Ferrous & Non-Ferrous Material Properties Flashcards

In CNC machining, which steel designation indicates a free-machining grade with improved chip breaking due to added sulfur?

Answer: 1215

AISI 1215 is a free-machining steel with added sulfur and phosphorus that form inclusions, promoting short chips and reduced tool wear.

What is the effect of annealing on a cold-worked steel part?

Answer: Relieves internal stresses and restores ductility

Annealing heats the steel and allows slow cooling, recrystallizing the grain structure, relieving residual stresses, and restoring ductility.

Which of the following best describes the property of malleability?

Answer: Ability to be hammered or rolled into thin sheets without fracturing

Malleability is the ability of a material to undergo plastic deformation in compression (rolling, forging, hammering) without fracturing.

Which type of cast iron has superior tensile strength due to its spheroidal graphite morphology?

Answer: Ductile (nodular) cast iron

Ductile iron (also called nodular iron) has graphite in spherical nodules rather than flakes, which greatly reduces stress concentrations and improves tensile strength.

Bronze is an alloy primarily composed of:

Answer: Copper and tin

Bronze is traditionally copper alloyed with tin, though modern 'bronzes' may substitute other elements while keeping copper as the base.

When machining 304 stainless steel, a machinist should be aware that it tends to:

Answer: Work harden rapidly, increasing cutting forces as machining progresses

Austenitic stainless steels like 304 work harden very quickly, so dwell and rubbing without cutting increases hardness and cutting forces.

The Rockwell C scale (HRC) is most appropriate for measuring hardness of:

Answer: Hardened steel and hard alloys

The HRC scale uses a diamond cone indenter under a 150 kgf load and is designed for hard materials like hardened steels and carbides.