US 12,344,907 B2
Laser hardening of cylinder bore
Garrold A. DeGrace, Frankenmuth, MI (US); Sheri K. Kurgin, Macomb Township, MI (US); Daniel T. Berry, South Lyon, MI (US); and Kirk R. Frame, Clarkston, MI (US)
Assigned to GM GLOBAL TECHNOLOGY OPERATIONS LLC, Detroit, MI (US)
Filed by GM Global Technology Operations LLC, Detroit, MI (US)
Filed on Feb. 17, 2023, as Appl. No. 18/170,796.
Prior Publication US 2024/0279761 A1, Aug. 22, 2024
Int. Cl. C21D 1/09 (2006.01); B23K 26/08 (2014.01); B23K 26/352 (2014.01)
CPC C21D 1/09 (2013.01) [B23K 26/083 (2013.01); B23K 26/352 (2015.10); C21D 2221/00 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of heat treating a plurality of cylinder bores within an engine block, comprising:
moving a laser head, adapted to heat treat a localized area of an inner surface of a cylinder bore, sequentially to each of a plurality of cylinder bores within the engine;
at each cylinder bore, moving the laser head, sequentially, in a star pattern, to each one of a first plurality of positional zones extending circumferentially around the cylinder bore;
at each one of the first plurality of positional zones, creating, with the laser head, sequentially, one at a time, a first plurality of discrete hardened pills therein;
moving the laser head sequentially to each of the plurality of cylinder bores within the engine;
at each cylinder bore, moving the laser head, sequentially, in the star pattern, to each one of the first plurality of positional zones extending circumferentially around the cylinder bore;
at each one of the first plurality of positional zones, creating, with the laser head, sequentially, one at a time, a second plurality of discrete hardened pills therein;
moving the laser head sequentially to each of the plurality of cylinder bores within the engine;
at each cylinder bore, moving the laser head, sequentially, in a star pattern, to each one of a second plurality of positional zones extending circumferentially around the cylinder bore;
at each one of the second plurality of positional zones, creating, with the laser head, sequentially, one at a time, a first plurality of discrete hardened pills therein;
moving the laser head sequentially to each of the plurality of cylinder bores within the engine;
at each cylinder bore, moving the laser head, sequentially, in the star pattern, to each one of the second plurality of positional zones extending circumferentially around the cylinder bore; and
at each one of the second plurality of positional zones, creating, with the laser head, sequentially, one at a time, a second plurality of discrete hardened pills therein.