WD 110 Final

Which of the following gases is the least dense

Helium

Welds that are more difficult to perform than most other welds

Horizontal butt

Provide the necessary shielding because they do not form compounds with any other substance

Inert gases

In a (n) ____________ welding machine the incoming power is changed from 60 cycles per second to several thousand cycles per second

Inverter

A (n) _______ Joint is made by overlapping the edges of two plates, and can be welded on one side or both sides with a fillet weld

Lap

A (n) _________ Electrode angle pushes the molten metal and slag ahead of the weld

Leading

What can a welder do to prevent possibly swaying while welding

Lean against or hold onto a stable object

What can be done to keep the spatter to a minimum when using CO2 as a shielding gas?

Maintain a very short uniform arc length while welding

What can a welder do to make the necessary adjustments in the set up and manipulation to achieve a good weld

Make a few test welds

Is a thin layer of dark gray or black iron oxide formed during the rolling process

Mill scale

___ Machines are adjusted by turning a handwheel that moves the internal parts closer together or farther apart

Moveable coil

What material should shielding gas hoses be made of

Plastic

At low amperages and high voltage settings the wire may

Pop violently as a result of the uncontrolled arc

How should the conduit or an extension be aligned with the grooved rollers

Set as close as possible without touching the roller

The only difference between all GMA welding machines and some FCA welding machines is that all GMA welding machines must have a

Shielding gas solenoid

Is true of breaking and remelting tungsten

Should be broken squarely

A work clamp_

Should be carefully touched occasionally to determine if it is hot

Which of the following is true of erosion of the tungsten electrode

Slow erosion results in limited tungsten inclusions in the weld

Welding with the current set to high results in...

Spatter

A transformer with more turns of wire in the primary winding then in the secondary winding is known as a

Step down transformer

If arc length is shortened metal transferring across the gap may short out the electrode causing it to

Stick to the plate

Well that is high and has little or no fusion is too cold. to correct this...

Stop welding and make the needed adjustments

A (n) _______ joint is made by tack welding one piece of metal on another piece of metal at a right angle

T

The quantity of heat in a material is a function of both

Temperature, mass

Why is an inert shielding gas required for GTA welding?

To keep the air away from the hot tungsten and molten weld metal

Why is it important to keep portable welders properly tuned?

To reduce air pollution.

When the shielding gas flow rate is high, air is drawn into the gas envelope by a(n) _________ effect around the edge of the nozzle

Venturi

_________ Measure of electric pressure

Voltage

The unit of measure of electrical pressure is

Volts

Measurement of amount of electrical energy or power in the arc

Wattage

Measurement of the amount of electrical energy or power in the arc

Wattage

Slight changes in ____ Can be used to control the world as the groove spacing changes

Welding gun angle

When used as pure gases for welding ferrous metals, ____ may produce an erratic arc action, promote undercutting, and result in other flaws.

argon and helium

In generators the welding current is produced on the ____.

armature

Welding cables should _______.

be sufficiently long to reach the work station

The correct flow of a shielding gas can be set by ____

checking welding guides

The longer the ____, the greater the ____ to the welding current.

electrode extension, resistance

The _____ at which an alternating current cycles is the rate at which it makes a full change in direction

frequency

Resistance to the flow of electrons produces

heat

A weld bead made at a(n) ____________________ amperage setting is wide and flat with deep penetration, produces excessive spatter, and is mostly hard.

high

Water hose fittings have ____ threads, and gas hose fittings have ____ threads.

left hand, right hand

At any one voltage setting, ____ amperage is required to melt the wire the ____ it is fed.

more, faster

The ____ machine allows the selection of different current settings by tapping into the secondary coil at a different turn value.

multiple-coil

A ____ gap may require ____.

narrow, more penetration

In GMA welding, the voltage is set ____ and the amperage is set ____.

on the welder, by changing the wire-feed speed

The space between plates in a square butt joint is called

root gap

A 60% duty cycle means that the machine can be used a total of _____ minutes out of every ten minutes at the maximum rated current.

six

To make threading electrode wire easier, ____.

straighten about 12 in. of the end of the wire and cut off any kinks

Mixtures of argon with less than ____ percent carbon dioxide may not have enough arc voltage to give desired results.

