Chapter 2 - Sheet Metal Structures Flashcards
What are the two different types of sheet metal structures?
Monocoque and Semimonocoque
What are the five major stresses?
- Tension - primary stress that tries to pull a body apart
- Compression - another primary stress that tries to squeeze a part together
- Bending - Tries to pull one side of a body apart while at the same time squeezing the other side together
- Torsion - a twisting force
- Shear - opposing forces are applied on opposite sides of a body
Identify the Aluminum alloy series
1xxx
2xxx
3xxx
4xxx
5xxx
6xxx
7xxx
1xxx Aluminum - Pure aluminum 99% or higher
2xxx Copper
3xxx - **Maganese **
4xxx - Silicon
5xxx - Magnesium
6xxx - Magnesium and silicon
7xxx - zinc
Define annealing
Annealing is a process that softens a metal and decreases internal stresses by heating the metal to the annealing point and heald there until the metal becomes heat soaked. It is then cooled to 500 degrees F of a rate of about 50 degrees F per hour
Name what these aluminum alloys are commonly used for:
2117
2024
5052
7075
2117 - Mostly aircraft rivets
2024 - Majority used on structures
5052 - Gas tanks and fuel lines
7075 - When high strength is needed
What is alclading and why is it important?
Alclad consists of a pure aluminum coating rolled onto the surface of heat-treated aluminum alloy. The thickness of this coating is approximately 5% of the alloy’s thickness on each side. Alclading a surface greatly increases the corrosion resistance of an aluminum alloy.
Which alloys are heat treatable and non-heat treatable?
Non-heat treatable alloy
1100
3003
5052
Heat treatable alloy
2017
2117
2024
6061
7075
When appropriate, the metal hardness, or temper, is indicated by a letter designation seperated from the alloy designation by a dash. Name the following temper designations:
- O
- T3
- T6
O - Annealed
T3 - Soulution heat-treated and cold worked by the flattening or straightening operation
T6 - Solution heat-treated and artificially aged
Which two series of metals are heat-treatable?
7000 & 2000 series.
All others are non-heat treatable and must be hammered or cold worked to be treated.
Corrosion from two dissimalar metals is called what?
Glavanic corrosion
Artificial aging is another name for _______heat -treatment
Artificial aging is another name for precipitation heat -treatment
Name three disadvantages for using magnesium as a structural material.
cracks, corrodes, & burns easily
What is this tool and what should it and should NOT be used for?
Scribe
Should be used in sheet metal work only for marking the cut-off lines of a part. They should never be used for marking dimension lines for bending metal.
What is the purpose of a prick punch?
Once layout marks have been made with a soft pencil, permanent marks can be made in the location for holes with a sharp prick punch and a light tap with a small hammer.
What is the purpose of this tool?
Center punch
Enlarges a prick punch to begin for drilling