摘要 |
<p>A rolled steel product (concrete- reinforcing rod) containing at most 0.16% C, at most 2.0% Mn, and at least 0.03% Al, and optionally containing up to 0.55% Si, up to 0.05% Nb, up to 0.1 V, and up to 10% Ni, is reheated to austenitization temperature, held at this temperature for a time insufficient to cause grain- coarsening, and subjected to intense surface cooling. As a result the product has an outer region of martensite, which is then tempered as the core transforms to fine ferrite- pearlite.</p> |