Study on a Novel Electrical-Assisted Pressure Welding Process of Thin Metallic Foils

2012 ◽  
Vol 271-272 ◽  
pp. 147-151 ◽  
Author(s):  
Zhu Tian Xu ◽  
Lin Fa Peng ◽  
Pei Yun Yi ◽  
Xin Min Lai
Keyword(s):  
Stainless Steel ◽  
Electric Current ◽  
Room Temperature ◽  
Welding Process ◽  
Process Conditions ◽  
Pressure Welding ◽  
Metal Sheets ◽  
Effects Of Temperature ◽  
Metallic Foils ◽  
Joining Process

Joining of very thin metallic foils is required in vast applications such as fuel cell plates, micro reactor carriers, heat exchanger etc. Pressure welding is found to be an efficient method. However, some metals (e.g., stainless steel) are difficult to achieve successful solid state bond at room temperature. In present study, a novel electric assisted pressure welding (EAPW) process was proposed. In the EAPW process, electric current was introduced to the metal sheets under pressure welding in the purpose of reducing welding difficulty. An EAPW experimental setup was developed to study the joining process of Stainless Steel (SS) 316 sheets. The effects of electric current as well as process conditions on the final bond strength were experimentally studied. It was found that SS316 sheets could not be bonded without current at room temperature. However, they were successfully joined with electric current introduced. The co-effects of temperature and electric current were also investigated experimentally. It was found that elevated temperature caused by Joule heat is not the only reason for the improvement of the welding performance. The so-called electro-plastic effect also makes a contribution in EAPW process. Finite element method (FEM) was also employed to analyze the process and the welding behavior was discussed.

Characterization of Pressure Welding Process of Thin Sheet Metals in Cold and Warm Temperature Conditions

2007 ◽  
Author(s):  
Sasawat Mahabunphachai ◽  
Muammer Koc¸ ◽  
Jun Ni
Keyword(s):  
Stainless Steel ◽  
Bond Strength ◽  
Thin Sheet ◽  
Welding Process ◽  
Process Conditions ◽  
Sheet Metals ◽  
Pressure Welding ◽  
Temperature Levels ◽  
Copper Aluminum ◽  
Welding Pressure

The effects of material and process conditions in the pressure welding process of thin sheet metals on the minimum welding pressure and the final bond strength are investigated in this work. The studied parameters include the material type (copper, aluminum, nickel, and stainless steel), initial blank thickness (0.051–0.254 mm), welding pressure, welding temperature (25–300°C), surface condition (wet, dry, and brushed), and indenter size. Two sets of pressure welding apparatus were developed for testing of different materials and process conditions. Based on the experimental results, copper, aluminum, and nickel blanks were successfully bonded at room temperature (“cold welding”), while stainless steel blanks could only be joined at elevated temperature levels (150 and 300°C). The material type (i.e. strength) and thickness were shown to have significant impact on the welding pressure; in that more pressure is required to bond the blanks with higher strength or thinner. To reduce the required welding pressure, the process can either be carried out at elevated temperature levels or by scratch brushing the surfaces to be joined. In this study, the bond strength of the welded blanks was measured using tensile testing. The tensile test results showed that the bond strength could be increased by either scratch brushing the surfaces or by increasing the welding pressure or temperature. However, the increase in bond strength by increasing welding pressure was shown to have an optimal point, after which the bond strength would decrease with further increase in pressure. This critical pressure value appeared to be dependent on the material and process conditions. The width of the straight line indenter showed no significant impact on the minimum welding pressure. Finally, the bond formation mechanisms for different materials were studied through microscopic analyses. The microscopy images of the weld spots showed that for the bonding to take place, the contaminant layers at the surfaces must be removed or broken to allow the virgin metal underneath to be extruded through. The metallic bonds only form at these locations where both surfaces are free of contaminant layers.

Flow Stress Experimental Determination for Warm-Forming Process

2011 ◽  
Author(s):  
Ting Fai Kong ◽  
Luen Chow Chan ◽  
Tai Chiu Lee
Keyword(s):  
Stainless Steel ◽  
Flow Stress ◽  
Room Temperature ◽  
Warm Forming ◽  
Recrystallization Temperature ◽  
Process Conditions ◽  
Compression Tests ◽  
Forming Process ◽  
Forming Temperature ◽  
Flow Stress Data

