Types%20of%20 Welding[1]


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Types%20of%20 Welding[1]

  1. 1. Report for MTE521 Metallurgy in Welding By ndrilon 2009 Types of Welding
  2. 3. What is WELDING <ul><li>in engineering, any process in which two or more pieces of metal are joined together by the application of heat, pressure, or a combination of both. </li></ul>
  3. 4. Master chart of Arc Welding and Related Methods
  4. 5. Types of welds <ul><li>Bead </li></ul><ul><li>Groove </li></ul><ul><li>Fillet </li></ul><ul><li>Surfacing </li></ul><ul><li>Tack </li></ul><ul><li>Plug </li></ul><ul><li>Slot </li></ul><ul><li>Resistance </li></ul>
  5. 6. Bead weld <ul><li>Produced by a single pass </li></ul><ul><li>Stinger Bead - which is made without weaving motion. </li></ul><ul><li>Weave Bead- made by side-side oscillation </li></ul>
  6. 7. Groove weld <ul><li>Groove welds are simply welds made in the groove between two members to be joined. </li></ul>
  7. 8. Surfacing welds <ul><li>a  surfacing  weld  is  composed  of  one  or  more stringer  or  weave  beads.  Surfacing,  sometimes  known as hardfacing or wearfacing. </li></ul><ul><li>is often used to build up worn shafts, gears, or cutting edges. </li></ul>
  8. 9. Fillet weld <ul><li>This weld is used to join two sur- faces that are at approximately right angles to each other in a lap, tee, or comer joint </li></ul>
  9. 10. Plug and Slot weld <ul><li>are welds made through holes or slots in one member of a lap joint. </li></ul>
  10. 11. Tack weld <ul><li>  is a weld made to hold parts of an assembly in proper alignment temporarily until the final welds are made. </li></ul><ul><li>they are normally between 1/2 inch to 3/4 inch in length, but never more than 1 inch in length. </li></ul>
  11. 12. Basic Welding Positions
  12. 13. Common Welding Types <ul><li>Arc Welding (AW) </li></ul><ul><li>Oxyfuel Gas Welding(OFW) </li></ul><ul><li>Resistance Welding </li></ul>
  13. 14. Types of ARC Welding <ul><li>Shielded Metal Arc Welding (SMAW) </li></ul><ul><li>Submerged Arc Welding (SAW) </li></ul><ul><li>Flux Cored Arc Welding (FCAW) </li></ul><ul><li>Gas Tungsten Arc Welding (GTAW or TIG) </li></ul><ul><li>Gas Metal Arc Welding (GMAW or MIG) </li></ul>
  14. 15. SMAW <ul><li>is performed by striking an arc between a coated-metal electrode and the base metal. </li></ul><ul><li>Flux- the coating of the metal electrode will form as shield to the molten metal. </li></ul>
  15. 16. Shielded Metal Arc Welding
  17. 18. Arc Welding MAchines
  18. 19. Electrode and Holder
  19. 20. Advantages of SMAW <ul><li>High quality welds are made rapidly at a low cost. </li></ul><ul><li>Can be used easily even to thick and wide work piece to be joined. </li></ul><ul><li>Can be used from thinner to thicker materials. </li></ul>
  20. 21. Disadvantages SMAW <ul><li>Consumes bigger electric current </li></ul><ul><li>Dirty work finish </li></ul><ul><li>Root pass is lower than TIG and MIG </li></ul><ul><li>Prone to slag inclusions </li></ul><ul><li>Weld deposits is prone to blue holes </li></ul>
  21. 22. SUBMERGED ARC WELDING (SAW) <ul><li>Is a process in which is done by an automatic electrode feeding machine wherein the tip of the electrode is submerged into a granular flux which shields the arc and the molten metal. </li></ul>
  22. 23. SAW operations
  23. 24. SAW Welding Machine
  24. 25. SAW block diagram
  25. 26. SAW APPLICATIONS <ul><li>widely used in heavy steel plate fabrication work. </li></ul><ul><li>welding of structural shapes. </li></ul><ul><li>longitudinal seam of larger diameter pipe. </li></ul><ul><li>manufacture of machine components for all types of heavy industry. </li></ul><ul><li>manufacture of vessels. </li></ul><ul><li>pressure and storage tanks. </li></ul>
  26. 27. Advantages of SAW <ul><li>high quality of the weld metal. </li></ul><ul><li>extremely high deposition rate and speed. </li></ul><ul><li>smooth, uniform finished weld with no spatter. </li></ul><ul><li>little or no smoke. </li></ul><ul><li>no arc flash, thus minimal need for protective clothing. </li></ul><ul><li>high utilization of electrode wire. </li></ul><ul><li>easy automation for high-operator factor. </li></ul><ul><li>normally, no involvement of manipulative skills. </li></ul>
