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• Upon successful completion of this unit of study, you will be able to …
– Identify definitions and terminology associated with welding
– Demonstrate safe working habits in the welding environment
– Name the parts and types of welds and weld joints
– Interpret basic welding symbol information
– Identify opportunities available to welders

• Definition
A joining process that uses heat, pressure, and/or chemicals to fuse two materials together permanently.

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– Welding can help build a successful career so you can get the things you want in life
– Skilled welders are in demand – people use things that are welded everyday!
– Welding can be fun and safe
– It is challenging and high-tech

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• Many of the same concepts you learn in other classes are practiced in welding. In what other classes might you study the following terms?
• 75/25 – gas mixture
• Volts
• Amps
• Degree/hr – cooling rate
• In/min
• Angles/degrees
• Metallurgy
• Fillet size
 Current
 Tension
 Compression
 Tensile strength
 Yield
 Blueprints
 Depth/width ratio
 Preheat temperature
 Cubic feet per hour

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Job opportunities in welding are changing …
Welding can be valuable as a job skill or as a full-time job
• Engineering
• Racing
• Industrial Sales
• Farm Repair and Fabrication
• Production Welding
• Military
• Teaching
• Maintenance
• Robotics
• Ironworker/ Skilled
Trades
• Auto Technician
• Artist
• Metal Sculpting
• Owning Your Own
Business

How Much Money Can You Make?
• Recent statistics show that some welding jobs pay $25.00 per hour
• Local employers pay around $13-$22
• 83% of people with welding jobs were offered medical benefits
Higher than any other work sector except government

• http://www.indeed.com/q-Welding-l-
Manitowoc-County,-WI-jobs.html

• Welder
– One who performs a manual or semiautomatic welding operation
• Weld Operator
– One who operates adaptive control, automatic mechanized or robotic welding equipment.

• MA: Manual Welding
• SA: Semiautomatic
• ME: Mechanized Welding
• AU: Automatic Welding

• Welding with the torch, gun, or electrode holder held and manipulated by hand.
• Oxy-fuel welding
• Gas Tungsten Arc Welding (GTAW)
• Shielded Metal Arc Welding (SMAW)
• Shielded Metal Arc Welding (SMAW)

• Manual welding with equipment that automatically controls one or more of the welding conditions
• Gas Metal Arc Welding (GMAW)

• Welding equipment that requires manual adjustment of the equipment controls in response to a visual observation.

• Welding with equipment that requires only occasional or no observation and no manual adjustment of controls.
• Robots

Voltage pressure, force, or push Volts
Current flow of electron Amps
Resistance hinders current flow
DCEP Direct Current Electrode
Positive
Ohms
DC+
Straight polarity
(-) to (+)
DCEN
AC
Direct Current Electrode
Negative
DC-
Reverse Polarity
(+) to (-)
Alternating current
Changes polarity
120/second

• Welding Circuit Consists of Power Source,
Wire Feeder, and Work and Electrode
Cables/Leads
• Voltage is Proportional to Arc Length
• Current Changes Dramatically to Maintain Constant
Arc Length

• Welding Circuit Consists of Power Source,
Voltage Sensing Wire Feeder, Work and
Electrode Cables/Leads
• Voltage is Proportional to Arc Length
• Current Remains Constant
Even for Changes in Voltage
Due to Changes in
Arc Length

Math Terms in Welding
IPM Travel Speed = Inches per
Minute Travel Speed
IPM Wire Feed Speed= Inches per
Minute Wire Feed Speed
Lbs/hr = Pounds per Hour
The speed the electrode moves along the base material
The speed at which the wire is fed during wire welding
Electrode deposition rate
CFH= Cubic Feet per Hour
PSI=
L =
% =
Pounds per Square Inch
Leg percent
Shielding gas flow rate (wire welding)
Tensile strength of a material and the pressure in gas cylinders
Fillet size measurement
Shielding gas mixture composition
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PPE includes:
• Hat or Beanie
• #12-14 Mask
• Safety Glasses
• Ear Plugs
• Jacket
• Gloves
• Jeans
• Boots

