AMCR METAL WORKING PROCESS Flashcards
Any process involving controlled heating and cooling to develop certain desirable characteristics
Heat Treatment
3 Stage Process of Heat Treatment
heat, soak, cool
Above critical temperature that eliminates the stresses
Heat
Maintain high temperature for a time period
Soak
Fast cooling (quenching), makes the steel hard while slow cooling
Cool
It is controlled by the rate of cooling
Hardening
Reduces the brittleness and some hardness but it improves ductility
Annealing
It relieves internal stresses, it refines grain structure and softens metals
Normalizing
Relieves stress due to mechanical working like forging, welding, machining.
Case Hardening
3 Processes of Case Hardening
Carburizing, Cyaniding, Nitriding
Heating steels in contact with a carbonaceous material
it is also the oldest method
Carburizing
Heating steels in contact with a cyanide salt
Fast and cheap
Seldom used in aircraft work
Cyaniding
Heating special alloys with ammonia gas or other nitrogenous materials
Nitriding
Basic Temper Designation
F - As fabricated
H - Strain Hardened
T - Thermally Treated
O - Annealed
W - Solution Heat Treated
Hardness Designation of H1
Cold Worked
Hardness Designation of H2
Strain Hardened, then partially annealed
Hardness Designation of H3
Strain Hardened, then stabilized
Degree of Hardening
HX2 - 1/4 hard
HX4 - 1/2 hard
HX6 - 3/4 hard
HX8 - FULL HARD
HX9 - EXTRA HARD
Heat Treatments for non-ferrous metals
Natural Aging, Artificial Aging, Annealing
The process that removes effects of cold work; softens
Annealing
Metal Working Processes
Forming, Cutting, Joining
Formed by physically working the metal into desired shape
Wrought
Formed by pouring metal into mold
Casting
Forming metal at an elevated temp when it is in its soft state
Hot Working
Forming at elevated temp also but it is pressed or hammered
Forging
Forming hot metal ingots with roller mills
Rolling
Mechanical working performed at a temp below critical range
Cold Working
Finishes the hot rolled material, it gives smooth finish and accurate dimensions
Cold Rolling
Used in making seamless tubing, wire, tie rods.
Cold Drawing
Forcing solid metal through a die which imparts a required cross section to the metal
Extrusion
It is a cold working process in which the surface layer of a workpiece is plastically deformed by a hard tool
Burnishing
A cold work process in which metal is struck by a stream if small hard spheres creating dimples
Shot Peening
The process of joining two metallic pieces together in a permanent manner. Heat or pressure is applied
Welding
2 types of welding
Fusion, Non Fusion
Joining by blending compatible metals; used in small aircrafts
Fusion Welding
Joining by adhesion of one metal to another; brazing or soldering
Non-Fusion Welding
General Evaluation of Welds
Penetration, Dimension, Free of oxidation, Filler, Welding Technique
Poor Welds
Cold Weld, Excessive Heat, Adjacent Cracks
2 Types of Fusion Welding
Gas Welding, Electric Arc Welding
Fuel gas such as acetylene or hydrogen is mixed inside a welding torch
Gas Welding
Heat is produced via movement of electrons
Electric Arc Welding
Different Types of Flames
Neutral, Oxidizing, Carburizing
Elements that are used in welding (gasses)
Acetylene, Argon, Hydrogen, Helium, Oxygen
Parts of a Electric Arc Welding
Welding Rod, Electrode, Filler Metal
Types of Electrical Arc Welding
Shielded Metal Arc Welding, Gas Metal Arc Welding, Gas Tungsten Arc Welding
Used in fabricating tools. It works when a metal wire rod coated with flux is clamped in electrode holder, and also the metal piece to the power supply that makes an arc struck between the rod and the metal
Shielded Metal Arc Welding
Used in large volume production work
No filler and slags deposit
Gas Metal Arc Welding
Used most in aircraft maintenance. It uses a tungsten electrode.
Gas Tungsten Arc Welding
2 types of non fusion welding
Brazing, Soldering
Metal joining process in which the bonding material is a non ferrous metal, it operates at a lower temp than fusion welding.
Brazing
Performed only in minor repair jobs like joining electrical connections
Soldering
First Step of Rivet Removal
File a flat area on manufactured head
Second Step in Rivet Removal
Center Punch Flat
Third step of Rivet Removal
Drill through head using drill one size smaller than rivet shank
Fourth step of rivet removal
Remove Weakened head with Machine Punch
Last step of rivet removal
Punch out rivet with machine punch
The outside dimensions of a formed part. This is given on the drawing or blueprint or may be obtained from the original part.
Base Measurement
The longer part of a formed angle.
Leg
The shorter part of a formed angle—the opposite of leg.
Flange
Natural grain of the material is formed as the sheet is rolled from molten ingot.
Grain Metal
It refers to the curved section of metal within the bend (the portion of metal that is curved in bending).
Bend Allowance
When sheet metal is bent, it forms an arc known as the _______
Bend Radius
Where the metal starts to bend and the line at which the metal stops curving.
Bend Tangent Line
An imaginary line that has the same length after bending as it had before bending.
Neutral Axis
Bend Allowance for 90deg
2π(R+1/2T)/4
Setback for 90deg
R + T
Setback for other deg besides 90
K(R+T)
Formula for K Factor (other than 90deg)
K = tan (θ/2)
to obtain a smooth bend without flattening the tube.
Tube Bending
Types of Tube Flaring
Single, Double Flare
is a mechanical screw device consisting of two threaded terminals and a threaded barrel. These are fitted in the cable assembly for the purpose of making minor adjustments in cable length and for adjusting cable tension.
Turnbuckles
is the most positive and satisfactory method of safetying capscrews, studs, nuts, bolt heads, and turnbuckle barrels which cannot be safetied by any other practical means.
Safety Wiring
are used in shear applications and for safetying.
Pins
Main Types of Pins
Taper, Flathead, Cotter
These pins are used in joints which carry shear loads and where absence of play is essential.
Taper Pins
is used in locations where nonmagnetic material is required, or in locations where resistance to corrosion is desired.
Cotter Pin
is a pressed fit pin with chamfered ends. It is tubular in shape and is slotted the full length of the tube. The pin is inserted with hand tools and is compressed as it is driven into place.
Roll Pin