Foundry and Forging KPIs: Benchmarks for Yield, Melt Loss, Scrap, Sand, Die Life and Energy
Casting yield, melt loss, scrap, sand control, die life, OEE and melting energy: how to measure each KPI, what moves it, and which figures have a cited source.
Use these benchmarks as reference points for spotting a gap, not as targets. Measure each KPI per part family and per furnace, then compare against your own trend before you compare against an industry figure.
Every figure shows its basis. A superscript number links to a public source in the Sources list, and the sentence gives that source's context. A figure marked no cited source is kept as originally published because no public source stating it has been verified, so treat it as illustrative.
At a glance
Foundry, casting and forging KPI benchmarks at a glance
KPI
Typical
Strong
Basis
Casting yield
50 to 65% (U.S. sand casting, 2003)
65 to 75% (competent production foundries); 80 to 85% (world-class ductile iron)
Words in parentheses give each figure's framing in the original guide or its source. Tonnes are metric. The DOE figures describe U.S. foundries and furnace types; DOE's own 2003 estimates of shop returns and scrap, 4 to 7% by alloy, are given in the text1. The OEE references in the text are cross-industry, setting world-class at 85%3, 4.
Method: How the figures in this guide are sourced
A figure with a superscript number is stated by the cited source, listed under Sources with its publisher, location in the document and access date. A figure marked no cited source is kept exactly as originally published because no public source stating it has been verified. It is illustrative, not measured industry data. Worked examples show arithmetic only and are not benchmarks.
Casting yield
Casting yield is the headline KPI, because every point of yield is metal you melt but do not ship. In U.S. Department of Energy (DOE) estimates for 2003, sand casting processes typically ran 50 to 65 percent yield for most products1. A 1999 DOE profile put typical green sand foundry yields at approximately 60 percent2.
Across U.S. metalcasting in 2003, about 22 million tons were melted to ship 13.9 million tons of good castings, an average yield of about 63 percent1. Die casting and permanent mold processes with nonferrous alloys reach 65 to 75 percent, and cast iron pipe foundries using centrifugal casting machines typically exceed 90 percent1.
Competent production foundries run 65 to 75 percent no cited source, and world-class ductile iron work reaches 80 to 85 percent on favorable geometry no cited source. Measure yield per part family, not plant-wide, since a heavy hydraulic block and a thin bracket behave differently.
How to measure
Divide casting weight by the total weight of metal poured, gates and risers included.
Report it per part family, not plant-wide.
Track scrap alongside it, since a yield figure that includes castings later rejected overstates saleable metal.
What moves it
Gating and riser design.
Switching from natural to applied risering, or adding exothermic sleeves, which can lift yield 5 to 10 points by shrinking riser volume while still feeding solidification no cited source.
Part geometry, which sets how much feed metal a casting needs.
Melt loss is your metal-in versus metal-out efficiency in the furnace. The 1999 DOE profile of U.S. metalcasting puts induction furnace melt losses at 1 to 2 percent, against about 5 percent for electric arc furnaces2. Cupola melt losses typically run 7 to 10 percent2, and DOE's 2004 best-practice model assumes 1.5 percent for iron induction melters1.
Crossing 5 percent signals oxidized or dirty charge, excess turnover time, or poor slag practice no cited source. Each pass through the furnace burns another 2 to 4 percent of the metal no cited source, so remelts add up quickly.
Aluminum depends heavily on the furnace. The 1999 DOE profile gives aluminum melt losses of 2 to 12 percent in reverberatory furnaces and 2 to 3 percent in gas-fired crucibles2. DOE's 2004 report adds that losses can vary from less than 1 percent to more than 5 percent with similar charge materials, mainly because of furnace design1.
How to measure
Weigh the charge and the tapped metal for every heat.
Report melt loss per heat and per furnace.
Count remelts separately, so returns do not hide inside a single heat.
