Patent ID: 6303897
Filing Date: 2001-10-16
Classification: B23K,C21D

Abstract:
A process for the laser treatment of the internal surfaces of a hollow body with a rotationally-symmetric cylindrical axes, the body being an engine block having cylinder bores for receiving piston rings and consisting of a matrix alloy such as light-metal cylinder blocks with wear-resisting internal piston working surfaces, comprising the steps of:maintaining the hollow body in a stationary position;producing a beam spot on the internal surface of the body with a laser beam probe having a distance energy of 20 to 800 J/mm and an intensity of 0.5 to 4.0 kW/mM.sup.2 ;applying an alloying powder thereto in a continuous conveying and protective gas;displacing a probe along the axis of the cylinder;simultaneously rotating said probe producing a zone of added alloy in spiral-shaped windings over the entire surface to be treated, wherein the windings overlap each other and are disposed along the cylinder bores with a spacing smaller than the width of the piston rings; and,melting the alloying powder in the spot of the laser beam to a depth of from 0.2 to 2 mm.