Amt General Study Guide Ch7

Front 1

Which of the following describe the effects of annealing steel and aluminum alloys?

1. Decrease in internal stress

2. Soften of the metal

3. Improved corrosion resistance

Back 1

1 and 2

Hint 1

The process of annealing softens a metal and decreases its internal stresses. Improve corrosion resistance is incorrect because annealing does not improve and metals corrosion resistance

Front 2

Which heat training process of metal produces a hard, wear resistance surface over a strong, tough core?

Back 2

Case hardening

Hint 2

Low-carbon and low alloy steels may be case-hardened to give a wear resistance surface, &, at the same time, a tough internal core. This process is used on an aircraft crankshaft and camshaft as well.

Front 3

Which heat-treating operation would be performed when the surface of the metal is changed chemically by introducing a high carbide or nitride content?

Back 3

Case hardening

Hint 3

Case hardening is usually accomplished in one of the two ways. The first is a process known as carburizing, in which controlled amounts of carbon are added to the surface of the steel to form a carbide. the second method, night riding, introducing nitrogen to the surface of the steel

Front 4

Normalizing is a process of heat treating

Back 4

Iron base metals only

Hint 4

Normalizing is used to relieve stresses in ferrous or not iron base metal parts. It is similar to a annealing, but the particles of carbon that precipitate out or not as large as those formed during annealing. Normalizing also produces a harder and stronger material than that obtained by annealing.

Front 5

Which of the following occurs when a mechanical force is repeatedly applied to most metals at room temperature, such as rolling, hammering, or bending?

1. The metals become artificially agent

2. The metals become stress corrosion crack

3. The metals become a cold work, strain or work hardened.

Back 5

1 and 3

Hint 5

Mechanically working metals at temperatures below their critical range results in strain, or work hardening of the material. strain hardening can increase metal part's strength and hardness. however, work hardening does reduce and materials flexibility.

Front 6

The reheating of a heat treated metal, such as with a welding torch

Back 6

Can significantly alter a metals properties and their reheated areas

Hint 6

When a part is welded, internal stresses and strains set up in the surrounding structures that can significantly alter a metal's properties. In addition, the weld itself is a cast structure whereas the surrounding metals is wrought. These two types of structures can have different grain sizes and, therefore, are not very compatible. To refine the grain structure as well as relieve the internal stresses, all welded parts should be normalized after fabrication.

Front 7

Why is steel tempered after being hardened?

Back 7

To relieve its internal stresses and reduce its brittleness

Hint 7

When steel is hardened by quenching, it is usually too hard and brittle for use. Furthermore, rapid quenching causes stress within the steel. Tempering involves reheating the material to a temperature below its critical temperature to draw out some of the hardness and relieve its internal stress.

Front 8

What aluminum alloy designations indicate that the metal has received no hardening or tempering treatment?

Back 8

3003-F

Hint 8

The letter F following an alloy designation indicates that the middle is in an "as fabricated" condition, and has received no hard to think or tempering treatment. An "H" on the other hand, indicates the alloy was hard and while a "O" indicated the metal was annealed

Front 9

Which material can be heat treated repeatedly without harmful effects?

Back 9

Clad aluminum alloys

Hint 9

Because clad aluminum has a corrosion resistant coating of pure aluminum over an alloy core, repeated heat treatments can cause diffusion of the alloying agent into the pure aluminum, resulting in reduced corrosion resistance.

Front 10

What is descriptive of the annealing process of steel during and after it has been annealed?

Back 10

Slow cooling; low strength

Hint 10

Annealing of steel produces a fine-grained, soft metal. Annealing is accomplished by heating the metal to just above the critical temperature and cooling it very slowly in a furnace.

Front 11

What is generally used in the construction of aircraft engine firewalls?

Back 11

Stainless steel

Hint 11

Because of its corrosion resistance properties and high-temperature performance, stainless steel is frequently used in firewalls, exhaust collectors, stacks, and manifolds.

Front 12

Alclad is a metal consisting of

Back 12

Pure aluminum surface layers on an aluminum alloy core

Hint 12

"Alclad" is a proprietary name, and refers to the practice of rolling a thin coating of pure aluminum on to both sides of the aluminum alloy improve corrosion resistance.

Front 13

The Society of Automotive Engineering (SAE) and the American Iron and Steel Institute use a numerical index system to identify the composition of various steels. In the number 4130, designation chromium molybdenum steel, the first digit indicates the

Back 13

Basic alloying elements

Hint 13

The first digit of an SAE number indicates basic alloying element. Percentage of the basic element in an alloy is wrong because it is indicated by the second digit in the SAE number. Percentage of carbon in the alloy is incorrect because it is indicated by the 3rd and 4th digit.

Front 14

The core material of Alclad 2024-T4 is

Back 14

Heat-treated aluminum alloy, and the surface material is commercially pure aluminum.

Hint 14

The term Alcad is used to identify a sheet where a pure aluminum coating is bonded to an aluminum alloy core. The designation 2024 indicates that the core is an aluminum alloy which uses copper as its primary alloying agent. The -T4 means that the sheet has been solution heat treated, followed by natural aging at room temperature.

Front 15

The aluminum code number 1100 identifies what type of aluminum?

Back 15

99% commercially pure aluminum

Hint 15

Pure aluminum is assigned a code of 1100. it has a high degree of resistance to corrosion and is easily formed into intricate shapes. Pure Aluminum is not used in structural application because of its low tensile strength

Front 16

In the 4 digit aluminum index system number 2024, the first digit indicates

Back 16

The major alloying elements

Hint 16

In the 4 digit aluminum index system, the first digit indicates the alloy type, or the major alloying element. The 2000 series alloys have copper as their major alloying element.

Front 17

Why is it considered good practice to normalize a part after welding?

Back 17

To relieve internal stresses developed within the base metal.

Hint 17

Steel. Is forged, welded, or machined develops stresses within the structure that could cause failure. These stresses are typically relieved by a process known as normalizing. During the normalizing process, that part is he did above its critical temperature, then allowed to cool in still air

Front 18

Parts are rinsed thoroughly in hot water after they have been heat treated in a sodium and potassium nitrate bath to

Back 18

Prevent corrosion

Hint 18

Some forms of heat treatment required immersion of parts in a heated sodium or potassium nitrate bath. Sodium and potassium nitrate are salts, and salt is a highly corrosive agent. Therefore, all parts bathed in sodium or potassium nitrate must be rinsed to prevent corrosion.