Welcome to the Forum!
Could be several... You need to say more about the project... Purpose, process, service conditons etc.
D1.3 sheet metal code may be one option.
Qualifying procedures? Than B2.1 may be the place.
Really just guess work until you say more.
Mbloch
Welcome to the forum
To get the best answer you need for the question to contain more information.
Code, process,...
Welcome to the Forum
Marshall
Mbloch,
before we go any longer, a word of warning: SAE 1045 is a medium carbon steel, so it's not as easy to weld as low carbon steel, like 1010 0r 1020.
Giovanni S. Crisi
Sao Paulo - Brazil