Don't know about A529, but you have to watch the chem. with A36. The very loose spec. allows some combinations that will give poor results, esp. w/lam. tear. and weldability w/o preheat.
Try to buy steel with very low S and C, and Mn around 1.00. If the Mn is too low while the S is high, watch out. Make sure you check the CE (carbon equiv.--keep it below 0.40).