Weld

In: Science

Submitted By swooshns95
Words 277
Pages 2
weld * Fusion Welding Principles: * Base metal is melted * Filler metal may be added * Heat is supplied * Weld Metal Protection * During fusion welding, the molten metal in the weld ‘puddle’ is suceptable to oxidation * Weld Fluxes * SiO2, TiO2, FeO, MgO, Al2O3 * Produces a gaseous shield to prevent contamination * Act as scavengers to reduce oxides * Add alloying elements to weld * Inert Gases * Argon, Helium, Nitrogen, CO2 * Form a protective envelope around the weld area * Vacuum * High quality welds * Electron beam welding * Nucleaer/special metals * Types of Fusion Welding: * Oxyacetylene Welding (Torch) * Flame formed by burning a mix of acetylene and O2 * Fusion of metal is achieved by passing the inner cone of the flame over the metal * Oxyacetylene can also be used for cutting metals * Shieled Metal Arc (Stick) * Electric arc generated between a coated electrode and the parent metal * Process: * Intense heat at arc melts electrode tip * Tiny drops of metal enter the arc and are deposited into parent * As metal is deposited, a slag forms over the bead * Inert Gas Welding * Al or Ti which quickly forms oxide laters, a method to place an inert atmosphere * Uses a consumable electrode * MIG Welding * Tungsten Inert Gas (TIG) * Tungsten acts as cathode * Plasma produced between the tungsten cathode and the base metal which heats the electrode * Weld Defects * Overlaps/undercuts * Grain growth * Inclusions * Impurities or foreign substances are forced into the weld * Segregation * Some areas are enriched with alloy and some are not * Porosity * Pinholes generated by atmosphere * Residual Stresses * Rapid heating and cooling…...

Similar Documents

Incident Report

...and then weld them by hammering the red-hot metals together. By hammering the metals as they cooled, the weld would be made stronger. This heating-and-hammering method is known as forge welding. While forge welding worked quite well for most of the welding done back then, today's welding requirements are a bit more advanced. After all, it would be pretty difficult to heat all the metal needed to build an automobile in a big factory furnace and expect workers to hammer together each specific part used in the manufacturing process. We'd all still be riding horses to work! Fortunately, there are always a handful of brilliant people throughout history who are kind enough to invent newer, faster, and better ways of doing things. One of these people was a professor by the name of Elihu Thompson. Sometime in the year 1885, Professor Thompson invented a process called electric resistance welding. He discovered that to weld metals together, one could fire an electric current through the metals while they were tightly clamped together. When the current passed through the metals, it would create such a high heat that the metals would melt and run together and a weld would be made. Many times, the welded metal would be even stronger than the original metals used in the welding process. Variables in the Welding Process The many variables involved in welding can be broadly categorized into two basic sections: process variables and material variables. Process variables include: • Weld......

Words: 1221 - Pages: 5

High Performance Steel for Highway Bridges.Pdf

...difficult to define. During welding, the conventional 70 ksi steels typically require preheating of plates, control of temperature of weld passes, controlled handling of welding consumables, precisely controlled energy input, and post-weld heat treatment in some cases. When all of these operations are performed correctly, it is usually possible to produce high-quality welds in conventional high-strength steel. However, these steels are much more difficult to weld and much less forgiving to variations in welding practice http://services.bepress.com/eci/advanced_materials/1 Mistry : High Performance Steel For Highway Bridges 3 than the lower-strength steels. The reason for this is that higher strength levels usually are achieved by increasing content of carbon and alloying elements in steel. Unfortunately, weldability is inversely proportional to carbon content and the amount of alloying elements. High carbon content of current conventional steels, needed to achieve high strength, leads to cracking during construction or while in service. To reduce cracking problems from welding, these steels require pre- and post-heating during welding. These procedures lead to increased fabrication cost. The goal in developing HPS grades is to provide a steel that is forgiving enough to be welded under a variety of conditions without requiring excessive weld-process control that increases cost. Although High Performance Steels have the same strength levels as the currently......

