Efficient Production Technology for High-Purity Low-Alloy Steel Used in Special-Purpose Thick Sheet

摘要

Thick sheet is a special category of rolled steel, on account both of the increasing quality requirements on metal for key components (steel for high-pressure oil and gas pipes, large-capacity ships, marine drilling platforms, high-pressure vessels, and bridges) and of the smaller reductions employed in rolling thick sheet. If high-quality sheet is to be obtained from continuous-cast slabs, certain conditions on the macrostructure and surface quality must be satisfied. Often, the requirements on the technological parameters in order to obtain satisfactory surface quality and macrostructure of the billet are contradictory, and hence an optimization problem must be solved. In what follows, we consider a technological approach to the production of such billet. Elements of this technology have been introduced in industrial conditions at OAO Severstal continuous-casting machines. In the production of thick sheet, internal defects are observed in ultrasound monitoring. Also, the requirements on the mechanical properties in the Z direction (the load over the sheet thickness) are not satisfied, and the billet contains surface defects (cracks, blisters), deriving from defects of the slab.