Fastener Manufacturing & Thread Rolling worked example

Heat Treat Load at 99% furnace uptime during window: a worked example in fastener manufacturing & thread rolling

What does the result look like when furnace uptime during window reaches 99%? The full calculation is worked below with real intermediate numbers. Use it when planning quench-and-temper, carburize, neutral harden, or stress-relief capacity for headed and threaded fasteners.

The inputs for this scenario

  • Accepted fasteners per furnace load: 18,000 pieces or lb (unchanged)
  • Planned furnace loads: 6 loads (unchanged)
  • Furnace uptime during window: 99 % (raised for this scenario; the documented default is 92)
  • Heat treat first-pass yield: 98 % (unchanged)

Working through the calculation

  • Applying the documented formula (Gross heat treat load = accepted fasteners per load × planned furnace loads) to the inputs above produces each figure below.
  • At this operating point the engine returns 104,782 units for good output capacity, the number this scenario is built around.
  • At this operating point the engine returns 108,000 units for gross furnace load.
  • At this operating point the engine returns 1,080 units for uptime loss.
  • At this operating point the engine returns 2,138 units for heat treat yield loss.

How this compares with the baseline

  • Against the tool's baseline example, where furnace uptime during window sits at 92% and the headline result is 97,373 units, this scenario comes in 7.61% above the baseline at 104,782 units.
  • A figure at this level is achievable when furnace uptime during window is genuinely sustained, not just peaked for a shift. It treats uptime and yield as flat averages, so it won't capture a single bad quench, a furnace recovery period after a cold start, or load-to-load hardness drift that scrap a specific basket.

Results at a glance

  • Good output capacity: 104,782 units (headline result)
  • Gross furnace load: 108,000 units
  • Uptime loss: 1,080 units
  • Heat treat yield loss: 2,138 units

Run it with your numbers

  • Every input above is editable in the live Heat Treat Load calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.