Torch Brazing Research Articles

Microstructure, Mechanical Properties, and Heat Distribution ANSYS model of CP Copper and 316 Stainless Steel Torch Brazing

Microstructure, Mechanical Properties, and Heat Distribution ANSYS model of CP Copper and 316 Stainless Steel Torch Brazing

Effect of gap clearance on the mechanical properties of weld-brazed lap joints

Gas metal arc brazing (GMAB) is a non-fusion joining process used in the automotive industry for joining thin-gauge Zn-coated steel sheets to other steels or dissimilar metals. Unlike torch brazing, GMAB does not rely on capillary action to form a joint. Consequently, gap clearance has not been considered important for lap joining applications. In this study, the effect of gap clearance on the mechanical properties of arc-brazed lap joints was investigated experimentally and verified using finite element modeling (FEM). The results showed that the gap clearance of lap joints played a critical role in controlling the joint strength.

Microstructural Evaluation of Copper Brazed Joints Using Silver-Based Filler Metal

The oxy-acetylene torch brazing of copper tubes using silver-based filler metals (Ag-Cu-Zn-Cd) was investigated in this study. Filler metals containing silver content of 15% and 35%, designated by BR15 and BR35, were used to assess the influence of the silver content in the microstructure and mechanical performance of brazed joints. The brazed joints microstructure was analyzed by means of optical microscopy, scanning electron microscopy, and energy-dispersive spectroscopy. The microstructures of the BR15 and BR35 samples were composed mainly of Ag–Cd-rich phase, solid solution of Cu–Zn, and a eutectic structure of Ag and Cu. The increase in the Ag content changed the solidification mode from cellular to dendritic and caused an increase in the eutectic phase volume fraction. The tensile strength of the Ag–Cu–Zn–Cd filler and the phos–copper filler metals was compared. The tensile strength of silver-based filler metal was slightly higher than the phos–copper filler metal brazed joints.

Al-Si-Zn Behaviouron Interface of AR500 Steel and AA7075 Aluminium Alloy BrazedJoint

The brazing of steel and aluminium alloy using low melting point aluminium based fillers has been extensively studied and the technique has been used in many industries, especially the automotive industry. The strength and failure mode of AR500 steel and AA7075 aluminium alloy brazing joint using the Al-Si-Zn filler metal will be measured and calculated in this paper. However, the adverse effect of intermetallic phases formation on the joint strength has limited the application of this joining method.These dissimilar metals possessing a high strength joint would be of benefit to industry especially in reducing the weight of products. The torch brazing method using Al-Si-Zn base filler metal wasused to join AR500 steel and AA7075 aluminium alloy in this study. The intermetallic phase formation of the brazing on was investigated by scanning electron microscopy and the mechanical strength of the joints was evaluated by shear testing, flexural testing and low velocity impact testing. A maximum shear load of 6460 N was obtained. The presence of intermetallic phases was found to have some effect on the strength of the brazed joint. However, overall, this brazing process using Al-Si-Zn filler metal facilitates the joining of these dissimilar metals to improve the mechanical properties of the joint

A Study on the Wetting Behaviour of Al-Si-Zn Brazing Filler on AA7075 and AR500 Surface

This paper presents the results of an experimental study on wetting and spreading of Al-Si-Zn filler metal on AR500 steel and AA7075 aluminium alloy surface. Wetting and spreading conditions of filler metal onto the surface of the metal were analysed by contact angle and spread ratio with different surface conditions. The contact angle is the measured angle between the tangent to the liquid-vapour interface and the surface of the solid. While, spread ratio measured according to the change in diameter of spread shape geometry of filler metal. The use of the low melting temperature of filler metal is increasingly popular since they are able to reduce the effect of heat on metals. However, the low spreading and de-wetting condition have limited the application of filler metal due to the adverse effect of these conditions on the joint ability. However, overall, this study with different surface conditions of these metals is to identify the wetting and spreading behaviour of filler metal. In this work, Al-Si-Zn filler metal heated by torch brazing was applied to AR500 steel and AA7075 aluminium alloy surface with the different type of surface conditions. Experimental results showed that the higher spreading area of filler metal occurred on a smooth surface compared to the rough surface of metals.

