2. Introduction to Welding
Area: Ag Mechanics
Unit: Arc Welding

3. OAW
Oxyacetylene
Tank of Oxygen
Tank of Acetylene
Striker
Goggles

4. GMAW
Gas Metal Arc
Tank of C25 (Oxygen/ Argon Mix)
Mig Gun

5. SMAW
Shielded Metal Arc
Electrode

6. GTAW Gas Tungsten Arc Rods / Spool Gun (filler Metal) Pedal
Non Consumable Electrode
Aluminum / Softer Metals

7. OAC Oxyacetylene cutting Cutting Attachment
Different O2 & Acet. Settings
Striker
Goggles

8. PAC
Plasma Arc Cutting
Air Supply
Cutting Torch
Clamp

10. Objectives: To identify approved clothing for Arc Welding
To determine the proper safety equipment needed for Arc Welding.
To identify the parts of an Arc Welder.
To identify how an Arc Welder works.

11. Behavior Most accidents are caused by carelessness
Caused by human error
Refrain from getting involved in poor
shop behavior:
scuffling playing with tools
tripping running
pushing hurrying projects
disobeying shop rules loud talking

12. What are the approved safety clothing and gear for Arc Welding?
Do not wear clothes that you do not want to get dirty.
Body Protection
Tight woven cotton or denim fabrics are most common and inexpensive.
Leather is the most effective but is more expensive.
Foot Protection
Leather shoes that cover the entire foot and have a high top.

13. Approved safety clothing and gear cont’
Hand Protection
Gauntlet type leather gloves that are heavy enough to protect hands from the heat.
Welding Helmet
Most made of lightweight, heat resistant materials
Protection for the head and face
Welding Lens
Fitted to the helmet
At least a # 10 shade
Safety Glasses
MUST be worn at all times

14. Here’s a good example of a welder wearing all the proper welding protection

15. SAFETY: Eye Protection
“An ounce of prevention is worth a pound of cure” when it comes to eye protection
Always wear proper eye protection when working in the shop
A welder must be protected from harmful light radiation given off by the welding process
For welding you will be using chipping goggles and a welding helmet

16. Here are
examples of
proper eye
protection

17. What are some safety practices used in Arc Welding?
Safety First
Always check equipment for warn or damaged parts
Make sure all safety gear is on and in proper working order.
WEAR YOUR SAFETY GALSSES!!!

18. Safety practices cont’
Good Ventilation
Welding fumes can be harmful to the welder causing implications such as:
Irritation of the respiratory tract
Metal fume fever
A condition known as siderosis
Slightly increase the risk of lung cancer
For these reasons, one should take precaution with welding fumes

19. Welding Fumes Welding should be done in a well ventilated area
Should attempt to control fumes at the source
Common ways
Extracted benches
Local exhaust ventilation

20. Common Ventilation Practices
Extracted bench method Local exhaust ventilation

21. What are some ways to prevent/protect ourselves from fire?
Discard frayed cords and wires
Don’t wear auto clothes in the welding shop
Keep flammable liquids away from heat
Class C fire extinguishers
for electrical and chemical fires
Fire Blanket
Use on people before trying to use a fire extinguishers.

22. Examples of Welding Practices

23. What is Arc Welding?
Arc Welding is the process of fusing metal together using the heat of an electric arc.
Done by sending an electric current through a coated metal rod called an electrode
Creates temperatures greater than F.

24. What are the common terms used in Arc Welding?
Arc Welder
Machine that supplies power for the welding process
Electrode
Metal rod with a flux coating that carries the current to the base metal
Base Metal
The metal to be welded on
Arc Length
Distance from electrode to the base metal

25. Common terms cont’ Voltage Amperage Resistance Open Circuit Voltage
Measure of the electrical pressure.
Amperage
Measure of the electrical current flowing through a circuit.
Resistance
The opposite to the flow of current which converts energy into heat.
Open Circuit Voltage
Constant amount of current flowing between electrode and base metal

26. What are the parts of a SMAW welder?
The power supply unit.
2 types Alternating Current (AC) and Direct Current (DC)
Cables
2 cables the electrode (+) and the grounding (-) that carry the electrical current

27. Parts of a welder cont’ Electrode Holder Grounding clamp
Spring loaded clamp with insulated handles attached to the electrode cable.
Holds the electrode.
Grounding clamp
Spring loaded clamp attached to the grounding cable.
Attaches to the welding table or project to carry the current back to the welder.

28. How does electricity flow in a welder?
Positive Cable
Electricity flows from the POSITIVE cable holding the electrode, to the Base Metal and through the grounding clamp back through the NEGATIVE cable to the machine
Electrode
Base Metal
Negative Cable

29. AC vs. DC Current

30. Parts of the SMAW Welder

32. Parts of a GMAW Welder

36. A B C D E F
Welding current too low.
Welding current too high.
Arc too long.
Welding speed too fast.
Welding speed too slow.
Proper amperage, voltage, and speed.

37. Parts of OAW

38. Oxygen
Colorless
Odorless
Promotes combustion (Not a flammable gas)

39. Acetylene Colorless Odor Flammable Unstable(explosive above 15psi)
Left Handed Thread
Acetone in a “sponge” = consistent

41. 3 Types of Flames Carbonizing Neutral Oxidizing Too much acetylene
Metal turns black and you can’t control the puddle
Neutral
equal amounts of O2 and acetylene
Oxidizing
too much O2
Dirty and bubbling, lots of sparks

42. Problems with OAW Torch pops, whistles, or goes out.
If this happens you have experience backfire or a flashback
Backfire vs Flashback
Flashback is when gases burn in the TIP
Black smoke comes out the tip, handle gets hot.
Turn off torch valves
- Turn off Tanks
Let Ms. Haslam Know
Check Equipment

43. Other Problems Too cold – bead sits on metal
Too Hot- bead sags through the metal *holes
Filler Rod Sticks – just wave the flame over it to get it unstuck.
Dirty tips- get it cleaned

44. Parts of a OAW Setup Acetylene Side Acetylene cylinder Cylinder valve
Red cylinder pressure gauge
Regulator
Hose pressure gauge
Red hose
Acetylene valve on torch
Oxygen Side
Oxygen cylinder
Green cylinder pressure gauge
Green hose
Oxygen valve on touch

45. Torches Cutting vs. Welding
Oxygen blaster
3 torch valves
Oxygen
Acetylene
Oxygen Blaster
Welding
2 torch valves
Oxygen & Acetylene
Rose Bud
Heat Up

46. What are the two gauges on the regulator used for?
Regulators
What are the two gauges on the regulator used for?
Tank Pressure
Hose Pressure

47. Setting Up the OxyFuel ***Shut down:***
Check regulator thumb screws
Turn on the oxygen valve all the way
Set the correct oxygen working pressure
Open acetylene cylinder valve one half turn
Set the correct acetylene working pressure
Light the flame
Shut down the flame (Fuel first)
Turn of the acetylene cylinder valve
Empty acetylene hoses until gages register zero
Turn off the oxygen cylinder valve
Empty the oxygen hose until gages register zero
Loosen regulator thumbscrews.
***Shut down:***
To shut of a torch correctly, first close the acetylene
valve on the torch then close the oxygen valve

48. Misc Safety Info Hood Shades Potential Hazards Shock Fumes U rays
Arc / Mig = #10
OxyFuel = #5
Potential Hazards
Shock
Fumes
U rays
Spark spatter
Fire and explosion

49. Questions??

50. Review for the Test