Words: 3237 - Pages: 13

Lgal Doc

...INSTALLING ALUMINUM WIRE .............. 13 16 PREPARING TO WELD 17 17 17 18 18 2 3 COMPRESSED GASSES AND EQUIPMENT HAZARDS ................................... 3 ADDITIONAL SAFETY INFORMATION ......... 4 PREPARING A SAFE WELDING WORK AREA.. PREPARING THE WORK PIECE ............. ALUMINUM WELDING PREPARATION ........ CONNECT WELDER GROUND .............. PRODUCT DESCRIPTION 5 5 5 5 5 OPERATION GETTING TO KNOW YOUR NEW WELDER .... SETTING THE CONTROLS ................. HOLDING THE GUN ....................... Position of the Gun to the Work Piece ......... Distance from the Work Piece ............... LAYING A BEAD .......................... CLEANING THE WELD BEAD ............... 19 19 19 20 20 21 21 21 SPECIFICATIONS ......................... WELDER CONTROLS AND THEIR FUNCTIONS. DUTY CYCLE ............................. INTERNAL THERMAL PROTECTION .......... ASSEMBLY AND INSTALLATION 6 6 6 7 7 7 8 8 8 9 UNPACKING YOUR WELDER ................ INSTALL THE GROUND CLAMP .............. INSTALL WELDING GUN ASSEMBLY .......... PROVIDE REQUIRED POWER ............... Power Requirements ....................... Connect Welder to Power Source ............. Extension Cord Use ........................ INSTALL TANK TRAY AND BRACKET .......... SELECT SHIELDING GAS ................... WELDING TECHNIQUES 22 22 22 23 24 TRAVELING WITH THE GUN ................ TYPES OF WELD BEADS .................. WELDING POSITIONS......

Words: 14464 - Pages: 58

Heyy

...pressing, hammering, etc. ------------------------------------------------- Welding electrodes In arc welding an electrode is used to conduct current through a workpiece to fuse two pieces together. Depending upon the process, the electrode is either consumable, in the case of gas metal arc welding or shielded metal arc welding, or non-consumable, such as in gas tungsten arc welding. For a direct current system the weld rod or stick may be a cathode for a filling type weld or an anode for other welding processes. For an alternating current arc welder the welding electrode would not be considered an anode or cathode. The Four Positions from a Closer View Now that we have some background about the two basic types of welding, it’s time to take a closer look at those positions.  Flat In a flat position, a weld is performed along largely a horizontal access and from above the joint. It is the easiest type of weld to perform. Horizontal In the horizontal position, the weld’s axis is the horizontal plane. Horizontal welding is often used for fillet or groove welds. Vertical With a vertical position, the weld’s axis is largely in a vertical or upright position. It is typically more complicated to perform than flat and horizontal welding. Overhead In this the most complicated of the four, welding is performed from the underside of the joint. The main Types of welding used in industry and by home engineers are commonly referred to as Mig welding, Arc welding, Gas welding......

Words: 1406 - Pages: 6

Asdasddsa

... Figure 1-1 principal types of resistance weld In Resistance Spot Welding, passage of a relatively high welding current I [kA] throughout a locally compressed workpiece area (by means of an electrode force F [daN]) during a properly defined period of time t [cyc, ms] heats this area due to resistive heating following (Figure 1-2) Figure 1-2 principal of resistance of spot welding Values for Welding Force [daN], Welding Current [kA] and Welding Time [cyc, ms] are available in database format, and these values are commonly used to make a base setting to start from. Fine tuning within the parameter range (weldability lobe) can be done in order to optimise towards a specific application according to EN ISO 14327-2004 (Resistance welding – Procedures for determining the weldability lobe for resistance spot, projection and seam welding). Such a weldability lobe covers a range of combinations of welding current and welding time at a specific welding force level that lead to welds with sufficient dimensions, with a lower boundary indicating “stick” welds, and then an area of increasingly growing weld size towards the maximal possible weld size, followed by the upper boundary leading to splash welds. A so called stick weld is a weld that didn’t receive enough energy during its resistance welding cycle, resulting in the workpieces ‘sticking’ together without a molten weld nugget being formed. As a result, the......

