The size 4ft*8ft of 316 stainless steel plate is common on global market,usually this size called stable lenth.
So the price of this size are usually cheaper than other size.

Product ingredients
316 stainless steel plate, 316 stainless steel plate imports, Baosteel 316 stainless steel plate
GB 316 stainless steel plate, grade: 0Cr17Ni12Mo2

Chemical Composition of 316 Stainless Steel
P: 0.035
S: 0.03
Ni: 10.0-14.0
Cr: 16.0-18.5
Mo: 2.0-3.0

Product performance
Tensile strength (Mpa) 620 MIN
Yield strength (Mpa) 310 MIN
Elongation (%) 30 MIN
Area reduction (%) 40 MIN