| 摘要 |
<p>The steel according to the invention is characterized in that, in order to keep its molybdenum weight content below 0.45%, its chemical composition, besides iron and the inevitable residual impurities resulting from the smelting of the steel, corresponds to the following analysis, given in percentages by weight: 0.3 <= C% <= 0.5; 0.20 <= Mo% < 0.45; 0.4 <= Mn% <= 1.0; 0.4 <= Cr% <= 2.0; 0.04 <= Ni% <= 0.8; 0.02 <= Nb% <= 0.045; 0.03 <= V% <= 0.30; 0.02 <= Ti% <= 0.05; with Ti > 3.5 N; 0.003 <= B% <= 0.005; S% <= 0.015; P% <= 0.015, and optionally 0.05 <= Si% <= 0.20; A1% <= 0.05 and N% <= 0.015; by cold-forming of a hot-rolled wire rod resulting from continuous casting, it is possible to obtain, after heat treatment, "ready-to-use" coined parts, such as cap screws, for example for the automotive industry, that offer a tensile strength of 1200 to more than 1500 MPa while having a good resistance to hydrogen embrittlement, with a specially controlled "raw material" production cost.</p> |
