Mainly Cost. I do not need the 36 KSI min yield strength. I could go a little lower.
The manufacturer gets cobble steel from their vendor but doesn't know what steel it was meant to be. They do a 13 element analysis on every plate and certify it. They don't check the material properties...
I am currently using an A-36 3" thick plate in a design. I would like to change the material type to include "Cobble Plate" or SMP - Stip Mill Plate. I was wondering on how you can esitmate the yield point of a material based on its chemical composition? Is there any good books...