Abstract: Disclosed is a vehicle battery case including: a case body in which a vehicle battery is contained; and a side portion extending in a longitudinal direction of a vehicle and coupled to a side of the case body, thereby protecting a side of the vehicle battery. The side portion includes: a lower panel extending outwards from the case body and having multiple first protrusions formed to protrude upwards; an upper panel disposed above the lower panel and extending outwards from the case body so as to form a closed section together with the lower panel; and a reinforcement panel disposed between the upper panel and the lower panel so as to extend outwards from the case body, thereby reinforcing rigidity of the side portion together with the lower panel and the upper panel.

Abstract: A thermal refiningless, hot-rolled steel exhibits impact strength in excess of 10kgf.multidot.m/cm.sup.2 and contains, expressed in terms of weight percent, 0.30-0.50% carbon, 0.15-0.60% silicon, 0.80-1.60% manganese, up to 0.02% phosphorus, up to 0.015% sulfur, 0.07-0.20% vanadium, 0.015-0.06% aluminum, 0.005-0.015% nitrogen, up to 0.0015% oxygen, the balance iron and unavoidable impurities. The steel of the above-identified property and composition is produced by casting a steel product of predetermined cross-sectional shape; heating the steel product up to a temperature of 1,100.degree.-1,250.degree. C.; hot-rolling the heated steel product at a final rolling temperature of 850.degree.1,000.degree. C.; normalizing the hot-rolled steel product at a temperature of 880.degree.-950.degree. C.; and cooling the normalized steel product down to 300.degree. C. at a cooling speed of 5.degree.-100.degree. C./min.