Corrosin
which of the following describe the effects of annealing steal and aluminum alloys? 1. decrease in internal stress 2. softening of the metal 3. improved corrosion resistance
1, 2.
the primary alloying agent of 2024-T3 is indicated by the number
2
which part of the 2017-T36 aluminum alloy designation indicates the primary alloying agent used in its manufacture?
2
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 artifically aged 2. the metals become less corrosion cracked 3. the metals become cold worked, strain or work hardened
3
what aluminum alloy designations indicate that the metal has received no hardening of tempering treatment?
3003-f
The aluminum code number 1100 identifies what type of aluminum?
99 percent commercially pure aluminum
Which heat-treating operation would be performed when the surface of the metal is changed chemically by introducing a high carbide or nitride content?
Case Hardening
which heat-treating process of metal produces a hard, wear resistant surface over a strong, tough core?
Case hardening
which material cannot be heat treated repeatedly without harmful effects?
Clad aluminum alloy
what is likely to occur if unhydrated wash primer is applied to unpainted aluminum and then about 30 to 40 minutes later a finish topcoat, when the humidity is low?
Corrosion
what is indicated by a black 'smoky' residue streaming back from some of the rivets on an aircraft?
Fretting corrosion is occurring between the rivets and the skin
what type of corrosion may attack the grain boundaries of aluminum alloys when the heat treatment process has been improperly accomplished?
Intergranular
which properly applied finish topcoat is the most durable and chemical resistant?
Polyurethane
before applying a protective coating to any unpainted clean aluminum, you should
avoid touching the surface with bare hands
the society of automotive engineers (SAE) and the American Iron and Steel Institute use a numerical index system to identify the composition of various steels. In the number '4130' designating chromium molybdenum steel, the first digit indicates the
basic alloying element
Shallow scratches in sheet metal may be repaired by
burnishing
the reheating of a heat treated metal, such as with a welding torch
can significantly alter a metal's properties in the reheated area
Clad aluminum alloys are used in aircraft because they
have surface layers of pure aluminum or aluminum alloy bonded to the core material to inhibit corrosion
the aluminum alloys used in aircraft construction are usually hardened by which method?
heat treatment
the core material of Alclad 2024-T4 is
heat-treated aluminum alloy, and the surface material is commercially pure aluminum.
Normalizing is a process of heat treating
iron-base metals only.
(1) in the corrosion process, it is the cathodic area or dissimilar cathodic material that corrodes (2) in the galvanic or electro-chemical series for metals, the most anodic metals are regarding the above statements
only No. 2 is true
When riveting dissimilar metals together, what precautions must be taken to prevent an electrolytic action?
place a protective separator between areas of potential electrical difference
what precaution, if any, should be taken to prevent corrosion inside a repaired metal honeycomb structure?
prime the repair with a corrosion inhibitor and seal from the atmosphere
Alclad is a metal consisting of
pure aluminum surface layers on an aluminum alloy core
A correct use for acetone is to
remove grease from fabric
what is descriptive of the annealing process of steel during and after is has been annealed?
slow cooling; low strength
You can distinguish between aluminum and aluminum alloy by
testing with a 10% solution of caustic soda
In the four-digit aluminum index system number 2024, the first digit indicates
the major alloying element
Fretting corrosion is most likely to occur
when two surfaces fit tightly together but can move relative to one another.
