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Welding Basics. Manufacturing Technology HPEDSB. What is Welding?. The process of joining two or more pieces of similar metals, through the application of heat and sometimes filler material. Base Metal Part 1. Base Metal Part 2. The two pieces have been joined using a Butt Joint.
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Welding Basics Manufacturing TechnologyHPEDSB
What is Welding? The process of joining two or more pieces of similar metals, through the application of heat and sometimes filler material. Base Metal Part 1 Base Metal Part 2 The two pieces have been joined using a Butt Joint
Overview of the Weld Penetration The most important aspect of any weld is the amount of penetration or the depth that the filler material fuses into the original workpiece or parent metal.
Welding can be broken down into two sub-categories. 1. Fusion 2. Non-Fusion Any welding operation involving melting of the base or parent metal. The joining of metals without melting the base or parent metal. Each sub-category can be broken into methods of welding Gas Welding (oxy-acetylene torch) GMAW (Gas Metal Arc Welding) SMAW (Shielded Metal Arc Welding) GTAW (Gas Tungsten Arc Welding) Brazing (oxy-acetylene torch)
Fusion Welding # 1Gas Welding Oxygen Regulator Gauges Acetylene Regulator Gauges • Uses the heat created by a flame fueled by compressed acetylene gas and accelerated by compressed oxygen • The flame is created and maintained at the end of the torch tip and varied by controlling the line pressures as well as the valves for each compressed gas • Three main flame types known as: • Carburizing – too much acetylene in the mixture • Neutral – correct mixture of acetylene and oxygen to be used for welding • Oxidizing – too much oxygen in the mixture, sometimes required for cutting Acetylene Tank Oxygen Tank Shade 5 Goggles Torch Friction Lighter
Fusion Welding # 2GMAW (MIG Welding) • Gas Metal Arc Welding • Metal Inert Gas Welding • Uses an electric arc to create heat for the welding process • Uses an automatically fed filler rod to help join the pieces of metal together • Uses shielding gas to prevent contaminants from entering the weld
Main Unit Hose for Shielding Gas Gun Ground Clamp The circuit must be completed to create an arc.
1. 2. 3. 4. 5. 6. 7. The parts of a MIG gun and the weld itself Direction of travel Contact Tip (Copper) Wire Filler Rod Shielding Gas / Fumes Weld Pool Solidified Weld Parent or Base Metal
Fusion Welding # 3SMAW (Arc Welding) • Shielded Metal Arc Welding • Uses an electric arc to create the heat for the welding process • Uses a consumable electrode that provides the filler material for the weld • Electrode can be coated to provide a shielding gas when burning off during the welding process
Main Unit Electrode Holder Ground clamp The circuit must be completed to create an arc.
Arc Welding Electrodes vary in size, type, positional use and strength. The following example shows the meaning of the identifiers on a common electrode Power source (AC, DC or both), type of coating (low hydrogen, mineral, organic or rutile), type of arc (soft, medium or digging), penetration (light, medium or deep) and amount of iron powder in the coating. E 7 0 1 8 Electrode Position 1 – All 2 – Horizontal 4 - Vertical Tensile strength of weld in thousands of pounds per square inch
Fusion Welding # 4GTAW (TIG Welding) • Gas Tungsten Arc Welding • Tungsten Inert Gas Welding • Uses an electric arc to create the heat required for the welding process • Uses a torch with a tungsten electrode to produce the heat for the weld – torch also emits the shielding gas for the weld • Filler rod is fed in by hand which makes it a very controlled weld • Welding temperatures can be varied at any point during the weld via the foot pedal control
Non-Fusion Welding # 1Brazing • Brazing is a method of joining metals together without fasteners or by using a fusion welding process • A filler rod (usually bronze) is heated by an oxy-acetylene torch and melts at a lower temperature than the materials being joined, therefore allowing it to flow onto the material • When the bronze cools, it dries and forms a surface bond that is quite strong • Comparable to hot glue on wood products
Welding Safety Overview • Proper eye protection must be worn at all times • Shade 10 for all Arc welding processes • Shade 5 for brazing or gas welding • Welding curtains should always surround you to protect the other people working in your immediate area • Skin protection should also be worn including: • Welding Gloves • Welding Apron or Welding Coat
Prestart Checks • Dampness or water in welding area • Leaks in gas tanks (check with soapy water) • Cable and hose condition (free of cracks, tears) • Flammable or combustible materials in area • Proper ventilation (is system turned on)