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Formation and Distribution of Porosity in Al-Si Welds
Formation and Distribution of Porosity in Al-Si Welds by Pierre-Alexandre LEGAIT A Thesis Submitted to the Faculty Of the WORCESTER POLYTECHNIC INSTITUTE In partial fulfillment of the requirements for the Degree of Masters of Science In Material Science and Engineering By May 2005 APPROVED: Diran Apelian, Howmet Professor of Mechanical Engineering, Advisor Richard D. Sisson Jr., George F. Fuller Professor of Mechanical Engineering Material Science and Engineering, Program Head ABSTRACT Aluminum alloys are the subject of increasing interest (in the automotive industry, as well as aircraft industry), aiming to reduce the weight of components and also allowing a profit in term of energy saving. Concerning the assembly, riveting has been widely used in the aircraft industry, whereas welding seems to be promising in the car industry in the case of aluminum alloys. Nevertheless, welding can generate defects, such as porosity or hot cracking, which could limit its development. One of the major problems associated with the welding of aluminum alloys is the formation of gas porosity. Aluminum alloy cleanliness remaining one of the aluminum industry’s primary concerns, this project focuses on the formation and distribution of porosity in Al-Si welds. A literature review has been performed, to identify the mechanisms of porosity formation in welds and castings. Porosity distribution in welds has been investigated, based on three different welding techniques: hybrid Laser/MIG welding process, the electron beam welding process, and the MIG dual wire welding process. Porosity distribution results provide information on to the porosity formation mechanisms involved during welding. A complete microstructure, microhardness and EDX analysis have been carried out, to describe and quantify the solidification process within the welds. -
Parameter Optimization of Gas Metal Arc Welding Process on Duplex 2205 Stainless Steel Using Irb1410 Arc Welding Robot
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 08 Issue: 03 | Mar 2021 www.irjet.net p-ISSN: 2395-0072 PARAMETER OPTIMIZATION OF GAS METAL ARC WELDING PROCESS ON DUPLEX 2205 STAINLESS STEEL USING IRB1410 ARC WELDING ROBOT Anand Jayakumar A1, Yash Nigam2, Vighneswaran C3, Surender S4 1Asst. Professor, Dept. of Mechanical Engineering, Sri Ramakrishna Institute of Technology, India 2,3,4Student, Dept. of Mechanical Engineering, Sri Ramakrishna Institute of Technology, India ---------------------------------------------------------------------***---------------------------------------------------------------------- Abstract - This review paper outline the recent research consumable MIG wire electrode and the workpiece metal(s), works on parameter optimization of duplex 2205 stainless which will heats the workpiece metal(s), causing them to steel using IRB1410 arc welding robot. Gas metal arc welding melt and join. Gas metal arc welding, also known as metal (GMAW) process has widely been employed due to the wide inert gas (MIG) welding, uses a continuous solid wire range of applications, cheap consumables and easy handling. A electrode that travels through the welding gun, which is suitable model is needed to investigate the characteristics of accompanied by a shielding gas to protect it from the effects of process parameters on the bead geometry in the contaminants. Gas metal arc welding (GMAW) is a welding GMA welding process in order to achieve a high level of processby an arc in which the source of heat is an arc is welding performance and quality. This paper is intended to formed between the consumable metal electrode and the represent new algorithms in the robotic GMA welding process work piece with an externally supplied gaseous shield of to predict process parameters on top-bead distance. -
GSS-124 Welding Fabrication for Gunsmiths 1.0 Unit
Lassen Community College Course Outline GSS-124 Welding Fabrication for Gunsmiths 1.0 Unit I. Catalog Description Students will select and fabricate gunsmith related projects using appropriate welding processes and techniques. Students will also have an opportunity to learn or improve welding skills related to the gunsmith vocation. Does Not Transfer to UC/CSU 50 Hours Lab Scheduled: II. Coding Information Repeatability: Take 1 Time Grading Option: Pass/No Pass Only Credit Type: Credit - Not Degree Applicable TOP Code: 095650 III. Course Objectives A. Course Student Learning Outcomes Upon completion of this course the student will be able to: Safely handle equipment to gas tungsten weld selected joint designs to critical industry standards. B. Course Objectives Upon completion of this course the student will be able to: 1. Explain the setup of both oxygen/acetylene welding and cutting. 2. Demonstrate correct project layout. 3. Demonstrate oxy/ace cutting. 4. Employ oxygen/acetylene welding to construct project. 5. Demonstrate setup of SMAW machine. 6. Identify and select correct electrodes. 7. Fabricate project using SMAW. 8. Demonstrate cleanup procedures. IV. Course Content A. Safety precautions 1. Electrical shock 2. Radiation hazards 3. Compressed gases 4. Air contamination 5. Emergency shop procedures B. Oxyacetylene welding 1. T-joints 2. Open butt joint - flat C. Shielded metal arc welding 1. T-joint - flat 2. T-joint - vertical GSS-124 Welding Fabrication for Gunsmiths Page 1 D. Gas metal arc welding 1. T-joint - flat 2. T-joint - vertical E. Gas tungsten arc welding 1. T-joint - flat 2. T-joint - vertical F. Cutting 1. -
