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Equipment damage from stray welding current and electrical shocks to welders (personnel welding) at a mine in northern Canada led to considerable investigative work which has shown that the potential is high for serious injury, death, major equipment damage, and fire. Root cause analysis of incidents established the common failure parameter as, or equivalent to, a terminal fault to earth ground on the welding power source. This was described in the first paper on this subject. Further incident investigation found that equipment damage and work stoppages cost industry millions of dollars in repair and lost production costs. Documentation of fatalities from around the world has proven that even though welding voltages are normally well below the 100 V maximum established by mining regulators to be a "safe voltage", welders continue to die due to contact of the welding electrode with their body. Additionally, in at least one documented case in Canada, a welder died from electrocution due to an electrical system fault created by the welder's own stray welding current. Much of the work represented in this paper comes from the authors' own experience augmented by supporting research of others. This paper looks at the electrical hazards of welding including high frequency/ radio frequency, stray welding current, and electrical shock occupational injuries and fatalities from the welding electrode circuit. It considers the equipment damage and loss of life through stray welding current and considers industry, regulatory, and employer response in preventing these occurrences. [ABSTRACT FROM AUTHOR]

The IIW White Paper is a booklet produced by a panel of 80 experts of the IIW, aimed at providing reader with a picture on welding and allied technologies dated 2012, but mainly focused on the challenges and direction of these technologies for the next 20 years. Statistical data on value added by welding and welding related occupation are included in the first part, while the main content is devoted to evaluating technologies, processes, materials, inspection and testing techniques, standard and codes which can potentially become state of the art in the next years. A section is also devoted to identify those changes in the industrial world that can impress a driving force to welding and allied technologies. The article is a non-exhaustive resume of the IIW White Paper, while the full document is available for free on the IIW website (www.iiwelding.org). [ABSTRACT FROM AUTHOR]

The worldwide accepted standard for ensuring weld quality is ISO 5817. This standard developed from an old German standard, DIN 8563, which was originally intended as a means for understanding between welders in a workshop and the inspectors performing optical and non-destructive control of the welded joint. The criteria and groups were predominantly established in consideration of the effort to produce or to inspect a weld. Neither static nor fatigue strength of the welded joint were considered. Since that time research has progressed so that service behaviour can be assessed based on knowledge of the existing weld imperfections. This paper includes tables which correlate the fatigue strength of a joint with the quality criteria and groups of ISO 5817. The correlation has been established using butt and fillet welded joints in 10 mm thick plates as an example. The German Welding Society (DVS) has updated its guidance on the application of ISO 5817. Fatigue strength is one consideration in this effort. A revised version of ISO 5817 is under development. The present paper supports these activities by describing the current state of the art in terms of the relationship between weld quality criteria and groups with fatigue strength. It provides a realistic basis on which to define consistent quality levels in relation to fatigue strength. Thus, an economic specification of quality levels is made possible. [ABSTRACT FROM AUTHOR]

From cutting edge research of new processes for the manufacture of equipment for the energy production industry: Walter Tosto S.p.A. demonstrates in this paper, its experience in the highly specialized robotic welding process TIG narrow gap, widely used in the construction of the European segments of the Vacuum Vessel for ITER, in material 316L (N)-IG (ITER Grade). Following a brief general introduction of the process of TIG welding, this paper analyses: the technological, metallurgical and constructive features of TIG narrow gap, and combined with WT's technical know-how, shows how it was possible to overcome every critical aspect of its implementation. [ABSTRACT FROM AUTHOR]

The paper deals with the seismic behaviour of column bases and beam-to-column joints made with high strength steel tubular columns subject to seismic loading. A test programme was carried out at the University of Trento with the aim of evaluating the seismic performance of these joints under monotonic, cyclic and random loads. With these load protocols, it was possible to assess the activation and location of plastic hinges and the stiffness and resistance of beam-to-column joints and column bases, as well as to quantify the ductility behaviour of some joint components. The cyclic tests were performed by employing a standard loading protocol and the random tests utilised displacements provided by Finite Element based simulations of a five-storey steel-concrete composite building subject to seismic loading. The paper reports and describes experimental tests on both beam-to-column joint and column bases. [ABSTRACT FROM AUTHOR]

The paper aims to present new technique to fusion the glasses, by using the microwaves as thermal source to put the materials in fusion state. Microwaves are high frequency electromagnetic waves (usually 2.45 GHz) produced by specific generator usually known as magnetron. The interaction between the microwaves and different classes of materials produces the heating of the materials. The paper shortly presents the results of exhaustive study on the behaviour of the glasses which are exposed to the microwaves in order to weld them. [ABSTRACT FROM AUTHOR]

The paper deals with the development of a new monitoring solution to be used in fiber laser welding of titanium al-loys. Being based on the monitoring of the optical emission from the welding process directly from inside the optical combiner of the fiber laser source, the solution is called Through Optical Combiner Monitoring - TOCM. In the first part of the paper attention will be focused on the presentation of the proposed monitoring solution, while in the second part TOCM of a lap-joint welding configuration on TÌ6A14Vplates will be performer and discussed. [ABSTRACT FROM AUTHOR]

