ULTRA HIGH-STRENGTH AIR-HARDENING MULTIPHASE STEEL HAVING EXCELLENT PROCESSING PROPERTIES, AND METHOD FOR MANUFACTURING A STRIP OF SAID STEEL

摘要

The invention relates to a high-strength air-hardenable multiphase steel which has excellent processing properties and consists of a composition defined in claim 1 and in which, in order to allow for a process window that is as large as possible for the continuous annealing of hot and cold strips from said steel, the combined content of Mn+Si+Cr is adjusted as follows in accordance with the strip thickness obtained: up to 1.00 mm: sum of Mn+Si+Cr ≥ 2.800 and ≤ 3.000 wt%; more than 1.00 and up to 2.00 mm: sum of Mn+Si+Cr ≥ 2.850 and ≤ 3.100 wt%; more than 2.00 mm: sum of Mn+Si+Cr ≥ 2.900 and ≤ 3.200 wt%.