Cylinder liner of a hypereutectic aluminum/silicon alloy for casting into a crankcase of a reciprocating piston engine and process for producing such a cylinder liner

US5891273A · kind A · utility

Assignee

• Mercedes-Benz Group AG · DE

Inventors

• Franz Ruckert · Esslingen am Neckar, DE
• Peter Stocker · Murrhardt, DE
• Roland Rieger · Waiblingen, DE

Key dates

• Filing date: Jan 29, 1997
• Grant date: Apr 6, 1999
• Expiry date: Jan 29, 2017

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F05C2201/021
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The invention relates to a cylinder liner, cast into a reciprocating piston engine, of a highly hypereutectic aluminum/silicon alloy which is free of hard material particles independent of the melt and has such a composition that fine primary silicon crystals and intermetallic phases automatically form from the melt as hard particles. By spray-compacting, a blank of finely sprayed melt droplets is caused to grow, a fine distribution of the hard particles being produced by controlled introduction of small melt droplets. The blank can be transformed by an extrusion step into a form approximating the cylinder liner. After subsequent premachining with chip removal, the running surface is precision-machined and subsequently honed in at least one stage, after which the hard particles located in the running surface are exposed, plateau faces of the particles being formed, which faces protrude from the remaining surface of the matrix structure of the alloy. The exposing of the primary crystals and/or particles is effected chemically, using aqueous alkali. Owing to the fine-grained hard particles formed in the melt and to their large proportion in the matrix structure and owing to the expos…