Casting-rolling mill: 20 million tons of premium quality
The casting-rolling mill (CRM) at ThyssenKrupp Steel Europe AG in Duisburg-Bruckhausen recently produced its 20 millionth metric ton of hot strip. It will be used to help people stay cool in the summer heat: Processed into hot-dip galvanized sheet, the 20 millionth ton was supplied as part of a 21 ton coil to ventilation specialists Lindab AB, who will use it to build air conditioning systems.
ThyssenKrupp Steel Europe started production on the CRM in 1999. It was regarded as a technological leap in flat steel production and at the time was the first line of its kind to be installed in an integrated iron and steel mill. Today ThyssenKrupp Steel Europe plays a leading role in casting-rolling technology. The 600 million deutschmark line has proved to be an extremely lucrative investment: It produces hot strip faster, more energy efficiently and in excellent quality. That is why capacity on the CRM was taken up very quickly. "Today we could process far more orders than the annual capacity of two million tons permits," says Dr. Helmut Osterburg, casting-rolling mill team coordinator at ThyssenKrupp Steel Europe.
The CRM combines the normally separate production steps of casting and rolling in one continuous process. Material from the CRM has a more homogeneous microstructure than conventionally produced hot strip. As a result, mechanical properties such as strength and elongation are also more consistent. The modern technology of the connected rolling mill provides for particularly close production tolerances and lower thicknesses on CRM hot strip.
Two new product lines from ThyssenKrupp Steel Europe made possible by the CRM - SCALUR® and microalloyed steels with cold performance - highlight the line's strengths: After hot rolling, both products already possess a microstructure and dimensions with a level of uniformity and precision otherwise only attained through additional cold rolling.
Today the casting-rolling mill at ThyssenKrupp Steel Europe produces more than 50 different steel grades for customers in the automotive, appliance, construction and electrical sectors among others. These include grades which are regarded as difficult to produce due among other things to the higher casting speeds on CRMs.
For example, ThyssenKrupp Steel Europe produces large volumes of non-oriented electrical steel on the line, a soft-magnetic grade used in electric motors that helps significantly reduce energy losses. Another example of CRM products are manganese-boron steels for hot stamping, which are used among other things to produce safety-relevant automotive components.