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The University of Lahore

The University of Lahore. Department of Mechanical Engineering. Materials Process and Manufacturing. Group- 8. Munir Ahmad BME01083006 Farrukh Bashir BME01083013 Adeel Sajid BME01083040 Saleem Raza BME01083028 Javad Javid BME01083027.

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The University of Lahore

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  1. The University of Lahore Department of Mechanical Engineering Materials Process and Manufacturing Group- 8 Munir Ahmad BME01083006 Farrukh Bashir BME01083013 Adeel Sajid BME01083040 Saleem Raza BME01083028 Javad Javid BME01083027

  2. Main topics • Arc Welding • Oxy Fuel Gas Welding • Fusion Welding • Electrodes

  3. What is welding? Welding is a process that joins materials, usually metalss or thermoplastics. This is often done by melting the work pieces and adding a filler material to form a pool of molten material that cools to become a strong joint… • Description: • A thermoplasticsis a type of plastic that can be softened by heat, hardened by cooling, and then softened by heat over and over again.

  4. Welding Process

  5. FUSION WELDING

  6. Fusion Welding A welding process that melts the base metals at the joint. Upon cooling, the welded joint is often stronger than the base metals.

  7. Fusion Welding Machines • Electron Beam Welding Machine • Hot Plate Welding Machine • Plastic Welding Machine • Laser Welding Machine • Oxy fuel Gas Welding Machine • Thermite/Exothermic Welding Machine • Inertia Welding Machine • Electro Slag Welding Machine

  8. Fusion Welding Machine

  9. Fusion Welding--Heat Sufficient heat must be applied to the weld zone to raise the temperature above the melting point. Melting point is different for each material. Material Melting Point (oF) Steel (HC) 2,500 Stainless Steel 2,550 Steel (MC) 2,600 Steel (LC) 2,700 Iron 2,800 Chromium 3,000 Titanium 3,260

  10. Fusion Welding--Shielding • Steel is produced in an environment devoid of atmospheric air. • If atmospheric air is allowed to mix with the molten metal during the fusion welding process the quality of the weld is reduced.

  11. Fusion Welding--Filler Materialcont. • When a filler material is not provided during a fusion welding process the joint will not be filled = starved joint. • Starved joints have reduced strength • For this reason, joints are usually slightly over filled (reinforced) to insure the strength is not reduced. • Reinforcement does not increase the strength of the weld, just insures the joint is not starved. • Excessive reinforcement costs extra to produce. • Excessive reinforcement may need to be removed = additional cost..

  12. Advantages of Fusion Welding • Concentrated Arc • Hydraulically Smooth • Longevity • Lightweight • Strong and Ductile • Weather Resistant • Impact Resistant

  13. Process Of Fusion Welding • “Welding and cutting requires good eye-mind-hand coordination.” • Must be able to concentrate. • Must see and understand the activity in the molten metal as the process is occurring. • Thorough understanding of the operation of the equipment. • Must have good depth perception. • Must be able to determine the time and place to apply heat and/or filler metal. • Maintain a good body position so it is possible to look left and right, and ahead and behind the puddle. • Must know the quality standards. • Must understand the procedures for inspecting work. • Must learn safe work habits.

  14. ARC WELDING

  15. Arc Welding Arc welding process, in which the metal or metals are being joined by heating with an arc, with or without the application of pressure and with or without the use of filler metal. • Description: • A filler metal is a Metal which is added during a weld; has a melting point either approximately the same as or below that of the metals being welded

  16. History of Arc Welding The history of electric arc welding begins with the discovery of the electric arc by Sir Humphrey Davy in 1801. While experimenting with the infant science of electricity, he discovered that an arc could be created with a high-voltage electric circuit by bringing the two terminals near each other. This arc, which cast a bright light and generated considerable heat, could be struck and maintained at will, and its length and intensity could be varied within limits determined by the...

  17. Arc Welding Beads

  18. Welding Tools • Welding Machine • Cheeping Hammer • Eye Shield • Apron • Wire Brush

  19. Welding Machine

  20. Some types of Arc Welding • Spot arc welding • Gas arc welding • Tig arc welding • Shielded metal arc welding • Gas tungsten arc welding • Flux Cored Arc Welding (FCAW)

  21. Features For Arc Welding

  22. Advantages of Arc Welding 1. Arc Welding is the simplest of all the welding processes.2. The equipment is portable and the cost is fairly low. 3. A big range of metals and their alloys can be welded. 4. Welding can be carried out in any position with highest weld quality. 5.The joint of arc welding is permanent and easily repairable.

