Steel Material Science

Which image below best represents a Eutectoid composition steel micrograph.

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• 
• 
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Answer explanation

Eutectoids are lamellar (layered).

Which cooling curve would give a hard material with some ductility.

• Blue

• Green

• Orange

• None

Order the following phases as to their Carbon Diffusion Distances, farthest (1) to smallest (4). 

(The first in the list is to have the furthest relative diffusion distance.)

• Lower Bainite

• Pearlite

• Martensite

• Speroidite

Answer explanation

In the following AISI steel designations, which of the following have the lowest Austenitizing temperature?

• C1018

• C1045

• C1080

• C1095

Answer explanation

0.8 % C steel (C1080) has the lowest Austenitizing temperatures...

it is the Eutectoid composition.

Regarding Manganese (Mg) in Commercial Steel, choose all that are true...

• increases machinability

• reduce brittleness

• defeats sulfur

• difficult to remove from the raw ingredients

Answer explanation

FeS inclusions are brittle... they lower the ductility of the steel. 

Mn scavenges Sulfur, forming harmless (ductile) MnS.

The steel alloy shown...

(choose all that apply)

• is Carbon Steel

• can easily form Bainite

• is an Alloy Steel

• is only appropriate for small parts

Answer explanation

The diagram is for 4340 Alloy Steel/

There is a Bainite nose.