Strip cleaning technology using ultrasonic and high-pressure cleaning equipment

摘要

Cold rolled strips used as entry material for hot-dip galvanizing usually carry emulsion and residues from the rolling process. Deposits of approximately 500 mg/m~2 per side, consisting of rolling emulsions, abraded iron particles and other dirt, are therefore likely. These residues have to be removed from the steel strip before it undergoes further surface refining processes such as hot-dip coating. When the disturbing adhesions from the steel strip surface are removed, the strip comes into intensive contact with alkaline cleaning agents in the cleaning section. State-of-the-art technology is to build a multi-stage strip cleaning section after the entry section in a continuous galvanizing line (figure 1). A combination of alkaline spray cleaning with brush support for the removal of surface deposits, electrolytic cleaning for deep pore cleaning and final multistage rinsing including a second brushing operation with fully dem-ineralized water is usually applied. Cleaning agents are aqueous solutions mainly on alkaline basis with tensides and phosphates.