  23. Limitations of Arc Welding 1. In welding long joints when one electrode finishes, the weld is to be progressed with the next electrode. It is very difficult to start the weld from there with a new electrode. 2. The process uses stick electrodes and thus it is slower as compared to MIG welding.

  24. Applications of Arc Welding 1. Today, almost all the commonly employed metals and their alloys can be welded by this process.2. Arc welding is used both as a fabrication process and for maintenance and repair jobs. 3. Arc welding is also used in (a) tank, boiler and pressure vessel fabrications;(b) Ship building;(c) Pipes joining;(d) Building and Bridge construction;(e) Automotive and Aircraft industry, etc.

  25. OXY FUEL WELDING

  26. Oxy Fuel Welding Oxy-fuel welding (commonly called oxyacetylene welding, oxy welding, or gas welding in the U.S.) and oxy-fuel cutting are processes that use fuel gases and oxygen to weld and cut metals, respectively.

  27. Importance of Oxy Fuel Welding Oxy-fuel is one of the oldest welding processes, though in recent years it has become less popular in industrial applications. However, it is still widely used for welding pipes and tubes, as well as repair work. In oxy-fuel welding, a welding torch is used to weld metals. Welding metal results when two pieces are heated to a temperature that produces a shared pool of molten metal. The molten pool is generally supplied with additional metal called filler. Filler material depends upon the metals to be welded.

  28. Oxy Fuel welding

  29. Oxy Fuel Cutting

  30. Types of Oxy Fuel Welding 1. Neutral Flame (Acetylene oxygen in equal proportions) 2. Oxidizing Flame (Excess of oxygen) 3. Reducing Flame (Excess of acetylene) In oxyacetylene welding, flame is the most important tool. All the welding equipment simply serves to maintain and control the flame. The correct type of flame is essential for the production of satisfactory welds. The flame must be of the proper size, shape and condition in order to operate with maximum efficiency.

  31. Types of Oxy Fuel Welding • Oxyacetylene welding • Oxyhydrogen welding • Air acetylene welding • Pressure gas welding

  32. Disadvantages of Oxy Fuel Welding 1. Flame temperature is less than the temperature of the arc. 2. Refractory metals (e.g., tungsten, molybdenum, tantalum, etc.) and reactive metals (e.g., titanium and zirconium) cannot be gas welded. 3. Gas flame takes a long time to heat up the metal than an arc. 4. More safety problems are associated with the handling and storing of gases.

  33. Uses & Applications of Oxy Fuel Welding Some of the common uses of oxy fuel gas welding machine are: • Cutting steel alloys • Manufacturing industries • Soldering applications • Gas plants

  34. Oxy Fuel Welding Machine

  35. Equipment For Oxy Fuel Welding • Two cylinders (oxygen & Acetylene) • Torch • Electrodes • Apron

  36. Electrodes

  37. What is Electrode • In arc welding, the current-carrying rod or rods used to strike an arc between rod and work. • In resistance welding, the component of a machine through which current and pressure are applied to the work.

  38. WELDING ELECTRODES

  39. Types of Welding Electrodes • 6010 • 6011 • 6013LV • 7014 • 7018 • 7018 AC • 252 • 275

  40. ELECTRODE SIZE AND AMPS USED

  41. ELECTRODE IDENTIFICATION Arc welding electrodes are in sizes from 1/16 to 5/16 .For example 1/8" E6011. This shoes the electrode is 1/8" in diameter The "E" stands for arc welding electrode. Next will be either a 4 or 5 digit number stamped on the electrode. The first two numbers of a 4 digit number and the first 3 digits of a 5 digit number indicate the minimum tensile strength (in thousands of pounds per square inch) of the weld that the rod will produce, stress relieved. Examples would be as follows: E60xx would have a tensile strength of 60,000 psi E110XX would be 110,000 psi The next to last digit indicates the position the electrode can be used in. 1.EXX1X is for use in all positions 2.EXX2X is for use in flat and horizontal positions 3.EXX3X is for flat welding The last two digits together, indicate the type of coating on the electrode and the welding current the electrode can be used with.

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