Partiell oberflaechengehaertete Riffelwalze

According to the invention, a hardness zone of maximum 0.35 mm thickness formed in the shape of an arc is arranged at the crest of the corrugation. The width of this hardness zone is limited by the corrugation flanks under 45 degrees to the tangent applied to the crest plane. Surface hardness is performed by means of energy-rich radiation, in particular CO<2 cw laser beams. The crest area of the corrugation is thereby radiated axially with a laser beam with an output of <= 500 watts. During radiation, the crest plane of the corrugation is located between the focusing lens and the laser focus. The aperture angle of the radiation cone is adjusted to >= 9 degrees and the spot diameter in the crest plane of the corrugation is adjusted in such as way that the radiation density is >= 50 W/mm>2.

DE 3711451 A UPAB: 19970307 Rolls with a wavy surface for use in the mfr. of currugated cardboard receive a partially hardened surface structure with a hardened zone in the shape of a circular segment on each wave crest. The max.thickness of this zone is 0.35 mm. Its width is bounded by a tangent at 45 deg. to the radial plane through the crest. The pref. surface hardening method is based on a CO2 laser beam of under 500 W output. ADVANTAGE - The thickness of the hardened zone is now such that it has been removed completely, on reaching the max. permissible wear. It is not necessary, to soft anneal the roll before reconditioning its surface.