1. Flexible Manufacturing
Welding Skills
Flexible Manufacturing
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Welding
The term welding means joining two or more pieces of metal together along an edge or surface. This is done by heating the metal to a melting point and letting the metal fuse together to form one piece.
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Blacksmith Welding
Blacksmiths would heat two pieces of metal to a white hot, then use a hammer to forge them together.
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4. Theory of Shielded Metal Arc-Welding
Shielded Metal Arc-Welding is the process of arc welding. The American Welding Society has changed the term used. This is also called stick welding or arc welding.
This is the use of an electric arc for heating the base metal and a fluxed rod for the filler.
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5. Shielded Metal Arc-Welding
When the electricity passes through the fluxed rod or electrode an arc is struck between the metal to be welded and the electrode.
This arc heats the metal and electrode causing the pieces to melt and fuse together.
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6. Shielded Metal Arc-Welding Equipment
Welding equipment is sized by current type and duty cycle. The welder can be both direct current (DC) or alternating current (AC). DC welding equipment can be powered with a gas engine to be able to use it in the field. DC welding equipment produces a wider range of amperages for welding thicker materials.
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7. Shielded Metal Arc-Welding Parts
Power source and control
Electrode holder
Electrode cable
Ground clamp
Ground cable
Electrode B.
OFF A. F. D. E. C.
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Welding Duty Cycle
The duty cycle is the time the welder can be used at a specific current level in a 10 minute period. For example: 60% at 150 amps is the continuous use for 6 minutes of welding at 150 amps of power. Then the machine needs 4 minutes to cool down to protect it from overheating.
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Electrode
An electrode is a metal rod covered with a coating to shield the molten puddle from impurities in the air. This is known as flux. Electrodes are classified by diameter, tensile strength, welding current, type of coating and position for use.
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10. Electrode Classifications
Positions of welding:
1 = all positions (flat, horizontal,
vertical and overhead)
2 = horizontal and flat positions only
3 = flat position only
E = Arc welding electrode
E6013
Tensile strength
first two (or three)
numbers x 1000 or
60 X 1000 = 60,000 psi
power supply
type of coating
polarity
type of arc penetration
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11. Example of Electrode Classification
E6013 = 60,000 tensile strength, all position and a coating of titania potassium
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12. Electrode Classification Chart
Welding Current
Penetration
Coating
Application
E6010
DC reverse
deep
Cellulose
Best all positions
E6011
AC - DC
Cellulose potassium
Primarily for AC current
E6012
AC – DC straight
medium
Titania sodium
For joints with poor fit
E6013
AC – DC
both
shallow
Titania potassium
Best general purpose electrode
E6024
straight
Iron power titania
High deposition
E7018
reverse
Iron power, low hydrogen
For medium carbon and low carbon steel
E7024
AC DCEP
Wide passes, smooth beads
E11018
For heat treated steel
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Oxygen-Fuel Welding
This type uses a torch fueled by acetylene, propane, natural gas, hydrogen or MAPP gas
Acetylene is the most popular fuel to use for the welding and cutting because of the amount of heat produced.
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14. Oxygen-Fuel Welding Rods and Fluxes
mild carbon steel rod 1/16 to ¼ inch diameter
bronze rod for brazing with flux
cast iron filler rods with flux
A wire coat hanger can be used as a filler rod for gas welding.
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15. Oxy-fuel Welding EquipmentB. C.
Tanks
Regulators
Hoses
Torch handle
Torch tip B. A. A. D. E.
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16. Plasma Cutting Processes
Plasma is an ionized gas that will conduct electricity. The gas is compressed air, and electricity is added through an electrode. The more electricity, the hotter the plasma arc becomes.
The plasma rushes from the
torch forcing the molted
metal from the cut.
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17. Plasma Cutting Processes
The arc is concentrated in the torch tip and this heats the metal and forces the molten metal from the cut. The plasma cutter will cut any material that conducts electricity. The plasma cutter will cut metal up to 2” in thickness or down to sheet metal thickness. The cuts are clean with little or no material stuck to the back of the cut.
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Plasma Cutter Parts
Power Supply
Torch
Lines
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19. Oxygen-Acetylene Cutting Processes
The flame heats the metal to a molten state with an oxygen blast forcing the molten metal from the cut.
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20. Oxy-fuel Cutting Equipment
The oxygen-acetylene cutting process uses the same equipment as welding except the cutting torch head replaces the welding tip.
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21. Welding Assignment Criteria
Beads should be smooth and even; no splatter or slag left on material.
Welds can be made with the arc welder or oxy-fuel welder. The only difference will be the thickness of metal used.
Grades will be determined by appearance and penetration of weld as determined by a welding projects rubrics.
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22. Welding Assignment: beads across a metal plate
The metal for arc welding should be a
3” x 3” x ¼” metal plate.
The metal for oxy-fuel welding should be a 3” x 3” x 1/8 metal plate
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23. Welding Assignment: making joints
Use the cutting torch and cut (8) 1 ½” x 4” strips of metal to weld the following joints:
Corner Joint
Butt Joint
Lap Joint
T –Joint
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Resources
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