pipes were produced using Severstal’s own rolled metal, produced by Mill 5000 and the company’s sheet rolling shop, both based on the same industrial site as Izhora Pipe Plant. The ability to access its own rawmaterials base, in addition to steelmaking and rolling production facilities, affords

Severstal complete control over the price and quality of products at every stage of production. This, combined with the close proximity of Izhora Pipe Plant to the port of St Petersburg, ensures orders are able to be delivered promptly, and at a competitive price, to locations all around the world. Severstal www.severstal.com

IMS Messsysteme and voestalpine Tubulars sign contract as synergy continues to evolve

The next step in the synergetic business relationship between IMS Messsysteme and voestalpine Tubulars has now been contractually agreed for the summer of 2021. The IMS finished tube gauge has already been installed behind the stretch reducing mill (SRM) in the seamless tube mill of voestalpine Tubulars, which will be equipped with the IMS 3D tube surface inspection system ‘surcon 3D Tube’. Surface inspection of the hot-rolled finished tubes is moving a step closer to the manufacturing process: in the future, possible surface defects will be detected immediately after the SRM – the last of the three forming stages – and at tube rolling speeds of more than 10m/s. This extension of the existing system will enable voestalpine Tubulars to

detect even the smallest defects on the surface of the tubes even earlier and to initiate corrective measures regarding the process and tools correspondingly quickly. The project comprises integration of the IMS 3D tube surface inspection system into the existing IMS 4-channel tube gauge. The main advantages of this implementation variant compared to an additional, stand-alone gauge are that all measurement data such as wall thickness, diameter and profile, temperature and surface defects are determined simultaneously at the same measuring point and have the same tube length reference; the existing IMS gauge can continue to be used as before and there is no need to create additional installation space for another gauge. The two companies IMS Messsysteme GmbH in Heiligenhaus, Germany, and

voestalpine Tubulars GmbH & Co KG, Kindberg, Austria have been working together in the field of hot seamless tube measurement for more than 30 years. IMS Messsysteme GmbH www.ims-gmbh.de voestalpine Tubulars GmbH & Co KG www.voestalpine.com/tubulars

The seamless tube mill of voestalpine Tubulars will be equipped with the IMS 3D tube surface inspection system

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Business & market news

TMK completes acquisition of shares in PJSC ChelPipe to expand range of pipe products

TMK, a global supplier of steel pipes, pipe solutions and related services for the oil and gas industry, has announced the completion of a transaction for the acquisition of 86.54 per cent of shares in PJSC ChelPipe from controlling shareholder Andrey Komarov. The scope of the transaction includes production, sales and service assets, scrap procurement and processing, and other assets related to the activities of the pipe and pipeline division of PJSC ChelPipe. The oil services division Rimera Group was not included in the deal. TMK expects new synergy from the deal, resulting from optimising capacity utilisation, decreasing logistics costs, expanding its range of products and increasing the operational efficiency of its business. “Today’s event is another step in the implementation of TMK’s long-term strategy aimed at expanding its production base and sales markets, diversifying its product portfolio and developing the scientific, technical and innovative components of its business. The current situation requires us to accelerate the introduction of new technologies for the extraction and transportation of raw materials, arrangement and service of wells and infrastructure.

