Flashcards in Chapter 15 - Surface Hardening Deck (17)
What is the purpose of surface hardening?
It helps to create a thin hardened water resistant layer on the surface of a material, maintaining a soft and ductile inner core.
Why is surface hardening commonly called case hardening?
Surface hardening is commonly called case hardening because a hard metal case protects an unhardened core
Name four different applications or components that require surface hardening.
- piston pins,
- crankshaft and
Describe the differences between carburizing and nitriding?
Carburizing is the process that puts carbon on the surface while nitriding injects nitrogen to the surface.
What two surface-hardening processes use the principles of localized heating?
Flame hardening and
Explain the process of pack carburizing?
It is the oldest and most basic surface hardening process where the parts to be hardened are packed into a metal box along with a carbonaceous material and heated.
Name two advantages gas carburizing has over pack carburizing?
It is a faster process, and it requires less physical labor and handling.
What type of carbon-rich liquid is typically used in liquid carburizing?
A molten salt bath is typically used in liquid carburizing.
Of all the surface-hardening processes, which one is capable of producing the hardest case?
What range of heating temperatures is typically used in nitriding?
What is carbonitriding?
It is the gaseous process that introduces both carbon and nitrogen to steel parts.
Which surface-hardening process uses liquid to impregnate the surface of steel with carbon and nitrogen?
Cyaniding (Liquid Carbonitriding)
What two surface-hardening processes do not involve the addition of wither carbon or nitrogen to steel?
- Flame hardening,
- induction hardening
Explain the advantages of flame hardening over surface-hardening process.
- more controlled, and
- case depth.
What is the main disadvantage of cyaniding?
cyanide salts are poisonous.
In induction hardening, what is the source of electromagnetic induction?
The source of electromagnetic induction is the coil of wire that surrounds the surface.