ASTM No. 3

general purpose

Composition

100ml Ethanol, 5ml HNO₃

5%

Method

immersion

Time

15s

Basic Information

Category:General Purpose

Composition:100ml Ethanol, 5ml HNO₃

Concentration:5%

Reveals:Grain boundaries, ferrite, pearlite

Typical Results:ASTM standard etchant. Similar to 5% Nital. Good for carbon and low-alloy steels.

Color Effects:Pearlite darkens, ferrite remains light