1. Arc Welding Ag I Welding Unit 2

2. Electrodes • Wide variety available to allow welder to do different jobs and weld in different positions • Positions • Flat, horizontal, vertical up and down, overhead • Some electrodes are suitable for all positons, others only 1 or 2

3. Numberical Coding for Electordes • 4-5 digit number • Numbers preceded by the letter “E” to indicate that the number describes an electrode E 6011

4. Reading an Electrode • E 6013 • E-Electrode • 60—tensile strength (Thousands of pounds) • Tensile strength is the amount of pull the weld can withstand • 1—type of welding the electrode is capable of doing • 3—depth of penetration

5. 5 digit Electrode Numbers • The same as a 4 digit except • First 3 numbers represent tensile strength • Fourth number represents welding position • Fifth number refers to depth of penetration

6. All Around Electrodes • 6011 • Most commonly used • Not easy for beginers to use to make an attractive weld • 6013 • Popular for beginning welders • Inexpensive • Easy to use

7. Personal Protection in Arc Welding • Helmet with a No. 10 shaded lens must be worn • Safety glasses under the helmet or on your person to be worn when chipping slag • Other PPE that was already discussed

8. Shielded Metal Arc Welding • Also called arc welding or stick welding • Shielded refers to the gaseous cloud that forms around the weld as the flux burns • The flux removes impurities and floats them to the top of the weld to form a layer called slag

9. Duty Cycle • The percentage of time that a welder can operate without overheating • Example: a 20 percent duty cycle welder should only weld 12 minutes out of every hour.

10. Electricity for Welders • Amps-the measure of the rate of flow in a conductor • A conductor is any material that permits current to move through it • Volts- the measure of electrical pressure • Watt-the measure of electrical energy available for work that can be done

11. Alternating and Direct Current • Alternating Current (AC)-current that reverses in direction of flow frequently. • In the U.S. power plants produce electricity that reverses direction of flow 60 times per second. This is referred to as 60-cycle current • Direct Current (DC) • Really generators • Current only flows in 1 direction • Can be set for both straight (neg.) and reverse (pos.) polarity

12. Welding Table and Booth • Metal Table • Curtains around table to protect others from the flash of the arc • If working outside the booth, set up portable curtains to protect others

13. Electrode Holders & Ground Clamps • Electrode Holder • Spring loaded device with an insulated handle • Used to grip the electrode • Ground Clamp • Spring loaded clamp • Not insulated like the electrode holder • Should be connected to the welding table

14. Arc Welder Temperture • Arc from a welder has a temp of 9000 ˚F