US 11,986,879 B2
Method to increase local cooling rate and improve material properties in a low-pressure sand-casting head
Liang Wang, Rochester Hills, MI (US); Qigui Wang, Rochester Hills, MI (US); Dale A. Gerard, Bloomfield Hills, MI (US); Steven L. Burkholder, Archbold, OH (US); and Ronald C. Daul, Northville, MI (US)
Assigned to GM GLOBAL TECHNOLOGY OPERATIONS LLC, Detroit, MI (US)
Filed by GM Global Technology Operations LLC, Detroit, MI (US)
Filed on Apr. 13, 2022, as Appl. No. 17/719,737.
Prior Publication US 2023/0330744 A1, Oct. 19, 2023
Int. Cl. B22C 3/00 (2006.01); B22C 9/02 (2006.01); B22C 9/06 (2006.01); B22C 9/10 (2006.01); B22D 15/02 (2006.01)
CPC B22D 15/02 (2013.01) [B22C 3/00 (2013.01); B22C 9/02 (2013.01); B22C 9/061 (2013.01); B22C 9/101 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A method for low-pressure sand-casting a cylinder head of an automobile vehicle engine, comprising:
creating a port in an automobile engine cast cylinder head low pressure sand-casting mold;
applying a compressible material coating having graphite and carbon fiber on a metal core of a manifold port metal core assembly, wherein the compressible material coating includes an inner layer disposed on a first end of the metal core, a through-shell sand core disposed on the inner layer and having multiple through-thickness passages defining holes or open channels, and an outer layer disposed on the through-shell sand core;
predetermining an initial thickness (t) of the compressible material coating at least equal to a compression amount of the compressible material coating anticipated due to shrinkage of a casting material located proximate to the port and surrounding the compressible material coating as the casting material cools; and
inserting the manifold port metal core assembly into the port prior to filling the cylinder head sand-casting mold with the casting material.