ten

A _____ electrode angle pushes the molten metal away from the leading edge of the molten weld pool toward the back where it solidifies

trailing

Controls the maximum gap the electrons can jump to form the arc

voltage

The temperature of a welding arc is dependent on the ____, arc length, and atmosphere

voltage

The terms welding cables and ____ mean the same thing.

welding leads

SMAW is a widely used welding process because

Low cost, flexibility, portability and versatility. (All of the above)

A (n) _______ Joint is made by placing plates at a 90° angle to each other with the edges forming a V groove

Outside corner

To correct_____ Problem a welder can use a smaller electrode at a lower current setting

Overheating

Protects the molten weld pool, the filler rod, and the tungsten electrode as they cool to a temperature at which they will not oxidize rapidly

Postflow period

Tungsten electrodes that contain elements such as lanthanum or yttrium are referred to as...

Rare earth tungstens

What is the purpose of a gas lens

Reduces the turbulence in the shielding gas

Work angle

Relationship between center of electrode and surface of the work

Important to make cuts in the clean metal between welds on practice, why?

Reuse practice plates

Open circuit voltage

The voltage at the electrode before striking an arc.

In a standard welding transformer, the size of the iron core is determined by ______.

the length of time it takes for the magnetic field to build up and collapse

The selection of the correct size of welding electrode is determined by

the thickness and size of the metal

Large diameter electrodes may overheat the metal if..

they are used with thin or small pieces of metal

High gas flow rates ____.

waste shielding gases

DCEP concentrates ______ of the arc heat on the plate, and _____ of the heat on the electrode.

1/3, 2/3

If the current is set too high, the electrode covering is discolored more than ____ from the end of the electrode.

1/8 in. to 1/4 in.

DECN concentrates about ____ of its welding heat on the work, and about ____ on the tungsten

2/3 1/3

Inverter welders may have transformers as light as

7lbs

What can be done to counteract the loss of certain alloying elements such as chromium, vanadium, aluminum, titanium, manganese or silicon

Add a deoxidizer to the filler wire

The amount of heat produced by a welding arc is determined by

Amperage

_____. Controls the size of the arc

Amperage

The unit of measure of electrical flow is

Amps

The positive side of an electrode arc is called

Anode

High frequency maybe set so that it____ for DC and ____ for AC

Automatically cuts off after the arc is established; is kept on continuously

Why is the travel and work angle important?

Because of the jetting force of the electrode end

Students will find it easier to start with

Butt joints

Flowmeters measure flow rate of a shielding gas in... units

CFH or L/min

Too light of a feed roller pressure can

Cause erratic wire feeding

____ electrodes have a current carrying capacity similar to that of pure tungsten and may be used for both AC and DC welding currents

Cerium tungsten

A(n) ______ Is a large piece of metal used to absorb excessive heat

Chill plate

The more cost efficient welders can be, the more ______ They and their companies become

Competitive

Shielding gases in the gas metal arc process are used primarily to protect the molten metal from oxidation and...

Contamination

The useful life of a ceramic nozzle is affected by the

Current level and proximity to the work

Shielded metal arc welding machine's voltage output _____ as its current ______.

Decrease Increases

Filler metals and fluxes usually have ________ added to them so that the adverse effects of the mill scale are reduced or eliminated

Deoxidizers

Electrodes have forceful arc with little slag left on weld bead

E6010 and E6011

Rutile-based fluxes with a thick slag left on the weld bead

E6012 and E6013

Electrodes have a mineral based flux with very heavy slag left on the weld bead

E7016 and E7018

A(n) _____ joint is made by placing the edges of the plates together evenly with no gap between the plates

Edge

What may happen if too short of an arc length is used

Electrode may stick to the plate

When CO2 is being used as a shielding gas and the voltage is set near maximum..

Excessive spatter may occur

Perpendicular Welding gun angle produces welds that

Have a good balance between penetration and reinforcement

Which of the following is an inert gas

Helium

With ____, penetration and bead profile are sensitive to arc length, and the long arcs needed for feeding filler wires are more difficult to control.

Helium

_______ is a byproduct of the natural gas industry. It is removed from natural gas as the gas undergoes separation for purification or refinement

Helium

Any benefit to mill scale that can be found on almost all hot rolled steel?

Help to prevent rust from forming

Overfilling a molten weld pool will result in drips of metal called ________________

Icicles

Is true of grinding tungsten electrodes?

If the grinder is used for metals other than tungsten, particles of these metals may become trapped on the tungsten as it is ground, resulting in contamination when the arc is started