CISDI has smashed China’s steel mill roll change cycle time to a record 9 minutes 31 seconds.

This industry first has been achieved at Baosteel Desheng Stainless Steel Co. in China’s Fujian Province.

The achievement at the plant’s finishing mill has been made possible with a CISDI-supplied electric, instrumentation and computer system for the 1,780mm hot strip rolling line.

Generally the roll change time in China’s steel mills is around 15 minutes, as the process involves multiple pieces of equipment and instruments and requires precise electric and automation control.

Optimising roll change times plays a crucial role in increasing productivity and reducing production costs.

A one-minute reduction can increase the annual production capacity of a 1,780mm hot rolling line by 30,000 to 40,000 tonnes.

CISDI’s team spent six months continuously optimising the Desheng mill’s step sequential programme and sensor control method for the roll change.

Their control strategy and software initially reduced the time from over 46 minutes to 10 minutes 1 second.

Then came the challenge of how to break through the 10-minute barrier.

CISDI’s experts staged multiple sessions, painstakingly comparing all data for automatic roll changes. The entire process was broken down into eight major semi-automatic steps and around 100 minor steps.

They studied each minor step and calculated what control tech and supportive conditions were required to enable each to achieve its task in the shortest possible time. In some cases this reduction was as low as 0.1 seconds.

The team also optimised start and closure conditions for the semi-automatic steps, creating seamless connections between them.

To achieve the shortest possible roll change time, the team proposed multiple operation modes for selection, including fully automatic, semi-automatic and manual.

The control programme has been structurally optimised to achieve a roll change time of 9 minutes 31 seconds, which is resulting in greater productivity and competitiveness for Baosteel Desheng.

The 1,780mm hot strip rolling line at Baosteel Desheng, which now operates with a record FM roll change time