Ultrasonic Seam Welding Research Articles

Interfacial evolution behavior and mechanical properties of Ti/steel joint via ultrasonic seam assisted resistance spot welding with Cu interlayer

Ultrasonic seam assisted resistance spot welding, as a new joining technology, was proposed for welding TC4 titanium alloy and Q235 mild steel with Cu interlayer (abbreviated as US-RSW-Cu), in which, the Cu interlayer was consolidated on the Q235 mild steel by ultrasonic seam welding (USW) in advance, which was subsequently connected with TC4 by the traditional standard resistance spot welding (RSW) in the following experiments. To investigate the effect of pre-USW on the interface microstructure and mechanical properties, the final joints were compared with the other joints by the traditional RSW without interlayer directly (abbreviated as RSW-D), and with a single Cu interlayer (abbreviated as RSW-Cu). The results depicted that the welding nugget in RSW-D and the flat interfacial structure in RSW-Cu were replaced by the inhomogenous interfacial structure in US-RSW-Cu due to the pre-metallurgical bonding between Cu interlayer and steel by USW, which also effectively decreased the welding defects. The Ti-Cu intermetallic compounds (IMCs) were generated at the final joints via US-RSW-Cu instead of most Ti-Fe IMCs, which improved significantly the joint properties and reduced the nanoindentation hardness at the joint interface. The final shearing force of welding joints by this method was the highest and reached 12,380 N, which was 2.68 times with original joint strength via a single RSW-D. The reaction layer near the Ti side via US-RSW-Cu contained abundant Fe atoms, forming Ti-Cu and TiFe2 IMCs at this position. The final welded specimen fractured at the interfacial reaction layer near the Ti side due to the generation of TiFe2 IMC. The XRD results also proved the generation of the abovementioned Ti-Cu and Ti-Fe IMCs.

Разработка технологии и оборудования для шовной ультразвуковой сварки синтетических тканей

In this work, possible methods of ultrasonic welding of synthetic fabrics are considered and analyzed. Technological features of ultrasonic seam welding of synthetic fabrics are described. The key parameters of this type of welding that significantly influence the speed of achieving the maximum temperature in the fabric welding zone are identified. These parameters determine the intensity of the fabrics’ warm-up, and therefore, the efficiency of the welding process. Thermal processes occurring at seam welding of synthetic fabrics are studied. It is established that the welding time increases with an increase in the number of connecting layers as well as with addition of cotton to the fabric composition. It is determined that when welding synthetic fabrics of small thickness, heat removal to the waveguide and the support roller has virtually no influence on the maximum temperature at the border of the mating surfaces and on the time of achieving the maximum temperature. Experiments on welding lavsan, kapron and polypropylene fabrics are conducted. The dependence of the statistic welding pressure on the welding speed and the fixed gap between the waveguide and the support roller is investigated. It is determined that the movement of material under the waveguide doesn not have a warming-up impact on the neighbouring areas of the welded seam. The strength of the welded joints practically does not depend on the height and shape of the support roller.

Effects of ultrasonic welding parameters for solar collector applications

Abstract Today, ultrasonic welding is used in many different areas due to ease of application compared to other welding methods. Computer, electric, automotive and aerospace industries are the leading areas for these applications. With its ability to easily join materials like Al, Cu, Ni, ultrasonic welding has become a preferred method for use in the welding of solar collectors which are components in solar energy systems. The system parameters for welding solar collectors must of course be adjusted according to the properties of the materials used so that the heat transfer between specimens is not affected. In this study, the selective coated plate and the heat carrier pipes of solar collectors were welded using ultrasonic seam welding, and the optimum welding parameters were determined according to the Cu-DHP copper alloy used. For this purpose, copper specimens were welded using welding speeds of 4, 8, 12 and 16 m × min−1 and amplitudes of 4, 5 and 6 μm, while pressure and frequency values were fixed. The shear strength values of these welded specimens were calculated, and images of the weld areas were obtained with the help of a scanning electron microscope. Through hardness measurements made on the interfacial region of the welds, it was concluded that optimal welding performance was obtained at an amplitude of 4 μm and a welding speed of 12 m × min−1. At these parameters, a mean shear strength value of 0.1386 MPa and a mean hardness value of 112 HV were measured.