Words: 1388 - Pages: 6

Hoha

... Cast iron is difficult, but not impossible, to weld. In most cases, welding on cast iron involves repairs to castings, not joining casting to other members. The repairs may be made in the foundry where the castings are produced, or may be made to repair casting defects that are discovered after the part is machined. Mis-machined cast iron parts may require repair welding, such as when holes are drilled in the wrong location. Frequently, broken cast iron parts are repaired by welding. Broken cast iron parts are not unusual, given the brittle nature of most cast iron.While there are a variety of types of cast iron, the most common is gray cast iron, and these guidelines are directed toward this type of material. A few facts about cast iron help in understanding the welding challenges. Cast iron typically has a carbon content of 2% - 4%, roughly 10 times as much as most steels. The high carbon content causes the carbon to form flakes of graphite. This graphite gives gray cast iron its characteristic appearance when fractured.When castings are made, molten iron is poured into a mold and allowed to slowly cool. When this high carbon material is allowed to cool slowly, crack free castings can be made. Remembering this is helpful when welding cast iron: during and after welding, the casting must either be allowed to cool slowly, or should be kept cool enough that the rate of cooling is not important.A critical temperature in most cast iron is about 1450 degrees F. When at this......

Words: 8583 - Pages: 35

Electroslag Welding

...Electroslag Welding Electroslag Welding Electroslag Welding is a welding process, in which the heat is generated by an electric current passing between the consumable electrode (filler metal) and the work piece through a molten slag covering the weld surface. Prior to welding the gap between the two work pieces is filled with a welding flux. Electroslag Welding is initiated by an arc between the electrode and the work piece (or starting plate). Heat, generated by the arc, melts the fluxing powder and forms molten slag. The slag, having low electric conductivity, is maintained in liquid state due to heat produced by the electric current. Electroslag welding (ESW) is a highly productive, single pass welding process for thick (greater than 50 mm) materials in a vertical or close to vertical position. An electric arc is initially struck by wire that is fed into the desired weld location and then flux is added The slag reaches a temperature of about 3500°F (1930°C). This temperature is sufficient for melting the consumable electrode and work piece edges. Metal droplets fall to the weld pool and join the work pieces. Electroslag Welding is used mainly for steels. Electroslag Welding equipments Power source Wire feeder Electrode guide tube Retaining Blocks Welding head and Controls Power source 100 % duty cycle AC and DC (EP) power source 10,000 Amp OCV 60V (range is 30 V to 100 V) Remote controled Wire feeder Feed roller Drive motor Provide......

Words: 2360 - Pages: 10

Door Building Bible

...for correct measurement and Plunger Holes 3. Make parts Lock Mount and Plungers and (dead bolts if needed) check for right hinge. 4. Weld parts to angle Guide pipe and Dead Bolts if needed 5. Put angle frame together check for length width, then square weld 6. 14 gauge back panel, lay on table, put frame on top flat side down guide pipe away from you. Check for(right hinge) top would be to your right. Otherwise to your left. Puyt in spreader rod. Line up edge and top and bottom. Inside swing will be flush with angle on side with guide pipe. 7. Drill Holes, 21/65 weld on nuts. Stamp Number top end of angle 8. Remove angle frame oversize holes except top hole 25/64 stamp number in panel above top hole remove panel 9. Outer door panel LVD 3/16”, VD. ¼” HVD. 3/8”, MVD. ½”, MVDE 1” Safe Doors check work order best side down on table check for right hinge top is right of you. Get your center line. Put angle frame on panel flat side up. Safe doors and out swing Vault Doors ¾”, top 13/16” guide pipeside mark top and bottom corners, set I beams on top and clamp down. Recheck alignment inside swing doors ¾”, top ½” guide pipe side Mark top and bottom corners. Put cross tensioner in place snug it up. Leave gap roller rod 2” and 2-2 ½” L3”6” L3” and 7” no weld. Make sure spreader rod remains in place, weld frame to panel. 10. Clean plungers, buff stainless after cleaning with thinner. 11. Cut roller rod 2” less than length of frame.......

Words: 790 - Pages: 4

Studies on Friction Stir Welded Aa 7075

...Engineering, IIT Madras, Chennai - 600036 E-mail : vgthota@yahoo.com (Received 21 April 2004 ; in revised form 28 June 2004) ABSTRACT Friction stir welding is a promising solid state joining process and is widely being considered for aluminum alloys. In this work, the microstructural and corrosion properties of friction stir welded 7075 Al alloy were studied. The microstructures of the base metal, bore metal, thermo-mechanically affected zone (TMAZ) and weld region were characterized by optical microscopy and transmission electron microscopy. Micro-hardness profile was obtained across the weld. The pitting corrosion properties of the weldments were studied in 3.5% NaCl solution. Friction stir welding of this alloy resulted in fine recrystallized grains in weld nugget which has been attributed to frictional heating and plastic flow. The process also produced a softened region in the weld nugget, which may be due to the dissolution and growth of possible precipitates, identified as Mg32(Al,Zn)49. Corrosion resistance of weld metal has been found to be better than that of TMAZ and base metal. 1. INTRODUCTION High strength precipitation hardening 7XXX series aluminum alloys, such as 7075 are used extensively in aerospace industry. These alloys are difficult to join by conventional fusion welding techniques. Hence realizing a fusion-welded joint in such alloys without impairing the mechanical properties is a difficult task for the welding engineer. Consequently the......

