Table 1. Chemical compositions of the low-carbon steels.

	Chemical composition (wt%)
Steel	C	Mn	P	S (p.p.m.)	Sol-Al	B (p.p.m.)	N (p.p.m.)
BF	0.020	0.20	0.012	40	0.025	–	20
BA	0.020	0.20	0.011	40	0.025	20	20