• List PPE head to toe
__________________
__________________
__________________
__________________
__________________
__________________
__________________
__________________

• Clamps
• Magnets
• Side Cutter
• Wire Brush
• Slag Hammer

• A real welder takes the time!
• This should take longer than the weld
• Clean, clean, clean!
• Joint fit-up.
• Debur sharp edges
• Bevel material ¼” or thicker
• Preheat material ½” or thicker

• SHEET: measured by gauge (.0068″) to (.2391″)
• PLATE: measured by inch rule (1/4” and up)
For example, steel gauge and measurement in inches:
16 gauge = .062″ 14 gauge = .078″ 12 gauge = .105″ 10 gauge = .135″
PLEASE NOTE: As the gauge number gets smaller … the material thickness gets larger.
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• HOT PARTS can burn.
• FUMES AND GASES can be hazardous.
• ARC RAYS can burn eyes and skin.
• WELDING can cause fire or explosion
• FLYING METAL or DIRT can injure eyes.
• BUILDUP OF GAS can injure or kill.
• ELECTRIC AND MAGNETIC FIELDS (EMF) can affect Implanted Medical Devices.
• NOISE can damage hearing.
• CYLINDERS can explode if damaged.

• FIRE OR EXPLOSION hazard.
• FALLING EQUIPMENT can injure.
• OVERUSE can cause OVERHERATING
• FLYING SPARKS can injure.
• MOVING PARTS can injure.
• WELDING WIRE can injure.
• BATTERY EXPLOSION can injure.

LENS SHADES SELECTION FOR GAS METAL ARC WELDING
Operation
Electrode Size
in. (mm)
Arc
Current (A)
Minimum
Protective
Shade
Suggested *
Shade No.
(Comfort)
GMAW
Not Specified
Per
AWS / ANSI
Less than 60
60-160
160-250
250-550
10
11
7
8
10
12
12
14
* As a rule of thumb, start with a shade that is too dark to see the weld zone. Then go to a lighter shade, which gives sufficient view of the weld zone without going below the minimum.

The Arc Welding Circuit
• The electricity flows from the power source, through the electrode and across the arc, through the base material to the work lead and back to the power source
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• “Length of time a welder can be used continuously at its rated output in any 10 minute interval”
• Every welder has a duty cycle (60-80% common)
• TRHS Lincoln V350-PRO are 60% duty cycle
– May weld 6 minutes out of a 10 minute interval
– Fan kicks on and robes amperage

• Can you identify theses joints?

1: Flat
2:Horizontal
3: Vertical
4: Overhead
5&6: Pipe
G: Groove Weld
F: Fillet Weld

• Push, Pull
• Up, Down
• Lead Angle
• Work Angle
• Travel Speed
• Arc Length
IMPORTANT: Weld bead profile is affected by electrode angle, arc length, travel speed, and thickness of base metal.

• Push
– Push weld puddle
– Deep Penetration
– Less weld buildup
• Pull
– Pull weld puddle
– Less Penetration
– More weld buildup

• Vertical down is uncommon
• Heat rises making the puddle easier to control
• Arc hard to see

20-30°
Travel Angle
• Also commonly called
Lead Angle
• The travel (lead) angle is the angle between the electrode and the plane perpendicular to the weld axis
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90°
• The work angle is the angle between the electrode and the work as depicted on the left
• Work angles can vary depending on the position the weld is being made in

• The distance the arc stretches from the electrode to the work-piece.
• Distance varies between processes

• Stringer
• Weave
• Whip (6010, 6011, 6013 only)

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• The travel speed is the speed at which the electrode moves along the base material while welding
– Too fast of a travel speed results in a ropey or convex weld
– Too slow of a travel speed results in a wide weld with an excessive metal deposit
End of Weld
The travel speed impacts the shape of the bead.