Guidelines for the Welded Fabrication of Nickel-Containing Stainless Steels for Corrosion Resistant Services
NiDl Nickel Development Institute Guidelines for the welded fabrication of nickel-containing stainless steels for corrosion resistant services A Nickel Development Institute Reference Book, Series No 11 007 Table of Contents Introduction ........................................................................................................ i PART I – For the welder ...................................................................................... 1 Physical properties of austenitic steels .......................................................... 2 Factors affecting corrosion resistance of stainless steel welds ....................... 2 Full penetration welds .............................................................................. 2 Seal welding crevices .............................................................................. 2 Embedded iron ........................................................................................ 2 Avoid surface oxides from welding ........................................................... 3 Other welding related defects ................................................................... 3 Welding qualifications ................................................................................... 3 Welder training ............................................................................................. 4 Preparation for welding ................................................................................. 4 Cutting and joint preparation ................................................................... -
Analysis of Metal Transfer in Gas Metal Arc Welding
Analysis of Metal Transfer in Gas Metal Arc Welding This study shows that the transition of metal transfer mode in gas metal arc welding occurs much more gradually than is generally believed BY Y-S. KIM AND T. W. EAGAR ABSTRACT. Droplet sizes produced in transfer. These transfer modes show dif- metal transfer phenomenon. These have GMAW are predicted using both the ferent arc stabilities, weld pool penetra- had limited success. static force balance theory and the pinch tions, spatter production, porosity pop- In this study, the droplet size and instability theory as a function of weld- ulation and level of gas entrapment. droplet transfer frequency are analyzed ing current, and the results are compared Lesnewich (Ref. 1) showed that the mode both theoretically and experimentally. with experimental measurements. The of metal transfer depends on many op- In the first section of this paper, the equi- causes for the deviation of predicted erational variables such as welding cur- librium drop sizes are calculated using droplet size from measured size are dis- rent, electrode extension, electrode di- the static force balance analysis and the cussed with suggestions for modification ameter and polarity. Later, A. A. Smith pinch instability analysis. In the second of the theories in order to more accu- (Ref. 2) reported that an entirely differ- section of this paper, measurements of rately model metal transfer in GMAW. ent type of metal transfer mode is pro- droplet si'ze at different welding currents The mechanism of repelled metal trans- duced when using carbon dioxide gas are compared with the theoretical pre- fer is also discussed. -
Welding and Joining Guidelines
Welding and Joining Guidelines The HASTELLOY® and HAYNES® alloys are known for their good weldability, which is defined as the ability of a material to be welded and to perform satisfactorily in the imposed service environment. The service performance of the welded component should be given the utmost importance when determining a suitable weld process or procedure. If proper welding techniques and procedures are followed, high-quality welds can be produced with conventional arc welding processes. However, please be aware of the proper techniques for welding these types of alloys and the differences compared to the more common carbon and stainless steels. The following information should provide a basis for properly welding the HASTELLOY® and HAYNES® alloys. For further information, please consult the references listed throughout each section. It is also important to review any alloy- specific welding considerations prior to determining a suitable welding procedure. The most common welding processes used to weld the HASTELLOY® and HAYNES® alloys are the gas tungsten arc welding (GTAW / “TIG”), gas metal arc welding (GMAW / “MIG”), and shielded metal arc welding (SMAW / “Stick”) processes. In addition to these common arc welding processes, other welding processes such plasma arc welding (PAW), resistance spot welding (RSW), laser beam welding (LBW), and electron beam welding (EBW) are used. Submerged arc welding (SAW) is generally discouraged as this process is characterized by high heat input to the base metal, which promotes distortion, hot cracking, and precipitation of secondary phases that can be detrimental to material properties and performance. The introduction of flux elements to the weld also makes it difficult to achieve a proper chemical composition in the weld deposit. -