The evolution of the steam turbines in the last decades has led to the development of mobile low pressure blades, with large size and free standing technology, with superior performance in particular in the high stresses anchorage areas. The current market trend requires to manufacturers, that the control activities are carried out by minimizing downtime and by ensuring the proper functioning of the facilities. The need to ensure the structural integrity of the component, in this scenario, is satisfied with the development of a non-destructive "Phased Array" technique for finding operating defects in the dock, performed with and without the rotor in place the need for disassembly of the blades. In the present paper describes the stages of the project and the results obtained during inspection activities. [ABSTRACT FROM AUTHOR]

This paper analyzes the low cycle fatigue behavior of butt welded tubular joints with transversal bead, made of S235 and S355 steels. The fatigue tests were performed on specimens obtained by cutting the pipelines in the perpendicular direction compared to the weld bead. The tests were completed with deformation control and nominal cycle ratio R = -1. The first results show that, at medium and high number of cycles, there isn't a substantial difference in terms of fatigue strength between the two types of steel used despite of their different static behavior. [ABSTRACT FROM AUTHOR]

Enhanced cooling via forced convection using cryogenic liquid is an option for controlling grain growth in the heat afFected zone (HAZ) of ferritic stainless steel welds which improves joint strength. However, this technique seems to alter the martensite distribution in the high-temperature heat affected zone (HTHAZ) which is a critical constituent in rating the susceptibility to sensitization in ferritic stainless steel grades; any such information is not available in the literature. Thus, it is imperative to establish the influence of cryogenic cooling on sensitization dynamics in the HTHAZ. This paper discusses the influence of cryogenic cooling on sensitization in an AISI 430 ferritic stainless steel weld. It is established that cryogenic cooling increases the cooling rate in the HTHAZ and reduces the martensite volume percent by an average of 20%. This reduction in martensite content in the HTHAZ increases the level of ditched structure in cryogenically cooled welds and yields more ferrite-martensite ditched grain boundaries than in conventional welds. Although the cryotreated welds exhibit greater ditched boundary, the structure is still classified as nonsensitized, since no single grain boundary is completely surrounded by ditches. [ABSTRACT FROM AUTHOR]

La mattina del 12 agosto 2000, un sottomarino russo affondò in acque internazionali ad est della penisola di Rybatschi, nel Mare di Barents. Il sommergibile, un sottomarino russo da attacco classe NATO Oscar II, affondò ad una profondità di 108 metri, a nord-est di Murmansk a circa 250 km da Norvegia e 80 km dalla costa di Kola. Scopo di questo documento è la presentazione dei soli fatti secondo le fonti più autorevoli disponibili, tenendo conto che il rapporto ufficiale - anche se non disponibile - indicata una saldatura difettosa come causa della perdita di combustibile da uno dei siluri, che successivamente causato l'esplosione. On the morning of August 12th 2000, a Russian submarine sank in international waters east of Rybatschi Peninsula in the Barents Sea. The submarine, a Russian Oscar II NATO class attack submarine, sank to a depth of 108 meters, north-east of Murmansk about 250 km from Norway and 80 km from the coast of Kola. Aim of this paper is the presentation of the bare facts in accordance with the most authoritative available sources, taking into account that the official report - even if not available - indicated a faulty weld as the cause of the fuel leakage from one of the torpedoes, which subsequently caused the explosion. [ABSTRACT FROM AUTHOR]

The inner surface of pressure vessel steel used in the petrochemical industry is often coated with corrosion resistant materials. The industrial process that combines increased productivity with controlled dilution is ESSC (ElectroSlag Strip Cladding). The paper aims to overcome the current ESSC process limitations, analyzing the possible benefits introduced by Multi Strip technology, Twin type. The tests with combinations of carbon steel coated with Alloy 625 and Type 347 deposit on creep resistant low alloy steel were conducted. [ABSTRACT FROM AUTHOR]

The reheat cracking phenomenon (also known as stress relief cracking) is today a well known topic; since the first years of the 1950failure that can be brought to this kind of phenomenon appeared. Nevertheless today the causes and the factors that lead to this failure that interests different types of materials, are not totally cleared. This paper gives to the Reader an overview of the phenomenon, focusing the main causes, the materials that are susceptible, the preventive measures and, finally, the main tests for the characterization. [ABSTRACT FROM AUTHOR]

This paper describes the attempt to define a correlation criterion between fracture toughness, expressed in terms of Jintegral, J, and crack tip opening displacement, CTOD, and referred to the thickness (B) of a specimen. From a thick component (e.g. B > 150 mm) it is often difficult to take full-size specimens, because of their dimensions, and weight make handling and hence CTOD testing difficult too; therefore the need to find a correlation criterion between fracture toughness and thickness becomes relevant. A number of CTODtests were performed in accordance with BS 7448 part 1 [1] on carbon steel single edge notch bend (SENB) specimens of different size. Through the experimental data a correlation was found that allows to evaluate J and CTOD for specimens with different thickness (higher or lower) than the one characterising tested specimens. The toughnessthickness correlation was verified applying the Weibull statistical weakest link theory adopted by the ASTM standard E1921-13 [2][3][4], Furthermore, with the aim to use toughness temperature dependence for adapting testing conditions in reduced thickness specimens, data for specimens tested at different temperatures were compared. [ABSTRACT FROM AUTHOR]

