The existing plant
The 45 year old 20-roll cold rolling mill “SG 3” is designed as a monoblock and produces high-grade stainless steel strip. Last year in September, Outokumpu Nirosta had placed an order with SMS group for upgrading the rolling mill equipment. The upgrade should allow this mill to be used also for rolling ferritic grades in thin gages and high-gloss quality (2R bright annealed). In March 2015, SMS group received the follow-up order from Outokumpu Nirosta encompassing the upgrade of the rolling-oil treatment plant, making it suitable for the production of these high-gloss grades.
Elements of the current upgrading project
A part of the equipment will be retained and continued to be used. Key equipment to be newly installed includes a dirty-oil tank with automatic pre-separation and an ultra-fine filter system. In future, vertical filter pumps will convey the rolling oil containing contaminations from the rolling process out of the dirty-oil tank to the filter system, where it will be cleaned. The cleaned oil will be fed to the clean-oil tank and reused in the rolling mill.
The mixture of rolling oil and abrasive material resulting from the backwashing of the filters will be treated in a second filtration stage and the thus recovered rolling oil will be recycled back into the system.
As requested by Outokumpu Nirosta, SMS will perform and complete the work on the mechanical equipment of the mill stand and on the rolling-oil treatment plant within a very tight time schedule in the course of this year, guaranteeing that Outokumpu Nirosta can start producing the desired grades on this mill before the end of the year.
(Source: SMS group)