historical steel grade v50

huangyhg

historical steel grade v50
i have a set of structural drawings from 1974 in which v50 is used to specify steel type for a handful of girders.  an example of the usage is 鈥淲24x55 v50鈥?  it seems logical to infer that 50ksi steel is being called out.  is anyone familiar with the terminology?  i have the aisc steel design guide 15, which covers this sort of thing, but i can鈥檛 seem to find any reference to v50.
see page e-27 of this nist document (.pdf) about the steel used in the world trade center. the v50 steel properties are listed in a table on that page. it was a product of bethlehem steel. here is the link:
thank you, that is what i was looking for.