Testing And Inspection, Metallurgy Review

What is an Alloy?

A material that is made up of two or more elements, one of which is a metal

What are Ferrous Metals?

Metals and alloys which contain a large percentage of iron

What is an Alloy?

A material that is made up of two or more elements, one of which is a metal

What are Ferrous Metals?

Metals and alloys which contain a large percentage of iron

What is an Element?

A substance that cannot be broken down into other substances.

What is a Compound?

Is a substance that is composed of two or more elements

What are the three main ingredients used in a Blast Furnace?

Iron ore, Coke, and Limestone

How is coke produced?

Heating coal to drive impurities out. It’s a compound composed mostly of carbon

The product of a blast furnace is known as:

Pig Iron

What is a Basic Oxygen Furnace? What goes into it?

A pear shape furnace that tilts when being charged with scrap steel and molten pig iron and oxygen

What type of steel do Electric Furnaces produce?

Stainless steels, and Tool Steels, highly deoxidized steels

Carbon steels are available in what three grades?

Rimmed

Semi-killed

Fully Killed

What is rimmed steel?

Structural carbon steel with very low deoxidization

Ingots are made of ________ steel

Rimmed

What is Semi-Killed Steel? What is used as a deoxidizer?

Partially de-oxidized steel

Silicon

What is Fully Killed Steel? What is used as a deoxidizer?

A completely de-oxidized steel

Silicon AND Aluminum

What is the continuous casting process? What is made in this process?

Hot molten DEOXIDIZED steel is poured in the top and descends through water cooled mold

Billets, Blooms, and Slabs

What is the most common method of shaping ferrous metals?

What shapes are made in this method?

Hot Rolling

Angle iron, I-beams, other structural shapes

Forging is also known as:

Deformation by compressive forces

What does cold rolling do for steel?

Increases strength, more exact dimensions, and a bright shiny appearance.

What is the carbon content of Low Carbon Steel?

0.05% to 0.3%

What is the carbon content of Medium Carbon Steel?

0.3% - 0.45%

What is the carbon content of High Carbon Steel?

0.45% - 0.75%

What is the carbon content of Very High Carbon Steel?

0.75% - 1.5%

High Carbon Steel is very _________ to weld

Difficult

Low Carbon Steel is very _________ to weld

Easy

The higher the carbon content, the _______ the hardness

Higher

What is the carbon content of Cast iron

1.5% - 2%

What is the most common grade of cast iron?

Gray cast iron

How much chromium and nickel are in the most common group of Stainless Steel?

18 – 8

18% Chromium, 8% Nickel

Stainless cannot be cut with an oxy torch because:

Chromium oxides resist the fuel torch cutting process, oxyfuel does not get hot enough

Must be cut with plasma

At what percentage chromium content does steel become considered stainless steel?

11% - 12%

What is the definition of Mechanical Properties of metal?

Requires a force to determine it

What are three examples of a mechanical property of a material?

Ductility

Elasticity

Tensile Strength

What is Ductility? How is it measured?

The ability of a material to become permanently deformed without failure

Measured in % Elongation

What is Elasticity?

The ability of a material to return to its original shape.

What is Tensile Strength?

The resistance of a material to a force which is acting to pull it apart

What is Hardness?

The ability to resist indentation

What is the definition of Physical Properties of metal?

Characterists of a metal which do not require a force to determine them

What would be an example of a physical property of metal?

Thermal Conductivity

What is a High Strength Low Alloy Steel?

Low carbon content and a proportionally low content of alloying elements.

What is the Brinell Hardness Test?

Indenting the material with a 10 mm steel ball.

Mild steel would have a hardness of about ______

File is about _______

100 Brinell

600 Brinell

When lightly touched against a grinding wheel _________will produce sparks

Ferrous Metals

What is the resulting spark from Low Carbon Steel?

Long Yellow Carrier lines

Occasional Forks

Some lines end in Arrow Heads

What is the resulting spark from High Carbon Steel?

Abundant yellow carrier lines

Bright and abundant Star Burst

What is the resulting spark from Cast-Iron?

Dull red to straw yellow

Short Spark Stream with many small sprigs

Short and Repeating

What is the resulting spark from Stainless Steel?

Short Carrier Lines (dotted line)

No buds or Sprigs

What is added to high temperature ferritic steel to give it ‘creep resistance’?

Molybdenum

What is the heat affected zone?

The non-melted area of metal that has undergone changes in material properties as a result of being exposed to high temperatures.

What happens to metal when it is cold worked?

Metal stretches due to a slipping or shearing action

Metal Gains strength

Cold Rolling steel results in:

Accurate Dimensional Tolerances

Bright shiny surface appearance

What is residual stress a result of?

A result of weld stresses

When does volumetric expansion in steel occur?

When it is heated or cooled.

What is Flame Heat straightening?

Using heat to correct warpage or twisting.

Flame straightening is also known as:

Controlled Upsetting

What is one of the best ways to control distortion when welding?

Use a few large weld passes rather than a large number of small passes.

What is used as a deoxidizer in Steel?

Silicon

Manganese

Aluminum

Metals have a __________ structure

Crystalline

Grains are formed in irregular shapes and connect at what are called:

Grain Boundaries

The smaller grain size will give the steel ______________while larger grain size create _______

Increased Strength and Toughness

Weaker steel

At what temperature does Iron exist in its Body Centered Cubic (b.c.c.) Form?

Below 1333F but between 1333 F and 1670 F it’s a mixture

At what temperature does Iron exist in its Face Centered Cubic (f.c.c.) Form?

Above 1670 F

What causes the transformation from BCC to FCC?

Carbon causes the transformation over a range of temperatures

Under the AISI material specification: What do the first,second, third & fourth digit represent? (e.g. C1015)

First digit: Major Class of Steel

Second digit: Major or dominant alloying element

Third & Fourth digit: Percentage of carbon in the hundredths (.15%)

Describe A36 Steel

Carbon steel used for general construction (Structural)

Descibe A283 Steel

Carbon steel used for Tanks

Describe A515 Steel

Intermediate & High Temperature Service

Describe A516 Steel

Medium to Low Temperature Service

18-8 Stainless steels are _______ and are listed in which series?

Austenitic Stainless

300 Series

Define Austenite:

A solid solution of carbon/iron-carbide in the fcc cubic structure (face centered).

Exists in steels above 1333 F

Define Ferrite:

Pure iron of the BCC Crystal structure, Soft and Ductile

What is the purpose of stress relieving?

Heating and cooling at a uniform/controlled rate to remove residual stresses due to forming / welding

What is an annealing heat treatment?

Heat to 100 F above the upper critical temperature (1700 F)and held therefor a specified time then slowly cooled in a furnace.

Soften steel for machining / working to be re-hardened afterwards.

How is a Normalizing Heat Treatment accomplished?

Similar process to annealing except the steel is cooled in still air at room temperature. Higher strength and hardness than annealed steels. Pressure vessel plates are often normalized (SA516-70 MT <--indicates normalizing)

The rapid cooling of a metal from an elevated temperature is called:

Quenching

What is tempering?

Final heat treatment, done below lower critical temperature. Increases toughness and impact strength.

Reduces internal stresses and removes some degree of hardness.