Tailoring of Microstructures and Tensile Properties in the Solidification of Al-11Si(-xCu) Brazing Alloys

Ternary Al-11wt %Si-(xwt %)Cu alloys are highly recommended as commercial filler metals for aluminum brazing alloys. However, very little is known about the functional inter-relations controlling the solidified microstructures characterizing processes such as torch and furnace brazing. As such, we evaluated two commercial brazing alloys, which are the Al-11wt %Si-3.0wt %Cu and Al-11wt %Si-4.5wt %Cu alloys: Cu contents typically trend in between the suitable alloying spectrum. We analyzed the effects of solidification kinetics over features such as the dendrite arm spacing and the spacing between particles constituting the eutectic mixture. Also, tensile properties were determined as a function of the dendrite microstructure dimensions. The parameters concerned for translating the solidification kinetics were either the cooling rate, or growth velocity related to the displacement of the dendrite tip, or the eutectic front. The relevant scaling laws representing the growth of these brazing alloys are outlined. The experimental results demonstrated that a 50% increase in Cu alloying (from 3.0 to 4.5 wt %) could be operated in order to obtain significant variations in the dendritic length-scale of the microstructure across the produced parts. Overall, the microstructures were constituted by an α-Al dendritic matrix surrounded by a ternary eutectic consisting of α-Al + Al2Cu + Si. The scale measurements committed to the Al2Cu eutectic phase pointed out that the increase in Cu alloying has a critical role on refining the ternary eutectic.

Effect of Post-Braze Heat Treatment on the Microstructure and Shear Strength of Cemented Carbide and Steel Using Ag-Based Alloy

The aim of the present study was to investigate the effect temperature of heat treatment process on the interfacial microstructure and mechanical properties of cemented carbide/carbon steel single lap joint brazed using Ag based alloy filler metal. The brazing process was carried out using torch brazing. Heat treatment process was carried out in induction furnace on the temperature of 700, 725, and 750°C, for 30 minutes. Microstructural examinations and phase analysis were performed using scanning electron microscopy (SEM) equipped with energy dispersion spectrometry (EDS). Shear strength of the joints was measured by the universal testing machine. The results of the microstructural analyses of the brazed area indicate that the increase temperature of treatment lead to the increase of solid solution phase of enrichted Cu. Based on EDS test, the carbon elements spread to all brazed area, which is disseminated by base metals. Shear strength joint is increased with temperature treatment. The highest shear strength of the brazed joint was 214,14 MPa when the heated up at 725°C.

Multi-objective optimization of an aluminum torch brazing process by means of genetic programming and R-NSGA-II

This paper presents a hybrid of genetic programming (GP) and reference-point-based non-dominated sorting genetic algorithm (R-NSGA-II) for the multi-objective optimization of an aluminum torch brazing process for the fabrication of condensers for the automotive industry. The objectives to be optimized are a vacuum leakage test (quality of product), cycle time, and energy consumption (production cost). GP is used to find a mathematical model that describes the relationship between input and output process parameters. Thereafter, reference-point-based NSGA-II procedure is employed to provide the decision maker with a set of solutions close to her/his preferences. Results show that this approach may support the decision makers of the process to set the optimal input process parameters in order to achieve competitive advantages in quality and production costs.

Effect of Filler and Heat Treatment on the Physical and Mechanical Properties of the Brazed Joint between Carbide Tip and Steel

In this study, the effect of filler and heat treatment on the physical and mechanical properties of the brazed joint carbide tip and steel was investigated. Tip carbide YG6 and low carbon steel (SS400) is joining by torch brazing with two filler metals, silver, and copper filler. Heat treatment was performed in induction furnace. Microstructure and shear strength of the brazed joint have been investigated. Many silver filler layer are formed on the surface of the base metal rather then using copper filler. The highest shear strength is achieved using a silver filler metal at temperatur 725°C. The highest shear load is 18.62 kN.

INVESTIGATION ON BRAZING INTERFACE BONDING CHARACTERISTIC OF AA7075 AND AA6061 ALUMINUM ALLOY WITH AR500 STEEL USING Al-Si-Zn FILLER METAL

This paper presents the study on interface bonding characteristic of AA7075 and AA6061 aluminum alloy with AR500 steel by torch brazing bonding process. The weight reduction in vehicles component is required for energy saving in the automobile industry. Lightweight metals such as aluminum joining with other metal especially with steel, have started replaced steel parts in automobile structures but the effect of intermetallic compound (IMC) layer formation have limited the application in this industry due to strength matter. The torch brazing method was done to join the dissimilar metal with Al-Si-Zn base filler metal for the process. The shear strength of the AA6061/AR500 joint was higher than the AA7075/AR500 joint when the joining conditions were the same. The IMC formation was observed at the joint interface, and the joints mainly fractured at this region.

