Extrusions Flashcards
Extrusions are Ideal for making metal _________ that can be a variety of shapes, solid, hollow, and with tight tolerances
profiles
Extrusions requires relatively _______investment ($___-$___) and have a ______ time to market (_________)
cheap, 1-5, fast, 6 weeks
About _______of metal extrusions are ___________(most of which are __________)
90%, aluminum, 6000 series
The extrusion process is:
o Preheated __________ placed inside ____________
o Pressed by a ________ through the ___________
o __________ shape comes out the _________
Billet, ram, casting, extruded, die
Billets are ______________ bars made by __________
cylindrical bars, casting
Billet diameters can be as large as ___________ and must be _________ than the _________
350mm, larger, profile
Profiles are typically ________ of the billet diameter and the Cross-sectional ratio between _______ and
________ is known as _____________, R
20-80%, billet, profile, extrusion ratio
About ____________ of billet goes through the die in a single pass and the __________ can be recycled
80-90%, offcut
A _______________________ is when a second billet is place behind another which can produce ___________ in extrusion
Billet-to-Billet Extrusion, weak spots
To allow time to load subsequent billets, manufacturers aim for about _____________________
80% effective press time
Sometimes billets are heated with a “__________________” where the die end is __________ than the ram
end which allows the material near the ram end and sides of the material to be heated to optimal temperature via __________ and _____________
temperature taper, hotter, friction, deformation
The Flow of metal through die is similar to ______________from a larger channel to a
smaller one where metal funnels toward the ____________, with the largest deformations occurring in in
a _____________ region. Downstream of this region are wedge shaped “________________” where material does not pass through the die and is ______________
fluid, cone shaped, dead metal zones, scrapped
The Extrusion diagram shows the ________________that material can be extruded vs. __________________
o Ignores _____________
Initial billet temp, temperature taper
Line 1 of the Extrusion Diagram relates to the _________ where the _______ the billet, the ________ the ram will be able to extrude the billet
ram force, hotter, faster
Line 2 of the Extrusion Diagram relates to the ___________of the material where as the velocity goes up, material will __________, causing _____________(aka ______________)
melting, heat up, hot cracking, hot shortness
Line 3 of the Extrusion Diagram begins at the ______________ and increases with velocity again because material ___________ as velocity increases
cold cracking temperature, heats up
The __________________ is the temperature below which the material will crack because it cannot ______________ to fit through die
cold cracking temperature, deform enough
Overall, the Extrusion diagram shows the viable ______________ of initial billet temperature and exit velocity
combinations
In general, extruders will want the velocity to be as __________ as possible
high
Considering a Y- shaped profile:
The Die is a ________ made of ___________ and the material only makes contact with the die
over the ______________
flat disk, tool steel, bearing surfaces
Determining bearing surface lengths is a highly case-specific process and is often done by ________________
Trial and Error
Considering a Y- shaped profile:
You wish to distribute material evenly over profile but the material will want to flow ___________
near the center of the extrusion so the bearing surfaces are made ________
to increase the ________ and promote ___________ flow speed through the die
faster, thicker, friction, uniform
When creating profiles with slots the ratio between the slot depth, H, to width, B, is _____________
Limited
If H/B gets too _________, shear stresses in the die could be enough to break the ______________
high, tongue
Hollows are created in solid billets using ________________ where metal separates and flows in around the ____________to rejoin around the ___________ and create a hollow shape
multipart dies, legs, mandrel
There are several variations on hollows such as: “__________”, “___________”, and “_______________” (the most common)
Spider dies, bridge dies, porthole dies
In hollow dies, rejoining the metal creates ______________ down length of extrusion
Weld seams
6000 Series Extrusions are soft during extrusion which allows for ____________ and can be _______________ to gain strength
high exit speeds, Age Hardened
What process is described here?
Alloy is solutionized near the melting point to distribute
the alloy material uniformly
2. Then the it is rapidly Quenched to room temperature
3. Then it is aged at temperatures around 165 C for
about 10 hours
Age Hardening
In the cooling step of age hardening, the alloy elements (Mg and Si) form _____________ which restrict ___________ and thus increase strength
fine scale precipitates, dislocations
In age hardening there is a significant trade-off where faster quench improves ______________in age but can also cause rapid ____________ and __________
Strength gain, deformation, warpage
6000 series can be extruded in a large range or sizes, with profile weights of __________________ being a
practical range
.1kg/m - 20kg/m
What series of Extrusion is described below?
High-strength alloys with magnesium, Zinc and
copper as the alloying elements
o Can be heat treated like 6000 series, but are stronger
o Often used for bikes and aircraft to save
weight
o Poor corrosion resistance
o Harder material so lower extrusion speeds and less
form freedom
7000 Series
What other extrusion material is described here?
Sometimes extruded for tubing wiring, but difficult because of high temperatures involved
Copper
What other extrusion material is described here?
Extruded for heat exchanger tubes and feedstock for forgings, but also requires High Temperatures
Brass
What other extrusion material is described here?
Some niche applications, but very difficult
Carbon steel
What other extrusion material is described here?
Few applications because hot shortness is a problem
Magnesium
What extrusion method is described here?
o Uses a hollow ram with extrusion emerging through the center
o Used for hard materials materials and simple solid profiles
Indirect Extrusion
What extrusion method is described here?
o Some fluid is placed between the ram and the billet
o Eliminates friction between billet and container
o So far it is an experimental method
Hydrostatic Extrusion
