Several older sources I have seen (Including my copy of the Ryerson Engineering Data manual from the 60s) list the yield strength of 1018 cold drawn steel as 70,000 psi, which is nearly as high as 4130.

Current data from the top manufacturers & the better engineering texts list it as 54,000 psi.

(The advertised properties for hot rolled 1018 have stayed the same over the years)

I was just wondering if anyone had an explanation for the difference? My first thoughts are either manufacturing processes have changed or it is CYA by the manufacturers?