230502 - Advanced Materials

Question 1

Dual Phase Steel

Answer 1

Ferritic matrix containing a martensitic phase. Ferrite - ductile. Martensite - UTS increase.
* Advantages: Wide range of combinations of ductility and strength.
* Production: Continuous annealing, not bell annealing. Cooling strategy defines the percentage of each phase.
More ductility, more elongation at fracture.
DP: Dual phase steel, (drawing type), more flow of the material***
heterogeneous microstructure

Question 2

Complex phase steel

Answer 2

Ferrite, bainite and martensite.
High UTS, less ductility.
* Production: Continuous annealing, not bell annealing. Cooling strategy defines the percentage of each phase.
CP: Complex phase steel, (bending type)***
homogeneous microstructure

Question 3

What is hardening?

Question 4

Typical steel? UTS? Young’s modulus?

Question 5

TRIP Steel

Answer 5

Transformation induced plasticity
Ferrite, bainite, retained austenite - RA (even at room temperature, we still have austenite, normally does not exist at room temperature).

TRIP effect: While forming the component, the RA will change to martensite. Not by quenching.

Question 6

How do you form martensite?

Answer 6

Quenching

Question 7

Martensite steel

Answer 7

High strength (up to 1500MPa), low ductility.
Very fast cooling.

Question 8

Types of steels:

Answer 8

Dual phase steel, TRIP steel, Complex phase steel, martensite steel

Question 9

Different symbols for identifying steels

Question 10

What is a mild steel? Differences between mild steels and HSS?

Answer 10

Nomenclature.

HSS:
Advantages:
* high strength.
* price/kg decreases.
* property variations.
* light weight potential.

Disadvantages:
* Less ductility.
* wear tooling increases.
* machining forces and energy increases.