Electric Resistance Welding Research Articles

Investigation of the effects of different electrical resistance welding parameters on strength

Bu çalışmada otomotiv endüstrisinde kullanılan 5000 serisi alüminyum alaşımlarından olan Al 5754-H111 malzemesi elektrik direnç kaynak yöntemi ile farklı kaynak akımı, kaynak süresi ve sıkıştırma yükü ile birleştirilmişlerdir. Kaynak işlemi uygulanmış numunelerin mekanik özelliklerini belirlemek amacıyla kaynaklı bağlantılara çekme deneyi yapılmıştır. Test sonuçlarına göre elde edilen çekme mukavemeti ve çekme uzaması değerlerindeki farklılıklar, kaynak parametrelerindeki değişimin kaynağın mekanik özellikleri üzerinde önemli etkiye sahip olduğunu göstermiştir.

Cytotoxicity test of the titanium joints made using the WeldOne® electric resistance welding unit

Cytotoxicity test of the titanium joints made using the WeldOne^® electric resistance welding unit

Yield strength mapping in the cross section of ERW pipes considering kinematic hardening and residual stress

In the ERW (electric resistance welding) pipe manufacturing, material properties, process conditions and settings strongly influences the mechanical performances of the final product, as well as they can make them to be not uniform and to change from point to point in the pipe. The present research work proposes an integrated numerical model for the study of the whole ERW process, considering roll forming, welding and sizing stations, allowing to infer the influence of the process parameters on the final quality of the pipe, in terms of final shape and residual stress. The developed numerical model has been initially validated comparing the dimensions of the pipe derived from the simulation results with those of industrial production, proving the reliability of the approach. Afterwards, by varying the process parameters in the numerical simulation, namely the roll speed, the sizing ratio and the friction factor, the influence on the residual stress in the pipe, at the end of the process and after each station, is studied and discussed along the paper.

Development of a bonding technique for replantation of support leg on W-monoblock component

EAST upper divertor has been upgraded to ITER-like actively-cooled W/Cu components in May 2014. In the manufacture, assembling and disassembling of this W/Cu divertor, it was found that more than 10 support legs have dropped from the W/Cu-monoblock. In this work, the welding technique and drop reason of the support leg have been summarized and analyzed. To replant the dropped legs, some weld methods, including the middle-temperature brazing, electric resistance welding and 3D printing, have been performed and compared. Finally, the replantation technique based on 3D printing with laser beam has been developed and the nickel leg has successfully been printed on W block without the copper interface. In the development of the replantation technique, the microstructure and mechanical properties of the nickel leg have been researched to modify the printing technique. It is considered that this replantation technique also could be used in the ITER W divertor project.

Friction Stir Spot Welding of AZ31B Magnesium Alloy

The Electrical Resistance Welding (ERW) of Magnesium and Aluminium is more difficult than steel because the welding machines must provide high currents and exact pressures in order to provide the heat necessary to melt the magnesium for proper fusion at the interface in order to produce a sound weld. Further, resistance welding of magnesium requires a backup plate made of steel to conduct the heat to the workpiece material. To overcome this problem, Friction Stir Spot Welding (FSSW) has been developed. In this study, the hardness distribution and the tensile shear strength of FSSW welds in the AZ31B Magnesium alloy has been investigated and it has been found that tool rotational speed and dwell time plays a major role in determining the weld strength. From the experimental study, a tool rotational speed of 1100 rpm and dwell time of 20 s produced good shear strength of 2824 N and the corresponding grain size was 4.54 μm. This result is very well supported by microstructural examinations and hardness distribution studies.

Detection of HF-ERW status by neural network on imaging

To achieve online testing of high-frequency electric resistance welding (HF-ERW) tube quality, forecasting models were established for welding defect conditions with collected high-speed images of the joint melting phenomenon, based on a radial basis function neural network (RBFNN). Firstly, the dimensions of the collected image samples were deduced by principal component analysis (PCA). Then, the reduced-dimension image samples were set as inputs of both BPNN (back-propagation neural network) and, for comparison, RBFNN, which were trained so that the model parameters were optimized. Finally, the testing sample set was identified by trained networks. The experimental results show that RBFNN had better generalization ability for HF-ERW images than BPNN, which meant that the recognition rate of low-heat input status reached 100%, while the recognition rate of overheating input status reached 97.67%. They also show that the welding quality detection system based on a neural network is very effective and has a strong guiding significance for welding quality control.

Fatigue limits of titanium-bar joints made with the laser and the electric resistance welding techniques: microstructural characterization and hardness properties.

