1. Welding 101

2. Objectives
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
SECTION OVERVIEW:
This slide is included to explain the objectives of this unit of study.
TEACHER NOTES:
Teachers could use this opportunity to give a high-level overview of the importance and application of welding in today’s society.

3. What is it?
Definition
A joining process that uses heat, pressure, and/or chemicals to fuse two materials together permanently.

4. Why Learn to Weld?
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

5. STEM Connection
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

6. Careers in Welding 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

7. 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

8. Job Openings

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

10. Methods of Application
MA: Manual Welding
SA: Semiautomatic
ME: Mechanized Welding
AU: Automatic Welding

11. MA: Manual 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)

12. SA: Semiautomatic Welding
Manual welding with equipment that automatically controls one or more of the welding conditions
Gas Metal Arc Welding (GMAW)

13. ME: Mechanized Welding
Welding equipment that requires manual adjustment of the equipment controls in response to a visual observation.

14. AU: Automatic Welding
Welding with equipment that requires only occasional or no observation and no manual adjustment of controls.
Robots

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

16. Constant Voltage – CV Welders
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 4

17. Constant Current – CC Welders
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 4

18. Math Terms in Welding
IPM Travel Speed = Inches per Minute Travel Speed
The speed the electrode moves along the base material
IPM Wire Feed Speed= Inches per Minute Wire Feed Speed
The speed at which the wire is fed during wire welding
Lbs/hr = Pounds per Hour
Electrode deposition rate
CFH= Cubic Feet per Hour
Shielding gas flow rate (wire welding)
PSI= Pounds per Square Inch
Tensile strength of a material and the pressure in gas cylinders
L = Leg
Fillet size measurement
% = percent
Shielding gas mixture composition

19. PPE includes:
Hat or Beanie
#12-14 Mask
Safety Glasses
Ear Plugs
Jacket
Gloves
Jeans
Boots

20. Welding Safety List PPE head to toe __________________
__________________ __________________

21. Common Welding Tools
Clamps
Magnets
Side Cutter
Wire Brush
Slag Hammer

22. Metal Preparation 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

23. 16 gauge = .062″ 14 gauge = .078″ 12 gauge = .105″ 10 gauge = .135″
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″ gauge = .078″ gauge = .105″ gauge = .135″
PLEASE NOTE: As the gauge number gets smaller … the material thickness gets larger.

24. Welding Safety 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.

25. Welding Safety 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.

26. AWS/ANSI Lens Shade Numbers

27. 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

28. Duty Cycle
“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

29. 5 Basic Welding Joints

30. Welding Joints
Can you identify theses joints?

31. AWS: Welding Positions
1: Flat 2:Horizontal 3: Vertical 4: Overhead 5&6: Pipe
G: Groove Weld
F: Fillet Weld

34. Electrode Travel 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.

35. Push Vs. Pull Push Pull Push weld puddle Deep Penetration
Less weld buildup
Pull
Pull weld puddle
Less Penetration
More weld buildup

36. Up vs. Down Vertical down is uncommon
Heat rises making the puddle easier to control
Arc hard to see

37. 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
20-30°

38. Work Angle
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
90°

39. Work vs. Travel

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

41. Bead Manipulation
Stringer
Weave
Whip (6010, 6011, 6013 only)

42. Travel Speed
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.

43. Test Your Knowledge
Identify good, fast, slow

44. Acronym used to recall proper welding technique
C.L.A.M.S
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)

45. Types of Welds Tack Weld Intermittent (Stitch) Weld Groove Weld
Fillet Welds
Plug or Slot Weld
Multipass Welds
Root Pass
Hot Pass
Fill Pass
Cover Pass

46. Tack Welds 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

47. Tack Welds Tack welds prevent distortion and warping
Tack weldment to table if practical

48. Intermittent (Stitch) Welding
Welder doesn’t weld entire joint
Allows joint variation / flexibility
Lowers production cost
Reduces distortion

49. Grove Welds
Welding pass that deposits filler material into base material.
Butt Joint
Face Weld

50. Fillet Welds
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.

51. Fillet Weld Inspection
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:

52. Plug /Slot Welds
 A circular fusion weld made in the hole of a slotted lap or tee joint

53. Bead Overlap should cover ~ 75% of previous pass.
Multi-Pass Welding
Root Pass
Hot Pass (within 5 min.)
Fill Pass
4. Cover Pass
5. Cover pass
6. Cover Pass
Bead Overlap should cover ~ 75% of previous pass.

54. Multi-Pass Welding
Identify each pass (hot, fill, root, cover)

55. Weld Bead Terminology Concave vs. Convex Leg Toe Face Throat Root
Fusion Zone

56. Concavity

57. Convexity

58. Parts of a Weld
Heat Affected Zone
Joint and Weld

59. Joint Profiles
Cross sectional view of the weld

60. Welding Symbols
Information that you needs to complete weld!

61. Weld Symbols

62. Heat-affected Zone (HAZ)
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.

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

64. Controlling Distortion
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

65. Back-step Welding
Welding in short lengths reduces longitudinal bowing but increases welding costs (time)

66. Cooling Welds 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

67. Discontinuities & Defects
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!

68. Types Discontinuities
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

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

70. Good Weld Characteristics

71. Poor Weld Characteristics

72. Porosity
Single Pore
Uniformly Scattered
Cluster
Linear
Piping

73. Overlap / Cold Lap Toes do not tie in metal
Causes: Improper technique, low heat
No amount of overlap is typically allowed.

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

75. Spatter

76. Burn Through
Front
Back