We also heard this repeatedly: a more than seventy years from now (seventy-two, to be precise) there is no presentation or article in the field of fracture mechanics or brittle fracture that in the introduction does not show the black image of the "SS Schenectady" broken in half with some notes, sometimes unfortunately rather sketchy. Today, in light of knowledge acquired in the last few years, the problem can be said to be actually known and corrective actions are common for designers and builders; another thing is to try to understand what was the failure analysis approach at the time, given the tools and knowledge actually possessed. In the spirit of this series of articles, dedicated to the analysis of famous failure cases based on official available documentation, in this paper would like to explain the famous case of brittle failures occurred in some ships belonging to the "Liberty" project, during the second world war, in order to illustrate with the highest possible precision the sequence of events, both from the technical and the historical point of view. [ABSTRACT FROM AUTHOR]

The chemical process industries use a variety of equipment which sometimes requires the use of clad plates. These clad plates use carbon or low-alloy steel for the main structural or pressure-containing load bearing requirements and are clad on one side with a corrosion resistant material. These plates can be bonded through either high temperature roll bonding or by explosion cladding. After the cladding process a heat treatment is required to stress relieve the carbon or low-alloy steel and is required by either application requirements or by design code (such as ASME). Heat treating the clad plates will have an effect on the corrosion resistant clad layer and needs to also be considered. This paper will focus on the heat treat requirements of various substrate materials and how these impact nickel alloys used for the corrosion resistant clad layers. The use of standard laboratory corrosion tests to verify the corrosion resistance of the clad layer after heat treating is also reviewed here [ABSTRACT FROM AUTHOR]

In the welding field, hot cracks are considered one of the leading metallurgical defects. To assess the tendency to hot cracking of the base material or filler material may be appropriate to conduct a campaign of special tests. In this paper is proposed an overview on the available types of tests under the standard UNI EN ISO 17641: 2006 distinguishing between tests in terms of self-restraint conditions and externally loaded conditions. [ABSTRACT FROM AUTHOR]

In this paper, we propose a J-groove dissimilar weld crack visualization system based on ultrasonic propagation imaging (UPI) technology. A full-scale control rod drive mechanism (CRDM) assembly specimen was fabricated to verify the proposed system. An ultrasonic sensor was contacted at one point of the inner surface of the reactor vessel head part of the CRDM assembly. Q-switched laser beams were scanned to generate ultrasonic waves around the weld bead. The localization and sizing of the crack were possible by ultrasonic wave propagation imaging. Furthermore, ultrasonic spectral imaging unveiled frequency components of damage-induced waves, while wavelet-transformed ultrasonic propagation imaging enhanced damage visibility by generating a wave propagation video focused on the frequency component of the damage-induced waves. Dual-directional anomalous wave propagation imaging with adjacent wave subtraction was also developed to enhance the crack visibility regardless of crack orientation and wave propagation direction. In conclusion, the full-scale specimen test demonstrated that the multiple damage visualization tools are very effective in the visualization of J-groove dissimilar weld cracks. [ABSTRACT FROM AUTHOR]

The synergistic effects of niobium and molybdenum in lowering austenite-to-ferrite transformation temperatures have been known for approximately 45 years. The benefits have been widely exploited in linepipe steels since 1971 when 485 MPa (X70) linepipe produced by IPSCO [1] was installed in Canada in the TransCanada and Novacorp gas transmission systems. At that time the steels were cast as semi-killed ingots and had inferior transverse Charpy properties due to the presence of MnS and silicate inclusions. Other applications have been found in hot-rolled long products [2] and Nippon Steel's HT80 quenched and tempered plate [3,4], As linepipe yield strengths have increased to X80, X100 and above, and carbon contents have been reduced to 0.03-0.06 percent, the Nb-Mo combination has become indispensable for producing economical steels when used in combination with chromium, copper and nickel. This paper provides a brief chronology o f the adoption of Nb-Mo and Nb-Mo-B alloying since the mid 1960s. [ABSTRACT FROM AUTHOR]

Titanium and its alloys are entered in everyday life for a long time, considering the spread of their use for the realization of special and mass products; the exceptional mechanical and physical properties of these materials (with particular reference to atmospheric corrosion resistance and the possibility of surface thermochemical treatments to modifying their appearance), however, constitute a valuable resource within the civil engineering, which confer a particular functional and aesthetic value, at the same time. This paper offers to the readers a summary concerning the state of art, which not rarely shows the national manufacturers, focusing on the characteristics of the most significant constructions. [ABSTRACT FROM AUTHOR]

