Metallurgy Flashcards
What are Ferrous Metals?
Metals that have iron as the major ingredient and are usually magnetic
Punches, dies, shears blades, cutting tools all have high what?
What are some names for this steel?
- Carbon content in the steel.
- High speed steel, tool steel.
What are Non-ferrous Metals?
Metals that do not have large amounts of iron in them.
Name 3 examples of Non-ferrous metals.
Brass, lead, copper, zinc, aluminum, magnesium.
Which metal is non-ferrous but has magnetic properties?
Nickel
What is the difference between hot rolled steel and cold rolled steel visually?
Hot rolled has black mill scale on the outside while cold rolled has a shiny smooth surface.
What metals have these weights?
Can you cast aluminum into parts?
Yes
What is hardness?
The ability of a metal to resist penetration and plastic deformation.
Give two examples of hard materials
Ceramic, carbide
What is Ductility?
The ability of a material to be stretched perminently without breaking.
What is toughness?
The ability of metal to withstand shock and impact without breaking.
What is Tensile Strength?
The ability to withstand pull without breaking.
What is Machinability?
The ease with which you can cut and shape metal.
How is Hot-Rolled Steel produced?
By drawing red-hot billets through the rollers.
Which is the least expensive cold or hot-rolled steel?
Hot-Rolled Steel
How is cold-rolled steel produced?
By cleaning the scale from hot rolled billets and then drawing them through rollers or dies until the desired shape and size are reached.
Cold-Rolled steel has what problem?
Internal Stresses which causes cold-rolled steel to warp during any machining.
What is Brass?
A mixture of copper and zinc.
Carbon Steel with 1.7% Carbon is considered to be what?
Cast Iron
How much carbon is Low Carbon Steel considered to have?
Can it be hardened?
- 0.02 - 0.30% Carbon
- No, except for casehardening
How much carbon is Medium Carbon Steel considered to have?
- 0.30 - 0.60%
How much carbon is High Carbon Steel considered to have?
Where is it found?
- Over 0.60%
- Meant to be hardened and found in cutting tools (taps, drills)
Alloy Steel contains what?
Carbon, Iron and other significant amounts of elements to give the steel mechanical properties.
What is HSLA Steel?
What are its properties?
What is it used for?
- High Strength Low Alloy Steel
- Low Carbon Structural steel. The rust that forms on the outside is impervious to water and prevents further rust.
- Bridges, Truck trailers, structures exposed to enviroment.
What are the four heat treating processes for steel?
- Hardening
- Tempering
- Annealing
- Normalizing
Only steel with a carbon content of at least ___ can be hardened
- 0.20%
What are special types of Alloy Steels?
- High Strength Low Alloy Steel (HSLA)
- Quench and Temper Structural Steel
- Maraging Steel
What is Maraging Steel?
What is so special about it?
- Steel that uses elements other then Carbon for hardening. In fact carbon is considered a impurity.
- Intricate shapes can be machined and then hardened without fear of distortion. Easy to weld.
What makes Stainless Steel corrosion resistant?
Large amounts of Chromium
What are three types of Stainless Steels?
- Austenitic
- Ferritic
- Martensitic
What is Bronze?
Any copper alloy other then Brass
Which is stronger Bronze or Brass
Brass
What should you watch out for with Berylium Bronze?
The particales produced during machining are toxic to touch and inhale.
What are three atom structures for steel?
- Soft Steel: Pearlite
- Hardened Steel: Martensite
- Red Hot: Austenite
The hardening temperature varies with the __________ content of the steel.
Generally the higher the ______ content the ________________________.
- Carbon
- the higher the Carbon content the lower the hardening temperature.
What is Quenching?
Why?
- After heated sufficiently the material must be immersed in water, oil, air or brine immediately until cooled and hardened.
- If allowed to slowly cool it reverts to pearlite instead of martensite.
Moving the workpiece around in a figure eight pattern during quenching does what?
Ensure workpiece is cooled evenly.
What happens after steel has been quenched?
What step helps this after?
- The steel is very brittle and has internal stresses and strains caused by the severe quench.
- Tempering
What is tempering?
Immediately after quenching a piece heat the material to a temperature below the lower critical temerature and then allow the steel to cool at any desired rate.
What happens if you do not temper a piece immediately?
It will crack.
When tempering hardness decreases as _____________.
Tempering time and temperature increase.
Tempering does what?
Gives the piece Toughness
What is a more efficient way to temper a piece then torch?
Heating the piece in oil, sand or a salt or lead bath.
What is Full Annealing?
The opposite of hardening. It converts Martensitic steel to Pearlite. Make materials soft again for machining.
How does full annealing work?
Heat piece to above upper critical temperature for steels with less than 0.85% carbon or above lower critical limit for steels with more than 0.85% carbon. Steel is allowed to cool slowly.
What is Process Annealing?
How is it done?
- Related to full anealing but is used to restore ductility.
- Heat piece below the lower critical temperature point, hold it for a period of time and then let it air cool.
What is Normalizing?
The process that eliminates strains and restores the proper grain structure of steel.
How is normalizing done?
By heating the piece above its upper critical temperature and then allowing it to cool in air.
What are two ways of testing hardness?
- Rockwell Hardness Testing
- Brinell Hardness Testing
What is Rockwell Hardness Testing considered to be?
Destructive Testing.
How does a Brinell Hardness Test work?
Uses a hydraulic press to force a round penetrator into ferrous or non-ferrous specimens.
What are four ways other than weight, shape or other visual means of identifying materials?
- Chip Test
- Spark Test
- File Test
- Flame Test
Do all metals spark?
No, non-ferrous metals usually do not. But Nickel and Titanium do.
What is a spark test usually used to test?
To find the carbon content in steels and distinguish between a cast steel and a cast iron.
What do Low Carbon Steel Sparks look like?
What is Low Carbon Steel also known as?
- Bright
- Long
- Straight
- Yellowish
- Very little branching
- Few Carbon Bursts
- Mild Steel
What do High Carbon Sparks look like?
- Sparks Burst
- Branch Off
- Dark Yellow-orange
- Bursts Nearer to wheel
- Sparks curl around wheel
What do cast iron sparks look like?
- Many Bursts
- Red near grinder and orange-yellow further out.
- Stream not as long as carbon steels
- Apply considerable pressure for sparks
What do High Speed Steel sparks look like?
- Lines orange
- Very little branching
- End up in ball shaped sparks
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