“The acquired company is a strong, recognised player in the pipe market with modern production facilities, a highly professional team, its own scientific developments and its own established sales channels. “Combining these advantages with all TMK competencies will give a powerful synergistic effect both for our business and for the industry as a whole, ensure Russia’s energy security and solve strategic problems of import substitution. “It will completely cover the needs of domestic fuel and energy companies in special types of pipes and end Russia’s technological dependence on foreign developments and suppliers for complex oil and gas projects in this regard. “We believe that, taking into account the new capacities, we will be able to fully meet the needs of Russian oil and gas companies in high-tech products,” said Dmitry Pumpyanskiy, chairman of TMK’s board of directors. The owners of the remaining 13.46 per cent of shares in PJSC ChelPipe will be made an offer in accordance with Russian legislation. “In over 25 years of my participation in ChelPipe’s business, a lot has been achieved: the fundamental value of the company has been clearly established. This includes completion of a large-scale investment cycle, building new high-tech production facilities (which gave the world the concept of METAllurgy), a chain of vertical integration in the production of seamless pipes, a developed regional metal trading network within the framework of a client-centric strategy and a pipe services business specialisation. “The company now has a balanced portfolio of orders and operates in all key market segments (including exports). In recent years, ChelPipe has confidently taken a leading position in terms of efficiency in the world. A unique system of training of highly qualified workers in the regions where ChelPipe operates has been built on the basis of a dual education model, including the country’s best training methodology for the Future of METAllurgy program. “Most importantly, the company has a professional team capable of solving its most ambitious tasks. I am deeply satisfied with this deal. I am confident that the company’s consolidation with TMK, a successful global company that has a great reputation and develops its business on the principles of sustainable development and social responsibility, will allow ChelPipe and its team to continue moving forward, thereby contributing to the social and economic wellbeing of the country,” added Andrey Komarov, chairman of ChelPipe’s board of directors. PJSC ChelPipe www.chelpipegroup.com TMK www.tmk-group.com

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Business & market news

Eaton announces new CLS sectional load sense relief valve

Power management company Eaton has introduced a sectional load sense relief valve (LSRV) for its CLS mobile hydraulic control valve. The patented LSRV limits individual section pressure through feed oil reduction, eliminating the need for inefficient work port reliefs for feed-side pressure control. The CLS LSRV improves machine productivity and efficiency by helping prevent functions from slowing down during multi-section actuation and by eliminating unnecessary energy consumption and heat generation. “Most load sensing mobile valves make you choose between power management and pressure control,” said Jiri Foukner, EMEA product manager, advanced mobile valves, Eaton. “Eaton’s CLS valve eliminates this trade-off. With the new sectional LSRV, the CLS valve combines the

benefits of pre-compensated and post- compensated valves, providing pressure control while maintaining flow sharing and power management capabilities.” The CLS LSRV enables the use of full available inlet flow to maintain functionality during multi-section actuation, helping improve machine productivity. The LSRV limits pressure by reducing feed oil flow, rather than dumping the flow to the tank. Once the LSRV stops oil flow when a function reaches a specific pressure, which can be lower than maximum system pressure, that flow is available to other sections at full system pressure. This helps prevent machine functions from slowing down when multiple sections are operating at once. The CLS LSRV improves energy efficiency by minimising the power losses that

CLS mobile hydraulic control valve from Eaton

occur when using work port reliefs for feed-side pressure control. Unlike work port reliefs, which dump all oil flow to the tank, the LSRV discharges only 2 to 4 L/min. of flow to the tank, dramatically reducing energy consumption and heat generation. The CLS sectional load sense relief valve is designed for machinery with swing and clamp functions, including forestry equipment, excavators and backhoes. Eaton www.eaton.com

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Business & market news

New corrugated tubing technology from Solvay allows greater light-weighting potential

Solvay and Maincor Rohrsysteme GmbH & Co KG have introduced a new technique to manufacture a more flexible, extruded corrugated tubing with varying wall thicknesses and diameters. This advance will help meet new thermal management design challenges stemming from combining internal combustion engine (ICE) and e-mobility technologies including batteries, e-motors, and power electronics. The new technique follows the introduc- tion of Solvay’s Ryton ® PPS mono-layer extrusion grade Ryton ® XE3500BL, a high-performance resin now fully optimised for the production of corrugated tubing and commercially available worldwide. Automotive OEMs have specified this durable, lightweight material to replace heavier and bulkier rubber tubing/metal clamp systems to develop more flexible and agile solutions for fluid delivery lines.

