Materials

Insufficient Design

A design that contains flaws, errors, or lacks crucial elements necessary for a product, system, or solution to perform effectively and meet intended purpose user needs (ex. foldable stroller that clamped children’s fingers)

Insufficient Properties

The materials, chemicals, or physical properties of the product can be harmful to the user or self-destructive to the product itself (ex. a space heather melting due to the lac of heat resistant material it is made of)

Metals

Solids composed of atoms held together by a matrix of electrons, good conductors of heat and energy

Ferrous

Contains iron (ex. steels, stainless steel, iron)

Nonferrous

Does not contain any “appreciable” amounts of iron (usually 0%). (ex. aluminum, zinc, copper)

Aluminum advantages

Can be die cast, 1/3 weight of steel, won’t rust, nonmagnetic

Cast

Pouring into a mold to obtain shape

Wrought

Made into a sheet by rolling, drawing, and extruding it

First-Digit Wrought Aluminum

Indicates major alloying element

Second-Digit Wrought Aluminum

Mill control of specific elements

Last two digits of Wrought Aluminum

Insignificant except for 1XXX series, where aluminum content is about 99%

Steel

An alloy of iron and carbon, with the carbon being restricted within certain concentration limits. Carbon limits between 0.06%-2.0%, perfect for fabrication.

Pig Iron

4%-5% carbon, too brittle

Cast Iron

2%-4% carbon, too brittle for fabrication

Pure Iron

0.005% carbon, too soft and ductile

Continuous Casting

90% production of all steel begins here

Ingot

10% production of steel

Hot Finished Steel

Above recrystallization temps (400-700C), stays easy to roll or shape, soft and low strength, dull finish

Cold Finished Steel (Work Hardened)

Created by pickling hot finished. Below recrystallization temps (400C), much stronger, less ductile, better surface finish

Galvanized

Zinc-coated steel products

Tin Plate

Cold-rolled steel with a usual thickness range of 0.005 to 0.014in. May or may not be tin coated

Pickling

Use of acids to remove oxides and scale on hot-worked steels.

Conditioning process- annealing

Softening of a steel by heating just into the austenitic range.

Conditioning process- Normalizing

A heat treatment to homogenize a material and reduce composition gradients.

Hardening process- Quenching

Rapid removal of heat from a heating part.

Hardening process- Tempering

Reheating a hardened steel to reduce as-quenched hardness and brittleness

Hardening process- Age Hardening

Hardening of a metal which occurs if it is quenched and then stored at ambient temp or treated with mild heat

Mer

The smallest repetitive unit in a polymer

Degree of Polymerization

Represents the number of mere joined in one molecule/polymer

Copolymer

When a polymer consists of two different repeating units (mers)

Polymers

Natural or synthetic organic compounds; have chemical structures characterized by the repeating of 100+ mers

Plastics

A synthetic material made from a wide range of organic polymers such as polyethylene, PVC, nylon, etc., that can be molded into shape while soft and then set into a rigid or slightly elastic form

Are plastics and polymers the same? Why or why not?

No. A plastic is always a polymer, but a polymer may or may not become a plastic.

Two categories of plastics

Thermoplastics and Thermoset

Thermoplastic

Capable of being repeatedly softened by heat and hardened by cooling. Approx 80% of plastic products.

Thermoset

A network polymer that will undergo or has undergone a chemical reaction by the actin of heat, catalysts, ultraviolet light, leading to a relatively infusible state.

Elastomers

Natural or synthetic polymeric materials that can be stretched to at least two times their original length, return quickly to approx their original length while at room temp. Held together by cross links.

Amorphous

The molecular chains have no order (cooked spaghetti). Clear, low-shrinkage, softens (not melt), high impact

Crystalline

Regions in the plastic that take on a highly ordered structure (uncooked spaghetti). Opaque, high shrinkage, melts (not soften), low impact.