How do you calculate batch mix yield or scrap rate?

Divide reject castings by the total castings poured in the batch. With 8 rejects out of 250 poured, that's 8 ÷ 250 = 3.2% scrap for the batch.

What is a good foundry scrap rate?

It varies by casting complexity and alloy, but many iron and steel foundries target low single digits overall, with tight jobs held under 5%. The example's 3.2% sits inside a 95%-good target, leaving a 91.8-point gap to the ceiling.

What does the gap to target represent?

It's your target minus the actual rate — 95 − 3.2 = 91.8 points here — showing how much room you have before the batch breaches your scrap ceiling. Watch it shrink batch to batch as a drift indicator.

Should I count rework separately from scrap?

Yes. This rate is cleanest when it counts true scrap — castings you can't sell or salvage. Rework has cost too, but blending it in hides how much metal is actually lost and muddies the trend.

Why track yield per batch instead of per shift?

A batch maps to one melt chemistry, one sand mix, and one pour window, so a spike points at a specific cause. Roll everything into a shift number and a single bad heat gets averaged away until it's too late to fix.

How does the furnace lining affect batch yield?

A worn or contaminated lining can shift melt temperature and pick up slag or oxides, driving porosity and inclusion defects. When batch scrap climbs alongside rising heat loss, the refractory is a prime suspect.

Refractories, Furnace Linings & Foundry Consumables calculator

Batch Mix Yield Calculator

Batch Mix Yield here measures the defect rate of a poured batch — reject castings as a fraction of everything poured — so a foundry can judge how clean each melt-and-mold cycle ran. Melt-shop and molding-line supervisors use it to catch a bad sand mix, a fading inoculant, gas porosity, or a refractory-driven temperature swing before it eats a whole shift's output. It matters because in a foundry the raw metal, energy, and mold labor are already spent by the time a casting is judged scrap, so every reject is fully loaded cost with zero revenue. Tracking the rate per batch — and the gap to your scrap ceiling — turns a vague sense that quality slipped into a number you can act on and trend.

What this calculator does

Batch Mix Yield here measures the defect rate of a poured batch — reject castings as a fraction of everything poured — so a foundry can judge how clean each melt-and-mold cycle ran.
Use it when batch mix yield in refractories, furnace linings and foundry consumables needs a clean rate and gap-to-target you can put on a tier board.
It computes the batch defect rate as reject castings divided by total castings poured, then the gap between your scrap-rate ceiling and that rate.

Formula used

Batch Mix Yield rate = affected amount ÷ total amount
Gap to target = target rate - calculated rate

Inputs explained

Reject or scrap castings from the batch:
Total castings poured in the batch:
Target scrap-rate ceiling:

How to use the result

Use it batch by batch on the molding line to spot a process drift the moment scrap climbs past your target.
A batch rate is a lagging count — it tells you a batch went bad but not why, so pair it with defect-type Pareto data before you chase a root cause.

Current U.S. benchmarks

The producer price index for steel mill products stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. Quotes priced off last quarter's material cost miss this move.
Industrial electricity averages 8.66 cents per kWh across the U.S. (EIA, Apr 2026), up 5.5% from a year earlier. Energy-intensive steps carry this directly into unit cost.
The U.S. has 3,569 primary metal manufacturing establishments employing about 354,911 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate batch mix yield or scrap rate? Divide reject castings by the total castings poured in the batch. With 8 rejects out of 250 poured, that's 8 ÷ 250 = 3.2% scrap for the batch.
What is a good foundry scrap rate? It varies by casting complexity and alloy, but many iron and steel foundries target low single digits overall, with tight jobs held under 5%. The example's 3.2% sits inside a 95%-good target, leaving a 91.8-point gap to the ceiling.
What does the gap to target represent? It's your target minus the actual rate — 95 − 3.2 = 91.8 points here — showing how much room you have before the batch breaches your scrap ceiling. Watch it shrink batch to batch as a drift indicator.
Should I count rework separately from scrap? Yes. This rate is cleanest when it counts true scrap — castings you can't sell or salvage. Rework has cost too, but blending it in hides how much metal is actually lost and muddies the trend.
Why track yield per batch instead of per shift? A batch maps to one melt chemistry, one sand mix, and one pour window, so a spike points at a specific cause. Roll everything into a shift number and a single bad heat gets averaged away until it's too late to fix.

Last reviewed 2026-05-12.