  27. 28. Disadvantages of SAW <ul><li>used only to weld mild and low-alloy high-strength steels. </li></ul><ul><li>Unseen arc and puddle can cause poor penetration. </li></ul><ul><li>high-heat input, slow-cooling cycle can be a problem when welding quenched and tempered steels. </li></ul><ul><li>limited-position welding process only flat and horizontal </li></ul>
  28. 29. GTAW or TIG <ul><li>Gas Tungsten Arc Welding or Tungsten Inert Gas or HELIARC Welding </li></ul><ul><li>is a process in which the joining of metals is produced by heating therewith an arc between a tungsten (non consumable) electrode and the work. </li></ul><ul><li>A shielding gas is used, normally Argon. </li></ul><ul><li>normally done with a pure tungsten or tungsten alloy rod, but multiple electrodes are sometimes used. </li></ul><ul><li>Filler metals are used such as stainless steel, Aluminum and Bronze. </li></ul>
  29. 30. Flux Cored Arc Welding (FCAW) <ul><li>is an automatic or semi-automatic electric arc welding process that uses an arc between a continuously fed flux-filled electrode and the weld pool. The process is used with shielded gas from a flux contained within the tubular electrode with or without additional shielding from an externally supplied gas. </li></ul>
  30. 31. FCAW flux filled electrode and torch
  31. 32. No shielding gas (FCAW)
  32. 33. With Shielding Gas (FCAW)
  33. 34. Two Types of FCAW <ul><li>no shielding gas </li></ul><ul><li>- using flux core in the tubular consumable electrode </li></ul><ul><li>uses a shielding gas </li></ul><ul><li>- gas that must be supplied by an external supply. This is known informally as &quot;dual shield&quot; welding. </li></ul>
  34. 35. Uses of FCAW <ul><li>Mild and low alloy steels </li></ul><ul><li>Stainless steels </li></ul><ul><li>Some high nickel alloys </li></ul><ul><li>Some wear facing/surfacing alloys </li></ul>
  35. 36. Advantages of FCAW <ul><li>FCAW may be an &quot;all-position&quot; process with the right filler metals (the consumable electrode) </li></ul><ul><li>No shielding gas needed making it suitable for outdoor welding and/or windy conditions </li></ul><ul><li>A high-deposition rate process (speed at which the filler metal is applied) in the 1G/1F/2F </li></ul><ul><li>Some &quot;high-speed&quot; (e.g., automotive applications) </li></ul><ul><li>Less pre cleaning of metal required </li></ul><ul><li>Metallurgical benefits from the flux such as the weld metal being protected initially from external factors until the flux is chipped away </li></ul>
  36. 37. Disadvantages of FCAW <ul><li>Melted Contact Tip – happens when the electrode actually contacts the base metal, thereby fusing the two </li></ul><ul><li>Irregular wire feed – typically a mechanical problem </li></ul><ul><li>Porosity – the gases (specifically those from the flux-core) don’t escape the welded area before the metal hardens, leaving holes in the welded metal </li></ul><ul><li>More costly filler material/wire as compared to GMAW </li></ul><ul><li>Less suitable for applications that require painting, such as automotive body works. </li></ul><ul><li>Cannot be used in a rugged environment limited to shop use only. </li></ul>
  37. 38. FCAW Equipment set up
  38. 39. TIG WELDING
  39. 40. GTAW or TIG process
  40. 41. GTAW Welding Equipment
  41. 42. TIG Welding Machine
  42. 43. TIG Torch
  43. 44. ADVANTAGES of GTAW <ul><li>most popular method for welding aluminum stainless steels, and nickel-base alloys. </li></ul><ul><li>Produces top quality welds. </li></ul><ul><li>No smoke or fumes </li></ul><ul><li>clean – no slag and spatter to be clean during welding </li></ul><ul><li>reduced distortion in the weld joint because of the concentrated heat source. </li></ul><ul><li>is very good for joining thin base metals because of excellent control of heat input. </li></ul>
  44. 45. ADVANTAGES of GTAW <ul><li>especially useful for joining aluminum and magnesium which form refractory oxides, </li></ul><ul><li>excellent to use for the reactive metals like titanium and zirconium, which dissolve oxygen and nitrogen and become brittle if exposed to air while melting. </li></ul><ul><li>welding process by fusion alone without the addition of filler metal.( non-consumable electrode) </li></ul><ul><li>Used in very critical service application and on very expensive metal or parts. </li></ul>