In this paper are described the results of experimental tests performed by IIS PROGRESS Laboratory to evaluate shape and dimension of Hall sensor probes, lite accurate calibration of Hall probe, with square sensor and suitable surface, provides the possibility of a reliable control of components for which very low residual magnetism values are required. The application of ASME BPV Code, Article 7 Appendix, Section V, is a valuable reference for determining the accuracy and reliability of Hall sensors measurement, to achieve the control sensitivity required and to ensure the quality of the component inspected. [ABSTRACT FROM AUTHOR]

The so-called thermomechanical steels have undoubtedly reached an important diffusion at industrial level, as a semifinished products for designers and manufacturers, alternative to other comparable and available products, often in contrast to them, obtained with different manufacturing cycles. It's also evident that these steels are mainly used for fabricating structures, while it is less important their role in the pressure vessels construction, where it is not unusual to find specifications issued by major contractors, such as in the Oil & Gas field, for restricting or even prohibiting their application. In the fabrication of welded structures, the post weld heat treatment is notoriously less widespread than in the pressure vessels field: it's not surprising, that behavior and mechanical properties of these steels as a result of the post weld heat treatment are still relatively unknown. This paper was written after an experimental testing performed on FCAW welded joints of API 2W Gr. 60Z steel plates, with thickness 100 mm, compared with several heat treatment conditions and conducted by IIS Progress laboratories. The results are supplemented by a brief state of the art, which considers and summarizes the main references of the national and international technical literature. [ABSTRACT FROM AUTHOR]

This paper describes the new inspection methods of castings for oil and nuclear industry using phased array technique and dedicated probes. The phased array technique allows to considerably reduce the time of UT control thanks to a complete and exhaustive graphical representation of the analysis and thanks also to the use of a smaller number of transducers due to the versatility of the same. The time reduction joins a certain increase of the intrinsic quality of the PA technique, the ability to record the obtained results and the possibility of storage / display the performed exams. The PA technique is exactly at the halfway between the traditional ultrasonic inspection and the radiographic testing (often difficult to apply in service). It is possible to assume that, in the future, industrial radiography could be replaced by the phased array technique. [ABSTRACT FROM AUTHOR]

Performing an heat treatment may he necessary in order to satisfy the requirements that the final quality and the service conditions may impose to a welded component. The relevant technical and operational complexity often requires the application of codes and standards (European and International). In this respect, this paper is focused on AWS standard D10.10: "Recommended Practices for Local Heating of Welds in Piping and Tubing". This reference not only provides essential information related to the realization of localized heat treatment on pipes but is integrated with requirements included in other standards both European (e.g. the BS 2633) and International (e.g. ASME B31.1, B31.3). [ABSTRACT FROM AUTHOR]

For dissimilar metal welds, between austenitic stainless steels and ferritic steels, an austenitic stainless steel filler material with an adequate composition is normally used. To minimize the risk of hot cracking, the weld zone should preferably be constituted by an austenitic microstructure with a small amount of ferrite δ. During solidification, the microstructures depend on filler material and base material compositions. Useful indications of the weld zone microstructures can be drawn from such diagrams, for example the Schaeffler diagram, which defines the fields of existence of the phases as a function of composition expressed in terms of chromium equivalent (Creq%) and nickel equivalent (Nieq%). Recently alternative diagrams to Schaeffler diagram have been proposed. An amendment was introduced in one of these diagrams to better characterize the boundary area between martensitic-austenitic structure and fully austenitic structure. In this paper, by means of the experimental test results of austenitic stainless steel and ferritic steel joints, welded with laser beam process, some specimens were obtained with a weld zone composition near to the boundary between martensitic and austenitic zone in the Schaeffler diagram. The content of the elements was calculated by energy dispersive microanalysis (EDS). The microstructures were examined by optical microscopy and scanning electron microscopy (SEM) and by Vickers microhardness tests. For some microstructures, which were fully austenitic, the position of the corresponding points were located in the martensitic-austenitic zone below the line defined by the original Schaeffler diagram, while they were in accordance with the new definition of the boundary zone of the modified Schaeffler diagram. [ABSTRACT FROM AUTHOR]

This paper describes an experimental analysis of residual stresses conducted on thick and high constraint low alloy Cr-Mo-V welded joints, by the method called hole drill test. Data was collected on test specimens with nozzle geometry, welded with SAW process. The results were analyzed by comparison with manufacture requirements of pressure vessels for critical applications. In light of data collected, it was discussed the need of an Intermediate Stress Relief (ISR) heat treatment for this joint, required by applicable regulations and standards. [ABSTRACT FROM AUTHOR]

