Materials And Processes

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

To relieve internal stresses developed within the base metal.

To increase the hardness of the weld.

To remve the surface scale formed during welding.

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

Has little or no effect on a metal's heat treated characteristics.

Can significantly alter a metal's properties in the reheated area.

Has a cumulative enhancement effect on the original heat treatment.

3. Which of the following descirbe the effects of annealing steel and aluminum alloys?

Decrease in internal stress.

Softening of the metal.

1 and 2.

Tempering.

4. Which heat-treating process of metal produces a hard wear-resistant surface over a strong, tough core?

Case hardening.

Annealing.

Tempering

5. In the four-digit aluminum index system number 2024, the first digit indicates

The major alloying element.

The number of different major alloying elements used in the metal.

The percent of alloying metal added.

6. The aluminum code number 1100 identifies what type of aluminum?

Aluminum alloy containing 11 perfect copper.

Aluminum alloy containing zinc.

99 percent commercially pure aluminum.

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

Tempering

Normalizing

Case hardening

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

Prevent corrosion.

Prevent surface cracking.

Retard discoloration.

9. Why is steel tempered after being hardened?

To increase its hardness and ductility.

To increase its strength and decrease its internal stresses.

To relieve its internal stresses and reduce its brittleness.

10. What aluminum alloy designations indicate that the metal has recieved no hardening or tempering treatment?

3003-F

5052-H36

6061-O

11. The SAE and the American Iron and Steel Institute use a numerical index system to identify the compostion of various steels. In the number "4130", designating Chromium Molybdenum steel, the first digit indicates the

Percentage of the basic element in the alloy.

Percentage of carbon in the alloy in hundredths of a percent.

Basic alloying element

12. Normalizing is a process of heat treating

Aluminum alloys only

Iron base metals only

Both aluminum alloys and iron-base metals

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

Rapid cooling; high strength

Slow cooling; low strength

Slow cooling; increased resistance to wear.

14. Which material cannot be heat treated repeatedly without harmful effects?

Unclad aluminum alloy in sheet form.

6061-T9 stainless steel.

Clad aluminum alloy.

15. Alclad is a metal consisting of

Aluminum alloy surface layers and a pure aluminum core.

Pure aluminum surface layers on an aluminum alloy core.

A homogeneous mixture of pure aluminum and aluminum alloy.

16. The core material of Alclad 2024-T4 is

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

Commercially pure aluminum, and the surface material is heat-treated aluminum alloy.

Strain-hardened aluminum alloy, and the surface material is commercially pure aluminum.

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

Stainless Steel.

Chrome-molybdenum alloy steel.

Titanium Nickel alloy.

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

The metals become artificially aged.

The metals become stress corrosion cracked.

The metals become cold worked, strain or work hardened.

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