Descaling nozzles, generator of high-speed waterjets, are key components in high-pressure waterjet descaling system. Jet performance of the nozzle has great effect on hot-rolling steel billet descaling. Most domestic manufactures provide nozzle structural data and impact force scale with rated pressure, such as orifice diameter, injecting angle and scattering angle. However, jet distribution shape and jet impact force distribution and strength, which are major parameters affecting steel billet descaling quality, are not available from manufactures. A jet performance test device for nozzles was developed in this paper. Two and three dimensional graphs of jet impact force distribution with different standoff distance were obtained. Shape of jet distribution area was indicated in two dimensional graphs while jet impact strength and distribution were given in three dimensional graphs, providing evidence for jet performance judgement. Injecting angle, scattering angle and flow volume coefficient could also be measured with the device. A fan-type nozzle used for scale removal was tested. Results obtained were presented and discussed.