Thermal and Residual Stress Analysis on A36 Steel Plate Brazed with a Known Volume of Zn50 Brazing Alloy (Filler Metal)

The simulation of heat flow, residual stress, and thermal distortion developed in A36 steel plate using a known volume of Zn50 brazing alloy for torch brazing technique is presented in this paper. FEHT software and GTstrudle codes were used for the heat transfer and residual stress simulation, respectively. The result of the heat flow simulation showed excessive cooling at the joints corner following convective heat loss to the ambient and maximum heat flux gradient thereby making the joint predisposed to underfill. Also the von misses stress and strain distribution in the plate showed that the residual stress is compressive and is limiting at 1800 N/mm2, localized in the joint. This is a basic understanding for impedance to thermally induced cracking.

Effect of Pressure and Length of Lap Joint on Shear Load and Joint Clearance during Dissimilar Metal Joining using Torch Brazing for the Shipping Industry

Effect of Pressure and Length of Lap Joint on Shear Load and Joint Clearance during Dissimilar Metal Joining using Torch Brazing for the Shipping Industry

Effect of Pressure and Length of Lap Joint on Shear Load and Joint Clearance during Dissimilar Metal Joining using Torch Brazing for the Shipping Industry

Effect of Pressure and Length of Lap Joint on Shear Load and Joint Clearance during Dissimilar Metal Joining using Torch Brazing for the Shipping Industry

A Primary Study of Torch Brazing Pure Aluminum with Al-Si-Ge-Zn Solders

Based on the difficulty to accurately control temperature for torch brazing, the study is concerned with developing low-melting-point solders for brazing pure aluminum. For this purpose, Ge and Zn have been chosen to be added to Al-Si-based alloy. The melting characteristic, wetting property of solders with Al and mechanical property of the brazed joints were investigated. The results show that the addition of 10 wt. % germanium into the traditional Al-12Si (wt. %) filler metal causes its liquidus temperature to decrease by about 23 °C. An addition of 30 % zinc into such Al-Si-Ge ternary alloy will cause its liquidus temperature to drop further to 525 °C. The solders have good wettability with Al. With the increase of Zn content in the alloys, the spreading areas of solders exhibit nonlinear decrease, and there exist a very large value at the zinc content of 15%. When Al-Si-10Ge-30Zn solder was used to braze the pure aluminum, an optimized bonding strength of 116 MPa was achieved.

Development of Pressure Torch Brazing System

This study is to develop the process of torch brazing system which transmits the pressure on the workpiece to be brazed. Mechanical stress is given by 0, 0.7, 1.2 and 1.7 MPa. When the filler melts, it cause mechanical pressure to push each sample and cause a reduction in the thickness of the filler. The higher the static pressure is given, the smaller thickness of the filler. Therefore, when the sample is heated, stainless steel expands and resulting thermal stresses. The thinner the thickness of the filler due to mechanical pressure will result in the interaction distance is getting smaller. And with the same thickness of the filler, it will result in greater thermal stress with the increasing mechanical pressure. So the displacement will increase along with the amount of mechanical stress given. By giving stress on the joining process it will affect the joint brazed connections clearance. With the change in the joint clearance will certainly affect the strength of the connection as well. The study was conducted to investigate the effect of the pressure on the strength of joint.

Multiobjective optimization of torch brazing process by a hybrid of fuzzy logic and multiobjective artificial bee colony algorithm

This paper describes an application of a hybrid of fuzzy logic (FL) and multiobjective artificial bee colony algorithm (MOABC) for optimizing the torch brazing process of aluminum in the fabrication of condensers in the automotive manufacturing industry of Juarez, Mexico. This work aims to show how artificial intelligence is being applied in the manufacturing sector of Mexico for optimizing processes leading to cost reduction. The approach consists of using FL as surrogate model of the brazing process; after, MOABC is applied to find the nondominated solutions for leak rate which is a quality test of the condenser and production time. Results show the use of artificial intelligence is an excellent tool for optimizing manufacturing processes leading to improve productivity, mainly in the selected region, where this type of methodologies are fairly new in applicability.

