Metalurgy Flashcards
Very high carbon steel used to make punches, dies, sheer blades and cutting tools are often refers to as??
Tool steel or high speed steel
List two types of ferrous metals?
Carbon steel and cast iron
Non-ferrous metals are?
Aluminum Magnesium Zinc Copper Lead And brass
What non-ferrous metal is magnetic?
Nickel
Nickel is what color?
A white grey
Steel and cast iron are usually what color
Silver grey to grey
Hot rolled steel has what type of surface?
Black mill scale, cold rolled is shiny and smooth
What mechanical properties does copper have?
It can be easily beaten ad be formed into a new shape.
What material is used in bearings?
Brass
Hardness is..??
The ability of metal to resist penetration and plastic deformation.
Examples are:
Carbide, ceramic and hardened steel.
Ductility is..?
Is the ability of a metal to be deformed without breaking.
Ductile metals are:
Steel, copper aluminum and lead machine steel.
Toughness is..?
The ability of metal to withstand shock and impact.
Example:
Steel chisels are tougher than a steel tap.
Tensile strength is..?
Is the a lilting a metal to withstand pulling without breaking.
Machine-ability measures.. ??
The was with which you can cut and shape a metal
What steel is the most common used for building steel as most other structures..??
Carbon steel.
High strength, low alloy steels are also available.
Galvanized iron, stainless steel, aluminium, copper and brass are other materials available in sheet metal.
Y
N
Yes
Carbon and alloy steels (numbering system) use a four or five digit code
Ex.
Chromium-molybdenum 4140
What is the 41 ad the 40
41 is the material
40 is the percent of carbon content in the material.
Carbon steel mechanical properties
Low carbon 0.02-0.30% carbon
Medium carbon steel 0.30-0.60%
High carbon steel over 0.60%
Low carbon - can not be hardened
Medium carbon - has better mechanical properties than low carbon steel.
And has a high tensile strength (the ability of a metal to with stand pulling without breaking.
High carbon. Steel - meant to be hardened
Used for cutting tools
High strength low alloy steel is low carbon or high carbon steel?
Low carbon - and is ideal for structures exposed to the environment.
What material is a mixture of copper and zinc?
Brass
What material consists of copper and tin?
Bronze
What material is harder
Bronze or brass?
Bronze is usually harder than brass
What I are advantage and disadvantage of beryllium-bronze??
It is used because of it’s strength and hardened
But
It is a health hazard due to it’s toxicity
The structure of Soft steel is called
Pearlite
Pearlite steels consist of ferrite and cementite
The structure of hardened steel is called
Martensite - it consists of angular needle like Chrystal’s
The precise amount of ferrite and cementite in a steel depends on the percentage of…..
Carbon in the steel
How is austenite formed?
Austenite is formed when Pearlite steel is heated to a red hot.
The structure of hardened steel is called?
Martensite.
What is the heat treating process?
Hardening
Tempering
Annealing
Normalizing
What two processes are required for hardening a steel?
Steel is heated until it changes to austenite
Than quenched rapidly (steel must contain at least 0.20% carbon.
What is the most effective quenching medium?
Brine(salt water) followed by
Water
Oil
Air
What must be done to a steel immediately after hardening?
The steel must be tempered to relieve it’s brittle stresses and strains. If not it will crack.
Full annealing does what to steel ?
Converts martensite steel to Pearlite taking out all the stresses making a hardened work piece soft again.
Process annealing is used to restore what in the steels struxture.
Ductility - ability to be deformed without breaking.
What material can withstand more stress
Steel or brass
Steel
What material has the highest rte change of thermal growth
Aluminum
Forging is what?
Forging I a process involving the shaping of metal.