Casting scrap rate separates profitable foundries from struggling ones. Typical operations run 5 to 8 percent no cited source, and world-class sits at 2 to 4 percent no cited source.
DOE's U.S. estimates give a comparison point. For 2003, DOE put shop returns and scrap at 5 percent for gray and ductile iron, 4 percent for steel, 4 to 5 percent for aluminum and 7 percent for other nonferrous alloys, a weighted industry average of 4.6 percent1. Die casting scrap runs about 8 percent when warm-up castings are counted and about 5 percent without them2.
Anything above 10 percent means gas, shrinkage or sand defects are out of control no cited source.
For example, cutting scrap from 8 to 4 percent on a plant shipping 5,000 tonnes a year recovers roughly 200 tonnes of saleable castings.
How to measure
Divide scrapped weight by total good-plus-scrap weight.
Pareto the defect codes weekly.
What moves it
Metal cleanliness.
Mold hardness consistency.
Pouring temperature control within plus or minus 10 degrees C no cited source.
Sand-to-metal ratio and sand system stability drive green sand quality and downstream defects. A tight ratio of 5:1 to 7:1 by weight indicates efficient sand use no cited source, while ratios climbing past 9:1 flag over-mulling or oversized flasks no cited source.
Compactability should hold 38 to 45 percent no cited source and moisture 3.0 to 3.5 percent no cited source, with low variance. Hot return sand throws both out of band and spikes blow and scab defects.
Sand consumption is a different measure from the mold ratio. In U.S. federal reports from the late 1990s, typically about 1 ton of foundry sand is required for each ton of iron or steel casting produced5, and about 800 pounds of spent sand per ton of casting must be handled2.
How to measure
Measure compactability per shift with a compactability tester, not by feel.
Log moisture and return sand temperature on the same schedule.
Compute sand-to-metal ratio by weight for each flask size.
What moves it
Closed-loop sand control tied to return sand temperature below 50 degrees C no cited source.
Die life is the forging equivalent of tool efficiency, and it sets tooling cost per part. Hammer dies for carbon steel typically deliver 8,000 to 20,000 hits before resink no cited source, and precision press dies 10,000 to 30,000 no cited source.
Hot work tool steel like H13 at 48 to 52 HRC extends the upper end no cited source. Set a target hit count for each die and benchmark actual dies against it.
How to measure
Record hits to first resink for every die.
Record total hits to scrap separately.
What moves it
Better die lubrication and cooling, tighter billet temperature control and nitriding the die surface, levers that add 20 to 40 percent life no cited source.
Overall equipment effectiveness (OEE) ties the melt deck, molding line and finishing into one number. Foundry OEE commonly lands at 45 to 60 percent no cited source, and world-class continuous casting or high-pressure molding lines reach 75 to 85 percent no cited source.
The public references are cross-industry, not foundry studies, so they frame the range rather than confirm it. A 2018 Chalmers thesis found machines averaging 51.5 percent OEE6, and Vorne, an OEE vendor, sees most manufacturers closer to 60 percent3. The published world-class bar is 85 percent, from Seiichi Nakajima's work on total productive maintenance4, 3, so the lower end of the guide's world-class band sits below it.
Break OEE into availability, performance and quality. A plant with 92 percent availability and 96 percent quality still lands at 60 percent OEE if performance drags at 68 percent from slow molds per hour, since 0.92 x 0.96 x 0.68 = 0.601.
How to measure
Record availability, performance and quality separately for each line.
Measure performance in molds per hour against the rated line rate.
What moves it
Matching molding line rate to melt supply and shakeout throughput, so no single station starves the others.
Energy per tonne is a cost KPI that also flags process drift. Induction iron melting should sit near 550 to 650 kWh per tonne of liquid2, the overall consumption the 1999 DOE profile reports for medium-frequency coreless furnaces once holding power and ancillary equipment are included.