The developments of steel structures aim at light and slender constructions. Therefore, high-strength steels with good welding characteristics and a high ductility, aside from higher strength, have been developed by the steel industry. With increasing strength of the steel, the loads which have to be transferred in the welded connections are also growing. In building constructions, fillet and partial penetration connections are commonly used. When using high-strength steels, it is very important to ensure strength, as well as sufficient ductility and toughness of these welded connections, in order to allow for the necessary redistribution of stresses and internal forces. The use of high-strength steels can bring significant savings in terms of material consumption, weight, transportation and fabrication costs. Beside the savings due to the reduced material consumption, advantages result from the smaller construction weight and a faster fabrication by reduction of the weld thickness. However, especially for high-strength steel grades S460 and S690, the benefit of saving of material cannot be used, due to the present restrictive design rules. Therefore, the aim of this research project, realized by four partners, was the development of appropriate and modern construction and design rules, as well as manufacturing principles, in order to achieve an economical use of high-strength fine grained steels. This paper presents the results of a research project, investigating the strength and ductility of fillet welded connections of high-strength steels S460 and S690, by means of experimental and numerical analyses. Experimental and numerical investigations of the load bearing capacity and safety against brittle fracture at lap joints with longitudinal fillet welds, cruciform joints with transverse fillet welds and butt joints with partial penetration double-V-groove welds of high-strength steels S460M/ML and S690Q/QL have been carried out. Numerical investigations in terms of welding simulation and measurements of residual stresses have been performed, in order to identify the local microstructure, hardness, residual stresses and strength in the weld profile. These results support the assessment of strength and ductility of welded connections. Based on the investigations, recommendations for the design of welded connections of high-strength steels, in terms of load bearing capacity and safety against brittle fracture, as well as manufacturing principles, were derived. The results of the research project thus contribute significantly to an optimized use of high-strength steel in welded constructions. [ABSTRACT FROM AUTHOR]

The automotive industry deals with different challenges and market requires. In order to be competitive and meet the quality requirements, in accordance with product standards and end-users, it is necessary a constant stimulus for processes development and optimization. This is valid when it is applied to the processes defined special by the standard UNI EN ISO 3834, such as welding, soldering, brazing or riveting. The present paper highlights the main steps of the development of robotic laser brazing system of BIW - Alfa Romeo Giulietta roof welded joints and of SPR technology (Self Piercing Riveting) for the front dome suspension joint of Maserati Quattroporte and Maserati Ghibli cars. [ABSTRACT FROM AUTHOR]

Within the last years, the beneficial effect of boron addition in order to increase the creep strength of martensitic 9-12 % Cr steels has been widely investigated and demonstrated. Several boron-strengthened alloys are the outcome of an intensive European research activity within the scientific framework of COST. Tire most promising alloy for castings with a targeted application temperature of 650 °C for use in future ultra-super critical steam power plants is a modified 0.1C-9Cr-1.5Mo steel with the addition of approximately 110 ppm boron. For joining of this advanced steel grade, new "chemically matching" welding consumables have to be developed to provide similar creep strength in the weld. Within this paper, the development of an advanced flux-cored wire with a good "out of position weldability" - based on a rutile slag system is presented. The work discusses the optimization of the chemical composition of the filler, the influence of various post-weld heat treatments on short term mechanical properties, first results of creep tests and results of thick section welds. The boron content of the consumable was optimized to achieve highest creep strength combined with acceptable toughness and lowest hot cracking sensitivity. For a butt weld of a 34 mm-thick casting, the optimum welding parameters and layer sequence were determined. A post-weld heat treatment consisting of stress relieving twice at 730 °C for 12 h seemed to be the best compromise between applicability in the manufacturing of large turbine casings and achievement of acceptable weld toughness. [ABSTRACT FROM AUTHOR]

This paper provides information on the start and rapid development of training, research and laboratory activities of IIS and IIS Progress in Italy and abroad. In particular, two successive periods are considered separately for the first and the remaining tasks, the first one of affirmation and development of training and research activities and of start and growth of the Laboratory, the second one, characterized by the availability of the new modern IIS headquarters, of vigorous growth, also due to the reorganization of the corporate structure and to the preparation of the partition that led to the birth of the IIS Group. The latter includes, as it is now well known, along with IIS ente morale (Non-proflt Organization), IIS Cert srl (Ltd.), IIS Service srl (Ltd.), both created in early 2011, and IIS Progress srl (Ltd.) which was created in early 2013. At the same time the most important events are remembered related to the acquisition in 1988 of the new and well-equipped IIS headquarters in Genoa and, in the following years, of a number of offices in other Italian locations. IIS Group had in force at the end of 2013 approximately 225 employees (including about sixty graduates engineers and a hundred technical graduates), of which almost a quarter are employees and managers of IIS Progress. Appears as well as in over sixty years of activity before IIS and afler the IIS Group have been won a reputation for professionalism, reliability and expertise that have made it one of the most comprehensive European benchmarks in the field of joining and related and connected techniques, appreciated everywhere it has acted, in Italy, in Europe and in other continents. [ABSTRACT FROM AUTHOR]

To achieve good corrosion resistance in a weld is much more challenging than for plate or sheet material, which has undergone controlled rolling, heat treatment and pickling processe in the steel mill. The choice of weld procedure and parameters, filler metal and shielding gas all play important roles. For duplex and lean duplex grades it is essential to ensure that an adequate amount of austenite is formed in the weld metal and heat affected zone, in order to fulfil requirements in terms of austeniteferrite phase balance, but also to avoid the precipitation of detrimental phases such as intermetallics and nitrides. In addition, the importance of good post-weld cleaning to ensure good corrosion properties cannot be over-emphasised. This paper focuses on a number of different examples of pitting corrosion of welds in the duplex grades UNS S32101, S32304, S32205, S82441 and S32750. These illustra the role of microstructure control to attain good corrosion per formance. The effect of residual weld oxides or heat tint in degrading the corrosion performance is also explored, together with evaluation of the degree to which the corrosion resistance can be restored by the use of appropriate pickling processes. [ABSTRACT FROM AUTHOR]

