Abstract: Provided is a surface hardening method for surface hardening a sulfuric acid-anodized aluminum alloy oxide layer, which includes: pre-treatment in which various foreign substances, including an oxide film, attached to a surface of an aluminum alloy are removed; sealing treatment in which the aluminum alloy having been subjected to the pre-treatment is immersed in a sealing solution, whereby fine pores formed in a film are sealed; and heat treatment in which the aluminum alloy having been subjected to the sealing treatment is charged to, and thermally treated in, a heat treatment furnace and then naturally cooled. By lowering the withstand voltage of an aluminum alloy oxide layer and increasing the hardness by subjecting the same to sealing treatment and subsequent post-heat treatment, the present invention has the effect of providing an environmentally-friendly and crack-free lightweight material that can replace steel products.

Abstract: Provided is a surface hardening method for surface hardening a sulfuric acid-anodized aluminum alloy oxide layer, which includes: pre-treatment in which various foreign substances, including an oxide film, attached to a surface of an aluminum alloy are removed; sealing treatment in which the aluminum alloy having been subjected to the pre-treatment is immersed in a sealing solution, whereby fine pores formed in a film are sealed; and heat treatment in which the aluminum alloy having been subjected to the sealing treatment is charged to, and thermally treated in, a heat treatment furnace and then naturally cooled. By lowering the withstand voltage of an aluminum alloy oxide layer and increasing the hardness by subjecting the same to sealing treatment and subsequent post-heat treatment, the present invention has the effect of providing an environmentally-friendly and crack-free lightweight material that can replace steel products.