Block 4: SMAW
What size is the keyhole?
1 1/2 times the electrode diameter
The cover pass how far above the plate surface?
1/16 for 1/4" or less and 1/8 for more than 1/4"
How far should you overlap the previous bead when welding the filler pass?
1/3-1/2 inch width
What should the depth of penetration be for forming the crater?
1/3-1/2 the total thickness of the bead
What is the maximum undercut allowance?
1/32"
Vertical up welding is used for what thickness metals?
1/4" or greater
Vertical down welding is used for what thickness metals?
1/4" or less
Tack weld sizes
1/4-1/2 long
When using 200-400 amps what shade will you use?
12
What shade would you use for 400 amps or more?
14
For Overhead Joints what is the travel angle?
15 Degree Drag (for all OVERHEAD)
For Butt Joint, what is the FLAT travel angle?
15-30 Degree DRAG
For Lap Joint, Tee Joint, and Butt Joint what is the horizontal travel angle?
20 Degree DRAG
General recommendation for ventilation is a min. of what?
2000 CFM per welder
What is the primary voltage of a welding machine?
220-440 volts
Each layer of filler pass may not exceed what thickness for a butt joint?
3/16"
For Lap and Tee Joints what is the FLAT TRAVEL angle?
30 Degree DRAG
The 1st, 2nd, and 3rd pass work angles for the T-JOINT are what?
45 for 1st pass, 70 for the 2nd pass, and 30 degrees for the 3rd pass.
What is the standard overlap for a LAP JOINT?
5 times the thickness of the thinnest piece OR no less than 1 inch.
Resistance creates an intense arc heat ranging anywhere from what temp. range?
6000-10000 degrees Fahrenheit
For SMAC, what angle do you hold the electrode at to the metal surface?
70 degrees
When welding what amp range would you use Shade 10?
75-200
What are the ranges of auto darkening helmet shades?
8-14
Flat Butt Joint working angle is what?
90 Degrees
This current flows in one direction for the first half of the cycle and the opposite direction for the second half of the cycle?
AC
What causes overlapping?
AMP'S too low and extended the weld past the weld toes
The amount or rate of the current that flows in a circuit
AMPs
What is the main advantage of DC?
Allows greater flexibility for welding materials of different thicknesses by changing the slope of the output current to produce a soft or harsh arc
What must you always do before making repairs?
Always disconnect the power
How do you restart the weld?
Clean slag 1/2" behind the keyhole and strike the arc 1/2 behind the keyhole
If you must stop or change electrodes in the middle of a weld then you must?
Clean the weld, Strike 1/2" in front of the crater, and then bring back into the crater and weld through it.
What is done after first layer of surfacing is complete?
Clean thoroughly and start second layer (about 1/2" wide) at right angle to the first layer
What are the three types of butt joints?
Closed butt (up to 3/16 inches thick), Open butt joint (3/32-1/8 inch apart) and Beveled butt joint (should not exceed 60 degree angle)
Typical motions for flat position welding?
Crescent weave, figure 8, rotary weave, or zigzag weave
Typical motions for horizontal position welding?
Crescent weave, zigzag weave, slant weave(crescent weave)
What is the main advantages of repairs?
Cuts down cost of replacement and also limits the time a component is out of commission
What welding machine should be used for SMAC
DCEN (Provides more heat on base metal and less on the electrode)
DCEP produces what?
Deeper weld penetration and a narrower weld bead
what does DTF stand for
Down to F!@#
What is the preferred electrodes for SMAC?
E-6010 or E-6011 (Deep penetrating qualities)
What holds the electrode during welding?
Electrode holder (Stinger)
Under DCEN the electrode holder and the work are connected to what poles?
Electrode holder connected to the NEGATIVE POLE and the work is to the POSITIVE POLE
What joints do not require a "hot pass"?
Fillet Joints
One of many advantages of AC welding is?
Free from magnetic arc blow
Fill-freeze electrodes
General purpose electrode
Fast-fill electrode
Generally used for production welding
400-600 AMP Machine is used for what?
Heavy duty welding with large capacity
DCEP is preferred for what positions?