for fuel tanks, engine housings and crankcase conveying vapour, gases or condensates.” Solvay’s Ryton ® PPS has thermal stability up to 200°C (392°F), dimensional stability even at elevated temperatures and in harsh environments, mechanical strength, ductility, toughness, chemical resistance and is flame retardant. to manufacture corrugated tubing from Solvay’s Ryton ® PPS demonstrates Maincor’s processing knowledge and technical expertise,” said Manuel Zink, head of sales automotive/home appliances at Maincor. “We worked closely with Solvay to improve weight savings and efficiencies. Post-extrusion thermoforming trials ensured optimising tube geometries to fit available space.” Solvay www.solvay.com “Developing a process

Solvay’s Ryton ® PPS has thermal stability up to 200°C

“The trend for engine downsizing puts pressure on auto engineers seeking room to install ever more complex thermal management assembly systems as components compete for space in the engine bay,” said Brian Baleno, head of marketing-transportation at Solvay Specialty Polymers. “Corrugated tubing made from Ryton ® PPS will significantly broaden the range of under-the-hood thermal management applications such as turbocharger exhaust gas recirculation circuits and ventilation and vacuum lines

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Business & market news

Collaboration between DEPA Commercial, DEPA International Projects and Corinth Pipeworks

DEPA Commercial, DEPA International Projects and Corinth Pipeworks SA steel pipe segment of Cenergy Holdings, have signed a Memorandum of Understanding (MoU) regarding the implementation of joint actions for the promotion and expansion of the use of hydrogen in Greece’s energy system. The first stage of the agreement concerns the development of all the required technical specifications to support the modern infrastructure of the hydrogen pipeline network in Greece and the analysis of the prerequisites for the conversion of the existing gas line pipe network infrastructure, in order to support the distribution of hydrogen. The CEO of DEPA Commercial, Konstantinos Xifaras, stated: “The signing of the Memorandum of Understanding today is an important step towards the development and deployment of hydrogen technologies in Greece. DEPA supports the formation of new alliances for the implementation of initiatives and projects that will accelerate the transition to Green Energy, such as the White Dragon project that is being coordinated by DEPA Commercial and has the potential to become a lighthouse project for Europe.

The agreement aims to bring clean hydrogen fuel to Greece using its pipeline networks

“Our company is continuously putting effort into developing environmentally friendly fuels, such as hydrogen”. The agreement also includes an ongoing exchange of information on European-level hydrogen development activities, within the ‘European Clean Hydrogen Alliance’ and the European Hydrogen Association (Hydrogen Europe). At the same time, a common line was set up to resolve potential technical challenges on the transportation of other emerging alternative fuels, such as biomethane via pipelines. Nonetheless, it was decided to work closely on the design, material selection and certification aspects regarding Projects of Strategic Importance of DEPA Commercial and DEPA International Projects, such as the ambitious ‘White Dragon’ Project in Western Macedonia, the EastMed pipeline as well as and other important projects, which will contribute to achieving the energy transition. The president of DEPA International Projects, Ioannis Papadopoulos, noted that “DEPA International Projects, having the country’s energy security as a priority, develops projects, promotes new technologies and supports the transition to alternative green energy sources such as hydrogen, with agreements, such as the current, which lay the foundations for the implementation of the energy transition”. The CEO of Corinth Pipeworks SA, Elias Bekiros, added: “This agreement confirms our company’s commitment to the principles of sustainable development and to initiatives addressing climate change. Pure hydrogen from renewable energy sources is a key pillar in achieving the objectives of the European Green Deal and is at the centre of research at a European level. Our company is at the forefront of the industry for the provision of hydrogen transport solutions, through existing and new pipeline networks. Our goal is to achieve the viability of the EU economy and to ensure clean energy for future generations”. DEPA Commercial www.depa.gr DEPA International Projects www.depa-int.gr Corinth Pipeworks SA www.cpw.gr

