Metallurgy Week 5

Why do we heat treat aluminum alloys?

Increase ductility

Increase conductivity

Increase Strength

Increase corrosion-resistance

How do we make non-heat treatable alloys stronger?

Strain-Hardening

Solution-heat treatment

Alclading

Extruding

What is Strain-Hardening?

cold-working wrought products below their critical temperature

cold-working extruded products below their critical temperature

hot-working annealed products above their critical temperature

hot-working normalized products above their critical temperature

During the process of Strain Hardening, how do you make the metal softer or easier to form?

Annealing

Normalizing

Case Hardening

Tempering

To achieve desired strength during or after cold-working process, one must?

Heat from time to time during certain operations to remove the undesirable effects of the cold working

Take a smoke break time to time during certain operations in order to avoid fatigue

Cold from time to time during certain operations to remove the undesirable effects of the cold working

Bathroom break from time to time during certain operations to remove the tension in the atmosphere

'H1 Strain-Hardened Only process' achieves its desired strength without?

Thermal treatment

Surface Treatment

Chemical Treatment

Silence treatment

'H2 – Strain Hardened and Partially Annealed' involves process of?

Over-achieve the strength and anneal it to reduce the strength

Under-achieve the strength and anneal it to increase the strength

Over-achieve the strength and extrude it to reduce the strength

Under-achieve the strength and normalize it to increase strength

'H3 – Strain Hardened and Stabilized' only applies to which alloy?

Manganese containing alloys

Magnesium containing alloys

Magnesium and silicon containing alloys

zinc containing alloys

True or False? 'H3 – Strain Hardened and Stabilized' involves process of gradually age-soften at room temperature after strain hardening, and annealing at low temperature to stabilize its properties

True

False

How does strain hardening increase strength?

Hot working them, extruding them, to loosen the molecules

Carburizing them, adding carbon to its molecules

Cold working them, squishing them, pressing them to tighten the molecules

Nitriding them, by forcing the molecules inward

The total percentage of alloying elements is seldom more than?

3 or 4 percent in the wrought aluminum

4 or 5 percent in the wrought aluminum

5 or 6 percent in the wrought aluminum

6 or 7 percent in the wrought aluminum

Aluminum products are almost without exception produced from?

Pure Magnesium

Pure Aluminum

Pure Titanium

Pure Chromium

What is the disadvantage of aluminum alloys that are easily extruded?

difficult to weld

difficult to machine

difficult to increase its conductivity

difficult to increase its ductility

What is the disadvantage of aluminum alloys that machines well?

difficult to weld

difficult to machine

difficult to increase its conductivity

difficult to increase its ductility

Why do we rivet aluminum alloys?

difficult to weld

difficult to machine

difficult to increase its conductivity

difficult to increase its ductility

Aluminum alloys' oxidation from the surface of the heated metal prevents the weld from adhering to the material

True

False

Are all aluminum alloys difficult to weld?

Yes, all aluminum alloys are difficult to weld

No, some aluminum alloys are successfully welded

Which one is most vulnerable to corrosion?

Aluminum alloy with copper as the alloying element

Aluminum alloy with zinc as the alloying element

Aluminum alloy with magnesium as the alloying element

Aluminum alloy with titanium as the alloying element

Which characteristic of 1075 is not true?

What does the second digit of 1075 indicate?

special control or modifications on impurities

minimum aluminum %

maximum aluminum %

alloying element

Second and last two digits of one thousand series and two-seven thousand series indicate the same? (Example: In 1100 vs 2024, 00 and 24 is same?)

True

False

Which one of the following is not true in 2024?

Copper is major alloying element

With heat treating, has the same properties of mid steel

Has poor corrosion resistance

Last two digits indicate that it is 99.24% aluminum

What does the second digit in Aluminum alloy 2011 indicate?

Copper is the major alloying element

Alloy modifications

It is most free machining of the common aluminum alloys

It is Widely used for automatic screw machine products

Which one of the following is not true for 2017?

Has more than one alloy modifications

It is a tough, ductile alloy suitable for heavy-duty structural parts

Slightly less strength than 2014

2014 and 2017 are very similar

Which characteristic of aluminum alloy 6061 is false?