The paper aims at describing the approach and contents of the new edition of ISO 5817, the most important reference standard in the field of definition and evaluation of Quality Levels for imperfections in welded joints. This standard is analysed in comparison with the previous editions in order to outline the main differences and variations introduced so that users can be guided in its implementation. [ABSTRACT FROM AUTHOR]

In the construction of welded structures the research, evaluation and acceptability of imperfections in welded joints are fondamental aspects. In the field of metallic constructions, imperfections can be divided into two groups: linear and non-linear imperfections. Imperfection becomes a defect if it does not fall within the acceptance criteria defined by code or designer and from there derives several corrective actions, such as heat treatment, painting, repairing... The different international codes examined show some common points on implementation of non-destructive testing, but very different are their approaches to the acceptance criteria. A designer choice of a particular acceptance criteria can be summarized in a few key points: stress evaluation of the welded joints, in service conditions, mechanical properties of materials, inspection procedures. The purpose of this paper is a comparison of international standards (European, American and Russian Codes) for the acceptance of imperfections in welded joints. [ABSTRACT FROM AUTHOR]

This paper, starting with an introduction of passive and active thermography method, describes the possible control procedures and applications of this method in the oil industry. In particular, on the basis of in service experiences are described: predictive analysis (furnaces, boilers, fume pipes, chimneys, reactors, etc.) for the quantitative valuation of the insulating I refractory surfacing to recover during TA; coke search in ovens, with a focus on intervention procedures, monitoring of the thermal distribution (heat exchangers, air coolers or condensers) to verify the efficiency of the heat exchange; continuous monitoring of TIP temperature during transients (for example, during hydrogen plant start-up) in order to prevent critical events of such components; predictive analysis of electrical substations in order to monitoring thermal gradients, thermal map of the sliding contacts of turbine shafts to verify wear resistance, resulting in maintenance plan. [ABSTRACT FROM AUTHOR]

EST Plant (Eni Slurry Technology) consists of about 300 pressure vessels in the following principal units and section: * EST unit (unit 90); * Hydrogen production plant (Unit 95); * SWS sulphur recovery and tail gas treatment (Unit 92 and 94). More than 100 "critical" equipments exist in the EST complex, divided in units and sections on the basis of their type of service. In detail, the considered critical items include: carbon steel and low alloy steels heavy wall pressure vessels for high temperature, high-pressure hydrogen service; carbon steel pressure vessels in sour (wet H^S service) and amine service. For fabrication of such "critical" items special base materials and filler metals were adopted according to specific material requirement, special welding processes and fabrication sequences (including advanced automatic systems for non destrucutive testing) were used. This paper shows an overview on some critical aspects and experience of fabrication of main "critical" equipments of EST Plant. [ABSTRACT FROM AUTHOR]

In this paper the development of a welding procedure for the joining of steel type UNS S32760 (Super duplex F55) for use in the off-shore application is described. The joint was realized by means of the TIG (GTAW) manual process for the first passes and by a manual filling process with stick electrode (SMAW), in order to obtain the combination of mechanical and microstructural characteristics desired by the customer. The results obtained from the tests on the joints must provide proof of successful completion of all the tests to be part of the joint in accordance with the contractual requirements and stabilized the base for actual use in the production. The particularity of the case, in addition obviously to the inherent difficulties posed by the type of steel chosen, consisted in the request by the customer of a combination of mechanical and microstructural characteristics to the limit of the possibilities of a welding procedure suitable for use in production mode and times compatible with the internal market and production requirements. It was therefore necessary to design the welding procedure and choose the most suitable process parameters to achieve the required results. The evaluation of the joints to achieve in production and the characteristics to be obtained, has led to decide to perform welding with welding processes previously mentioned and in the welding position-frontal plane (PB/2G). The main problems to be considered in the design phase of the welding procedure, are to be found in the value of the maximum heat input, interval of interpass temperatures to be observed and the type of shielding gas to use with which material can be welded to avoid the formation of intermetallic microstructure phases of the joint and sappers of corrosion resistance. [ABSTRACT FROM AUTHOR]

In this paper for the evaluation of the fatigue strength of welded structures a simplified numerical analysis has been proposed. The approach considers the use of FE code for the estimations of the equivalent stress defined by the implicit gradient approach. Then, the equivalent stress can be used for the prediction of the fatigue life of the welded components. [ABSTRACT FROM AUTHOR]