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wiredIn USA

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The fundamentals of arc welding metallurgy By Michael Fletcher, PhD Metallurgy, Delta Consultants

overall, such as GMAW, may well be economically attractive but much better control is normally exercised by the GTAW technique. High rates of heating and cooling, particularly when welding low alloy and carbon steels, result in major structural changes that can make the weld and adjacent heat affected zone (HAZ) brittle and therefore prone to cracking. Low heat input processes generally produce wider welds and this can give rise to distortion. Joint design Careful selection of joint design is essential if weld defects are to be avoided. This is particularly important in applications such as aerospace, power engineering, petrochemicals, pharmaceutical and the processing industries where the weld may be subjected to high stresses and corrosive environments and where failure can be catastrophic. The simple fillet or lap joint may be quite acceptable when making garden furniture, but fully penetrating joints are necessary to meet demanding service conditions. Consideration also needs to be given to the suitability for post-weld inspection, even if this only requires visual access. Ultrasonic and X-Ray examination, for example, pose quite different problems. Reference 4: Welding Process Technology, by Peter Houldcroft Pre-weld preparation Having chosen the most suitable design of joint but before beginning to weld, attention needs to be given to cleaning. This may involve a simple degreasing operation, but some materials are highly sensitive to surface contamination and may require mechanical treatment by machining or wire brushing. Storage under clean conditions between preparation and welding may be essential. Pre-heat and post-weld heating Some materials are likely to exhibit significant changes in metallurgical characteristics during the heating and cooling cycles – these include the creep resistant Chromium/ Molybdenum/Vanadium steels. These changes, known to degrade the mechanical properties, can be avoided by modifying the thermal cycle. Some materials are likely to exhibit significant changes in metallurgical characteristics during the heating and cooling cycles – these include the creep resistant Chromium/ Molybdenum/Vanadium steels. These changes, known to degrade the mechanical properties, can be avoided by Reference 6: Tips for preparing your material before welding, by John Thompson Reference 5: Types of Welding Joints, by Rory Blake

The principle aim when fusion welding is to create a joint where the physical properties are identical to those of the parent material. In reality this is quite impractical. A large number of variables affect the final weld properties so we will examine the influence of the most significant variables. For simplicity we have to make some sweeping generalisa- tions throughout but this approach, simple though it is, serves as a basic introduction on how to minimise metallurgical disturbance during welding. Following each section, we have identified a useful reference where more detailed or specialist information is required. These references have been carefully selected and represent some of the best sources of further information. Let’s first of all define ‘weldability’. At its simplest this is a measure of how easy it is to make a weld in a specified material with adequate mechanical properties and with acceptable resistance to degradation in service. In practice this means comparing it with other joints. A standard test – for example the Patch Test (Ref 3) – can establish the sensitivity to cracking. Other tests may be required to assess corrosion resistance, mechanical strength and so on. The welding process Arc welding here is taken to include GTAW, GMAW, SAW and PAW, all of which can have a significant influence on weldability. Other arc welding processes are in regular use, but the same principles apply to these. Which technique is used for a particular application will often have been defined in a ‘welding schedule’, (‘welding specification’ and ‘welding procedure’ are also terms used to define how a joint should be made), a document prepared to instruct the welder on specific aspects of creating the joint. These aspects are examined later but the general rule is to create a Schedule that aims to produce a weld that is fit for purpose at an acceptable cost. The total thermal input and the rate of heating and cooling can have significant effects on joint metallurgy. A fast process Many learned texts have been published on welding metallurgy, particularly the excellent book written by John Lancaster, but very few approach the subject from a practical point of view. The majority of published work explains crack propagation, chemical reactions, alloy composition and heat flow in considerable detail but this document, part of the series published by Huntingdon Fusion Techniques, approaches the subject on a much more practical basis. Metallurgy plays a crucial role in the arc welding process and a basic understanding of this role is necessary if welding engineers are to fulfil their responsibilities effectively.

