Abstract: A method including preparing an aluminum scrap containing a total of about 0.3 to 2.0 wt % of Fe and Si; melting and then adjusting the material composition so as to attain an Mg content of about 3 to 10 wt % or a composition further containing at least one of the elements Cu, Mn, Cr, Zr and Ti, each in the amount of 0.02 to 0.5 wt %; subjecting the material to casting, hot rolling, cold rolling and continuous annealing to obtain an aluminum alloy sheet having a tensile strength of about 31 kgf/mm.sup.2 or more; and applying a lubricant surface coating to impart a coefficient of friction of not more than about 0.11.

Abstract: The invention provides an aluminum alloy sheet having improved formability, an elongation of at least 30%, a sliding frictional resistance of up to 0.13 and minimized surface pressure dependency of sliding frictional resistance, comprising an aluminum alloy substrate containing at least 4 wt % of Mg and a Fe rich plating layer on a surface thereof in a coating weight of 1 to 50 g/m.sup.2. Also provided is a bake hardenable, surface treated aluminum alloy sheet having improved formability, an elongation of at least 25%, a sliding frictional resistance of up to 0.13 and minimized surface pressure dependency of sliding frictional resistance, comprising a bake hardenable aluminum alloy substrate containing Mg and Si in an amount of at least 0.4 wt % calculated as Mg.sub.2 Si and a Fe rich plating layer on a surface thereof in coating weight of 1 to 50 g/m.sup.2. By forming a zincate layer as an undercoat below the Fe rich plating layer, the plating adhesion is further improved.

Abstract: An extra-low carbon cold rolled steel sheet useful for use in automobiles and the like, having an improved spot weldability is obtained by combining and adding Ti, Nb and B in predetermined amounts to an extra-low carbon steel to control the amount of fine Ti precipitate dispersed in steel to within a specified reasonable range. Furthermore, the spot weldability is improved by controlling the production conditions of the extra-low carbon steel sheet to within specified reasonable ranges.

Abstract: An extra-low carbon cold rolled steel sheet useful for use in automobiles, and the like, having an improved spot weldability is obtained by combining and adding Ti, Nb and B in predetermined amounts to the extra-low carbon steel to control the amount of fine Ti precipitate dispersed in steel to within a specified reasonable range. Furthermore, the spot weldability is improved by controlling the production conditions of the extra-low carbon steel sheet to within specified reasonable ranges.

Abstract: A Cr-Mo steel which is suitable for use as extremely thick plates of 75 mm or greater for pressel vessels of oil refinery, coal liquefaction and coal gasification equipment. The Cr-Mo steel includes 0.09 to 0.17 wt % of carbon, 0.03 to 0.50 wt % of silicon, 0.45 to 0.70 wt % of manganese, 1.80 to 3.40 wt % of chromium, 0.80 to 1.20 wt % of molybdenum, 0.035 to 0.1 wt % of aluminum and 0.0010 to 0.0040 wt % of boron and the balance iron and impurities inevitably mixed in steel-making processes. The Cr-Mo steel of such compositions is highly excellent in high-temperature strength, toughness and hydrogen attack resistance.