Fatigue behavior of the titanium bars is of utmost importance for the safe and reliable operation of dental implants and prosthetic constructions based on these implants. To date, however, only few data are available on the fatigue strength of dental prostheses made with electric resistance welding and laser welding techniques. This in-vitro study highlighted that although the joints made with the laser welding approach are credited of a superior tensile strength, joints made with electric resistance welding exhibited double the minimum fatigue strength with respect to the joints made with laser welding (120 vs 60 N).

Microstructure and Mechanical Properties of J55ERW Steel Pipe Processed by On-Line Spray Water Cooling

An on-line spray water cooling (OSWC) process for manufacturing electric resistance welded (ERW) steel pipes is presented to enhance their mechanical properties and performances. This technique reduces the processing needed for the ERW pipe and overcomes the weakness of the conventional manufacturing technique. Industrial tests for J55 ERW steel pipe were carried out to validate the effectiveness of the OSWC process. The microstructure and mechanical properties of the J55 ERW steel pipe processed by the OSWC technology were investigated. The optimized OSWC technical parameters are presented based on the mechanical properties and impact the performance of steel pipes. The industrial tests show that the OSWC process can be used to efficiently control the microstructure, enhance mechanical properties, and improve production flexibility of steel pipes. The comprehensive mechanical properties of steel pipes processed by the OSWC are superior to those of other published J55 grade steels.

Development of medium-to-high carbon hot-rolled steel strip on a thin slab casting direct strip production complex

ABSTRACTMedium-to-high carbon hot-rolled steel strip was developed on a thin slab casting direct strip production complex at Essar Steel Algoma Inc. to meet different specifications and special customer requirements. The effects of chemistry, casting and hot rolling process parameters on microstructure and mechanical properties were studied. Soft core reduction, secondary cooling, casting speed, as well as hot rolling and coiling temperature were optimised to achieve the required mechanical properties and other requirements such as ultrasonic test after electric resistance welding, wear resistance and corrosion resistance. These new developed medium-to-high carbon steel grades have extensive applications in oil and gas industries, general manufacturing, construction, automotive and mining equipment.

Fatigue Crack Growth at Electrical Resistance Welding Seam of API 5L X-70 Steel Line Pipe at Varied Orientations

Very few studies have been conducted concerning fatigue in steel line pipe and fewer using full-scale testing. Further, at the time of this study, no research on full-scale testing was available in open literature regarding fatigue behavior of line pipe with longitudinal cracks, despite being considered more critical than the line pipe with cracks oriented in the circumferential direction. In the current research work, fatigue crack growth was investigated in NPS 20, API 5L X-70 grade, electrical resistance welding (ERW) straight-seam steel line pipes in the base metal and at the weld seam for various orientations. It was found that there was no significant difference between fatigue crack growth in the base metal and at the weld seam for the tested stress ratio. Increasing the angle of inclination of the crack with respect to the weld line was found to decrease the rate of fatigue crack growth due to a decrease in the mode I stress component. Finally, it was observed that despite the difference in fatigue crack growth rates, the crack aspect ratios were nearly identical for all cracks at the same crack depth.

ДОСЛІДЖЕННЯ ПРОЦЕСІВ МАСОПЕРЕНЕСЕННЯ У ПРОЦЕСІ ПРЕЦИЗІЙНОГО ЕЛЕКТРОКОНТАКТНОГО ЗВАРЮВАННЯ АЛЮМІНІЮ

Urgency of the research. Wide application of aluminium and its alloys in industry causes the necessity of improvement current getting ways of their permanent joints in solid phase.Target setting. Investigation of diffusion processes and ascertainment of mass transfer regularities is the actual task for studying of joint formation process during welding in solid phase and it has a practical importance during the development of new welding technologies.Actual scientific researches and issues analysis. One of the most perspective joining methods of aluminium in solid phase is high-precision electric resistance welding through intermediate layers of welded material. Their application promotes to activation of metal surface and localization of heat energy in the joint.Uninvestigated parts of general matters defining. Mass transfer processes in joining zone and identification mechanisms of optimal quantity of interlayers during electric resistance welding of aluminium and alloys remain unstudied.The research objective. Aim of the paper is the investigation of the influence of quantity interlayers on mass transfer processes during electric resistance welding of aluminium and alloys.The statement of basic materials. Tryout of research technique has been carried out in terms of electric resistance welding of aluminium alloy AlMn1 with using of intermediate layers of aluminium foil by thickness 11 μm. Welding has been implemented in next conditions: the current density 300‑350 A/mm2; the specific pressure 2-3 MPa; the duration current impulse 0.1‑1 sec. The investigation of mass transfer characteristics has been carried out by the radioactive tracer technique.Conclusions. Features of mass transfer during electric resistance welding of alloy AlMn1 through interlayers have been examined. The dependence of mass transfer coefficient on the interlayers’ quantity has been determined. It has been indicated that the diffusion zone width is maximal during welding through four layers.

