Job Shop Quoting

Heat Treatment Cost Estimation for Job Shops and OEMs

Heat treatment cost per part equals cycle cost divided by parts per load. Here is how furnace energy, labor, and load density drive it.

Heat treatment cost per part = total cycle cost divided by parts per load, and total cycle cost includes energy, labor, fixturing, and overhead. For a 4 hour batch furnace drawing 85 kW at $0.095 per kWh, energy is 85 x 4 x $0.095 = $32.30 per cycle. Add one technician at $42 per hour for 4 hours, $25 of overhead, and $15 of fixturing, and the cycle total becomes $240.30. At 240 parts per load, cost per part is about $1.00. That is the baseline the quoting team needs before discussing freight or margin.

Load density is usually the strongest cost lever in batch heat treatment because more parts per load directly reduce cost per part. A furnace running at only 60% of practical load density is carrying the same heat-up and labor cost across too few parts. Good rack design, better part orientation, and mixed-part loading can reduce cost per part by 20% to 40% without changing the furnace itself. The limiting inputs are part geometry, fixture design, quench requirements, and the furnace uniformity zone. Those inputs should come from process sheets, TUS results, rack drawings, and actual charge history.

The biggest mistake is overpacking the load without checking temperature uniformity or atmosphere flow. A furnace qualified to AMS 2750 Class 2, with about plus or minus 10 F variation, cannot be treated like a loose commercial batch furnace if the process window is tight. Another common miss is ignoring cycle support time such as loading, unloading, paperwork, and hardness verification, especially when small lots dominate the schedule. Plants also leave out outside freight when parts go to a commercial heat treater, which can materially change the make versus buy decision. If the heat treat quote is based only on oven time, it is incomplete.

Use the result to compare in-house processing, outsourcing, and schedule changes on the same basis. If a furnace load is running half empty, the quickest cost reduction may be better lot grouping rather than a search for cheaper electricity. If outsourcing looks cheaper, test the comparison at actual plant utilization, because in-house furnaces usually need roughly 40% to 60% utilization to beat commercial rates. The cycle cost also helps justify fixture improvements, basket redesign, and loading standards. Small gains in parts per load often pay back faster than furnace capital projects.

Advanced analysis should separate cost per cycle, cost per pound, and cost per finished part, because different alloys and geometries behave very differently. Continuous furnaces can be more energy efficient than batch furnaces for steady high volume, but they lose flexibility on mixed work. Atmosphere gas use, quench media maintenance, and routine calibration costs should also be tracked if the process is critical. Review utilization quarterly, because make versus buy decisions drift when demand drops or product mix changes. Heat treat is one of those processes where honest load data usually matters more than theoretical furnace capacity.

Published 2026-05-28.