NMLK Clabecq, the Belgian division of a large group in the steel industry, approached us with a specific request. They specialise in producing steel plates of various thicknesses ranging from 3 to 120 mm for construction, shipbuilding, energy industries, transport and yellow goods, quarrying and mining equipment manufacturers. Their demand was to improve the surface quality of their steel sheets with minimal energy input.
Question: Could CYAGO help improve the surface quality of their steel plates and do so with minimal energy consumption?
La grenailleuse, a blasting with metal beads is a pre-treatment of the plates. This is a cleaning step to remove impurities and rust on the surface of the plates. Built-in brushes and a built-in blow-off system remove much of these metal beads after the radiation step. However, some of the beads remain on the plates. When the beads enter the rolling mill with the plates, they are pushed into the sheet steel by the rollers. This causes pits and cracks in the surface of the plates – in short, non-conformities. The part that is rejected annually has a value of 80,000 to 100,000 euros.
The challenge lays in finding a more efficient blow-off system to remove excess blasting beads from the steel sheets, thereby minimising sheet steel coil rejection and surface defects. This had to be done within a short period, given the production line shut down in August.
After thorough testing in their test lab, CYAGO proposed a solution: three air knives, a fan and associated piping.
We mounted an installation at the customer’s site consisting of a combination of a steel structure and low-pressure air knives. These are attached to an existing customer chassis above a production line. A fan, along with silencers and ducting, stands on a platform. The air pipes split to form a structure called ‘the octopus’. The exhaust of the fan is connected to the entrance of the air blades through this octopus. The assembly is placed on the customer’s chassis, under which the air knives are hung.
The air knives consist of three parts: a smaller one in the middle that blows the metal balls apart, followed by two larger air knives that blow the balls to the side of the plate. Only the top is blown, while the bottom is cleaned with steel brushes.
The fan has silencers at the inlet and outlet, and the fan housing is insulated for noise reduction. The customer also provided plates to prevent the balls from entering the production hall. The noise from the new installation was so minimal that the customer could not tell if the new installation was even on, which was received as a great compliment.
Installation went smoothly, with supervision and assistance from CYAGO. Production resumed within a week and the results were positive, resulting in a satisfied customer.
M. Jeremie Remy, Responsible Maintenance NLMK:
“A very good collaboration and communication for achievement 100% accomplished.”
This successful project resulted in improved steel surface quality, reduced downtime, lower than expected energy consumption and a short payback period. CYAGO looks back on a successful project with opportunities for future cooperation.