Medium strength alloy

Corrosion resistant

Heat treatable

Non-heat treatable

True or false? Aluminum alloy 5052 is corrosion resistant, good with welding and is non-heat treatable

True

False

Which characteristic of aluminum alloy 7075 is false?

High strength

Often mixed with other elements

heat-treatable

Non-heat treatable

True or false? Temper is the quality of metal that describes it’s ability to spring back after it is flexed

True

False

True or false? Hard Temper: What is bent, springs back flat, and it takes a lot of force to put a kink into it

True

False

True or False? F in 2024F involves rolling or forming where there is no special control over the thermal or work-hardening conditions.

True

False

True or false? The difference between natural ageing and artificial ageing, is that artificial ageing is solution heat treated above room temperature, while natural ageing is stored at room temperature after solution heat treatment and quenching

True

False

True or false? Aluminum oxide is not really visible, but it comes off on your hands as a black smudge if touched

True

False

Polishing invovles?

Abrasive finish or high polish

Smooth finish or high polish

Hard finish or high polish

Insane finish or high polish

Which one of the following is incorrect in regards to Lacquering?

It involves abrading the surface with the abrasive finish

Lacquering results in silvery look

It is a chemical bond that helps adhere correctly

Lacquering is used to increase fusibility

True or false? Anodizing involves process of dipping the aluminum into a liquid solution that contains chemicals that clear the metal surface of its coating of aluminum oxide

True

False

Which one of the following is incorrect in regards to Anodizing?

Helps coating to be thicker

Helps colouring

Increases durability

Increases thermal conductivity

Cladding process involves?

Laminating thin sheet of relatively pure aluminum to most aluminum flat stack

Extruding thin sheet of relatively pure aluminum to most aluminum flat stack

Calburizing thin sheet of relatively pure aluminum to most aluminum flat stack

Nitriding sheet of relatively pure aluminum to most aluminum flat stack

which one of the following is not a benefit of adding finishing to aluminum alloy?

Corrosion resistant

Fatigue resistant

Increased strength

Increased conductivity

which one of the following is incorrect in regards to superficial corrosion?

Not as detrimental in comparison to other forms of corrosion

It is white

generally more voluminous then the original base metal

Noticeable in its early stages aluminum corrosion is evident as general etching, pitting or roughness of the aluminum

It is thick (Thicker than 0.025 inches)

Which one of the following is not one of three types of serious corrosion?

Surface Oxidation

penetrating pit type corrosion

stress corrosion cracking of materials under sustained stress

intergranular attack (certain heat treated aluminum alloys)

Difference between intergranular corrosion and other serious corrosions?

Intergranular corrosion is noticeable on the surface

Intergranular corrosion starts inside the metal

What does aluminum alloy 2024T tell us?

Copper major alloy element, 2 alloy and solution heat treated

Zinc major alloy element, original alloy and solution heat treated

Copper major alloy element, original alloy and tempered

Copper major alloy element, original alloy and solution heat treated

What does solution heat treating do to aluminum alloy?

Improves the mechanical properties

Makes the alloys more porous

improve the flexibility

makes the alloys softer

What does letter T mean after the numbers? (Example: 2024T)

Annealing

As found

Solution heat treatment

As formed

What is an alloy?

A mixture of metals melted together to form a new metal

A mixture of ferrous and non-ferrous metals

A mixture of aluminum dust water and flour

A mixture of metals welded together

What is the advantage of alloying aluminum?

Makes it stronger

Makes it water proof

Makes it more magnetic

Makes it more recyclable

What is the disadvantage of alloying alluminum?

Makes it not as magnetic

Makes it not as recyclable

Makes it difficult to weld

Makes it not waterproof

In an aluminum alloy numbering, if the first number is a 2, What is the main alloy?

Copper

Siliocn

Aluminum

Zinc

What is quenching?

Cooling the alloy fast enough to retain a alloying constituents without introducing adverse metallurgical or mechanical conditions

Cold-working the alloy fast enough to retain a alloying constituents without introducing adverse metallurgical or mechanical conditions

Hot-working the alloy fast enough to retain a alloying constituents without introducing adverse metallurgical or mechanical conditions

Annealing the alloy fast enough to retain a alloying constituents without introducing adverse metallurgical or mechanical conditions

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Metallurgy Week 5