MMK boosts efficiency of electric steelmaking shop equipment

The first stage of modernisation of the continuous casting machine (CCM) No. 5 has been completed at the Magnitogorsk Iron & Steel Works electric steelmaking shop. These measures made it possible to reduce the duration of long scheduled preventive repairs, to increase the inter-repair interval of replacement equipment and boost the unit's productivity.

The continuous slab double strand caster No. 5 was introduced in June 2006. The capacity of the machine is about 1.5 million tonnes of billets per year, with the supplier being Uralmash Metallurgical Equipment. At that time CCM No.5 was a combination of advanced Russian equipment, and became the first continuous casting machine with a vertical section at the mill. During the operation of CCM No. 5, due to its design features, it was not possible to reach the desired production threshold as well as the durability of the equipment to levels declared by the supplier.

After the reconstruction of the 2500 hot-rolling mill at LPTs-4 of MMK PJSC, it became necessary to supply it with a large volume of slab billets at CCM-5 of the electric steelmaking shop. Therefore, in 2020 it was decided to modernise CCM-5 in order to increase its production by improving the reliability of its main components. The increase in the maintenance periods of CCM-5 is an important condition for achieving the stated annual capacity of the electric steelmaking shop.

Thanks to the measures taken it became possible to reduce the duration of long scheduled preventive maintenance, increase the inter-repair interval of shift equipment and increase the productivity of the unit.

Slab caster No. 5 was commissioned in June 2006. The capacity of the CCM is about 1.5 million tons of billets a year, the supplier was Uralmash Metallurgical Equipment. At that time CCM No.5 was a complex of quite up-to-date Russian equipment and was the first continuous casting machine with vertical section at the Works. During the equipment operation CCM No.5, due to its design specifics, could not achieve the productivity and the scheduled service life of the equipment, as declared by the plant-supplier.

After the reconstruction of Mill 2500 hot-rolling mill at LPTs-4 of MMK PJSC, it became necessary to supply it with a large volume of slab billets at CCM-5 of the ESC. Therefore, in 2020 it was decided to modernise CCBM-5 in order to increase its productivity by improving the reliability of the main components. The increase in the overhaul interval of CCBM-5 is also an important condition for solving the problem of achieving the stated annual productivity of the electric steelmaking shop.

A joint project was prepared for CCM No. 5 modernisation with the participation of technical specialists from MMK, Mekhanoremontny Kompleks LLC and SMC Zimag Metallurgical Service Magnitogorsk LLC.

Here are the technical solutions selected to increase equipment reliability and its technical service life were chosen:

- Reinforcing surfacing of the working surface of the vertical, radial and curvilinear sections of CCM's rollers;

- Modernisation of bearing units, using a new type of bearings with increased wear resistance and modern contact seals;

- Replacement of obsolete mounted drives of all roller sections of CCM by gearboxes of gear pump type, with a centralised supply of grease to the gearbox.

These modernisation measures will allow reducing the duration of planned preventive maintenance from 952 to 490 hours per year.

MMK's Commercial Service has identified the suppliers of new equipment and ensured its delivery within the planned time frame.

Cladding of rollers, completion of bearing units, assembly and adjustment of the upgraded CCMZ sections were performed at CRMO-3 of MRK LLC, with the participation of the quality and engineering service and the design and engineering department of MRK LLC. The quality of all works was high and in accordance with the schedule approved by PJSC MMK.

In the period from July to December 2021 the first operational campaign of the modernised sections of the radial section was carried out. The overhaul interval of the first campaign was 2,418 heats, which is twice as long as the durability of the sections before modernisation. The equipment worked without faults and remained in a satisfactory condition. At the same time there was also a 50% improvement in the quality of finished metal products in LPTs No. 4 compared to the previous campaign. Analysis of the dismantled equipment did not reveal any comments on the condition of the upgraded caster's roller guide, lubrication system and bearing units. Abrasive wear of the surface of the roller guide with cladding does not exceed 0.7 mm (abrasive wear on the sections without cladding is 1.0 mm and more). Slab billet macrostructure meets the requirements of the internal standard.

Comprehensive operation of the modernised sections simultaneously of the whole caster's roller guide started in December 2021.

Total investments in this project amounted to 400 million rubles. The expected economic effect from the implementation of the project will be at least 323 million rubles per year, with a payback period of 1.3 years.

These investment projects allow MMK to meet the challenges of increasing the efficiency of MMK's production processes within a short period of time, achieving the goals of the strategic initiative "Leadership in Operational Efficiency".

MMK's steelmakers continue their efforts in modernisation: they have begun pre-project work on the reconstruction of long product slabs at the electric steelmaking shop.