Chapter 14/15 Study guide

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

Which of the following is true of breaking and remelting tungsten?

It should be broken squarely

The letter that refers to the range of manganese can either be ______

L,M, or H

Which of the following is an advantage of electroslag welding?

Minimum distortion

In the electrogas welding electrode classification system, the letter S indicates a ________

Solid wire

Tungsten erosion can be limited by using water-cooled torch

True

_________ wire is used to give the arc some oscillating movement as the wire enters the weld

Twisted

In general the current-carrying capacity at DCEN is about ______ than that at DCEP.

ten times greater

The first digit in the flux classification system indicates ______

the 10,000 psi minimum tensile strength of the weld

Which of the following 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

The _______ directs the shielding gas directly on the welding zone.

Nozzle cup

All three types of welding current can be used for GTA welding.

True

The classification of flux depends on ______

the mechanical properties of the weld metal deposited

DCEN concentrates about ______ of its welding heat on the work, and about ______ on the tungsten.

2/3,1/3

Flux can be dried using a direct flame

False

When the GTAW process was first developed, argon was the primary shielding gas used.

False

______ fluxes are mixtures that have been heated until they melt into a solid metallic glass

Fused

______ additions are restricted to stainless steels because it is the primary cause of porosity in aluminum welds.

Hydrogen

__________ is the time during which the gas continues flowing after the welding current has stopped

Postflow.

_____ is used for surfacing applications

Strip electrodes

The gas tungsten arc welding process is sometimes referred to as _____

Tig

A welder using SAW does not have to wear a welding helmet

True

More than _____ lb./hr can be deposited using large diameter SAW wires.

40

_____ results in welds with deep penetration, and a smaller-size tungsten can be used.

DCEN

Electrode classifications are prefixed with the letter ___

E

The same chemically composed flux will have the same classification

False

The shielding gas flow rate should be as high as possible.

False

With SAW, unfused ______ flux can be retrieved and reused

Granular

Which of the following is an inert gas?

Helium

_____ is a by-product of the natural gas industry. It is removed from natural gas as the gas undergoes separation for purification or refinement.

Helium

_____ is the time during which gas flows to clear out any air nozzle or surrounding the weld zone.

Preflow

If the letter K is used, it refers to _____

Silicon-killed, oxidized steel

The contact tip used in SAW is usually made of ______

beryllium-copper

In the flux classification system, the letter Z indicates _____

no impact strength test is required

The _____ protects the molten weld pool, the filler rod, and the tungsten electrode as they cool to a temperature at which they will not oxidize.

post-flow period

The _____ is the cone-shaped sleeve that holds the electrode in the torch.

Collect

In the electrogas welding electrode classification system, T indicates ______

a tubular or flux cored electrode

In SAW, the heat is produced from ____

an arc between the work and a metal electrode

A _____ provides the source of welding current to the wire

contact tip

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

frequency

SAW filler metals are available in wires that come in sizes ______

from 1/16 inch to 1/4 inch

In SAW, a blanket of molten flux and slag is formed from the ______ material pre-placed on the work

granular flux

Water hose fittings have _____ threads and has hose fittings have _____ threads

left hand, right hand

With SAW, ESW, and EGW, the total cost of fabrication is, _____, and it provides the same or _____ service.

lower, better

_____ produces wide welds with shallow penetration

DCEP

______ has the poorest heat resistance and electron emission characteristic of all tungsten electrodes

Pure tungsten

Which of the following is true of electroslag welding?

The slags produced are highly conductive in a molten state.

In the flux classification system, the letter P indicates ______

The weld was tested after the post weld heat treatment

If an electrode is classified as EH12, it has a normal carbon point of _____ percent carbon

.12

AC concentrates about ______ of its welding heat on the work and _____ on the tungsten.

1/2,1/2

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

1/3, 2/3

Although the yearly tonnage of SAW electrode wire used has increased, its percentage of the total amount of filler metals used has remained below _____ percent

10

In GTAW, the arc temperature is around ______ degrees Fahrenheit.

11,000

If a flux is classified as F3A2, it has _____ psi minimum tensile strength

30,000

____ 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

Which of the following is true of DCEP?

DCEP has the highest heat concentration on the electrode tip

The basic flux classification is prefixed with the letter ____

F

As much as 20% of the heat generated by a GTA welding torch does not enter the weld

False

DCEP has the lowest heat concentration on the electrode tip.

False

Fused quartz nozzles are no more expensive than ceramic nozzles, but are more easily broken

False

If flux becomes damp it must be discarded

False

Mechanical travel can not be automated by a computer

False

One disadvantage of the electroslag welding process is that it has a very slow welding speed

False

In EGW, the molten weld pool isn protected from the atmosphere by ____ or by a flux core in the filler electrode.

Shielding gas

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

Slow erosion results in limited tungsten inclusions in the weld

The improved electron emission of the _____ allows it to carry approximately 20% more current than pure tungsten.

Thoriated tungsten

_____ is very well suited for making welds on steel, steel alloys (including stainless), nickel alloys, and most other metals other than aluminum or magnesium.

Thoriated tungsten

One carbon point equals ____ percent carbon

.01

Submerged are welding was introduced in the _____

1930's

Which of the following is true of DCEN?

With DCEN, a pointed tip concentrates the arc.

Adding _____ has the same effect on the electrode characteristic as thorium, but is not radioactive.

Zirconium

_____ is denser than air, so it effectively shields welds in deep grooves in the flat position

Argon

______ is relatively easy to ionize and thus is suitable for alternating-current applications and easier starts

Argon

_________ fluxes are mixtures of fine particles of fluxing agents, deoxiderz, alloying elements, metal compounds, and a suitable binder that holds the material together.

Bonded

Argon and helium are ______ gases, which means they will not combine chemically with any other material, and will not affect the molten weld pool in any way.

Inert

If an electrode is classified EL5K, which of the following is true?

It was drawn from silicon-killed, deoxidized steel

In SAW, the molten weld pool is protected from the surrounding atmosphere by_______

Molten flux and slag

__________, when added in percentages of up to 0.6 percent to tungsten, improves its current carrying capacity.

Thorium oxide.

Strip electrodes can be as wide as ______ inches

Three

A steep angle between the torch and the work may draw in air.

True

A strong alkaline can be used to chemically clean and point tungsten

True

Mechanical travel can be provided by moving the work past a fixed gun

True

One advantage of the electroslag welding process is that it requires minimum joint preparation

True

SAW has a deposition rate nearly two times the rate of FCAW and four times the rate of SMAW

True

SAW, ESW, and EGW can be used to cover large areas with welded coverings of special alloys.

True

Tungsten is hard but brittle, and has a low impact strength.

True

Which of the following is a way to minimize erosion of the tungsten electrode?

Using DCEN current.

In SAW, the drive rollers are usually either knurled or smooth _______ type.

V-groove

When the shielding gas flow rate is high, air is drawn into the has envelope by a ________ effect around the edge of the nozzle.

Venturi