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Alternative oxides such as ceria have been used with success but the use of oxide mixtures to create what are referred to as multivariate electrodes, such as Multi-Strike, offer improvements in arc striking and longevity and are non-toxic. Reference 9: Storage and use of thoriated tungsten electrodes, The Health and Safety Executive Reference 10: Thoriated tungsten electrodes, American Welding Society Filler metals A common practice when welding thin section, identical materials, using the GTAW or PAW processes, is to melt both sides of the joint together without filler – autogenous welding. Where mechanical properties are important, for thicker materials or with GMAW and SAW it is necessary to use additional filler metal. This can perform the role of preventing undesirable chemical changes. An example is provided in welding some stainless steels where a filler with a higher chromium content is employed in order to compensate for chromium loss during welding. Dissimilar metals With identical alloys, control can be exercised over the welded metal by the judicious choice of filler material. Fusion welding metals with different chemical composition together presents additional metallurgical problems. Avoiding the creation of compositions with poor mechanical properties is extremely difficult and, in some cases, impossible. Two examples can be given here. Joints made between copper and aluminium lead to the production of extremely brittle alloys, referred to as intermetallic compounds, irrespective of what filler metals are used. They are thus of no commercial use whatever. The only way to make copper-aluminium joints successfully is to employ non-fusion processes such as friction welding and diffusion bonding. A combination that for a long-time baffled welding engineers was the production of mechanically strong joints between stainless steel and low alloy steel. This a crucially important combination because it is needed in power generation where high temperature creep strength is required. Reference 11: Which filler metal should you choose? by Kevin Trik

Pipe and tube purging concept

modifying the thermal cycle. Slowing down the rate of heating and cooling using an external heat source offers the opportunity to control the weld and heat affected zone structures so that mechanical properties are much less compromised and cracking due to high residual stress eliminated.

Reference 7: Preheating can be critical to welding success, by Caleb Haven

Shielding gas Crucial to successful welding is the protection of materials at high temperature against contamination, particularly oxidation, from the environment. This is especially so with the GTAW and PAW processes in which tungsten, highly sensitive to contamination, is used as the electrode in the formation of the electric arc. Argon is widely used here to provide effective protection of the electrode, but also to ensure that adjacent metal is also shielded. With SAW a blanket of powdered flux covers the arc and adjacent metal while with GMAW a range of gases are in use depending on specific applications. Often overlooked is the subject of protection of the weld metal at the base of the joint. This will be explored later under ‘Purging’. Selection of gas for any application depends largely on the materials being joined. While argon and helium are in common use with GTAW, other gases such as nitrogen, hydrogen and carbon dioxide may be preferred when using GMAW. Electrode properties With GMAW and SAW the filler wire also performs the task of an electrode. The only constraints here are that it is electrically conducting, clean and must be fed smoothly and at constant speed into the weld pool. A non-consumable electrode is used in GTAW and PAW. Tungsten is normally used, but this material can oxidise unless protected by an inert gas. A carefully prepared electrode tip is necessary, but this can degrade rapidly if not protected. Pure tungsten is not stable but by adding other materials this problem can be overcome. Thoria has been used as a stabilising compound for many years but is known to be radio- toxic and presents serious health hazards. Reference 8: Shielding the weld. Sandvik Technical Centre

Deterioration of electrodes. Thoriated electrode (left) after 20 welds. Multivariate electrode (right) after 200 welds

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Complex metallurgical changes take place leading to weld cracking. The basic solution is to separately clad the low alloy steel with stainless steel, referred to as buttering, and then make a stainless-stainless joint.

