Metallurgy (160102d) Flashcards
Define a Metal.
A metal is an element or mixture of elements.
What are 6 characteristics of metals?
It is solid at room temperature It is opaque It conducts heat and electricity It reflects light when polished It expends when heated and contracts when cooled (expect bismuth) It has a crystal structure
What are Ferrous Metals? Give a few examples of the types of metals.
Ferrous metals are metals that have iron as the major ingredient and are usually magnetic.
Carbon steel
Cast iron
What are Non Ferrous metals? Give a few examples of the types of metals.
Non-ferrous metals do not have iron in large enough amounts to have any major influence on the properties od the metals.
Aluminum Magnesium Zinc Copper Lead Brass
You can identify metals by their appearance, what is the difference between HRS and CRS?
Hot-rolled steel has a black mill scale or heat scale surface, while cold-rolled steel has a shiny and smooth surface.
Describe SAE grade 4142 steel.
Chromium-molybdenum steel with 0.42% carbon
Define the Mechanical properties of metals?
Hardness
Hardness – is the ability of a metal to resist penetration and plastic deformation.
What has better machining properties? Aluminum vs Tool steels
Aluminum
Describe how structural steel is formed. What is the most common steel used for building?
Structural steel is manufactured by forming a red-hot billet of steel into the desired shape, which could include angle iron, channel iron or beams. This process results in the formation of a single piece of steel. The hot rolling process produces a structural shape that is much stronger than if the pieces were welded together.
Carbon steel is the most common material used for building steel and most other structures.
When identifying structural steel we use inches for imperial and millimeters for metric, what are three characteristics we would look for when selecting this steel.
Cross section
Composition
Strength
What are three common shapes you see at your shop? Answer as a symbol.
HSS – Square
HSS – Round
L
Which of these shapes have a fillet corner?
L
On a “C” & “MC” shape piece of structural steel identify the following sizes:
C6x10.5= nominal size 6 inches and 10.5lb/ft C150x16= nominal size 150 mm and 16kg/m
HSS is available in two shapes, what are they?
Rectangular
Round
The process of pulling a steel rod through one or more dies is known as which process?
Cold-drawing
Describe the difference between a pipe and a tube?
Pipe is any tubular product that is producec in a size commonly used for piping systems. Tubing is any tubular product, other than pipe and include square and rectangular shapes, as well as round.
For pipes over 14” in diameter the nominal size equals what?
The outside diameter of the pipe.
Metals produced in round, square or flat form are known as ______ stock.
Bar
What size (thickness) is sheet steel available in?
28 ga to 18 ga
Steel plate is available in thicknesses of _______ or greater.
3/16
The seven classification of metals are:
Carbon steel Alloy steel Tool steel Stainless steel Aluminum and its alloys Copper and its alloys Cast iron
Describe the make up of 4140 steel?
Chromium-molybdenum type steel with 0.40% carbon content.
List the following percentages in carbon steel:
Low carbon: 0.02% – 0.30%
Medium carbon: 0.30% - 0.60%
High carbon: over 0.60%
What percentage of carbon in steel will make it into cast iron?
Anything over 1.7% is considered to be cast iron
At what temperature does Maraging steel harden?
480°C or 896°F
What are the six types of tool steels?
- Water hardening
- Cold work
- Hot work
- Shock resisting
- Mold steel
- High speed
List the alloys in brass
copper and zinc
Three main structures we see under a microscope when looking at iron and carbon atoms are?
- Pearlite
- Martensite
- Austenite
What are the basic heat treating process for steel?
- Hardening
- Tempering
- Annealing
- Normalizing
What is the minimum carbon content needed for hardening?
0.20%
How do we quench a long thin part?
Plunge it straight in to the quenching medium.
What color we want to see when tempering back our heat treated steel? Roughly at 230˚C(445˚F)
Light straw color
What is the difference between tempering vs annealing?
Tempering draws out brittleness and strain from the previously hardened steel. Annealing makes a hardened workpiece soft again.
What are the two ways we can check for hardness and which on is more common?
Rockwell hardness testing – more common
Brinell hardness testing
Is Rockwell testing a form of destructive testing?
Yes, it leaves a small mark by the penetrator.
What are the two types of penetrators used for rockwell testing?
- Diamond penetrator (brale)
- Steel ball penetrator
What are the different scales for Rockwell testing? Describe one.
“A” – for extremely hard materials such as cemented carbides and for thin, hard sheets.
What are four different ways we can identify a metals carbon content?
- Chip test
- Spark test
- File test
- Flame test
The most precise way to identify the composition of a metal?
Mill test report (MTR)
Which number can be found on both the MTR and metal specification tags?
Heat number
List the alloys in bronze
Originally - copper and tin
Now - any copper alloy other than brass
Define the Mechanical properties of metals?
Ductility
Ductility – is the ability of a material to be stretched permanently without breaking.
Define the Mechanical properties of metals?
Toughness
Toughness – is the ability of metal to withstand shock and impact without breaking or shattering.
Define the Mechanical properties of metals?
Tensile strength
Tensile strength – is the ability of a metal to withstand pull without breaking.
Define the Mechanical properties of metals?
Machinability.
Machinability – measures the ease with which you can cut and shape a metal.
A ferrous metal has a high content of:
Iron
A non-ferrous metal:
contains little or no iron and is usually non-magnetic
A metal is a red or yellow color is most likely what type of metal?
Copper or brass
What is the normal color for steels and cast irons?
Silvery gray
Which property allows a metal to be formed by bending?
Ductility
Given two identical pieces of metal, zinc die cast and aluminum, what would be the simplest way to identify them?
By their weight
If an object is irregularly shaped, what might you conclude about the object?
It is a casting
If an piece of metal has a smooth outer surface, what might you conclude about the object?
It has been formed
In using a chip test to identify a metal, what would a smooth continuous chip indicate?
A soft material like aluminum
How is cast iron distinguished from low carbon steel in a spark test?
The sparks given off by cast iron are short with red bursts near the grinder.
How can using a new hand-held file give you an estimate of a metal’s hardness?
If the file bites into the metal easily, it is likely a soft material.
If you are told a workpiece has a Rockwell C-65, what would that mean?
It has been hardened
Which metal, when ignited using the flame test, burns violently?
Magnesium
What is the minimum amount of carbon content required in steel for hardening?
0.20%
What is the proper specification for an unequal leg angle iron that has legs of 60 mm and 40 mm and is 5 mm thick?
60 x 40 x 5
What shape is the designation L6 x 6 x 1
Equal leg angle
When the heat code identification number is cut from a piece of plate, what should you do?
Transfer the ID number to the remaining plate
What is the most precise method for the identification of a metal that has been shipped from a steel mill?
Study the mill test report
In addition to the mill test report, what else do steel mills usually attach to the straps that hold bundles of bar stock together?
Metal specification tags