This paper will present the experimental and numerical investigation on the fatigue crack failure at the root of the enhanced partial joint penetration welds in the circular hollow section X-joint specimens subjected to constant - amplitude brace in-plane bending actions. The enhanced partial joint penetration welds, which include a portion of the brace wall as the inherent "back-plate" for the welds, reduce the workmanship requirement on the welding procedure and improve the quality control of the welded joint. This study compares the fatigue crack developments observed at both the weld toe and the weld root in three large-scale X-joint specimens with different post-weld surface treatments. Root cracking does not take place in as-welded tubular X-joint specimens, of which the fatigue life depends on the weld toe failure. In specimens with post-weld grinding treatments to enhance fatigue resistance of the material near the weld toe, however, the finite-length root face triggers the initiation and propagation of fatigue cracks with an applied number of cycles more than that required to initiate a toe crack in the same tubular X-joint. Ultimate strength testing of specimens with large fatigue cracks, and post-test sectioning, reveals that fatigue failure weld-toe fatigue cracks remain more critical than the root cracks. [ABSTRACT FROM AUTHOR]

A unique study of structural and chemical analysis of crystalline phases in developed agglomerated fluxes was carried out. Thirty-two fluxes were developed by using a mixture of oxides, halides, carbonates, silicates, and ferroalloys for submerged arc welding. The present paper focuses on only ten (out of thirty-two) fluxes which were analyzed by X-ray diffraction (XRD) to know the different types of oxides formed and changed in oxidation number of metallic centers after sintering process at around 850 °C. To know the effect of temperature over phase transformation and melting of different compounds, differential thermal analysis (DTA) was carried out from 1000 to 1400 °C. This study aims to know the quantity of ions present (percentage) and melting behavior of developed agglomerated fluxes for submerged arc welding process. [ABSTRACT FROM AUTHOR]

The sixty-sixth Annual Assembly of "International Institute of Welding, "a word of joining experience", was held in Essen, important economic city of the German region Ruhr, from 11 to 17 September 2013. It was attended by 755 experts, researchers, engineers, students and accompanying persons of 46 countries of four continents. IIW Working Units hold over one hundred meetings; some five hundred documents, recommendations, guidelines and draft standards were presented, studied and discussed, 132 of which have been recommended for publication and 6 for transmission to ISO and CEN for publication as standards or other regulatory actions. Significant also the meetings of IAB (International Authorization Board), the body created to manage in the context of IIW the "International IIW Qualification, Certification and Authorization System". Good well as the success of the International Conference "Automation in Welding", of some specialized seminars, as well as of various scientific and technical visits and of social events in and around the city. It was also partially renewed the Board of Directors of IIW; the latter has currently 56 Member Countries. Finally are presented too the lists of documents ap proved for publication and for standardization, so as the list of papers submitted to the International Conference and the final technical evaluations of the Italian delegation. [ABSTRACT FROM AUTHOR]

Modern superaustenitic stainless steels are quaternary alloys extensively used to resist severe aqueous corrosive service, with large contents of Cr, Ni, Mo and PREn index generally higher than 45. Fusion welding is the major joining method for fabricating components and vessels using these grades. In this paper, the behavior of these alloys and the consequence of their use infusion welded structures are illustrated. The typical microstructures of the base materials, the transformations followed during welding or heat treatment and their influence on the mechanical properties and corrosive resistance of the joints are presented. Fabrication practices, filler materials and the aspects common to the nickel alloys welding are discussed, as well. During the welded fabrication, the major difficult is to retain the fully austenitic microstructure with sufficient homogeneity throughout all the high temperature manufacturing operations, and to limit the tendency to the hot solidification cracking. The recent understanding of the segregation mechanisms during the solidification and the associated kinetic will allow a more effective control of the micro structural evolution, also by using high energy welding methods and newly formulated filler materials with non-austenitic primary solidification mode. [ABSTRACT FROM AUTHOR]

Due to their good corrosion resistance in high-temperature and wet corrosive environments, nickel-based alloys are widely used as construction materials in the chemical industry, as well as in offshore applications and other energy and environmental technologies. Their outstanding corrosion performance, however, is often accompanied by a limited weldability due to a high hot cracking sensitivity. This paper presents a comparative overview of the hot cracking susceptibility of iron and nickel-based alloys type 1.4958 (alloy 800 H), 2.4663 (alloy 617), 2.4816 (alloy 600 H), 2.4856 (alloy 625) and 2.4605 (alloy 59). Hot cracking tests are performed by PVR test (deformation crack test), using GTA-welded externally loaded specimens to rank the hot cracking sensitivity of the base metals. In order to gain further knowledge regarding formation and propagation of the hot cracks, optical microscopy and EDX-analyses were performed. In addition to a ranking of materials and processes, interim results regarding the crack types and the metallurgical causes of cracking are discussed. [ABSTRACT FROM AUTHOR]