Effect of HF Welding Process Parameters and Post Heat Treatment in the Development of Micro Alloyed HSLA Steel Tubes for Torsional Applications

The aim of the present study is to investigate the effect of High frequency (HF) Electric resistance welding process parameters and post heat treatment on the torsional fatigue life of micro alloyed HSLA steel tubes. Micro alloyed grades exhibit higher strength and formability owing to the presence of fine recrystallized ferritic grains due to thermo mechanical treatment and presence of alloying elements like Vanadium, Niobium and Titanium. Welded tubular components made of micro alloyed HSLA steel grades are highly emerging and manufacturing them remains quite challenging. Weld bond width, HAZ width and bond angle are the significant factors that directly influences the Weld quality and strength. The effect of key welding parameters like Heat input, welding temperature, squeeze roll pressure, Vee-angle, Vee-length and Impeder diameter on the above mentioned significant factors was analysed. Narrow bond, Minimum HAZ width with pronounced Hour glass pattern and optimum bond angle resulted in superior bond strength and formability of HSLA tubes. Microstructural characterization of the samples was carried out using Light optical microscopy and Scanning electron microscopy. Residual stress was determined using X-ray diffract meter and tube slitting method. Higher tensile residual stress of magnitude 200 MPa was observed in the weld region. Since such high magnitude of tensile residual stress is detrimental to torsional fatigue life, stress relieving of the tubes was carried out at different subcritical temperatures 650°C and 700°C with soaking time of 45 minutes. Without significant drop in the tensile properties, compressive residual stress of magnitude 129 MPa was observed at a particular stress relieving cycle. As an effect of stress relieving heat treatment below Ac1 temperature, there is a significant improvement in the Torsional fatigue life of the HSLA steel. Thus, High Frequency welded micro alloyed HSLA steel tubes with enhanced torsional fatigue performance were successfully developed.

ПРЕЦИЗІЙНЕ ЗВАРЮВАННЯ ТИСКОМ АЛЮМІНІЄВИХ СПЛАВІВ

Urgency of the research. Aluminum alloys are widespread materials in constructions of different branches of industry. Apart from ensuring the strength of permanent joints in typical units of constructions, their production requires to retain their designed form.Target setting. Precision joining of aluminum alloys by pressure welding is complicated owing to their high thermoplastic properties, heat- and electro conductivity. It requires the search of effective methods for obtaining products with low deformation level.Actual scientific researches and issues analysis. One of perspective joining methods of aluminium alloys is precision electric resistance welding through intermediate layers of aluminium foil. Their application promotes to localization of heat energy in the contact of welded components and decrease of product deformation level.Uninvestigated parts of general matters defining. Heat release process in the contact of welded components during electric resistance butt-welding of aluminum alloys through interlayers remains unstudied.The research objective. Aim of this paper is the development of precision electric resistance welding of aluminium alloys.The statement of basic materials. The investigation of heat release process has been carried out by estimated way with using of finite-element modeling. The joining of aluminum alloy 6063 has been realized by electric resistance butt-welding through intermediate layers of aluminum 1050 foil by thickness 11 μm. Welding conditions: the current density 300 A/mm2, the specific pressure 8 MPa, the welding time 0.5‑0.7 sec.Conclusions. It is shown, that quantity of heat generated in the contact zone during electric resistance butt-welding depends on number of layers in the interlayer. It has been determined that welding of aluminum alloy 6063 under offered conditions through 6 layers of aluminum foil allows to obtain welded joints with strength by 95 % from base metal strength and deformation level up to 2 %.

Mechanical Analyses of Welding in Practical Field

In order to produce reliable welded product quality accumulated experiments are basic requirements.But nowadays production conditions are changing and quality requirements are becoming more and more severe. In these cases using achievement of computer in hardware and software can be a nice tool for improving welding production in efficiency and time saving. In this study three samples are shown in order to show the improvement in welding products with the aid of computer. (Repair welding, Tack welding and High frequency electric resistance welding)

Failure Investigation of Hydrotest Rupture on a Natural Gas Pipeline

A land-based natural gas pipeline, API 5L Grade B pipe with an electric resistance weld (ERW), failed during hydrotesting inspection along the ERW seam, which led to further investigation. Linear indications, indicative of surface cracks, were observed on the outer diameter of the pipe below the fracture surface, made visible by fluorescent light. Using transmission electron microscopy, it was evidenced that a crack may have initiated within the martensite/austenite islands and propagated through the ferrite bands seen beneath the fracture surface in the heat-affected zone. It was also evidenced by scanning electron microscopy (SEM) that the primary fracture mode consisted of high volume fractions of transgranular cleavage and low volume fractions of transgranular microvoid coalescence. Also evidenced in SEM, were regions of non-fracture evidence indicative of inadequate fusion within the ERW seam.

