Methods for Removing Mill Scale from Hot-rolled Steel Profile

The drawbacks of traditional manual grinding and pickling modes are evident. Manual cleaning is inefficient, and the generated dust poses health hazards to workers. Furthermore, the pickling process frequently produces acid and alkali wastewater, causing environmental pollution. High-pressure water descaling also faces challenges in recovering fine, fragmented mill scale. These factors have long constrained the dimensional accuracy of finished steel sections and production stability.

Currently, mainstream and mature removal technologies in the industry fall into three categories: roller conveyor shot blasting, which utilises high-velocity steel shots to strip surface scale and is suitable for long profiles such as I-beams and H-beams; high-pressure water jet descaling, commonly employed for upstream rolling pre-treatment; and intelligent negative pressure collection combined with magnetic separators, capable of capturing scattered fine scale online with a recovery rate exceeding 98%. Furthermore, new environmentally friendly mixed-jet descaling technologies are being gradually adopted to completely replace highly polluting pickling processes.

Following the implementation of these new processes, the surface qualification rate of steel sections has improved by 12%. The volume of mill scale recovered for recycling has risen substantially, whilst labour and environmental management costs have declined significantly.