| 摘要 |
PROBLEM TO BE SOLVED: To improve the erosion capacity of a descaling nozzle, to reduce scale flaws of a high-Si steel, and to prevent the nozzle breakage caused by the rebound flow on the surface of a steel plate by providing an expansion of the discharge direction of a discharge flow in the width direction in a plane perpendicular to the axis of the nozzle, and providing a specified erosion thickness angle in the thickness direction perpendicular to the width direction. SOLUTION: In a descaling nozzle 1, water is discharged from a nozzle 1 at the discharge pressure of >=40 MPa, and collided with a surface of a steel plate 5 at the distance of <=150 mm from a discharge port 2 to the steel plate 5 to remove scales. The discharge direction of the discharge flow is preferably expanded in the width direction 7 in the plane perpendicular to the axis of the nozzle, and the erosion thickness angleϕof 1.5 to 2.5 deg. is preferably provided in the thickness direction 8 perpendicular to the width direction 7. The erosion thickness b mm of the jet is the thickness when the jet is ejected for 30 seconds against an Al grounded surface, and the erosion thickness angleϕdeg. is calculated by the formulaϕ=2tan-1 (b-ds)/2H}, where b is the erosion thickness, ds is the minor diameter of the nozzle discharge hole, and H is the jet distance.
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