B-148-52 is a nickel-aluminum bronze casting alloy produced to ASTM B148 (UNS C95800), and it's one of the highest-strength standard copper-base casting alloys available. Roughly 9% aluminum combines with 4% iron and 4.5% nickel in a copper matrix to form a complex, multi-phase microstructure — the aluminum and iron together provide strength and oxidation resistance, while the nickel refines the grain structure and suppresses a brittle phase that would otherwise reduce toughness and corrosion resistance. The DIN equivalent designation, G-CuAl10Ni, and Wnr. 2.0975 both describe the same family of alloy, sometimes seen as CuAl10Fe5Ni5-C or EN CC333G.

This is the classic nickel-aluminum bronze used for ship propellers and propeller hubs, valve bodies, pump impellers, and gears in marine and heavy-industrial service, prized for a combination of high strength, wear resistance, and corrosion/cavitation resistance in seawater that far exceeds standard brass or tin bronze castings. The "52" in the historical B-148-52 designation refers to an older alloy-numbering convention within the B148 specification family; UNS C95800 is the current, unambiguous identifier for this composition.

Nickel-aluminum bronze is a fundamentally different machining challenge from the brasses on this site. The hard intermetallic phases formed by the aluminum, iron, and nickel additions make this alloy considerably tougher and more abrasive to a cutting edge than standard yellow or red brass — closer in cutting character to a cast iron or low-alloy steel than to a free-machining copper alloy. There is no lead and no soft, gummy matrix to fight here; the concern shifts almost entirely to tool wear and edge durability rather than built-up edge or chip evacuation.

Because of that abrasive intermetallic structure, the sharp, high-positive-rake geometry that works well on brass is the wrong choice here — a more neutral or lightly positive edge with better support handles the combined mechanical and abrasive load far better. A tough, wear-resistant carbide grade with good hot hardness outlasts a fine, aggressive edge by a wide margin, and cutting speeds need to run well below what any of the brasses on this site tolerate. Rigidity and steady feed matter as much here as they do on a hard cast iron, and coolant helps manage both heat and abrasive wear at the edge.