High-pressure water descaling pilot facility uses Micro-Epsilon thermal imaging cameras

High-pressure water (HPW) descaling is the process of removing oxide scale by spraying the hot steel surface under a range of moderate- to high-pressure water, using stationary (usually flat jet nozzles) or rotary (rotor descaler) systems. The aim is to remove loose
to sticky, primary to tertiary scale under optimum impingement and surface chilling, as well as power-water flow rate consumption. This improves the surface quality of rolled products and minimises work roll wear. Complex solid-fluid, thermomechanical mechanisms are acting through the scale, scale interface
and sub-surface of the steel substrate – depending on the descaling process parameters of impact pressure, descaling energy, and temperature.

The HPW descaling process is a harsh process where, in particular, the measurement of the temperature and surface state is difficult to
achieve (in view of steam/water, oxide scale debris and confined descaling boxes). Measuring surface losses using IR technology can provide benefits to thermomechanical processing for difficult-to-roll steel grades that are prone, for example, to ductility cracking and/or surface defects. This leads to efficient
descaling under robust and energy-efficient regime maps.

To study and optimise the descaling process, Tata Steel, together with the Steel and Metals Institute (SaMI) in South Wales, have revamped an HPW descaling rig to optimise the process.

Read the full article in the April issue of DPA