Papers by Keyword: Explosive Welding

Abstract: 1060Al/AZ31/1060Al composite plates were fabricated by explosive welding. The microstructure and properties of the composite plate after explosive welding were investigated. The results showed that all bonding interface had a wavy morphology. The wavelength and amplitude of the lower interface were larger than that of the upper interface. Diffusion layer occurred in both interfaces and the thickness were both approximate 4 μm. Adiabatic shear bands and twin structure were observed in AZ31. The shear bond strength of the lower interface was larger than that of the upper interface. Larger amplitude and wavelength of the waveform implied higher bonding strength.

Abstract: The stereomicroscope, microscopic metallograph and scanning electron microscope (SEM) were adopted to investigate the fracture mechanism of two-layer steel/aluminum composite plates impacted by spherical fragment. The composite plates with the same total thickness (5mm) were fabricated by the method of explosive welding. In ballistic experiment, the spherical fragments were launched by a 14.5mm slip chamber gun to penetrate the composite plate. The effect of the combination state of the interface on the fracture mechanism was analyzed based on the experimental results. The results show that the fracture mechanism of the steel front plate is shearing and plugging and that of aluminum rear plate is ductile prolonging deformation when the tied interface failed by tension (or shearing and plugging when the interface combination remained connected).A narrow adiabatic shear band was formed in the local yield plate damaged by shearing and plugging during the penetration process.

Abstract: This paper assesses the effect of various values of detonation velocity on the quality of the bond zone. The results of structural, static and fatigue studies were presented for bonds in the initial state. Depending on the applied technological settings of welding, most cases displayed a wavy bond with highly diversified parameters of the wave. High detonation velocities favoured the formation of waves with great height and length and clearly affect the increase in the volume of hard and brittle regions of melt in the bond zone. Increased volume of the melted regions in the bond zone results in the decrease of fatigue resistance and strength properties of the clads.

Abstract: The paper presents the results of physical modelling of the plastic deformation of the Mg/Al bimetallic specimens using the Gleeble 3800 simulator. The plastic deformation of Mg/Al bimetal specimens characterized by the diameter to thickness ratio equal to 1 was tested in compression tests. The aim of this work was determination of the range of parameters as temperature and strain rate that mainly influence on the plastic deformation of Mg/Al bars during metal forming processes. The tests were carried out for temperature range from 300 to 400°C for different strain rate values. The stock was round 22.5 mm-diameter with an Al layer share of 28% Mg/Al bars that had been produced using the explosive welding method. Based on the analysis of the obtained testing results it has been found that one of the main process parameters influencing the plastic deformation the bimetal components is the initial stock temperature and strain rate values.

Abstract: An investigation is performed on the influence of the temperature and duration of heating of the explosively welded titanium ВТ1-0+ Steel 20 composite on the phase composition of the diffusion layer formed at the interface. It is shown that after heating to 800 oС the diffusion layer consists of α + α’-Ti , an iron solid solution in titanium and a decarburized zone. When heated at the temperature range from 900 – 1000 oС, the composition of the diffusion layer is as follows: α + α’-Ti acicular structure, Fe₂Ti and FeTi intermetallics, TiC titanium carbide, titanium solid solution in α-Fe and a decarburized zone.

Abstract: Ti-Al composite tube has the merits of high hardness, corrosion resistance, heat resistance and low specific gravity; and is widely used in aerospace industry, petroleum industry, and nuclear industry. Explosive welding is used to produce the Ti-Al composite tube in this paper. The effect of Sodium chloride emulsion explosive and detonation velocities on the interface characteristics are investigated. The bond interface wave and mechanical properties are analyzed. From the Scanning Electron Microscopy (SEM), it can be found that the interface is wavy, which can produce best welding characteristics. And detonation velocity has great effect on the bond interface wave. Mechanical tests including the flattening test, compression test, and bending test are conducted on the Ti-Al composite tube. Research showed that the interface bond properties and strength can fully withstand large plastic deformation.

Abstract: The explosive welding is a non-conventional technique gaining popularity due to its ability to join dissimilar metals. The technique is very successful in achieving area joining by using the controlled energy of explosives which creates a metallurgical bond between two similar or dissimilar materials. This paper explains the technique of explosive welding for joining SS304 and AA6061 using pure aluminum (2 mm) as an interlayer. The joining was done in two stages. The explosive used is a mixture of Trimonite and salt having velocity of detonation (VOD) in the range of 1500-1600 m/sec. Ultrasonic testing showed good bonding over more than 80%. Micro-hardness variations as compared to parent materials have been evaluated along with microstructure study done to analyze the interface characteristics. SEM/EDS also have been used to check the presence of any possible brittle phases. Both the interfaces are found to be laminar, continuous, uniform and free from micro-cracks.

Abstract: This paper explains the technique of explosive welding for joining SS304 and Al 6061 using Copper interlayer. The joining was done in two stages. In the first stage SS304 (thickness: 20 mm) was joined to Copper (thickness: 3mm). Second stage involved joining of SS-Cu plate to Al 6061 (thickness: 8 mm).The paper presents detailed discussion on important parameters required for explosive welded process. The most important parameter is minimum and maximum flyer plate velocity required for creating the impact. Collision angle and angle of impact are also discussed. Another important parameter is the Velocity of detonation (VOD) of explosive to be used. The explosives used have VOD of the order of 2500 m/s and 1600 m/sec. Since the explosive welding process involves formation of jet between two surface, therefore surface conditions of the base and flyer plate like its flatness, roughness and cleanliness which are very critical for proper joining have been discussed in this paper. Chisel test (which is considered to be most rugged test) was conducted on the joint. The test confirmed successful joining.The paper explains how use of trimonite expands the weldability window in comparison to NGU when used for direct SS to Al alloy welding.It also compares the results obtained by use of two different powder explosives to obtain the same tri-layered plate via two different routes. The results are particularly interesting because both the explosives have substantial difference in their properties such as Velocity of Detonation, Gurney Characteristic Velocity, density and homogeneity which can be used as advantages from different angles of views.

Abstract: The main goal of the paper is development of a numerical model for explosive welding involving geometry and properties of major process components, i.e. base plate, flyer plate and explosive material. To properly replicate material behavior under these severe conditions the Coupled Eulerian Lagrangian (CEL) approach is used. Series of numerical simulations are realized based on the developed model in order to relate the process variables to the physical parameters. That will be used in further work to establish how these can be used to predict whether or not bonding will occur.

Abstract: Analysis of structural variations taking place at the stainless steel (09Cr18Ni10Ti) - bronze (CuBe2Ni) interface obtained by explosive welding was conducted in the current work. The produced weld joint was post heat-treated in the temperature range from 500 to 800 °С. Microstructural characterizations were carried out using optical and scanning electron microscopy. The results of the analysis revealed the presence of 2 zones at the interface: mixing zone of bronze and stainless steel and a diffusion zone. The diffusion processes in the weld joint during heating were studied by the energy-dispersive analysis (EDX). EDX studies revealed that at 800 °С copper contained in bronze completely migrated from the diffusion layer to the mixing zone whereas iron concentration, on the contrary, increased in the diffusion layer. Voids appeared in the mixing zone of stainless steel and bronze due to the difference of diffusion coefficients of basic elements in the composite.