Sn含量对银钎料焊接性的影响

通过往Ag-Cu-Zn系钎料内添加适量的Sn和Ni元素，利用OM、SEM、XRD研究了钎料内Sn含量对钎料组织与焊接性能的影响。结果表明：Ag-Cu-Zn系钎料内主要成分为：Ag基固溶体；Cu基固溶体；CuZn化合物；当Sn含量达到4 wt%时，出现少量的Ag2Cu2O化合物。在本研究设计的成分范围内，钎料内并未出现Cu-Sn金属间化合物。差热分析表明：随着Sn含量的增加，钎料的固液相线温度均出现不同程度的下降。润湿试验表明：相同的加热温度下，不同Sn含量的银钎料均可对不锈钢形成良好的润湿。此外，采用该系列钎料手工火焰钎焊了不锈钢与不锈钢，得到的接头内母材/钎料界面处形成了致密的连接，无缺陷存在；当Sn含量为3.0 wt%时，得到接头的最高拉伸强度达到了450 MPa；当Sn含量超过3.0 wt%时，由于钎料内少量氧化物的存在使接头性能出现大幅度下降。 Sn and Ni element were introduced into Ag-Cu-Zn filler alloy, and the effect of Sn content on microstructure and brazing properties of Ag based filler alloy was analyzed by OM, SEM and XRD. The results indicated that the Ag-Cu-Zn filler alloy was mainly comprised of Ag based solid solution, Cu based solid solution and CuZn compounds. A trace amount of Ag2Cu2O occurred in the filler alloy while the content of Sn exceeded 4 wt% in the filler. However, the Cu-Sn intermetallics were not detected in the range of composition in the research. By using DSC analysis, the melting temperature of the filler alloy was decreased with increasing Sn content. The wettability test showed that the stainless steel could be wetted by the Ag-Cu-Zn based filler alloy with different Sn content. Besides, this kind of filler alloy was used to join stainless steel by torch brazing, and a compact bonding could be obtained at the substrates/filler alloy interface. The maximum joint strength could reach 450 MPa while the filler contained 3.0 wt% Sn element. While the content of Sn exceeded 3.0 wt% in the filler, the joint strength decreased sharply due to the existence of few oxides.

Microstructure and phase constitution near the interface of Cu/3003 torch brazing using Al-Si-La-Sr filler

It has been mainly studied in this paper on brazing of Cu to Al using Al-Si filler metal. The optimized scanning rate of 2.5 mm/s is first obtained through simulating the temperature field of Cu-Al brazing process based on ANSYS software. Then the brazing of Cu-C11000 to Al-3003 using Al-Si-La-Sr filler is carried out by torch brazing technology. It is found that the brazing seam region is mainly consisted of α-Al solid solution and CuAl2 IMC. Further experimental results also show that the rare earth element La in filler metal can not only refine the grain, but also promote the dispersion of intermetallic compounds into the brazing seam, which significantly improves the brazing seam microstructure and mechanical properties of the joints.

Torch brazing 3003 aluminum alloy with Zn—Al filler metal

Using Zn—Al filler metal with Al content of 2%–22% (mass fraction) and improved CsF–AlF3 flux, wetting properties of Zn–Al filler metal on 3003 Al substrate were investigated. The mechanical property as well as the microstructure of the brazed joints was also studied. The results indicate that excellent joints can be produced by means of torch brazing when the Al content is less than 8%. The metallographic structure in the brazing seam is mainly composed of Al based solid solutions and Zn based solid solutions. The high hardness value of brazing seam of the 3003 aluminum alloy is higher than that of the base metal due to the effect of solid solution strengthening. The results also show that three microstructure zones could be found at the brazing interface; i.e., base metal, diffusing zone and interface zone. The distribution of the solid solution in the brazing seam is the main factor of the tensile strength rather than the diffusion zone width near the interface.

Effect of plasma welding parameters on the flexural strength of ti-6al-4v alloy

The aim of this study was to assess the effect of different plasma arc welding parameters on the flexural strength of titanium alloy beams (Ti-6Al-4V). Forty Ti-6Al-4V and 10 NiCr alloy beam specimens (40 mm long and 3.18 mm diameter) were prepared and divided into 5 groups (n=10). The titanium alloy beams for the control group were not sectioned or subjected to welding. Groups PL10, PL12, and PL14 contained titanium beams sectioned and welded at current 3 A for 10, 12 or 14 ms, respectively. Group NCB consisted of NiCr alloy beams welded using conventional torch brazing. After, the beams were subjected to a three-point bending test and the values obtained were analyzed to assess the flexural strength (MPa). Statistical analysis was carried out by one-way ANOVA and Tukey's HSD test at 0.05 confidence level. Significant difference was verified among the evaluated groups (p<0.001), with higher flexural strength for the control group (p<0.05). No significant differences was observed among the plasma welded groups (p>0.05). The NCB group showed the lowest flexural strength, although it was statistically similar to the PL 14 group (p>0.05). The weld depth penetration was not significantly different among the plasma welded groups (p=0.05). Three representative specimens were randomly selected to be evaluated under scanning electron microcopy. The composition of the welded regions was analyzed by energy dispersive X-ray spectroscopy. This study provides an initial set of parameters supporting the use of plasma welding during fabrication of titanium alloy dental frameworks.