This article offers information on the beginning and the development in Italy and abroad of technical assistance activities performed by IIS and later on by IIS Service srl. At the purpose, three subsequent periods are considered: a first one of affirmation of such activities; an intermediate one of consolidation of IIS on the market and of beginning of organization of its structure; a final one of further growth of such activities and of development and completion of IIS restructuring in order to prepare the partition which originated the IIS Group. The latter comprehends IIS Ente Morale (no profit distributing society), IIS Cert srl (Ltd) and IIS Service srl (Ltd), established at the beginning of 2011, and IIS Progress srl (Ltd), established at the beginning of 2013. In particular, the paper shows how, in some sixty years of activity, IIS gained a fame of seriousness, reliability and competence, that have made it one of the most comprehensive benchmarks in the field of welding, allied processes and connected techniques, appreciated everywhere it acted, in Italy, in Europe and in other continents. Finally, it is remembered that in 1988 IIS acquired with its own resources a modern and well-equipped headquarters in Genoa, that, in mid-2013, IIS Group owned various other regional offices and that at the time had in force some 225 employees (including some sixty graduate engineers and some one hundred technical licentiates), about half of whom are employees and managers of IIS Service srl. [ABSTRACT FROM AUTHOR]

This paper describes recent developments in the welding of thermoplastics, including laser welding of microfluidic devices and friction stir welding of fibre-reinforced plastics. It also describes new developments in the assessment of welds in thermoplastics, including the long-term mechanical testing and phased array ultrasonic inspection of welded joints in polyethylene pipes. [ABSTRACT FROM AUTHOR]

Following the first part, which was about the ultimate resistance check of the welded connections, the present paper focuses on the fatigue design criteria. After an introduction about the general problem of the fatigue, the article presents the standard design criteria based on the simplified Wöhler curves and with respect to the load history and structural detailing available. The final part handles with the Hot Spot Method, increasingly used and well-linked to the FEM. [ABSTRACT FROM AUTHOR]

Presently, many economical and technical efforts are made by pipeline industry aimed to satisfy the needs to transport gas from far away regions to the final market and to set new solutions in terms of both design criteria and new high performance materials. Due to the fact that easy Oil and Gas is largely exploited and new fields will be more and more in deeper water (it means water depths greater 305 m), that means higher pressures and temperatures and more corrosive environments, material requirements are increasing. In this situation low-alloy carbon steels tend to be structurally satisfactory, but lack in terms of corrosion resistance. On the other hand stainless steels and nickel alloys resist to corrosion environments but are lack in terms of strength or extremely costly. Clad pipes, low-alloy carbon steel with a thin layer of a corrosion-resistant alloy, is presently considered, more and more, a suitable solution to the most demanding requirements of strength, corrosion resistance and cost-effectiveness. In a cladded pipe, the (generally) unalloyed carbon steel outer pipe handles the internal and external pressure, while the high-alloy cladding provides the corrosion protection. The paper describes the pipes and fittings production starting from metallurgical clad plates. In particular the experience developed by Allied Group is described. The developed products and components represent the ideal candidate for the most severe offshore and subsea applications typical of the Oil&Gas sector. [ABSTRACT FROM AUTHOR]

The paper is going to discuss the basic topics about distortions and geometrical tolerance in steel structures manufacturing and erection. The theoretical aspects about the residual strain of welded joints are shortly presented and the practical consequences of the distortions on welded panels or slender structures are discussed. Finally the European Standard recommendations are taken into account and the methods to restrain the welded joint or to reduce the distortion as flame straightening are discussed. [ABSTRACT FROM AUTHOR]

The opening of the new Panama Canal is planned in 2014. Cimolai started in October 2010 the construction of the sliding gates for the opening and closing of the locks. The work consists of 16 gates of significant size, for a total weight of about 55,000 tons, and it will require a commitment of about 4 years for the manufacture, the installation and the commissioning. This paper presents the main characteristics of the "lock gates" and an overview of the most critical steps of the construction activities. [ABSTRACT FROM AUTHOR]

The materials coating applied by Thermal Spraying techniques are used in different sector at industrial level. Railway wheelset is an assembly of two wheels on the axle, where the railway axle component is the most critical component of the railway vehicle from the point of view of safety. The assembly of the wheels on the axle is generally guaranteed by the interference of each wheel with the axle in correspondence of its dedicated area (wheel seat). More in general, on the railway axle are mounted axle boxes at the areas known as journal and can be mounted, on further axle seats', one or more brake disc and a gear for traction group. These axle seats, being subject to the stresses due to the contact pressure between the components and the external forces acting on the wheelset, may be subjected to phenomena such as the mechanical wear and fretting and by the necessity to be restored to the original dimensions. In this context, the aim of this paper is to present the experience gained by Lucchini RS, with the technical support of the Italian Institute of Welding, in the application of molybdenum coating by means of Thermal Spraying technique on railway axle seats in order to ennoble their surface state. [ABSTRACT FROM AUTHOR]

In recent years ultrasonic flaw detection in welded components has taken advantage from the developments in robotic, electronic and IT fields. New ultrasonic techniques, such as TOFD and Phased Array, have deserved an increasing interest in NDT market. Their main purpose is to increase the reliability and repeatability of the results through the registration of data, allowing the substitution of radiographic technique which has well-known problem of safety and is time-consuming for thicker components. These techniques, in front of undeniable advantages, are limited by technical constraints that have to be taken into account in order to detect and evaluate in a proper way the defects. This paper focuses on experience gained by IIS Service in this field, showing the advantages and limitations possibly arising from a not correct application of automatic ultrasonic techniques. [ABSTRACT FROM AUTHOR]