WELDING, BRAZING, SOLDERING AND BONDING

Question 1

The definition of joining two pieces of metal by brazing typically meant using ______ as the filler metal which adhered to both pieces.

Answer 1

brass or bronze

Question 2

any metal joining process in which the bonding material is a nonferrous metal or alloy with a melting point higher than 800°F, but lower than that of the metals being joined.

Answer 2

BRAZING

Question 3

A brazing rod can be purchased with a flux coating already applied, or any one of the numerous fluxes available on the market for specific application may be used. Most fluxes contain a mixture of _____.

Answer 3

borax and boric acid

Question 4

Torch brazing of aluminum is done using similar methods as brazing of other materials. The brazing material itself is an _________ having a slightly lower melting temperature than the base material.

Answer 4

aluminum/silicon alloy

Question 5

Soft soldering is generally performed only in _____.

Answer 5

minor repair jobs

Question 6

_______ produces joints of higher strength than those produced by other brazing processes.

Answer 6

Silver soldering

Question 7

The three recommended types of joint for silver soldering are _______.

Answer 7

lap, flanged, and edge

Question 8

The oxy-acetylene flame for silver soldering should be a ___________.

Answer 8

soft neutral or slightly reducing flame

Question 9

_______ is accomplished by heating the ends or edges of metal parts to a molten state with a high temperature flame.

Answer 9

Gas welding

Question 10

The oxy-acetylene flame, with a temperature of approximately _______, is produced with a torch burning acetylene and mixing it with pure oxygen.

Answer 10

6 300°Fahrenheit (F)

Question 11

Hydrogen may be used in place of acetylene for aluminum welding, but the heat output is reduced to about ________.

Answer 11

4 000°F

Question 12

________ is used extensively by the aircraft industry in both the manufacture and repair of aircraft.
It can be used satisfactorily to join all weldable metals, provided that the proper processes and materials are used

Answer 12

Electric arc welding

Question 13

_______ is the most common type of welding and is usually referred to as “stick” welding.

Answer 13

Shielded metal arc welding (SMAW)

Question 14

_______ was formerly called Metal Inert Gas (MIG) welding

Answer 14

Gas metal arc welding (GMAW)

Question 15

an uncoated wire electrode is fed into and through the torch and an inert gas, such as argon, helium, or carbon dioxide, flows out around the wire to protect the puddle from oxygen.

Answer 15

Gas metal arc welding (GMAW)

Question 16

______ is a method of electric arc welding that fills most of the needs in aircraft maintenance and repair when proper procedures and materials are used. It is the preferred method to use on stainless steel, magnesium, and most forms of thick aluminum.

Answer 16

Gas tungsten arc welding (GTAW)

Question 17

It is more commonly known as _______ welding and by the trade names of Heliarc or Heliweld.

Answer 17

Tungsten Inert Gas (TIG)

Question 18

In ____, the electrode is a tungsten rod that forms the path for the high amperage arc between it and the work to melt the metal at over 5 400°F. The electrode is not consumed and used as filler so a filler rod is manually fed into the molten puddle in almost the same manner as when using an oxy-acetylene torch.

Answer 18

TIG welding

Question 19

Two copper electrodes are held in the jaws of the _____ machine, and the material to be welded is clamped between them.

Answer 19

spot welding

Question 20

_______ was developed in 1964 as a method of bringing better control to the arc welding process. ______ provides an advanced level of control and accuracy using automated equipment to produce high quality welds in miniature and precision applications

Answer 20

Plasma arc welding (PAW)

Question 21

In the ______, a non-consumable tungsten electrode is located within a fine-bore copper nozzle. A pilot arc is initiated between the torch electrode and
nozzle tip. This arc is then transferred to the metal being welded By forcing the plasma gas and arc through a constricted orifice, the torch delivers a high concentration of heat to a small area. The plasma process produces exceptionally high quality welds.

Answer 21

plasma welding torch

Question 22

________ systems can cut all electrically conductive metals, including aluminum and stainless steel. These two metals cannot be cut by oxy-fuel cutting systems because they have an oxide layer that prevents oxidation from occurring

Answer 22

Plasma arc

Question 23

Plasma arc systems can cut all electrically conductive metals, including ______.

Answer 23

aluminum and stainless steel

Question 24

The______ machine works by constricting an electrical arc in a nozzle and forcing the ionized gas through it. This heats the gas that melts the metal which is blown away by the air pressure.
By increasing air pressure and intensifying the arc with higher voltages, the cutter is capable of blasting through thicker metals and blowing away the dross with minimal cleanup.

Answer 24

plasma cutting

Question 25

This is the primary fuel for oxy-fuel welding and cutting.

Answer 25

ACETYLENE

Question 26

The acetylene pressure gauge should never be set higher than ____ for welding or cutting

Answer 26

15 psi

Question 27

______ is a colorless, odorless, tasteless, and nontoxic inert gas. Inert gas cannot combine with other elements. It has a very low chemical reactivity and low thermal conductivity. It is used as a gas shield for the electrode in MIG, TIG, and plasma welding equipment.

Answer 27

ARGON

Question 28

_________ is a colorless, odorless, tasteless, and nontoxic inert gas. Its boiling and melting points are the lowest of the elements and it normally exists only in gas form. It is used as a protective gas shield for many industrial uses including electric arc welding.

Answer 28

HELIUM

Question 29

_______ is a colorless, odorless, tasteless, and highly flammable gas. It can be used at a higher pressure than acetylene and is used for underwater welding and cutting. It also can be used for aluminum welding using the oxy-hydrogen process

Answer 29

Hydrogen

Question 30

______ is a colorless, odorless, and nonflammable gas. It is used in the welding process to increase the combustion rate which increases the flame temperature of flammable gas.

