Ferrous & Non-Ferrous Material Properties Flashcards

Which heat treatment process increases the surface hardness of low-carbon steel by introducing carbon into the outer layer?

Answer: Case hardening (carburizing)

Carburizing diffuses carbon into the surface of low-carbon steel, allowing the outer layer to be hardened while the core remains tough.

What is the primary alloying element that makes stainless steel corrosion resistant?

Answer: Chromium

Chromium (minimum 10.5%) forms a passive oxide layer on the steel surface that prevents corrosion.

Which aluminum alloy series is primarily alloyed with copper and is commonly used in aerospace applications?

Answer: 2xxx series

The 2xxx series aluminum alloys use copper as the primary alloying element and offer high strength, making them popular in aerospace structures.

Gray cast iron is easy to machine primarily because of which material characteristic?

Answer: Graphite flakes that act as chip breakers and lubricants

The graphite flakes in gray cast iron interrupt the chip and act as a built-in lubricant, reducing tool friction and producing short, manageable chips.

Titanium alloys are significantly more difficult to machine than aluminum primarily because of:

Answer: Low thermal conductivity concentrating heat at the cutting edge

Titanium's poor thermal conductivity traps cutting heat at the tool tip, accelerating tool wear and requiring lower speeds.

Which property describes a material's ability to be drawn into wire without breaking?

Answer: Ductility

Ductility is the ability of a material to undergo plastic deformation in tension (wire drawing) before fracture.

A CNC machinist is selecting a material that must resist wear but also absorb impact without fracturing. Which combination of properties is most important?

Answer: High hardness and high toughness

Wear resistance requires hardness while impact resistance requires toughness; balancing both is critical for applications like dies and gears.