The scale on steel surface is being produced due to oxidation of base material during re-heating of the billet / material. To prevent this layer from fusing into base material during rolling process, De-scaling system is used. The scale gets loosened when High pressure water jet strikes the surface between scale and base material with high pressure through strategically placed nozzles at different angular positions causing cooling of scale. The loosened scale is washed away with water at High Pressure.
Benefits Of Descaling System (Why Water De-scaler Required)
Improves quality of Rolled Product by preventing fusion of oxidized scale into base material
Reduces Rejection by preventing surface defects of parent material
Increases life of Pressure Rolls of Rolling Mill and reduces down time for repair & maintenance
Improves productivity & efficiency by eliminating trimming pass for Billets.
There are two types of Decaling System
Direct De-scaling system, the de-scaling is being done directly from High Pressure Triplex Plunger Pumps through Valves & De-scaling Header.
Operating Pressure range : 100 Bar to 400 Bar.
The de-scaling is being done through accumulator, which accumulates the water at high pressure by High Pressure reciprocating pumps and use the pressurized water as and when required through emergency valve, operational valve and de-scaling Header.
The operating pressure range: 100 bar to 330 bar.
Advantages Of Direct De-scaling Over De-scaling System With Accumulator
|SNo.||Direct De-scaling||De-scaling with Accumulator|
|01||No accumulator required||Required Accumulator of cap. 5000-7000 liter.with high pressure compressor|
|02||Operating pressure required high 325 bar & discharge low 170 lpm per pump.||Operating pressure required low 160-215 bar & discharge required high 215 lpm per pump.|
|03||Required small sizes of valves & pipe line||Required large size of valves & pipe line|
|04||Running pump at load condition during de-scaling operation only and rest of the time at no load condition||Running pump at load condition.|
|05||Less maintenance as only pump & valves to maintain||Required compressor, pumps, valves, accumulator, control system to maintain.|
|06||less costly||Need more money for pumps/valves/compressors/pipe line etc.|
|07||No Time required for filling air||Required 24039 hrs, to fill the air in accumulator when air leaked during operation hence loss in production.|