Warm forming is a manufacturing process in which a workpiece is formed into a desired shape at a temperature range between room temperature and material recrystallization temperature. Flow stress is expressed as a function of the strain, strain rate, and temperature. Based on such information, engineers can predict deformation behavior of material in the process. The majority of existing studies on flow stress mainly focus on the deformation and microstructure of alloys at temperature higher than their recrystallization temperatures or at room temperature. Not much works have been presented on flow stress at warm-forming temperatures. This study aimed to determine the flow stress of stainless steel AISI 316L and titanium TA2 using specially modified equipment. Comparing with the conventional method, the equipment developed for uniaxial compression tests has be verified to be an economical and feasible solution to accurately obtain flow stress data at warm-forming temperatures. With average strain rates of 0.01, 0.1, and 1 /s, the stainless steel was tested at degree 600, 650, 700, 750, and 800 °C and the titanium was tested at 500, 550, 600, 650, and 700 °C. Both materials softened at increasing temperatures. The overall flow stress of stainless steel was approximately 40 % more sensitive to the temperature compared to that of titanium. In order to increase the efficiency of forming process, it was suggested that the stainless steel should be formed at a higher warm-forming temperature, i.e. 800 °C. These findings are a practical reference that enables the industry to evaluate various process conditions in warm-forming without going through expensive and time consuming tests.

scholarly journals Electric current effect on mechanical properties of SMAW-3G on the stainless steel AISI 304

2018 ◽  
Vol 197 ◽  
pp. 12003
Author(s):  
Edi Widodo ◽  
Iswant Iswanto ◽  
Mirtza Adi Nugraha ◽  
Karyanik Karyanik
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Tensile Test ◽  
Electric Current ◽  
Welding Process ◽  
Welding Current ◽  
Test Results ◽  
Aisi 304 ◽  
Steel Aisi ◽  
Stainless Steel Aisi

Parameters in the welding need to be known because the effect on the mechanical properties of the material after the welding process. This research purposes to find out the influence of variation of SMAW welding current on Stainless Steel AISI 304, with variation of electric current equal to 70A, 80A and 90A.The electrode of AWS A5.4 E308-16 with diameter of 2.6 mm is used. Dye penetrant test, tensile test and metallographic test applied to analysis the characteristic. Based on data from tensile test results obtained the highest value on the specimen welding current 90A is equal to 632 MPa. The lowest tensile strength value recorded on the specimens of current 70A is 498.66 MPa.

scholarly journals Analysis of the Effect of Ultrasonic Welding on Microstructure

2018 ◽  
Vol 1 (1) ◽  
pp. 49-52
Author(s):  
Tünde Kovács ◽  
Péter Pinke
Keyword(s):  
Mechanical Properties ◽  
Cold Rolling ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Grain Structure ◽  
Welding Parameters ◽  
Recrystallization Process ◽  
Thin Sheets ◽  
Metal Sheets ◽  
Joining Process

Abstract Ultrasonic welding is very useful for joining thin metal sheets [1, 2]. The effect of ultrasound on microstructure is currently not well understood because the changes produced depend very much on the welding parameters and the properties of the metal being considered. Thin sheets formed by cold rolling acquire a special grain structure. During the welding process the heat produced causes recrystallization; even where heat is not applied in the joining process the recrystallization process alters the mechanical properties within the heat affected zone (HAZ). The mechanical properties of the welded samples depend on the microstructure. In this work we analyse the ultrasonic welding effect on the joint and the HAZ [3, 4].

Pressure Welding of Thin Sheet Metals: Experimental Investigations and Analytical Modeling

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Sasawat Mahabunphachai ◽  
Muammer Koç ◽  
Jun Ni
Keyword(s):  
Stainless Steel ◽  
Elevated Temperature ◽  
Bond Strength ◽  
Thin Sheet ◽  
Sheet Thickness ◽  
Process Conditions ◽  
Sheet Metals ◽  
Pressure Welding ◽  
Temperature Levels ◽  
Welding Pressure

Emerging applications, such as fuel cell, fuel processor, heat exchanger, microreactors, etc., require joining of thin metallic plates in confined places with small dimensions and minimal damage to the surrounding areas. In this study, the feasibility and modeling of pressure welding (solid state bonding) process are investigated, specifically for bonding of thin sheet metals. The effects of material type (e.g., copper, nickel, and stainless steel) and initial plate thickness (51–254 μm) as well as process conditions (e.g., welding pressure and temperature, 25–300°C) on the minimum welding pressure and the final bond strength are experimentally studied. A pressure welding apparatus was developed for testing of different materials and process conditions. Based on the experimental results, the effects of material and process conditions on the final bond quality are characterized. At room temperature, copper and nickel blanks were successfully bonded, while stainless steel blanks could only be joined at elevated temperature levels (150°C and 300°C). The material type (i.e., strength) and thickness were shown to have significant impact on the welding pressure; in that more pressure is required to bond the blanks with higher strength or thinner. To reduce the required welding pressure, the process can be carried out at elevated temperature levels. In this study, the bond strength of the welded blanks was characterized with uniaxial testing. The tensile test results showed that the bond strength could be increased by increasing the welding pressure or temperature. However, the increase in bond strength by increasing the welding pressure was shown to have an optimal point, after which the bond strength would decrease with further increase in pressure. This critical pressure value was found to be dependent on the material and process conditions. In addition, bond formation mechanisms for different materials were studied through microscopic analyses. The microscopy images of the weld spots showed that for a successful bonding to take place, the contaminant layers at the surfaces must be removed or broken to allow the virgin metal underneath to be extruded through. The metallic bonds only form at these locations where both surfaces are free of contaminant layers. Finally, a model for bond strength prediction in pressure welding was developed and validated. This model includes the sheet thickness parameter, which is shown to be a critical factor in bonding thin sheet metals with the sheet thickness in the range of a few hundred micrometers.

