Cast-in cylinder liner

The utility model discloses a cast-in cylinder liner which is mainly applied to automobile engines. The cylinder liner is characterized in that an irregular burr-shaped structure is arranged on the excircle surface of the cylinder liner formed through machining. The cylinder liner cancels the defects of metallurgical phase, dimension and the like related to the cast excircle surface, removes insulated residual fireproof coating from the surface of castings, ensures that an aluminum body and a cast iron cylinder liner form mechanical combination through the excircle surface, provides a combined surface applicable to semipermanent die casting, precision sand casing or a high-pressure casting aluminum body, and provides the design flexibility of engines; and the irregular burr-shaped structure on the excircle surface of the cylinder liner is beneficial to preventing production of gas defect on an aluminum-iron interface. The clean excircle surface promotes the conductivity between aluminum and iron; the whole cy