Cost-effective enclosures made from engineering plastics are now in use in the aerospace industry and are readily available with volumes up to 5 cubic metres. Reference 14: Gas Purging for Weld Root Control during Pipeline Fabrication, by Georgia Gascoyne Reference 15: Flexible Enclosure Welding, by Ron Sewell Conclusions While this introduction is very basic, albeit containing selected references to detailed aspects, it does bring attention to the prominent role played by metallurgy in welding. In particular it highlights the need for care when selecting tungsten electrodes, now that the toxic effects of some based on tungsten are better understood. Weld contamination caused by poor cleaning procedures and loss of mechanical strength and corrosion resistance due to inadequate inert gas protection need to be addressed. Recent developments in equipment for inert gas purging and the availability of cost-effective protective enclosures have been introduced. References 1 Metallurgy of Welding, Lancaster J F, Springer Publishing 2 Welding Metallurgy, Kou S, Wiley & Sons, New Jersey, USA 3 How can I asses the weldability of a material? Technical Knowledge Series, The Welding Institute, Cambridge 4 Welding Process Technology, Houldcroft PT, Cambridge University Press 5 Types of Welding Joints, Blake R, The Welding World, September 2018 6 Tips for preparing your material before welding, Thompson, The Welder, May 2018 7 Preheating can be critical to welding success. Haven C, The Fabricator, December 2016 8 Shielding the weld, Sandvik Technical Centre, Sandviken, Sweden 9 Storage and use of thoriated tungsten electrodes, The Health and Safety Executive HSE 564/6 (Rev) 10 Thoriated tungsten electrodes, American Welding Society, Safety and Health Fact Sheet No 27 11 Which filler metal should you choose? Trik K, The Welder, March 2017 12 Dissimilar Metal Welds in Grade 91 Steel, Totemeier T, Structural Integrity Associates News and Views, Issue 44 Spring 2018 13 All you need to know about the heat-affected zone, Bustreo A, The Fabricator June 2016 14 Gas Purging for Weld Root Control during Pipeline Fabrication, Kuwait International Pipeline Conference 2010, www.kuwaitpipetech.com 15 Flexible Enclosure Welding, Sewell R A, White Paper WP 59 from www.huntingdonfusion.com

Reference 12: Dissimilar Metal Welds in Grade 91 Steel, by Terry Totemeier

The Heat Affected Zone (HAZ) This is accepted as the area of the base metal that was not melted, but was heated to a temperature where the microstructure or mechanical properties was changed during welding. Such temperatures vary widely. Some heat-treated aluminium alloys are susceptible to change if heated above 120ºC. On the other hand, plain carbon steels are little affected below 700ºC. The width of the HAZ itself is largely dependent on the welding process – some have greater heat input than others – but the welding speed and thermal conductivity can have a major influence. An often-overlooked aspect is the cooling rate of the HAZ. The quenching effect of a weld in a small component made from a 1 per cent carbon steel can result in a HAZ hardness likely to induce cracking. Pre-heating and post-heating to control thermal gradients are in common use especially with heat treatable steels. Reference 13: All you need to know about the heat-affected zone by Andrea Bustreo. The Fabricator June 2016 Inert gas purging Additional to the need to provide an inert gas for protection of the electrode and adjacent metal during welding it is also desirable to provide protection of the weld root. This is particularly important with the more sensitive metals such as stainless steels, titanium alloys and other materials likely to suffer from oxidation or other contamination during the welding procedure. Where access to the root of the completed joint is accessible, for example with flat plate joints, the contaminated or oxidised metal can be removed mechanically, but with pipe or tube joints access is severely restricted. For this purpose, specialist inert gas purging equipment has been developed. This type of fully integrated inflatable equipment, typified by the QuickPurge ® and PurgEye ® systems, provide inert gas protection with oxygen levels as low as 10ppm. “A perfect welding result, without impairment of corrosion resistance and mechanical properties, can only be obtained when using a backing gas with very low oxygen content. For best results, a maximum of 20ppm O 2 at the root side can be tolerated.” (Sandvik). When welding complex structures or individual components, the ideal solution to weld shielding would be to place the objects inside a chamber that can be evacuated of air and replaced with an inert gas. Traditional chambers for this kind of work have been fabricated from metal with doors, windows and glove ports included. These enclosures are expensive, permanent and have a large footprint.

Huntingdon Fusion Techniques – UK hft@huntingdonfusion.com www.huntingdonfusion.com

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