5A06H14 sheet metal with thickness of 8.5mm, and preparation method thereof

The invention relates to a preparation method of a 5A06H14 sheet metal with a thickness of 8.5mm. The invention relates to a sheet metal and a preparation method thereof. The invention aims at solving the problems of unstable alloy ingot strength, low yield strength, low tensile strength, and large unevenness of 8.5mm-thick 5A06H14 sheet metals produced with prior arts. The preparation method comprises the steps of: 1, material blending; 2, smelting; 3, casting; 4, homogenizing annealing; 5, sawing, edge planing and surface milling; 6, aluminum coating; 7, hot rolling; 8, cold rolling; 9, pre-stretching; and 10, sawing. With the steps, the 8.5mm-thick 5A06H14 sheet metal is obtained. With the method provided by the invention, the prepared 8.5mm-thick 5A06H14 sheet metal has a yield strength of 373-420MPa, a tensile strength of 285-330MPa, an elongation of 8% to 12%, an unevenness less than 8mm/m, and a same plate difference less than 0.25mm. The method provided by the invention is applied in industrialized productions of 5A06 sheet metals.