AMT 116 AIRCRAFT WELDING Flashcards
are composed of many individual
pieces that must be securely fastened together to form a complete
structural unit. Fusion welding, non-fusion welding, hardware
fasteners, and adhesives are the principal methods used in the
construction and repair of metal aircraft joints.
Metallic aircraft structures
is the blending of compatible molten metals
into one common part or joint.
Fusion Welding
This joint can only be used where
load stresses are not significant.
Corner Joints
is uniform in width, with
even ripples that taper off smoothly into
the base metal.
Good Weld
describes the equipment and basic procedures
needed to join metals using fusion and non-fusion welding
techniques, and the methods used to repair welded aircraft
structures.
Aircraft Welding
has irregular edges and considerable variation
in depth of penetration, while a weld from excessive heat
shows pitting along its edges and long, pointed ripples.
Cold weld
are the principal methods used in the
construction and repair of metal aircraft joints.
Fusion welding, non-fusion welding, hardware
fasteners, and adhesives
is essential for the assembly and repair of a wide
range of products and structures, contributing significantly to
manufacturing, construction, and various other industrial
sectors
Welding
Before being exposed to a welding arc, you must
wear an?
arc-welding Helmet, Gloves and Proper
Clothing.
It shows good penetration, or depth of
fusion. In fact, penetration is the most
important characteristic of a ____.
Good Weld
for some time,
been the method of choice for
constructing the structural framework
of aircraft.
Fusion welding
which is com-posed of
approximately the same chemical
compo-sition as the metal to be
welded, is clamped in an electrode
holder.
Metal wire-rod
is a fabrication process that joins materials, usually
metals or thermoplastics, by using high heat to melt the parts
together and allowing them to cool, causing fusion.
Welding
To obtain the proper amount of
penetration and proper weld dimensions,
a welder must use the correct type and
size of filler rod and appropriate welding
technique for the thickness and type of
the material to be joined.
Good Weld
such as argon, helium or
carbon dioxide flows out around the
wire to protect the weld zone from
oxygen.
Inert Gas
If cracks appear adjacent to a weld, it means a part may
have cooled too quickly after being welded.
Poor weld/Cold Weld
Its ability to create strong, permanent joints is crucial for the
integrity and durability of many applications.
Welding
is the exposed surface of the weld.
Face
results in superior
strength joints because the metal
parts are melted together into a
single solid object.
Fusion Welding
also needs
appropriate protective gear. Heavy clothing or
leather aprons should be worn to cover as much
skin as practical.
Electric arc welding
The two most prominent methods of welding air-craft
structures and components are:
Fusion and Non-fusion
Where load stresses are not significant,
_____ joints may be used to join two
pieces of sheet metal.
Edge joints
It is distinct from lower temperature metal-joining techniques
such as brazing and soldering, which do not melt the base
metal.
Welding
In welding processes that use an electric arc for heat, other methods
of shielding the weld are used, including coating electrodes with flux,
or using gases to flood the area around the arc to shield the weld from oxygen.
Oxidation
is the depth that fusion penetrates into
the base metal.
Root
If a welded joint displays any of these defects, all of the
old weld must be removed and the joint rewelded.
Poor Weld
Welding thicker metals requires larger equipment; however, welding
techniques remain much the same.
OXYACETYLENE WELDING
is the joining of metals by adhesion of one
metal to another
Non-fusion Welding
Pressure is applied to hold the electrodes tightly together
while electrical current passes between the electrodes.
Spot Welding
is used primarily in large
volume production work.
Gas Metal Arc Welding
often referred to as gas welding, gets its name
from the two gases, oxygen and acetylene, that are used to produce a flame.
Oxyacetylene welding
The most prominent non-fusion welding processes used on aircraft
are:, which are covered in detail later in this
section.
Brazing and Soldering
To form an _____ joint, bend the edges
of one or both parts upward and place
the two ends parallel to each other.
Edge joint
is a primary concern to a welder. Metal oxides are formed in
the welding zone of most metallic alloys when sufficient heat is
applied.
Oxidation
Fusing of metals is accomplished by producing sufficient heat for
the metals to melt, flow together and mix.
Fusion Welding
is the distance through the center
from the root to the face.
Throat
is the form of
elec-tric arc welding that is used most in
aircraft mainte-nance.
Tungsten inert gas welding (TIG)
Aircraft structures of steel tubing are usually fabricated by welding the tubes together into a strong, lightweight structure.
OXYACETYLENE WELDING
The three principal methods of fusion
welding are:
Gas, Electric Arc, and Electrical Resistance.
While it would be possible to create a ____ with a series of
closely spaced spot welds, a better method is to use a ___ welding
Seam Welding
Electric arc welding includes
Shielded Metal Arc
Welding (SMAW), Gas Metal Arc
Welding(GMAW), and Gas Tungsten Arc Welding
(GTAW).
The plain _____ joint is suitable for
most aircraft metal thickness.
Tee Joint
is the fuel for the flame and oxygen sup-ports combustion and
makes the flame hotter.
Acetylene
Weld along the outside of the seam
formed by the two edges.
Edge Joints
The heat is then removed to allow the fused joint to solidify.
Fusion Welding
chemically reacts with the heated surface of the metal and
forms metal oxides such as iron oxide (rust) or aluminum oxide.
Oxygen
When ____ welding, two copper electrodes are held in the
jaws of a vise-like machine and the pieces of metal to be
welded are clamped between them.
Spot Welding
is the edge formed where the face of the
weld meets the base metal.
Toe
The temperature of the oxyacetylene flame ranges from _____ to _____ F.
5,600 to 6,300 F
is the most common
type of arc welding.