Galvanic corrosion of the seam weld in Zn–Al coated steel pipes manufactured by electric resistance welding

Severe corrosion attack at the seam weld was observed in Zn–Al coated steel pipes of a closed heating system. This system was operating with tap water at about 70 °C and in the presence of an unknown amount of oxygen due to water reintegration. The corroded pipes showed a preferential corrosion of the seam weld along the longitudinal direction of the pipe. In order to investigate the cause of this attack, the electrochemical behavior of the seam weld was studied by means of an electrochemical micro‐cell. This technique was used for the characterization of non‐corroded and corroded pipe samples. The study proves that the damage mechanism is due to Zn–Al coating depletion at the seam weld and the potential coupling reversal between the coating and the steel substrate under service conditions. This caused strong galvanic corrosion between the steel exposed along the seam weld and the Zn–Al coating leading to the failure of the pipes.

Technological Peculiarities of Electric Resistance Welding of Intеrsecting Crosswise Rods Made of Aluminum Alloys

Technological Peculiarities of Electric Resistance Welding of Intеrsecting Crosswise Rods Made of Aluminum Alloys

Dynamic observations of welding phenomena and finite element analysis in high-frequency electric resistance welding

High-frequency electric resistance welding (hereinafter referred to as HFW) pipes and tubes are used for high-grade line pipes. To cope with the high need for weld seam reliability, the clarification of welding phenomena is important. To clarify the HFW phenomena, at first we developed a HFW simulation system by using electromagnetic, heat conductive and elastic plastic finite element analysis (FEA) methods. Continuous electromagnetic and heat conduction analysis was conducted by subdividing the cross section containing the electrode and the welding point into a large number of two-dimensional models. The temperature distribution in the HFW pipe welding procedure can be successfully simulated by this system. The deformation behaviour in which a portion of the weld rises to the inner and outer surfaces as the result of pressurization from welding rolls can be analysed with this system. Secondly, HFW phenomena have been visualized dynamically using a high-speed video camera technique. The high-intensity part visualized by high-speed images has good accordance with the temperature distribution of the FEA result. High-speed images have visualized the dynamic phenomena of molten metal flow and sputtering of molten steel. Very rapid movement of molten metal in the forming direction along the welding line was observed at the V-convergence point with a speed of 2–50 m s−1, which was far faster than the welding speed. This rapidly moved molten metal generated the peculiar sputtering which spread the molten metal particles as describing an arc perpendicular to the welding line. These phenomena were assumed to be caused by the electromagnetic force concerning the molten steel at the V-convergence point.

Understanding the spark plasma sintering from the view of materials joining

Spark plasma sintering (SPS) is an attractive consolidation process. However, the mechanism behind this process is still an open topic for debate. This paper presents the first attempt to understand the SPS mechanism from perspective of materials joining. For this, TiNif/Al composites were fabricated by SPS, and the interfacial microstructures were investigated using field emission scanning electron microscopy and transmission electron microscopy. According to the experimental results, several joining processes were reflected well during SPS, involving micro-arc welding, electric resistance welding and diffusion welding. The proposed understanding of SPS will be helpful to the control of sintering quality.

Experimental study on web crippling strength of hollow flange channels under end-one-flange and interior-one-flange load cases

LiteSteel beam is a hollow flange channel made from cold-formed steel using a patented manufacturing process involving simultaneous cold-forming and dual electric resistance welding. LiteSteel beams are currently used as floor joists and bearers in buildings. However, there are no appropriate design standards available due to their unique hollow flange geometry, residual stress characteristics and initial geometric imperfections arising from manufacturing processes. Recent research studies have focused on investigating the structural behaviour of LiteSteel beams under pure bending, predominant shear and combined actions. However, web crippling behaviour and strengths of LiteSteel beams still need to be examined. Therefore, an experimental study was undertaken to investigate the web crippling behaviour and strengths of LiteSteel beams under end-one-flange and interior-one-flange load cases. A total of 23 web crippling tests were performed and the results were compared with the current AS/NZS 4600 and AISI S100 design standards, which showed that the cold-formed steel design rules predicted the web crippling capacity of LiteSteel beam sections very conservatively under end-one-flange and interior-one-flange load cases. Therefore, suitably improved design equations were proposed to determine the web crippling capacity of LiteSteel beams based on experimental results. In addition, new design equations were also developed under the direct strength method format. This article presents the details of this experimental study on the web crippling behaviour and strengths of LiteSteel beams under end-one-flange and interior-one-flange load cases and the results.