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Power Screws, Fasteners, and Connections
Published in Ansel C. Ugural, Youngjin Chung, Errol A. Ugural, Mechanical Engineering Design, 2020
Ansel C. Ugural, Youngjin Chung, Errol A. Ugural
Metallic arc welding, the so-called shielded metal arc welding (SMAW), refers to a process where the heat is applied by an arc passing between an electrode and the work. The electrode is composed of suitable filler material with a coating ordinarily similar to that of base metal. It is melted and fed into the joint as the weld is being formed. The coating is vaporized to provide a shielding gas-preventing oxidation at the weld as well as acting as a flux and directing the arc. Either direct or alternating current can be used with this process. A weld thickness greater than about ⅜ A in. is often produced on successive layers. In metal inert gas arc welding or gas–metal arc welding (GMAW), heat is applied by a gas flame. In this process, a bare or plated wire is continuously fed into the weld from a large spool. The wire serves as an electrode and becomes the filler in the union. Uniform-quality welds are attainable with metal–gas welding.
Power Screws, Fasteners, and Connections
Published in Ansel C. Ugural, Youngjin Chung, Errol A. Ugural, MECHANICAL DESIGN of Machine Components, 2018
Ansel C. Ugural, Youngjin Chung, Errol A. Ugural
Metallic arc welding, the so-called shielded metal arc welding (SMAW), refers to a process where the heat is applied by an arc passing between an electrode and the work. The electrode is composed of suitable filler material with coating ordinarily similar to that of base metal. It is melted and fed into the joint as the weld is being formed. The coating is vaporized to provide a shielding gas-preventing oxidation at the weld as well as acts as a flux and directs the arc. Either direct or alternating current can be used with this process. A weld thickness greater than about 10 mm is often produced on successive layers. In metal–inert gas arc welding or gas–metal arc welding (GMAW), heat is applied by a gas flame. In this process, a bare or plated wire is continuously fed into the weld from a large spool. The wire serves as electrode and becomes the filler in the union. Uniform-quality welds are attainable with metal–gas welding.
Weld Design and Joining
Published in Zainul Huda, Manufacturing, 2018
Shielded Metal Arc Welding: The SMAW process involves the use of a stick electrode that is covered with an extruded coating of flux. The heat of the arc melts the flux coating that generates a gaseous shield to protect the molten pool against oxidation (see Figure 13.1). The flux ingredients react with unwanted impurities producing a slag that floats to the surface of the weld pool and forms a crust that protects the weld during cooling. When the weld is cold, the slag is chipped off.
Importance of shielding and mechanical characterization of GTAW on Ti-6AL-4V alloy sheet
Published in Welding International, 2023
Karpagaraj Anbalagan, Sarala Ramasubramanian, Charles David, S. Manivannan, A. Rajesh Kannan, Dhanesh G. Mohan
The literature on the welding of Ti-6Al-4V alloy sheets was limited. Available research reports mainly focus on implementing the beam welding (Laser and Electron beam) processes for joining Titanium and its alloys. Beam welding equipment was too costly, making it difficult to use for onsite work. To overcome this gap, low-cost welding processes like GTAW, Flux-Cored Arc Welding (FCAW), Shielded Metal Arc Welding (SMAW), and Gas Metal Arc Welding (GMAW) are developed for welding reactive materials and superalloys. In the present study, bead-on-plate trials were performed on 2 mm thick, Ti-6Al-4V sheets by the GTAW process with predetermined welding speed, current, and arc length. A customized shielding arrangement was employed to achieve excellent weld quality on titanium alloy. Based on the trials, an optimized parameter was identified, and defect-free butt joints were produced on 2 mm thin Ti-6Al-4V alloy sheets. This research investigated and analyzed the microstructure and mechanical properties of the welded joint.
Evaluation of the optimal strength and ductility of a mild steel arc welded plate based on the weld design
Published in Welding International, 2021
Samuel Oro-oghene Sada, Joseph Achebo, Kessinton Obahiagbon
In designing the weld, another requirement necessary in achieving the listed structural parameters is the choice of the welding process. According to [11,12], as strength level builds up, obtaining required impact toughness diminishes when arc welding processes such as shielded metal arc welding (SMAW), submerged arc welding (SAW), or flux-cored arc welding [FCAW) are employed. However, [13] record that with the tungsten inert gas (TIG] welding process, the welded zone exhibits an increase in its size at controlled heat input, making it more preferable than the metal inert gas (MIG) welding. The GTAW process is reputable for its stable and enhanced arc penetration, a major reason it is widely accepted in high-tech industries, aircraft maintenance, and many other fabrication works [14]. However, in GTAW the selection of the filler metal is important to ensure the production of good-quality weld joints. As [15] reports one major effect of the filler material, is the strong bond it creates between weld materials resulting from the weld pool of molten formed after solidification. Studies [16] reveal that the selection of unsuitable filler metal materials and joint designs have contributed immensely to the development of weak welds. Hence, to avoid variation in the weld performance, determining the filler metal and weld design with the most suitable effect on the ductile properties of the weld remains a very important task.
Application of Flaw Updating Process on Probabilistic Integrity Analysis for a Reactor Pressure Vessel Subjected to Pressurized Thermal Shocks
Published in Nuclear Technology, 2021
Hsoung-Wei Chou, Pin-Chiun Huang, Yuh-Ming Ferng
In VFLAW, the weld embedded flaw distributions in three weld materials are considered. They are submerged arc welding (SAW), shielded metal arc welding (SMAW), and repair welding. According to the inspection results of the PVRUF and Shoreham vessels, the parameters of uncertainty distributions of flaw depth and density for small and large flaws had been determined and written in the source code of VFLAW. The threshold between small and large flaws is 0.26 in. defined as a bead thickness of welds. Using the Matlab routine of NUREG-2163, Appendix C, the updated flaw distribution parameters per Bayesian inference process based on BVPS’s NDE results are produced. Table I presents the original and updated flaw depth and density uncertainties of small and large flaws. Figure 1 shows the prior and posterior distributions of flaw depth for the small flaw. It can be seen that the mean flaw depth decreased significantly after the updating process based on the NDE results because most detected flaws were smaller than 0.125 in. (102 in 103 flaws).17 Replacing the relevant parameters in the source code of VFLAW by the updated parameters listed in Table I and compiling them, the modified VFLAW that considers BVPS’s NDE results can be obtained.