The most common question about heat treating What is the difference between case hardening and through hardening? The most common metal is steel which is available in many different alloys. The most common type of steels are: 1: Those which may be grouped under the heading mild steel and generally contain less than 0.25% carbon. 2: Those classed as medium to high carbon which contain carbon over 0.25%. medium carb. 0.25% - 0.5%.
Noun. 1. NRC-an independent federal agency created in 1974 to license and regulate nuclear power plants. Nuclear Regulatory Commission. independent agency-an agency of the United States government that is created by an act of Congress and is independent of the executive departments. 1  Facebook.
A noise reduction coefficient (NRC) is a single number that represents an average of the sound absorption coefficients in the 250 Hz, 500 Hz, 1000 Hz, and 2000 Hz octave bands. Detail of its calculation can be found in the ASTM C-423 standard.