AMT 116 AIRCRAFT WELDING Flashcards by John Cordopez

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

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is the blending of compatible molten metals
into one common part or joint.

Fusion Welding

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This joint can only be used where
load stresses are not significant.

Corner Joints

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is uniform in width, with
even ripples that taper off smoothly into
the base metal.

Good Weld

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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

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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

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are the principal methods used in the
construction and repair of metal aircraft joints.

Fusion welding, non-fusion welding, hardware
fasteners, and adhesives

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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

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Before being exposed to a welding arc, you must
wear an?

arc-welding Helmet, Gloves and Proper
Clothing.

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It shows good penetration, or depth of
fusion. In fact, penetration is the most
important characteristic of a ____.

Good Weld

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for some time,
been the method of choice for
constructing the structural framework
of aircraft.

Fusion welding

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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

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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

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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

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such as argon, helium or
carbon dioxide flows out around the
wire to protect the weld zone from
oxygen.

Inert Gas

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If cracks appear adjacent to a weld, it means a part may
have cooled too quickly after being welded.

Poor weld/Cold Weld

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Its ability to create strong, permanent joints is crucial for the
integrity and durability of many applications.

Welding

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is the exposed surface of the weld.

Face

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results in superior
strength joints because the metal
parts are melted together into a
single solid object.

Fusion Welding

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also needs
appropriate protective gear. Heavy clothing or
leather aprons should be worn to cover as much
skin as practical.

Electric arc welding

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The two most prominent methods of welding air-craft
structures and components are:

Fusion and Non-fusion

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Where load stresses are not significant,
_____ joints may be used to join two
pieces of sheet metal.

Edge joints

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It is distinct from lower temperature metal-joining techniques
such as brazing and soldering, which do not melt the base
metal.

Welding

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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

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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:

1. Distributing heat more evenly. 2. Reducing the amount of heat applied to the metal. 3. Using jigs to hold the metal firmly in place. 4. 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.