Answer 30

Oxygen

Question 31

A _______ is attached to a gas cylinder and is used to lower the cylinder pressure to the desired working pressure.

Answer 31

pressure regulator

Question 32

A ______ installed on each hose prevents a high pressure flame or oxygen-fuel mixture from being pushed back into either cylinder causing an explosion.

Answer 32

flashback arrestor

Question 33

The ______ stops the reverse flow of the gas and can be installed either between the regulator and the hose or the hose and the torch.

Answer 33

check valve

Question 34

The _______ burns at approximately 5 850°F at the tip of the inner luminous cone and is produced by a balanced mixture of acetylene and oxygen supplied by the torch. The _______ is used for most welding because it does not alter the composition of the base Metal. When using this flame on steel, the molten metal puddle is quiet and clear, and the metal flows to give a thoroughly fused weld without burning or sparking.

Answer 34

neutral flame

Question 35

The ________ burns at approximately 5 700°F at the tip of the inner core. It is also referred to as a reducing flame because it tends to reduce the amount of oxygen in the iron oxides. The flame burns with a coarse rushing sound, and has a bluish-white inner cone, a white center cone, and a light blue outer cone

Answer 35

carburizing flame

Question 36

The _______ burns at approximately 6 300°F and is produced by burning an excess of oxygen. It takes about two parts of oxygen to one part acetylene to produce this flame. It can be identified by the shorter outer flame and the small, white, inner cone.

Answer 36

oxidizing flame

Question 37

A ______ is used for fusion welding of brass and bronze.

Answer 37

stronger oxidizing flame

Question 38

A _______ is used for bronze welding (brazing) of steel and cast iron.

Answer 38

slightly oxidizing flame

Question 39

There are two essentially similar methods of striking the arc. One is the ______ method. When using this method, the electrode should be held in a vertical position and lowered until it is an inch or so above the point where the arc is to be struck. Then, the electrode is lightly tapped on the work piece and immediately lifted to form an arc approximately 1/4 inch in length

Answer 39

tough or tapping

Question 40

The second (and usually easier to master) is a ______ method. To strike the arc by the scratch method, the electrode is held just above the plate at an angle of 20°-25°. The arc should be struck by sweeping the electrode with a wrist motion and lightly scratching the plate. The electrode is then lifted immediately to form an arc

Answer 40

scratch or sweeping

Question 41

Either method takes some practice, but with time and experience, it becomes easy. The key is to raise the electrode quickly, but only about ______ from the base or the arc is lost. If it is raised too slowly, the electrode sticks to the plate.

Answer 41

1/4 inch

Question 42

The _____ utilizes the same technique that is used when depositing a bead on a flat metal surface. The only difference is that the deposited bead is at the butt joint of two steel plates, fusing them together. Square butt joints may be welded in one or multiple passes. If the thickness of the metal is such that complete fusion cannot be obtained by welding from one side, the joint must be welded from both sides. Most joints should first be tack-welded to ensure alignment and reduce warping

Answer 42

bead weld

Question 43

______ may be performed on a butt joint or an outside corner joint. _______ are made on butt joints where the metal to be welded is 1/4-inch or more in thickness. The butt joint can be prepared using either a single or double groove depending on the thickness of the plate. The number of passes required to complete a weld is determined by the thickness of the metal being welded and the size of the electrode being used. Any groove weld made in more than one pass must have the slag, spatter, and oxide carefully removed from all previous weld deposits before welding over them.

Answer 43

Groove welding

Question 44

______ are used to make tee and lap joints. The electrode should be held at an angle of 45° to the plate surface. The electrode should be tilted at an angle of about 15° in the direction of welding. Thin plates should be welded with little or no weaving motion of the electrode and the weld is made in one pass. _____welding of thicker plates may require two or more passes using a semicircular weaving motion of the electrode.

Answer 44

Fillet welds

Question 45

The procedure for making fillet weld in a _____is similar to that used in the tee joint. The electrode is held at about a 30° angle to the vertical and tilted to an angle of about 15° in the direction of welding when joining plates of the same thickness

Answer 45

Lap Joint Weld

Question 46

The _______ of a metal is the amount in inches that a one inch piece of metal expands when its temperature is raised 1°F.

Answer 46

coefficient of linear expansion

Question 47

A ______ is made by placing two pieces of material edge to edge, without overlap, and then welding. This type of joint is usually made without the use of a filler rod. If the metal is thicker than 1/8 inch, it may be necessary to bevel the edges so that the heat from the torch can completely penetrate the metal

Answer 47

butt joint

Question 48

A ______ is formed when the edge or end of one piece is welded to the surface of another. The plain _______ is suitable for most thicknesses of metal used in aircraft, but heavier thicknesses require the vertical member to be either single or double beveled to permit the heat to penetrate deeply enough.

Answer 48

tee joint

Question 49

An _______ is used when two pieces of sheet metal must be fastened together and load stresses are not important. Edge joints are usually made by bending the edges of one or both parts upward, placing the two ends parallel to each other, and welding along the outside of the seam formed by the two joined edges

Answer 49

edge joint

Question 50

The ______ is seldom used in aircraft structures when welding with oxy-acetylene, but is commonly used and joined by spot welding.

Answer 50

lap joint

Question 51

Cracks in parts and materials can vary from tiny ______, that are visible only with magnification, to those easily identified by unaided eyes. _____ are the worst type of defect for two reasons; they are often hard to detect, and they produce the worst form of notch effect/stress concentration

Answer 51

Micro-fissures