Words: 2022 - Pages: 9

Paper

... BODY WELDING - CAN IT BE FLEXIBLE? Some 250~300 pressed panels from in-house and vendor facilities are brought to different subassembly stations of Body Weld Shop. Subassemblies of pressed components are carried out mainly by resistance welding and other joining methods in a planned sequence at number of stations. Some subassemblies are done in off-line manufacturing cells and fed in at appropriate locations into the main assembly line. Fig. 6.1 shows a layout of a typical Body Weld Shop. Front end, rear floor, and front floor, are transported to underbody body line, where all these are welded together in sequence to form the floor structure. Underbody is then transferred to main body welding station. Right hand and left hand body side panels are brought from two sides to main body weld station, after completion of all subassembly operations in separate lines. Preframing of body structure is carried out on special fixture. At same or next station, roof is added to form the body shell, Fig. 6.2. Thereafter, rear doors, front fenders, hood and decklid/ tailgate fitments are carried out to complete the body-inWhite. If necessary, a metal finish line may be added for minor repair of Body-in-White before it moves for painting. Fig. 6.3 illustrates the sequences of subassemblies and the main body weld. Typically, Body weld shop activities cover fixturing, welding, and transportation between the work stations, and the related support services.. Fig. 6.1 A Typical Body Welding...

Words: 7585 - Pages: 31

Welding Techniques

...years for a welder to acquire the skills to arc weld thin metal and ever the most experienced welders mess up and ruin product. TIG welding would work with the thin metal but will take a lot longer and cost a lot more. It also takes the longest to master. Gas MIG (GMAW) is the process I recommend for the thin metal. I will explain the three processes in the following paragraphs. Arc Welding is one of the oldest welding processes around. It can be the cheapest to start with as there is not a lot of equipment needed. It is also very versatile as there are a lot of specialized electrodes available. These specialized electrodes are used for different types of preferences which include: hardening, high-strength, stainless, mixed, cast iron and other meter alloys. This process requires a flux coating to shield the weld and the flux will have to be cleaned from the weld. This process is very difficult to accomplish of thin metals of all types. Therefore, takes a considerable amount of training and practice to master. Also this process requires no gas or wire feeder which allows this process to be portable. This process works of AC (used on aluminum) or DC (used on ferrous metals (steels)). TIG welding is also very versatile and produces the highest quality welds. It also takes a considerable amount of practice and is the least productive of the different types of welding. TIG uses a torch with a tungsten electrode. To protect the weld and tungsten, argon must be used as a......

Words: 622 - Pages: 3

Prediction and Optimisation of Fsw

...properties of Aircraft fuselage aluminium (AA5083). Firstly, data-driven modelling techniques such as Artificial Neural – Fuzzy networks and regressive analysis are used and by making the effective use of experimental data, FIS membership function parameters are trained. At the core, mathematical model that functionally relates tool rotational speed and forward movement per revolution to that of Yield strength, Ultimate strength and Weld quality are obtained. Also, simulations are performed, and the actual values are compared with the predicted values. Finally, multi-objective optimization of mechanical properties fuselage aluminium was undertaken using Genetic Algorithm to improve the performance of the tools industrially. AIMS AND OBJECTIVES Objectives of the dissertation include  Understanding the basic principles of operation of Friction Stir Welding (FSW).  Gaining experience in modelling and regressive analysis.  Gaining expertise in MATLAB programming.  Identifying the best strategy to achieve the yield strength, Ultimate Tensile strength and Weld quality of Friction Stir Welding.  Performing optimization of mechanical properties of FSW using Genetic Algorithm. I  To draw conclusions on prediction of mechanical properties of FSW optimization of aircraft fuselage aluminium. ACHIEVEMENTS  The basic principles of friction welding of the welding operations are well studied and understood.  The theoretical concepts of modelling techniques are......