Submerged Arc Welding
SAMPLE Welding Process Training Series Submerged Arc Welding 265558 Submerged Arc Welding CC 2014_EN.indd 1 4/17/15 15:35 SAFETY Safety in Welding, Cutting, and Allied Processes, CSA Standard W117.2, from Canadian Standards Association, Standards Sales, 5060 Arc Spectrum Way, Suite 100, Ontario, Canada L4W 5NS (Phone: 800-463- Welding 6727, website: www.csa-international.org). Safe Practice For Occupational And Educational Eye And Face Protec- and Cutting tion, ANSI Standard Z87.1, from American National Standards Insti- tute, 25 West 43rd Street, New York, NY 10036 (Phone: 212-642-4900, the website: www.ansi.org). Safe Way! Standard for Fire Prevention During Welding, Cutting, and Other Hot Work, NFPA Standard 51B, from National Fire Protection Association, Quincy, MA 02269 (Phone: 1-800-344-3555, website: www.nfpa.org.) OSHA, Occupational Safety and Health Standards for General Indus- try, Title 29, Code of Federal Regulations (CFR), Part 1910, Subpart As in all occupations, safety is paramount. Because there are Q, and Part 1926, Subpart J, from U.S. Government Printing Of- numerous safety codes and regulations in place, we recommend fice, Superintendent of Documents, P.O. Box 371954, Pittsburgh, that you always read all labels and the Owner’s Manual carefully PA 15250-7954 (Phone: 1-866-512-1800) (There are 10 OSHA Re- before installing, operating, or servicing the unit. Read the safety gional Offices—phone for Region 5, Chicago, is 312-353-2220, information at the beginning of the manual and in each section. website: www.osha.gov). Also read and follow all applicable safety standards, especially Booklet, TLVs, Threshold Limit Values, from American Confer- ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes. -
Welding of Aluminum Alloys
4 Welding of Aluminum Alloys R.R. Ambriz and V. Mayagoitia Instituto Politécnico Nacional CIITEC-IPN, Cerrada de Cecati S/N Col. Sta. Catarina C.P. 02250, Azcapotzalco, DF, México 1. Introduction Welding processes are essential for the manufacture of a wide variety of products, such as: frames, pressure vessels, automotive components and any product which have to be produced by welding. However, welding operations are generally expensive, require a considerable investment of time and they have to establish the appropriate welding conditions, in order to obtain an appropriate performance of the welded joint. There are a lot of welding processes, which are employed as a function of the material, the geometric characteristics of the materials, the grade of sanity desired and the application type (manual, semi-automatic or automatic). The following describes some of the most widely used welding process for aluminum alloys. 1.1 Shielded metal arc welding (SMAW) This is a welding process that melts and joins metals by means of heat. The heat is produced by an electric arc generated by the electrode and the materials. The stability of the arc is obtained by means of a distance between the electrode and the material, named stick welding. Figure 1 shows a schematic representation of the process. The electrode-holder is connected to one terminal of the power source by a welding cable. A second cable is connected to the other terminal, as is presented in Figure 1a. Depending on the connection, is possible to obtain a direct polarity (Direct Current Electrode Negative, DCEN) or reverse polarity (Direct Current Electrode Positive, DCEP). -
2020 School Catalog Volume XVI Published: December 2019 Effective: January 01, 2020
MT Training Center 2020 School Catalog Volume XVI Published: December 2019 Effective: January 01, 2020 1801 S. Great Southwest Pkwy. Grand Prairie, Texas 75051 972-262-5395 www.mttrainingcenter.org MT Training Center – School Catalog: 2020 Page 1 of 67 MT Training Center Table of Contents ADMINISTRATION AND STAFF ............................................................................................................... 4 ACCREDITATION AND LICENSURE ....................................................................................................... 5 Accreditation .............................................................................................................................................. 5 Licensure .................................................................................................................................................... 5 MISSION ....................................................................................................................................................... 6 VISION OF THE INSTITUTION .................................................................................................................. 6 EDUCATIONAL PHILOSPHY ..................................................................................................................... 6 HISTORY OF THE SCHOOL ....................................................................................................................... 6 FACILITY ..................................................................................................................................................... -