Shielded metal arc welding (SMAW), or
stick weld-ing
This equipment is commonly used to manufacture fuel tanks
and other components where a continuous weld is needed.
Seam Welding
When excessive oxide is present, it often results in porous pockets,
causing a weak joint. Limiting the effects of oxidation is critical to
maintaining strong weld joints.
Oxidation
In some situations, the bent-up edges
may provide enough material to form
the bead so that a filler rod is not
required.
Edge Joints
Improperly formed welds typically are caused by:
► Undercutting the base metal at the toe of the weld.
► Lack of adequate penetration.
► Poor fusion of the weld metal with the base.
► Oxides, slag or gas pockets in the weld.
► Improper heat.
produces a blinding light, with
infrared and ultraviolet rays, which can burn both
skin and eyes.
Electric Arc Welding
must be formed correctly to achieve the intended strength and to
resist joint fatigue.
Weld
Thicker metals require the vertical
member to be either single or
double beveled to permit the heat
to penetrate deeply enough.
Tee Joints
An advantage of _____ over stick welding is that no slag is deposited on the weld bead.
Gas Metal Arc Welding
is the metal that is deposited as the
weld is made.
Bead
formerly called Metal Inert Gas (MIG)
Gas Metal Arc Welding (GMAW),
is the quantity of weld metal
added above the surface of the base metal.
Reinforcement
Most aircraft gas welding is done on thin-gauge steel that ranges from __-to ___-gauge, or about .027- to .050-inch thick.
16-20 gauge
You may find _____welding useful for
fabricating tools and shop equipment,
but it is not generally used for the
fabrication or repair of aircraft.
Stick
techniques include dye-penetrant,
magnetic-particle, x-ray, ultrasonic and eddy-current.
Non-destructive inspection (NDI)
If a ____ joint is pitted, rough, dirty or uneven, the weld is almost
always defective on the inside.
Welded Joint
If a ____ is not made properly, the strength can be reduced as much as 50 percent.
Joint
The gas welding processes generate carbon dioxide (CO2), which
shields the welding zone from oxygen. CO2 is a natural by-product of
oxygen and acetylene combustion.
Oxidation
Unlike SMAW and GMAW, which use consumable
electrodes, it uses a tungsten electrode that does not act as filler rod.
Tungsten Inert Gas Welding (TIG)
The result of a weld is a ____.
Joint
is seldom used in aircraft structures when welding
with gas, but is commonly used when spot welding.
Lap Joint
is necessary to reduce distortion, warping and
residual stress.
Expansion and Contraction of Metal
There are two methods of TIG welding using
DC:
straight polarity and reverse polarity.
To evaluate the quality of an aircraft
welding repair, it is essential to
understand the various types of
____ and be able to recognize
whether proper techniques were
used to create these joints.
Joints
is the most cost-effective and easy test to
perform in the field, but does not identify internal flaws.
Dye-Penetrant Inspection
The three most important proportions of a weld are:
depth of penetration, width of the bead, and the height of reinforcement.
It also is known as gas tungsten arc welding (GTAW), and by the trade names of Heliarc and Heliweld.
Tungsten Inert Gas Welding
The single ____ joint has very little resistance to bending and
will not withstand shearing stresses.
Lap joint
2 types of ELECTRIC RESISTANCE WELDING:
Spot Welding, Seam Welding.
These trade names were derived from the fact
that the _______ originally used was helium.
Inert Gas
the inspection equipment must be certified for
accuracy and the personnel conducting the inspection must have received special training.
Non-destructive inspection (NDI)
are used to join metal forms such as sheet, bar,
plate, tube and pipe. In aircraft applications, ____ joints
generally are not used for joining tubing because they are too
weak for aircraft structures.
Butt Joints
will have a uniform rippled appearance. To achieve
this, it must have been completed with the proper amount of
heat and the correct filler rod size for the thickness of the
material.
Good Weld
These effects are more noticeable when welding long sections
of thin sheet metal.
EXPANSION AND CONTRACTION OF METAL
The double ____ joint is stronger, but requires twice the welding
of the simpler, more efficient, butt weld.
Lap Joint
The height of the bead above the surface of the base metal
should be approximately ____ T to ____ T.
1/4 T to 1/2 T.
6 Parts of the Weld
Bead, face, root, throat, toe, reinforcement
has uniformity when its width is three to five
times the thickness of the metal (T), with its edges flowing
evenly into the base metal.
Finished Bead
results when two
pieces of metal are brought together
so that their edges form a corner of
a box or rectangle.
Corner Joints
You can control EXPANSION AND CONTRACTION OF METAL distortions in the following ways:
- Distributing heat more evenly.
- Reducing the amount of heat applied to the metal.
- Using jigs to hold the metal firmly in place.
- Allowing for space between the edges of the joint
are quite common in
aircraft work, particularly in tubular
structures.
Tee Joints
To ensure proper fusion on lap and butt joints, penetration should
be to a depth of ____ percent of the thickness of the base metal.
100%
For other joints, ________ must be adequate to impart enough
strength that the metal sheets will fail before the joint fails
Penetration
A properly completed weld should exhibit the following attributes:
-The bead should be smooth and uniform in thickness.
-The weld should be built up to provide extra thickness at the seam.
-The bead should taper off smoothly into the base metal.
-No oxide should be formed on the base metal further than 1/2-inch from the
weld.
-There should be no blowholes, porosity or pro truding globules.
-There should be no signs of pitting, cracking, burning or warping.
5 types of Welded Joints:
Corner Joint, Edge Joint, Tee Join, Lap Joint, and Butt Joint.