scholarly journals Thermo-Mechanical Characterization of Laser Weld 316L(N) Stainless Steel

2013 ◽  
Vol 3 (1) ◽  
pp. 77 ◽  
Author(s):  
D. Harish Kumar ◽  
A. Somi Reddy ◽  
P. Parameswaran ◽  
T. Jaya Kumar ◽  
M. Nandagopal ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Welded Joints ◽  
Room Temperature ◽  
Welding Process ◽  
Solid Solution Hardening ◽  
Nitrogen Laser ◽  
Deformation Bands ◽  
High Temperature Mechanical Properties ◽  
Transmission Electron

316L(N) stainless steel is an austenitic stainless steel variety strengthened by nitrogen through solid solution hardening. The effects of nitrogen on the mechanical properties of 316L(N) SS have not been studied extensively in the past and is the study of current research. The nitrogen content when added to 316L stainless steel in the range 0.07 wt% - 0.21 wt% improves room temperature and high temperature mechanical properties. The loss in strength due to reduced carbon content in 316L(N) SS can be more or less compensated by the addition of nitrogen. Laser welded joints have been fabricated on 316(L)N SS using CO2 laser protecting the environment by employing nitrogen shielding and tested the welded joints under tension at room temperature and at 650 ?C (923 K). In the as - welded condition Transmission Electron Microscope (TEM) revealed the presence of the deformation bands, high density of dislocations and carbides or carbo -nitrides on dislocations near the grain boundary regions which may be in the Heat-Affected Zone(HAZ). At both the test temperatures failure occurred in the base metal by transgranuler mode with the nucleation of cavities. In the present work, laser welding process has proved to be effective in producing satisfactory welded joints.

scholarly journals Effects of temperature on COVID-19 transmission

2020 ◽  
Author(s):  
Shrikant Pawar ◽  
Aditya Stanam ◽  
Mamata Chaudhari ◽  
Durga Rayudu
Keyword(s):  
Infectious Disease ◽  
Stainless Steel ◽  
Mortality Rate ◽  
Room Temperature ◽  
Chinese Patients ◽  
Mode Of Transmission ◽  
Effects Of Temperature ◽  
Human Coronaviruses ◽  
Respiratory Droplets ◽  
The Relationship

AbstractCoronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), it was first identified in 2019 in Wuhan, China and has resulted in the 2019–20 coronavirus pandemic. As of March 1, 2020, 79,968 patients in China and 7169 outside of China had tested positive for COVID-19 and a mortality rate of 3.6% has been observed amongst Chinese patients. Its primary mode of transmission is via respiratory droplets from coughs and sneezes. The virus can remain viable for up to three days on plastic and stainless steel or in aerosols for upto 3 hours and is relatively more stable than the known human coronaviruses. It is stable in faeces at room temperature for at least 1-2 days and can be stable in infected patients for up to 4 days. Heat at 56°C kills the SARS coronavirus at around 10000 units per 15 minutes. Thus, temperature is an important factor in survival of COVID-19 virus and this article focuses on understanding the relationship between temperature and COVID-19 transmission from the data available between January-March 2020.

Metodología para el desarrollo de trayectorias en la aplicación por el proceso de soldadura GMAW en un robot industrial

2019 ◽  
pp. 1-4
Author(s):  
Josué Rafael Sánchez-Lerma ◽  
Luis Armando Torres-Rico ◽  
Héctor Huerta-Gámez ◽  
Ismael Ruiz-López
Keyword(s):  
Mechanical Properties ◽  
Automotive Industry ◽  
Industrial Robot ◽  
Welding Process ◽  
High Strength ◽  
Test Material ◽  
Advantages And Disadvantages ◽  
Application Characteristics ◽  
Joining Process ◽  
Gmaw Welding

This paper proposes the development of the methodology to be carried out for the metal joining process through the GMAW welding process in the Fanuc LR Mate 200iD industrial robot. The parameters or properties were considered for the application to be as efficient as possible, such parameters as speed of application, characteristics of the filler material, gas to be used as welding protection. The GMAW welding process can be applied semiautomatically using a hand gun, in which the electrode is fed by a coil, or an automatic form that includes automated equipment or robots. The advantages and disadvantages of the GMAW welding process applied in a manual and automated way were commented. The mechanical properties of the materials to which said welding can be applied were investigated; The materials with which this type of welding can be worked are the high strength materials, which are used in the automotive industry, for the forming of sheet metal. To know the properties of the material, destructive tests were carried out on the test material to be used, as well as the mechanical properties of the welding.

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