  45. 46. Disadvantages of GTAW <ul><li>EXPENSIVE </li></ul><ul><li>a. Arc travel speed and weld metal deposition rates are lower. </li></ul><ul><li>b. high price of Inert gases for shielding such as Argon and Helium. </li></ul><ul><li>c. price of Tungsten electrode is high. </li></ul><ul><li>d. Equipment costs are greater than that for other processes, such as SMAW, which require less precise controls. </li></ul><ul><li>MANY LIMITATIONS and cannot be used in full welding operations </li></ul>
  46. 47. Limitations of GTAW <ul><li>SLOWER WELDING PROCESS </li></ul><ul><li>slower than consumable electrode arc welding. </li></ul><ul><li>FAST CONTAMINATION </li></ul><ul><li>1. During transfer of molten tungsten from the </li></ul><ul><li>electrode to the weld. </li></ul><ul><li>2. tungsten inclusion(unbalance gas shielding the inclusion is hard & brittle) </li></ul><ul><li>3. During exposure of the hot filler rod to air. </li></ul><ul><li>4. When there is improper welding techniques along the line </li></ul>
  47. 48. GMAW or MIG <ul><li>is an electric arc welding process which joins metals by heating them with an arc established between a continuous filler metal (consumable) electrode and the work. </li></ul><ul><li>Shielding of the arc and molten weld pool is obtained entirely from an externally supplied gas or gas mixture both inert and reactive gases. </li></ul>
  48. 49. GMAW Welding Operations
  49. 50. MIG Machine with Spool feeder
  50. 51. GUN used in GMAW
  51. 52. MIG Torch
  52. 53. GMAW Weld Diagram
  53. 54. Advantages of GMAW <ul><li>Produced High quality welds & much faster than with SMAW and TIG welding. </li></ul><ul><li>No flux is used no slag entrapment in the weld metal. </li></ul><ul><li>Very little loss of alloying elements as the metal transfers across the arc. </li></ul><ul><li>Minor weld spatter is produced, and it is easily removed. </li></ul>
  54. 55. Advantages of GMAW <ul><li>Versatile and can be used with a wide variety of metals and alloys, such as Aluminum, Copper, Magnesium, </li></ul><ul><li>Nickel, Iron and many of their alloys. </li></ul><ul><li>The process can be operated in several ways, including semi- and fully automatic. </li></ul><ul><li>MIG welding is widely used by many industries for welding a broad variety of materials, parts, and structures. </li></ul>
  55. 56. Disadvantages of GMAW <ul><li>IT cannot be used in the vertical or overhead welding positions due to the high heat input and the fluidity of the weld puddle. </li></ul><ul><li>Has complex equipment compared to equipment used for the shielded metal-arc welding process. </li></ul>
  56. 57. Oxygen Fuel Gas Welding (OFW) is a group of welding processes which join metals by heating with a fuel gas flame or flares with or without the application of pressure and with or without the use of filler metal.
  57. 58. Types of Oxy-fuel Gas Welding <ul><li>Oxy-Acetylene or Oxygen- Acetylene Gas Welding </li></ul><ul><li>Oxy-Hydrogen or Oxygen- Hydrogen Gas Welding </li></ul><ul><li>Methylacetone-Propadiene Gas Welding </li></ul><ul><li>Pressure Gas Welding. </li></ul>
  58. 59. Advantages of Oxy-fuel Gas Welding <ul><li>Easy to use both welding and cutting </li></ul><ul><li>Controlled heat input </li></ul><ul><li>Controlled bead size </li></ul><ul><li>Convenient to use in welding thin sheets, tubes and small diameter pipes </li></ul>
  59. 60. Disadvantages of Oxy-Fuel Gas Welding <ul><li>Cannot be use to weld on thick work piece. </li></ul><ul><li>Expensive gas </li></ul>
  60. 61. Oxy-Acetylene Diagram Welding Equipment
  61. 62. Complete Oxy-Acetylene Welding Equipment
  62. 63. Resistance Welding <ul><li>  is a process in which the fusing temperature is generated at the joint by the resistance to the flow of an electrical current . </li></ul><ul><li>is  accomplished  by  clamping  two  or  more  sheets  of metal  between  copper  electrodes  and  then  passing  an electrical  current  through  them.  When  the  metals  are heated to a melting temperature, forging pressure is applied through either a manual or automatic means to weld  the  pieces  together. </li></ul><ul><li>Two common types are Spot  and Seam  welding </li></ul>
  63. 64. 2 Types of Resistance Welding SPOT WELDING SEAM WELDING
  64. 65. SPOT WELDING <ul><li>The metal to be joined is placed between two electrodes and pressure is applied. </li></ul><ul><li>A charge of electricity is sent from one electrode through the material to the other electrode. </li></ul>
  65. 66. SEAM Welding <ul><li>is </li></ul><ul><li>like spot welding except that the spots overlap each other, making a continuous weld seam. </li></ul>