419 Flashcards
Which of the following is part of conventional friction welding?
Spinning part
Using a chemical cleaner to clean aluminum before welding slows the rate at which the
Oxidation reforms
The hardest and most wear resistant hard-facing metals are
Tungsten carbide
The purpose of the GTAW electrode is to
Conduct electricity
Electrodes covered with ______ must not be allowed to become too dry.
Cellulose
Welding pipe in high-pressure systems requires that a welder have which AWS qualification level?
AR-1
Plasma arc welding is unique in that the electricity passes through a layer of
Ionized gas
Which of the following is a step in edge preparation for ferrous metals?
Cutting or gouging the edge
Important factors to consider when selecting SMAW electrodes include the
Composition of the base metal
When preparing to operate a GMAW gun, position its nozzle about ______ in. above the work and tilt it about ______
3/4; 20
Submerged arc welding is unique in that the electricity passes through a layer of
Flux
Generally, the main consideration when selecting an electrode wire for a GMAW application is the
base metal composition
Weld backup rings are special accessories that help prevent ______ in pipe welding
icicles
Which of the following is the most widely used pipe welding process?
SMAW
Which of the following items offers protection from arc flash?
Welding helmet
Which of the following conditions indicates a possible need for postheating?
Rapid cooling after preheating
Uneven or rapid heating during welding causes _______ in a metal, which can in turn cause _______
expansion; deformation
What should be your primary consideration when deciding whether or not preheating of a ferrous metal part is necessary?
Carbon content
One advantage of ultrasonic welding over other types of welding is that it
can make leak-tight joints in thin matenals
What is the best way to determine the kind of metal a part is made of?
Contact the part manufacturer
When welding nickel, use the _____ process and a ______ power supply.
GTAW, DCEN
Which of the following is a common GMAW shielding gas?
Argon
When welding alloy steels, you should use ______ electrodes and _______ current
low-hydrogen; DCEP
SMAW is started by touching the end of an electrode to the base metal, then lifting the electrode about _____ in. to make an arc. The arc produces temperatures in the range of ____ °F
1/4; 10,000
castiron can be welded at low currents in any positon with _______ SMAW electrodes
Nickel-based
When selecting an electrode for SMAW, you should consider the current range, which depends mainly on the
diameter of the electrode
compared to other kinds of pipe joints, welded pipe joints are
Stronger
Cross-checking is desirable in some surfacing deposits because it
relieves residual stress
The need for preheating and postheating when welding pipe depends on
base metal composition and pipe thickness
The technique of ______ Is especially useful for building up thin-edged tools.
Oxyacetylene hard facing
Which of the following is an advantage of GTAW over other welding processes?
Can weld a large variety of metals
An important property of aluminum that you should be aware of is that it
readily forms an oxide coating
The best shielding gas for a flat or horzontal GMAW weld is one that (IS)
Heavier than air
Ferrous metals are those metals that are _____ based
Iron
The most widely used are process for cutting nonferrous metals is
Air carbon
In shielded metal are welding, the shield is made of
Gas
Wear caused by grinding or scratching action of hard particles is called
Abrasion
In SMAW, it is important to understand that lengthening the arc _____ the resistance, which _____ the temperature
Increases; increases
Preheating parts before welding them reduces the
distorton of the welded structure
Resistance welding uses electric current and ______ to join metals
Pressure
Most automatic hard facing is done with _______ machines
SAW
Welding electrodes are identified by the letter _____ followed by a number. The first two digits of the number identify the ______.
E; tensile strength of the deposted metal
The most common method used for welding cast iron Is
SMAW
When using GTAW to weld a very thick piece of low-carbon steel, you should use _____ as a shielding gas and _____ as the filler metal
Helium; low carbon steel
The heat-affected zone of a metal can undergo permanent changes in its
Mechanical properties
SMAW electrodes are classified by their
Core meterial
GTAW equipment and supplies may include which of the following?
Air cooled torch
In wnich of the following is electrode metal deposited when direct contact occurs between the electrode and the base metal?
Short circuit
When welding stainless steels with GTAW, you should use ____ current, and when welding aluminum, you should use _____ current
DCEN; ACHF
What kind of covered electrode allows you to use high welding current without causing excessive penetration?
Iron powder