• Identify good, fast, slow

Acronym used to recall proper welding technique
• C…Current (DCEP, DCEN, AC)
• L….Length of arc (Drag, 1/16, 1/8, ½”, etc.)
• A…Angles (Travel angle, work angle)
• M…Manipulation (Straight, weave, whip, etc.)
• S…Speed of Travel (How fast you move)

• Tack Weld
• Intermittent (Stitch) Weld
• Groove Weld
• Fillet Welds
• Plug or Slot Weld
• Multipass Welds
– Root Pass
– Hot Pass
– Fill Pass
– Cover Pass

• Temporary but very important!
– Small enough to be welded over
– Strong enough to hold metal in position
– Position every 3-4 inches
– Tack all sides if possible

• Tack welds prevent distortion and warping
• Tack weldment to table if practical

• Welder doesn’t weld entire joint
• Allows joint variation / flexibility
• Lowers production cost
• Reduces distortion

• Welding pass that deposits filler material into base material.
– Butt Joint
– Face Weld

• A fillet is a closed weld, which means the base metal is not cut through to accommodate weld metal.
• The process of joining two pieces of metal together whether they be perpendicular or at an angle.

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• Fillet welds should:
– Have a flat to slightly convex face
– Be uniform in appearance
– Have equal leg size
– Have good wash-in into base materials
• This is an example of a good fillet weld:

• A circular fusion weld made in the hole of a slotted lap or tee joint

1. Root Pass
2. Hot Pass (within 5 min.)
3. Fill Pass
4. Cover Pass
5. Cover pass
6. Cover Pass
Bead Overlap should cover ~ 75% of previous pass.

• Identify each pass (hot, fill, root, cover)

• Concave vs. Convex
• Leg
• Toe
• Face
• Throat
• Root
• Fusion Zone

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Heat Affected Zone
Joint and Weld

• Cross sectional view of the weld

Information that you needs to complete weld!

• Area of base metal which is not melted and has had its microstructure and properties altered by welding or heat.
• The heat from the welding process and subsequent re-cooling causes molecular change in the base metal.

• Distortion: Metal expands with heat
• Warping: Contracts even more as it cools
• Impossible to get rid of it but able to manage it!

• Quality tack welding
• Intermittent welding
• Weld little material as possible
• Clamp or secure weldment to table
• Alternate weld locations (front, back, front, etc)
• Cool in sand or heated oven
• Backstep welding

• Welding in short lengths reduces longitudinal bowing but increases welding costs (time)

• Always handle hot metal with a pliers
• Assume metal is hot at all times
Sand - slow
Air - medium
Purge/Quench - Fast
* Swirl figure 8 pattern

• Defect
– A flaw or flaws that by nature or accumulated effect render a part or product unable to meet minimum applicable acceptance standards or specifications.
– The term designates rejectability.
• Discontinuity
– An interruption of the typical structure of a material, such as a lack of homogeneity in its mechanical, metallurgical, or physical characteristics.
– A discontinuity is not necessarily a defect!

• Misalignment
• Undercut
• Underfill
• Concavity or Convexity
• Excessive reinforcement
• Improper reinforcement
• Overlap
• Burn-through
• Poor Penetration
• Incomplete Fusion
• Surface irregularity
• Arc Strikes
• Inclusions
• Spatter
• Arc Craters
• Cracks
• Base Metal Discontinuities
• Porosity
• Heat-affected zone microstructure alteration
• Base Plate laminations
• Size or dimensions

Knowing what discontinuities are, is the key to quality welds.
It is important for a welder to produce and confirm a proper weld!

• Single Pore
• Uniformly Scattered
• Cluster
• Linear
• Piping

• Toes do not tie in metal
• Causes: Improper technique, low heat
• No amount of overlap is typically allowed.

• Definition: Under fill along the toes of the weld.
• Cause: High amperage, electrode angle, long arc length, rust

• Front
• Back