Drifting toward 700 signals worn linings, poor charge density, or excess holding no cited source. In DOE's 2004 best-practice model, a modern batch induction melter uses about 530 kWh per short ton including holding, against about 954 for a heel melter including holding power and charge preheating1.
Gas-fired aluminum reverberatory melting uses 2,899 to 5,797 MJ per metric ton of metal melted in the 1999 DOE profile, about 805 to 1,610 kWh per tonne of fuel energy2. The lower end reflects advanced burners.
Idle holding alone can waste 40 to 60 kWh per tonne on a furnace left energized between pours no cited source. Every minute the lid is open on a 12-ton induction furnace costs about 14 kWh1.
How to measure
Meter each furnace separately.
Normalize energy to tapped weight, not charged weight.
Log holding time between pours alongside the energy reading.
Improve in sequence, not all at once, and let each KPI verify the last. Stabilize the sand system and pouring temperature first, because they gate scrap. Scrap then unlocks true yield, and yield sizes honest energy and melt-loss targets.
For example, with yield measured on castings poured and scrap counted separately, a foundry moving yield from 62 to 72 percent and scrap from 8 to 4 percent lifts saleable output about 21 percent from the same melt tonnage, with no new furnace capacity. Saleable metal per tonne melted goes from 0.62 x 0.92 = 0.570 to 0.72 x 0.96 = 0.691.
Write down each KPI's definition and keep it fixed.
Measure per part family and per furnace, not plant-wide.
Re-baseline every metric quarterly and track the trend, not the single reading.
Compare against your own trend first and published ranges second.
Record what changed in the process whenever a KPI moves.
Sources
Theoretical/Best Practice Energy Use in Metalcasting Operations. U.S. Department of Energy, Industrial Technologies Program (J. F. Schifo and J. T. Radia, KERAMIDA Environmental, Inc., under contract to Advanced Technology Institute). published May 2004. Ch. 1 induction melting, pp. 21-24 and Table 14; aluminum melting, Tables 19-21 (pp. 37-39); Ch. 2 Sec. 2 Casting Yield and Scrap, Tables 29-30 (pp. 51-52). Tons are U.S. short tons (2,000 lb).. Accessed September 30, 2026.
Energy and Environmental Profile of the U.S. Metalcasting Industry. U.S. Department of Energy, Office of Industrial Technologies (prepared by Energetics, Inc.; N. Margolis, K. Jamison, L. Dove). published September 1999. Sec. 1.7 (spent sand, PDF p. 14); Sec. 3.6 (cupola melt losses, PDF p. 38); Fig. 4-1 key facts (PDF p. 43); Sec. 4.3 and Table 4-2 (induction energy, PDF pp. 45-46); Sec. 4.6 (induction melt losses, PDF p. 51); Table 5-1 (gas-fired aluminum melting energy, PDF p. 58); Sec. 5.6 (aluminum melt losses, PDF p. 60); Sec. 7.6 (green sand yield, PDF p. 81); Sec. 10.6 (die casting scrap, PDF p. 99). Accessed September 30, 2026.
World-Class OEE: Set Targets To Drive Improvement. Vorne Industries (OEE.com). Sections 'What Is World-Class OEE?', 'TPM and World-Class OEE', 'Some Perspective on World-Class OEE'. Accessed September 30, 2026.
Anatomization of the overall equipment effectiveness (OEE) for various machines in a tool and die shop. Journal of Intelligent Manufacturing and Special Equipment, Vol. 3 No. 1, pp. 97-105 (Emerald, CC BY 4.0), DOI 10.1108/JIMSE-01-2022-0004. published 2022. p. 101 (PDF p. 5): sentence "Seiichi Nakajima included the above four “world-class” numbers." and Table 1 "The world-class OEE factor"; p. 103 (PDF p. 7): "worldwide threshold of >85% set by the Japan Institute of Plant Maintenance (JIPM)". Accessed September 30, 2026.