Question

Which method of surface hardening, the surface remains free from scales?​

Answer 1

Answer:

Nitriding

Explanation:

Answer 2

Answer:

Case hardening or surface hardening is the process of hardening the surface of a metal,

thus forming a thin layer of harder metal (called the "case") at the surface.

(only 80% sure)

Case hardening is usually done after the part has been formed into its final shape.

For a better understanding:

Search this ques in Google:

"Nitring method of surface hardening"

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