Material Science Flashcards

Which stainless steel series is most commonly used in trade applications due to its good corrosion resistance and weldability?

Answer: 300 series (austenitic)

The 300 series austenitic stainless steels, such as 304 and 316, are most widely used because of their excellent corrosion resistance and weldability.

What does the Rockwell hardness test measure?

Answer: The depth of indentation made by a standard indenter under a fixed load

The Rockwell hardness test measures material hardness by the depth of penetration of an indenter under a specific load.

Which alloying element is added to steel to improve its hardenability and wear resistance in tool steels?

Answer: Chromium

Chromium improves hardenability, wear resistance, and corrosion resistance in steel alloys.

What is the primary advantage of using aluminum alloys over pure aluminum in structural applications?

Answer: Significantly improved strength

Alloying aluminum with elements like copper, magnesium, or silicon greatly increases its strength while maintaining its light weight.

In welding and metal fabrication, what is 'scale' that forms on heated steel?

Answer: Iron oxide formed during heating

Scale is iron oxide (FeO, Fe2O3, Fe3O4) that forms on the surface of steel when it is heated in the presence of oxygen.

Which process is used to increase the surface hardness of a steel part while keeping its core tough?

Answer: Case hardening

Case hardening (carburizing, nitriding, induction hardening) creates a hard outer shell while preserving a tough, ductile core.

What is the primary purpose of adding manganese to steel?

Answer: To deoxidize and increase strength and hardenability

Manganese acts as a deoxidizer, increases strength, hardenability, and counters the harmful effects of sulfur in steel.