1. Exposure Data
1. EXPOSURE DATA 1.1 Description of major welding are used as part of the welding process (e.g. the processes and materials shielding gas) (ISO, 2009). While there are many welding processes Welding is a broad term for the process routinely employed in occupational settings, the of joining metals through coalescence (AWS, most common arc welding processes are manual 2010). Welding techniques tend to be broadly metal arc (MMA, ISO No. 111), gas metal arc classified as arc welding or gas welding. Arc (GMA, ISO No. 13), flux-cored arc (FCA, ISO Nos welding uses electricity to generate an arc, 114 and 136), gas tungsten arc (GTA, ISO No. 14), whereas gas or oxyfuel welding (ISO 4063:2009 and submerged arc (SA, ISO No. 12) (Table 1.2 process numbers 3, 31, 311, 312, and 313) uses fuel and Table 1.3). Electric resistance welding (ER, gases such as acetylene or hydrogen to generate ISO Nos 21 and 22) is also commonly used for spot heat. Welding results in concurrent exposures or seam welding, and uses electric currents and including welding fumes, gases, and ionizing force to generate heat. In occupational settings, and non-ionizing radiation, and coexposures these processes are most commonly used to weld from other sources such as asbestos and solvents mild steel (MS, low carbon) or stainless steel (SS). (Table 1.1). Flame cutting (ISO No. 81), the process of using Welding fumes are produced when metals oxygen (O) and a fuel to cut a metal, is a closely are heated above their melting point, vapourize related process that is often grouped occupation- and condense into fumes. -
AC/DC Submerged Arc Welding
THE LINCOLN ELECTRIC COMPANY NEXTWELD® AC/DC Submerged Arc Welding Processes >>> MODULAR For over 50 years, Lincoln Electric has offered its submerged arc welding (SAW) customers high The Power Wave AC/DC1000 SD power source deposition rates, reliable penetration, and smooth is designed for easy paralleling, overcoming the bead appearance. problems typically associated with synchronization of AC waveforms for increased amperage Now, Lincoln brings you an advance in SAW technology that applications. provides the option of variable polarity. Changes in the >>> balance of positive and negative polarity of the AC waveform MULTI-ARC enable the operator to change penetration and deposition, without changing the current or voltage settings. AC/DC welding is designed for applications that require up to five independently controlled Lincoln’s AC/DC submerged arc process with the Power welding arcs. Wave® power source gives the operator real-time control. >>> Instead of making a weld, stopping and re-programming EASY INTEGRATION the new parameters, and running a test weld to make sure they worked, changing the weld characteristics is as easy as Digital Communications provide a simple solution turning a knob.. for the integration of the welding power source to the motion controlling Programmable Logic Controller (PLC). >>> INCREASED PROCESS CONTROL Digital Communications also enable the use of software tools to record the actual welding values for each weld as well as monitoring the status of the welding system. >>> WAVEFORM CONTROL TECHNOLOGY® The Power Wave AC/DC1000 SD power source is equipped with factory-programmed procedures for fast setup. The Power Wave® AC/DC 1000® SD power source takes submerged arc welding to the next level. -
Chemical and Physical Properties of Fluxes for SAW of Low-Carbon Steels
13 Chemical and Physical Properties of Fluxes for SAW of Low-Carbon Steels Ana Ma. Paniagua-Mercado and Victor M. Lopez-Hirata Instituto Politécnico Nacional (ESFM-ESIQIE) Mexico 1. Introduction The submerged-arc welding of steels has been used since 1930. It is well known that the mechanical properties of steel weldments depend on the chemical compositions of electrodes and fluxes. The development of welding electrodes has been based on practical experiences. The study of welding deposits by means of physical metallurgy permitted to develop electrodes and fluxes for SAW process of steels. In contrast, the use of chemical and physical properties of fluxes for the development of welding process started in the 70´s. (Shah, 1986). Most of the works concerning with the fluxes for SAW process have been focused on its effect on microstructure and mechanical properties. Likewise, it has been interesting the study of the thermochemical and electrochemical reactions that occur at the welding pool which are very important for the transferring of metallic elements to the welds. In addition to the stated above, the electrode coverings is also a very important aspect to obtain weld metal with good mechanical properties. The covering materials are fluxes which are composed of different mineral chemical compounds such as, oxides, fluorides and carbonates (Singer & Singer, 1979). The firing and sintering process of fluxes during welding electrode processing promotes chemical reactions and phase transformations of these minerals. All these factors determine the valence or electric charge of the different elements which are deposited to the weld metal. All the oxides from flux may contribute to the dissolution process of different metallic elements and oxygen in the welding pool.