Words: 9686 - Pages: 39

Aws A5.18

...Standards Institute June 9, 2005 Specification for Carbon Steel Electrodes and Rods for Gas Shielded Arc Welding Supersedes AWS A5.18/A5.18M:2001 Prepared by AWS A5 Committee on Filler Metals and Allied Materials Under the Direction of AWS Technical Activities Committee Approved by AWS Board of Directors Abstract This specification prescribes the requirements for classification of solid carbon steel electrodes and rods, composite stranded carbon steel electrodes, and composite metal cored carbon steel electrodes for gas shielded arc welding. Classification is based on chemical composition of the electrode for solid electrodes and rods, chemical composition of weld metal for composite stranded and composite metal cored electrodes and the as-welded mechanical properties of the weld metal for each. Additional requirements are included for manufacture, sizes, lengths, and packaging. A guide is appended to the specification as a source of information concerning the classification system employed and the intended use of the electrodes and rods. This specification makes use of both U.S. Customary Units and the International System of Units (SI). Since these units are not equivalent, each system must be used independently of the other. --`,,``,`-`-`,,`,,`,`,,`--- Copyright American Welding Society Provided by IHS under license with AWS No reproduction or networking permitted without license from IHS 550 N.W. LeJeune Road, Miami, Florida......

Words: 20552 - Pages: 83

Training

...1. SCOPE This module shall give general information on how to achieve good sound weld by familiarizing the imperfections, joint configuration, types of joints and welds and the enhancement of the welders’ skill/technique. 2. PURPOSE The purpose of this training module is to equip the welder with the ability to conduct visual inspection, familiarization with weld imperfection and to enhance welders ability make a weld free of any imperfection/defect inside the weld metal and weld surface. 3. REFERENCE 3.1 CSWIP Book 2008 3.2 TWI Course Reference WIS7 3.3 ASME I 3.4 ASME V 3.5 ASME IX 4 TRAINING PROGRAM Welder’s training would help to enhance the skill of each welder. It takes a lot of practice in order to be acquire a very good welding skill specially in boilers which has limited distance between weld joints and are quite restricted which gives a welder a hard time to perform. Before Welding • Ensure that all operations are carried out in complete compliance with local, company, or National safety legislation (i.e. permits to work are in place) etc. • Welding Machine, grinder, quiver, electrode holder, ground clamp and other tools they will use must be check if in good condition. • Proper PPE (i.e. welding mask, arm sleeve, respirator, welding cloves, welding apron, etc.) must be prepared. • Materials must be confirmed for the proper welding consumable issuance. • Analysis on the joint must be done to determine if need rectification in......

Words: 272 - Pages: 2

Norne Paper

...12th A-PCNDT 2006 – Asia-Pacific Conference on NDT, 5th – 10th Nov 2006, Auckland, New Zealand AUTOMATIC ULTRASONIC INSPECTION OF PIPELINE GIRTH WELDS WITH A CORROSIVE RESISTANT ALLOY (CRA) LAYER Jan van der Ent1 ; Niele Findlay2 ; Niels Portzgen3 ; Oddbjørn Nupen4 ; Geir Endal5; Olav Førli6 1 RTD Rotterdam The Netherlands 2 RTD Perth Australia 3 RTD Rotterdam The Netherlands 4 Technip Oslo Norway 5 Statoil Stavanger Norway 6 DNV Oslo Norway Abstract Development of the Norne Satellite Field comprises the connection of the two oil fields Stær and Svale to the Norne FPSO (see Figure). A unique solution, a common, single pipeline was selected by Statoil for transport of the multiphase well stream from the two oil reservoirs. The Norne field is located at 66° North and subjected to strict environmental requirements. Therefore a Carbon steel pipeline, built with a corrosive resistant alloy layer ( CRA ), had been selected for the resistance against the corrosive fluid without the use of chemicals. An implication of this construction method is that the pipeline girth welds have to be made with an austenitic welding consumable (typically Inconel), which is very difficult to inspect using ultrasonic testing method. Furthermore the reeling process used for the pipeline installation require severe weld flaw detection capabilities. An extensive AUT-CRA qualification program has been utilized by Technip and Statoil to confirm that the proposed CRA inspection method meet the quality......

Words: 6161 - Pages: 25

Rockstar Games | Daddy Yankee - Sígueme y te sigo | Frequency