Horizontal, vertical, overhead, and for welding cast iron
What does slag do?
Insulates the bead from the contaminates in the surrounding atmosphere
Definition of SMAW
Is the process in which the arc is shielded by the decomposition of the electrode covering
150-200 AMP Machine is used for what?
Light and medium duty welding
What are the four basic elements to sustaining an arc?
Machine setting Proper arc length Electrode angle Speed of travel
What steels are the most popular in welding?
Mild and low alloy steels
What is "the law" on how electrical equipment is to be installed?
National Electric Code "NEC"
When welding two pieces of different thicknesses where do you want to concentrate the heat?
On the thickest piece. This will help prevent burning away the thinnest piece.
When is the range switch to be operated?
Only when the machine is idling and the current is open
What are the limitations of SMAW?
Operator duty cycle and over all deposition rates, Usually less for covered electrodes than with a continuous electrode process, SMAW electrodes have a fixed length, Welding must be stopped and the slag must be removed after each electrode has been consumed before welding can be continued, Not all metals can be welded with this process due to the heat output and chemistry make up of certain non-ferrous metals.
DCEP is referred to as what?
Reverse Polarity
In OVERHEAD Welding what must you do to the AMP'S?
Set slightly lower than what is used for flat position to help minimize puddle sagging.
In OVERHEAD Butt Joints complete the Root Pass with what motion?
Slight Whipping motion
DCEN is often referred to as?
Straight Polarity, It produces a shallow weld penetration compared to DCEP
What can develop on ungrounded machines and could cause severe shocks when ungrounded parts are touched?
Stray current
What are the 2 ways of striking the arc?
Tapping and Scratching methods- Raise the electrode 3/8" to 1/2" to preheat the metal.
This indicates the direction of the current flow in the circuit ?
The Polarity
What shields the weld arc and molten pool from contaminates in the surrounding atmosphere?
The Vapor
What provides the heat when welding, and what is the ranges?
The amperage and it ranges from 25-500 amps
This produces the heat that is required to melt the electrode and the base metal, and burn the electrode coating?
The arc
If the cable diameter is to small what will happen?
The cable will overheat
What burns on the electrode and produces a vapor?
The flux
What must you not operate while the machine is under load?
The range switch
What does the Hot Pass penetrate?
The root pass and the root face
The electrode should not be larger than what?
The thickness of metal being welded.
This pushes the current through the wires
The voltage
This produces the welding current and what are the ranges?
The voltage output and it ranges from 18v-36v
What determines the settings for the welding machine, electrodes, type and thickness of the metal to be welded, and the position of the joint?
The welder
What is hard surface welding used for? (AKA Surfacing)
To repair worn surfaces and other machine parts
What are the three types of welding machines?
Transformer (AC only), DC machine, Rectifier (AC and DC)
Typical motions for vertical position welding?
Triangular weave, rotary weave, zigzag weave
What do you do when you're completely done with welding?
Turn the machine OFF, Main power switch OFF, and hang up the electrode holder when finished welding
You want to hold a long arc (3/8"-1/2") until what?
Until the arc stabilizes
Fast-freeze electrodes
Used for all types of all-position welding
250-300 AMP Machine is used for what?
Used in plants for average welding requirements
Fill-Freeze and Fast-Freeze electrodes are preferred for what types of welding?
Vertical and overhead
What are the travel angles for vertical welds?
Vertical down is 15-30 degree DRAG, Vertical up is 10-15 degree PUSH
If the cable diameter is to large what will happen?
Voltage will drop
What is the difference between Volts and AMP'S?
Volts-The force that causes current to flow in a circuit. AMP'S-The amount or rate of current that flows in a circuit.
What causes undercutting?
When the amperage is too high
Typical motions for overhead position welding?
Zigzag weave, rotary weave
Cap or cover pass
adds additional reinforcement to the weld and adds a nice appearance
Filler pass
fills the remaining portion of the weld after the root pass
Root Pass
the first weld which is the initial pass that provides complete penetration through the thickness of the joint member (weave motion is NOT used..just drag it. Whipping motion may be used)