A BFGS and simple step method for estimating the interface temperature in 2D ultrasonic seam welding

An inverse method for estimating unknown interface heat generation in an ultrasonic seam welding process based on a combination of the Broyden–Fletcher–Goldfarb–Shanno (BFGS) and Simple Step Method is presented. In this study, a nonlinear direct problem is solved by using the Hybrid Spline Difference Method (HSDM). Heat generation and interface temperature, which are extremely difficult to directly measure, can be determined inversely through the Direct Problem, Adjoint Problem, and the Simple Step Method without sensitivity analysis. Special features of proposed method are stable, accurate, and efficient for estimating moving heat sources and interface temperature even including measurement error. The predicted interface heat generation and temperatures are in very good agreement with exact solutions for different heat sources profiles. Furthermore, the influence of the measurement location on the accuracy of estimated solutions with or without error of measurement was also discussed. These findings indicate that the estimated heat generation is more sensitive than the temperature to different measured errors and locations. According to analysis of results, the occurrence of thermal defects can be avoided during the welding process. In addition, the proposed method strongly provides good information for optimization of the welding process.

Study on TIG Arc Preheating Auxiliary Aluminum-copper Ultrasonic Seam Welding

Study on TIG Arc Preheating Auxiliary Aluminum-copper Ultrasonic Seam Welding

Joining of magnesium and aluminum via arc-assisted ultrasonic seam welding with Sn/Zn composite interlayer

Mg and Al alloys were successfully joined via a novel arc-assisted ultrasonic seam welding technique with Sn/Zn composite interlayer. Effects of Sn/Zn composite interlayer on the microstructure and mechanical properties of the joints were investigated in detail. The results indicated that Mg2Sn, Sn-based solid solution and Mg-based solid solution were formed at Mg/Sn interface while Al-based solid solution and Zn-based solid solution were formed at Al/Zn interface. The addition of Sn/Zn composite interlayer could suppress the formation of brittle Mg-Al intermetallic compounds and improve the mechanical properties of the joints obviously. The average peak load of the joints with Sn/Zn composite interlayer was 2.5kN, which was 150% increase over the joints without Sn/Zn composite interlayer. The joints fractured roughly in Mg substrate rather than Mg/Al interface.

Improving weld strength of arc-assisted ultrasonic seam welded Mg/Al joint with Sn interlayer

Welding of Mg and Al alloys is hugely challenging due to the formation of hard and brittle MgAl intermetallic compounds (IMCs). In this research, gas tungsten arc welding (GTAW) assisted hybrid ultrasonic seam welding with Sn interlayer was designed to join Mg to Al alloys. Effects of Sn interlayer and GTAW current on the microstructure and mechanical properties of the joints were investigated in detail. The results indicated that Sn interlayer could restrain the formation of MgAl IMCs, which were replaced by Mg2Sn and Sn-based solid solution. The peak load of the joints increased with the GTAW current increasing and then decreased dramatically at higher GTAW current. The maximum peak load of the joints with Sn interlayer was approximately 1.3kN, which about 30% increase over the joints without Sn interlayer. All the joint failures occurred by the interface mode at the Al/Sn interface and the fracture patterns exhibited entirely brittle fracture mode with cleavage facet feature surface.

Arc assisted ultrasonic seam welding of Mg/Al joints with Zn interlayer

6061 aluminium alloy and AZ31B magnesium alloy was successfully joined together with the addition of Zn interlayer by gas tungsten arc welding assisted hybrid ultrasonic seam welding. The effects of Zn interlayer on the microstructure and mechanical properties of the joints were investigated in detail. The results indicated that the Zn interlayer could restrain the formation of brittle Mg–Al IMCs, which were replaced by Mg–Zn IMCs. The maximum lap strength of the joints with Zn interlayer was ∼16.25 MPa, which was ∼30% increase over the joints without Zn interlayer. All the joint failures occurred by the interface mode rather than the pullout mode at the Mg/Zn interface.

HSDM and BFGS method for determining the heat generation and range of heat distribution in 2-D ultrasonic seam welding problems

ABSTRACTAn inverse method based on the Broyden–Fletcher–Goldfarb–Shanno (BFGS) method and the simple step method is proposed to estimate unknown heat generation at the welding interface during actual ultrasonic seam welding with knowledge of temperatures taken in a workpiece. The efficiency of the hybrid spline difference method (HSDM) compared to the finite-difference method (FDM) is presented. In addition, a comparison of the BFGS method and the conjugate gradient method (CGM) is made. Results show that the estimated temperature is in very good agreement with the measurement temperature. In addition, the heat generation and its distributed range are predicted rapidly. According to the analysis results, the proposed method is an accurate, robust, and efficient method for the prediction of temperature and moving heat generation in an ultrasonic welding process.

