V2A, V4A ?

http://www.tobsteel.de/index.php?id=v2a-v4a&L=1

What do the abbreviations V2A and V4A stand for?
In 1912 the optimum balance between corrosion resistance and good mechanical properties was achieved, by combining nickel and chromium, and subjecting the resulting alloy to precisely controlled heat treatment.
The (German) abbreviations used at that time, V for "Versuch" (melting or other trial) and A for Austenite, are still used in German and English today. They have given us the descriptions V2A for CrNi steel and V4A for CrNiMo steel.
They continue to be used as synonyms for "stainless steel".
Note: V2A – melting trial 2 Austenite – for alloy type X12CrNi18-8, also called 1.4300, is no longer manufactured.