Despite carrying the Uranus brand name shared with Aperam/Industeel's duplex family, Uranus 65 is not a duplex alloy — it's a fully austenitic, single-phase 25Cr-20Ni stainless steel, essentially a tightly controlled 310L variant registered as EN 1.4335 / UNS S31002 and often described as an AISI 310L "NAG" (nitric acid grade). There's no ferrite phase and no dual-phase microstructure here, which is the key distinction to keep in mind when comparing this page to the Uranus 45N/47N/52N duplex grades also stocked by FM Carbide.

What makes Uranus 65 specialized is what its chemistry deliberately excludes rather than adds: carbon is held below 0.02%, silicon below 0.3%, and molybdenum is capped near 0.3% — low because molybdenum is known to degrade performance in boiling nitric acid rather than help it, unlike its role in chloride-resistant grades. That tight control on residual elements produces a stable, precipitate-free austenite structure purpose-built for boiling 50-65% nitric acid service: fertilizer and nitric acid production equipment, chemical processing vessels, and nuclear fuel reprocessing hardware are the alloy's core applications.

Because Uranus 65 is fully austenitic — no ferrite phase splitting the load the way it does on the duplex Uranus grades — it machines like a more heavily alloyed cousin of 310/316 rather than like duplex stainless. The high combined chromium and nickel content keeps the matrix soft and ductile, which sounds favorable but actually works against the machinist: that ductility makes the material gummy, prone to smearing rather than shearing cleanly, and it work-hardens aggressively wherever the tool rubs instead of cutting decisively.

Sharp, positive-rake inserts with a chipbreaker geometry designed for stainless are essential — anything that lets the edge ride the surface instead of biting in leaves a hardened skin that makes the next pass tougher. Feed rates need to stay firm and consistent to keep the edge engaged. Low thermal conductivity concentrates heat at the cutting edge rather than carrying it off in the chip, so coolant delivery and a rigid, well-supported setup matter more here than on standard 304/316 austenitic grades.