AISI no longer maintains any standards for steel chemical composition.  ASTM and SAE do.  Section 7 of ASTM A 108 lists the applicable references for chemical compositions.  ASTM A 29 is the probably the most common reference for ASTM A 108, since it defines the requirements for the hot-rolled bars that are turned into cold-finished bars according to ASTM A 108.  Grade 1045 appears in ASTM A 29.

If you are using the internet, you can also obtain mechanical properties free from the web site below for Grade 1045 (AISI Type 1045);

http://www.matweb.com/membership/reg-start.asp?ckck=1

SAE 1045;  "NOTE 3—A more complex ordering description is as follows: Steel Bar; ASTM A 108, dated ____; SAE 1045; Fine Grain; Cold Drawn, Turned, Ground and Polished; chamfer both ends; Mechanical Property Test Results; Hardness test; 2.000-in. (50.80 mm) diameter round; 12 ft
(3657.61 mm) long; Heat Analysis ..."