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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]

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]