Microstructure and properties of Mg/Al joint welded by gas tungsten arc welding-assisted hybrid ultrasonic seam welding

A novel gas tungsten arc welding (GTAW) assisted hybrid ultrasonic seam welding MgAZ31B and Al6061 alloy sheets with satisfactory joint strength were successfully achieved using a previous GTAW preheating heat source. The preceding GTAW reduced the sheet hardness but enhanced the acoustic softening effect and materials plasticity. Therefore, the direct joining of 1 mm thick MgAZ31B and Al6061 alloy sheets can be obtained without improving the ultrasonic power. The effect of GTAW current on the microstructure and mechanical properties was investigated. The tensile shear strength of the joint increased with GTAW current up to a maximum strength and then decreased dramatically with higher GTAW current. The maximum lap shear strength was 1 kN at a GTAW current of 30 A, approximately 40% of AZ31B Mg alloy base metal. The failure occurred by interface fracture mode, and the fracture patterns exhibited brittle fracture mode with cleavage facet feature.

Thermal Transients During Processing of 3003 Al-H18 Multilayer Build by Very High-Power Ultrasonic Additive Manufacturing

Previous investigations suggested a gradient in bond microstructure along the height of a “build” made by very high power ultrasonic additive manufacturing—a rapid prototyping process that is based on ultrasonic seam welding. The bonding of foils is associated with the occurrence of dynamic recrystallization at the interfaces between them. To understand heating patterns across the build that may be responsible for such microstructure evolution, temperatures from different interface regions were recorded simultaneously during the fabrication of a 3003 Al-H18 multilayer build under a given processing condition. Thermal transients were observed over multiple interfaces of the build during welding of each layer. The temperatures were the highest for the layer processed and were found to diminish beneath with each subsequent layer. Such maximum temperatures also depended on the height at which the new layer was bonded. The occurrence of transients across the build is rationalized based on heat being conducted away from the processed layer.

Welding Characteristics of Aluminum and Copper Plate Specimens Welded by a 19 kHz Complex Vibration Ultrasonic Seam Welding System

The welding characteristics of aluminum and copper plate specimens welded using a 19 kHz ultrasonic welding system with a complex-vibration welding tip were studied. The welding tip part vibrates in an elliptical or circular locus. The seam welding system uses a rotating circular disk welding tip and a shifting stage for continuous welding of the metal sheets. Using the complex-vibration system, metal plates of various thicknesses can be welded continuously at multiple positions with large and uniform welded areas and large weld strengths independently of the welding position and direction. The required complex-vibration amplitude is less than one-half of that of a conventional linear-vibration system. Aluminum-aluminum, aluminum-copper and copper-copper plate specimens were welded with weld strengths almost equal to the specimen strength.

Welding Characteristics of Ultrasonic Seam Welding System Using a Complex Vibration Circular Disk Welding Tip

The continuous welding characteristics of a 27 kHz ultrasonic seam welding system using a complex vibration circular disk welding tip are studied. The vibration characteristics of a complex vibration converter were improved compared with the prototype model. The circular disk welding tip vibrates in both transverse and torsional vibration modes and an elliptical vibration locus is obtained at the circumference of the circular disk welding tip. An ultrasonic seam welding equipment consists of a complex vibration circular disk welding tip that is driven by a longitudinal vibration system through a longitudinal-torsional vibration converter, and an automatic specimen shifting stage. A large number of aluminum plate specimens of 0.3 mm to 0.5 mm thickness and 50 mm to 300 mm length were continuously joined to a thick aluminum plate at multiple welding parts.

Transverse and torsional complex vibration systems for ultrasonic seam welding of metal plates

Transverse and torsional complex vibration systems for ultrasonic seam welding of metal plate specimens, using a 27 kHz complex vibration disk welding tip vibrating in transverse and torsional vibration modes, were studied. Using a complex vibration welding system with a welding tip vibrating in elliptical or circular locus, thick plate specimens can be welded with a more uniform and larger area compared to a conventional ultrasonic welding system. The disk welding tip vibrates in an elliptical or circular locus. The complex vibration system can continuously weld multiple parts of metal plate specimens such as heat sinks with a large number of fins.

Ultrasonic Seam Welding System Using a Complex Vibration Circular Disk in Transverse and Torsional Vibrations

Ultrasonic seam welding of metal plate specimens using a 28 kHz complex vibration disk welding tip vibrating in transverse and torsional vibration modes is studied. Conventional ultrasonic seam welding equipment using one-dimensional vibration locus can only join metal foil or very thin plate specimens and not join thick metal plate specimens. Using a complex vibration welding system with a welding tip vibrating in elliptical or circular locus, thick plate specimens can be welded with a more uniform and larger area weldment compared to a conventional ultrasonic welding system. An ultrasonic seam welding system consists of a complex vibration disk welding tip which is driven by a longitudinal vibration system through a longitudinal-torsional vibration converter. The disk welding tip vibrates in elliptical locus. Aluminum plate specimens 0.3 mm and 3.0 mm in thickness were successfully joined with such weld strengths that the specimens were broken at the plate parts adjacent to the welded area under tensile strength test. Aluminum plates 50 mm in width were successfully joined by the ultrasonic seam welding system.