...(i) Injection Molding Demonstration Battenfeld HM 40/130 is the machine used in the laboratory session to mold Polypropylene. Thermoplastic materials such as nylon, polystyrene, polythene and polypropylene can be used in a process called injection molding. How injection molding works? 1. The hopper is filled with granules of plastic powder. The hopper stores the material until it is needed. 2. The heater starts heating up the tube until it reaches a high temperature, then a screw thread starts turning. 3. The granules are pushed along the heater section by a motor, which pushes the granules along the heater section. The heater melts the granules until they reach the liquid state. This liquid is then forced under pressure into a mold where it cools down the liquid and solidifies it, which then turns into a shape. 4. The mold then opens and the ejector pins remove the molded part. In one molding cycle, the maximum amount of plastic injection mold that can be injected is called the “shot size”. For best quality, parts must use about 60% to 70% of a machines rated shot size. Larger shot sizes will not allow sufficient melt cushion for packing. Smaller shot sizes produce greater irregularities and loss of precision. The relatively high melting point of polypropylene allows continued use at 104°C. The resin begins to soften at about 121°C. The polymer “Polypropylene” (C3H6)n properties: Property Value Molecular weight of repeat unit 42.08 g/mol...
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...America was in the midst of social turmoil. Women’s right advocators and abolitionists were sprouting throughout the country, ferociously demanding change to the social system that was intact for more than 100 years. Among those who demanded for emancipation and denounced the slavery system, Theodore Dwight Weld was well known for his impasse stance on slavery. Theodore Dwight Weld was a leading architect and participant of the American Abolitionist movement and was heralded the most prominent American antislavery crusader during the pre-Civil War period. (Britannica) Weld was born in Hampton Connecticut in November 23, 1803 as a son of a Congressional minister. Although his father entreated him to follow in his footsteps, Weld was forced to leave Phillips-Andover, a well-known ministry school at the time, due to his failing eyesight. He then joined Hamilton College in New York a few years later at his parents’ requests and was extremely influenced by evangelist Charles Grandison Finney, who conducted regular revivalist meetings near his school. In fact, Weld frequently toured with Finney and developed his oratory skills by...
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...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 standards...
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...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 welding...
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...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. 2”...
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...TIG welding is cleanest and most precise welding procedure available. The operator can change parameter during welding without stop of weld and also complete control on welding variable. 7. Possible welding in all position. 8. Distortion is low. 1.8 Limitation of (TAGS) Welding 1. The deposition rate is lower. 2. In case of thick section it is costly. 3. Process is slow compare to MIG. 1.9 TIG Welding Application The TIG welding process is best suited for metal plate of thickness around 5- 6 mm. Thicker material plate can also be welded by TIG using multi passes which results in high heat inputs, and leading to distortion and reduction in mechanical properties of the base metal. In TIG welding high quality welds can be achieved due to high degree of control in heat input and filler additions separately. TIG welding can be performed in all positions and the process is useful for tube and pipe joint. The TIG welding process is extensively used in the so-called high-tech industry applications such as 1) Nuclear industry 2) Aircraft 3) Food processing industry 4) Maintenance and repair work 5) Precision manufacturing industry 6) Automobile industry 7) Welding of transistor...
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...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 and...
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... 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...
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... 5 Types of resistance welding 6 Advantages and disadvantages of resistance welding 10 Application of resistance welding 11 Conclusion 12 Overview of Resistance Welding Introduction In simplest terms, welding is a process by which two or more pieces of metal are joined by applying heat and pressure. Back in the good old days, blacksmiths and other crafty people would heat metals in a furnace 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...
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...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 temperature...
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...acetylene storage 100 % safe[7]. Figure 2.3: Gas welding equipment 2.2.3 Arc Welding Arc welding was initially carried out using carbon electrodes, developed by Bernardos, and then by the use of steel rods. The weld was however not protected from the air and there were problems with quality. The Swede Oskar Kjellberg made an important advance when he developed and patented the coated electrode. The welding result was amazing and arc welding using coated electrodes became the foundation of the ESAB welding company[8]. Figure 2.4: Principle of manual metal arc (MMA) welding Later, in the 1930s, new methods were developed. Up until then, all metal-arc welding had been carried out manually. Attempts were made to automate the process using a continuous wire. The most successful process was submerged arc welding (SAW) where the arc is “submerged” in a blanket of granular fusible flux[8]. Figure 2.5: Submerged arc welding Figure 2.6: The TIG welding method During the Second World War the aircraft industry required a new method for the welding of magnesium and aluminum. In 1940 experiments began in the USA with the shielding of the arc by inert gases. By using an electrode of tungsten, the arc could be struck without melting the electrode, which made it possible to weld with or without filler material. The method is called Tungsten Inert Gas or TIG welding[9]. Figure 2.7: The MIG/MAG welding method The Metal Inert Gas or MIG welding process was also improved using a continuously...
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...Instructions Carefully 811-309-000 SEARS ROEBUCK AND CO., CHICAGO, IL 60684 U.S.A. Table of Contents IMPORTANT SAFETY INSTRUCTIONS 1 1 2 SHOCK HAZARDS ......................... FLASH HAZARDS ......................... FIRE HAZARDS ........................... FUME HAZARDS .................... ...... Changing the Drive Roller ................... 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...
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...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 shielding...
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...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 oscillation...
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... 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...
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