B163 is not a discrete alloy in its own right — it's the ASTM/ASME specification number (ASTM B163, covering seamless nickel-iron-chromium alloy tubing) commonly used to call out Alloy 800 tube and pipe stock, the same iron-nickel-chromium heat-resisting alloy registered as UNS N08800 and Wnr. 1.4876 (DIN designation X10NiCrAlTi32-20). Because valve, heat exchanger, and process piping prints frequently reference the ASTM tube spec directly, B163 shows up on shop travelers and purchase orders as its own line item even though the underlying material is Alloy 800.

Alloy 800 balances roughly equal parts nickel and iron against 19-23% chromium, with small aluminum and titanium additions (0.15-0.60% each) that form fine intermetallic precipitates for a useful margin of strength. That iron content keeps cost down relative to a solid nickel-base superalloy while still delivering strong resistance to oxidation and carburization well beyond what standard austenitic stainless steel can handle — which is exactly why it shows up in valve trim, furnace and heat-exchanger tubing, and other elevated-temperature process equipment. From a machining standpoint, treat B163/Alloy 800 as a nickel-alloy-class material rather than a standard austenitic stainless: its behavior under the tool is much closer to Incoloy or Inconel than to 304 or 316.

Note: this page's prior content listed only nickel (12%) and carbon (0.33%) — figures that don't match this alloy at all (the 0.33% carbon value appears to be misplaced data from an unrelated high-carbon secondary-hardening steel elsewhere on this chart). The full, correct composition per UNS N08800 / Wnr. 1.4876 is used above.

Nickel-iron-chromium alloys like B163/Alloy 800 are demanding to machine for a consistent set of reasons: low thermal conductivity concentrates heat generated by the cut right at the tool edge instead of carrying it off in the chip, the alloy work-hardens noticeably wherever a previous pass rubbed instead of cut cleanly, and it holds onto its strength at elevated temperature rather than softening the way steel does as the cutting zone heats up. Together these push cutting forces, edge temperature, and abrasive wear well above what a similarly hard stainless steel would produce.

The alloy's substantial iron content dilutes the tough nickel-chromium matrix that makes solid nickel-base alloys like Inconel or Hastelloy so punishing on tooling, so B163/Alloy 800 machines somewhat more forgivingly than those grades even though it is still firmly in the "difficult" category — closer to a nickel alloy than a standard stainless in practice. Chips tend to be tough and stringy rather than brittle, so chip control and evacuation deserve as much attention as tool wear itself. A rigid setup is essential, since any flex or vibration burnishes and work-hardens the surface before the next pass. Use sharp, positive-rake carbide with a coating built for heat-resistant alloys, run at moderate-to-low cutting speeds, and keep feed rates high enough that the edge consistently cuts beneath the hardened layer left by the prior pass instead of skating across it.

Values assume favorable cutting conditions: a well-matched insert grade, rigid tool and workpiece clamping, good-quality raw material, short tool overhang, and annealed nominal hardness. Reduce further for interrupted cuts, poor rigidity, or work-hardened stock.

Turning

Parting / Grooving

Milling