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Lean playbook · Steel, metals and foundry

Lean playbook for steel mills, foundries and die casters

Short answer

Start lean in a mill or foundry on the equipment that sets the pace, usually the furnace, the caster or the molding line. Give operators a daily care routine and a quick way to tag what they find, and analyse every long breakdown with maintenance. Then count casting defects by type and by the step that makes them, and work on the costliest first. Good castings per tonne poured is the number that joins scrap, returns and energy. Shorten die, roll and pattern changes with SMED, and write the shutdown jobs and the experts' know-how down before people retire.

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7 problems on the floor, and the lean methods for each

Each problem says what it looks like, which methods address it, the first moves to make and the number to watch. Pick the one or two that cost your plant most; you do not need all of them at once.

Where a steel mill or foundry loses time and quality

  1. Melt (arc, induction or cupola furnace)

  2. Cast (caster, sand molding, die casting)

  3. Roll, forge or shake out

  4. Heat treat and finish

  5. Inspect and ship

Across the whole line

A simplified line, not a plant layout. Select a number to jump to that problem.

  1. Furnace, caster and mill stops that hold up everything behind them

    The furnace, caster, mill or molding line sets the pace, and when it stops the metal waits. Hot, heavy equipment wears fast, and leaks, worn rolls, cooling faults and refractory damage are seen by operators long before they cause a stop, but rarely logged.

    Lean methods

    In LeanSuite

    Build visual CILR routines and schedule them through Daily Standard Work.

    First moves

    1. Rank the equipment by what a stop costs the plant, and start on the one at the top.
    2. Write a short daily care routine for it with the operators, with photos of the OK condition, and tag every abnormality found.
    3. Analyse every breakdown over an agreed length with maintenance and the crew, and fix the cause, not just the part.
    4. Keep critical spares for that equipment, and check their condition.

    Number to watch: Unplanned downtime hours, and mean time between failures, on the pacing equipment.

    Equipment criticality analysisAutonomous maintenance (CILR) checklistBreakdown analysis reportCritical spare parts list and stocking levelsMTBF and MTTR calculatorDowntime cost calculator

  2. Casting defects made at pouring and found much later

    Porosity, shrinkage, inclusions, cold shuts and sand defects are made at pouring and molding but found at shakeout, finishing or the customer's machining. Each scrapped casting is metal melted and poured again, and the defect people talk about most is not always the one that costs most.

    Lean methods

    In LeanSuite

    The QA Matrix gives every internal and customer defect an AA, A, B or C priority from cost, frequency, severity and detection point, with weights you set.

    First moves

    1. Record every scrapped casting with the defect type, the pattern or die and the step that made it, not only where it was found.
    2. Pareto the scrap by cost each week, and start on the top defect on the top part.
    3. Draw a fishbone for that defect with the melt, molding and finishing crews, and check the process settings against what was planned.
    4. Chart the settings that drive it, such as pouring temperature, sand properties or die temperature, and act when they drift.

    Number to watch: Scrap percentage and good castings per tonne poured.

    Defect catalogue template with boundary samplesQA matrix templatePareto chart templateX-bar and R control chart templateScrap rate calculatorPareto chart makerFishbone diagram maker

  3. Off-spec heats and claims that arrive weeks later

    A heat outside chemistry, a coil or bar out of tolerance or a lot with a hidden defect reaches the customer, and the claim comes in long after the material was made. Finding every affected heat or lot takes days, and the cause is guessed instead of proven.

    Lean methods

    In LeanSuite

    Each non-conformance is captured with photos and routed to quality and engineering.

    First moves

    1. Agree a containment routine for a claim: which heats or lots to hold, where they are and who checks them, within hours.
    2. Post a quality alert at the step that made the defect, with photos, the same shift.
    3. Run an 8D for every repeat claim, and close it only when the fix has held on the next heats or lots.

    Number to watch: Customer claims per thousand tonnes or per million parts, and days to contain.

    8D report templateQuality alert formNon-conformance report (NCR) formCAPA log template

  4. Long die, roll and pattern changes

    Die changes on die casting machines, pattern changes on molding lines and roll changes on the mill take the equipment down. The first castings or tonnes after the change are often scrap while the die or mill comes up to temperature and size.

    Lean methods

    In LeanSuite

    Run each changeover as a visual checklist in Lean Creator and require a photo on the steps that matter most.

    First moves

    1. Film one change and mark which steps need the equipment stopped.
    2. Preheat the next die and stage the next pattern, rolls, tools and lifting gear before the stop.
    3. Count the warm-up scrap after each change, and set the first good part as the end of the change.
    4. Plan the sequence so changes between similar dies or sections come one after the other.

    Number to watch: Change time to the first good casting or tonne, and warm-up scrap per change.

    SMED changeover worksheetChangeover checklistChangeover matrix templateSMED changeover calculator

  5. Molten metal, cranes, heat and silica

    Molten metal splashes and moisture explosions are a risk at the furnace and on the pouring floor. Ladles and heavy loads move on overhead cranes, and hot surfaces and respirable silica at shakeout, in the cleaning room and from refractory are part of every shift.

    Lean methods

    In LeanSuite

    Anyone can report a near miss by scanning a station QR code with their phone, anonymously if you allow it, and each hazard becomes a corrective action with a due date.

    First moves

    1. Write a job safety analysis for charging, tapping, pouring and ladle moves, with the crews who do them.
    2. Inspect cranes and lifting gear on a schedule, and make the pre-use check a signed step.
    3. Keep scrap, tools and ladles dry before they meet molten metal, and check it at the furnace.
    4. Make near-miss reporting quick, and give everyone the right to stop the job.

    Number to watch: Near misses reported and closed, and the recordable injury rate.

    Job safety analysis (JSA) templateOverhead crane inspection checklist: frequent and periodicNear miss report formSafety observation card templateNoise dose and TWA calculatorTRIR and DART rate calculator

  6. Shutdown and reline jobs that live in notebooks

    Relines, caster segment changes, roll shop work and shutdown jobs are done a few times a year. Steps, torque values and isolation points live in people's notebooks, so each job takes longer than it should and carries more risk.

    Lean methods

    In LeanSuite

    LeanSuite drafts a standard maintenance procedure from one filmed walkthrough: steps, tools, PPE and warnings.

    First moves

    1. Write a standard maintenance procedure for each shutdown job, with the steps, tools, parts, torque values and every isolation point.
    2. Review each procedure after the job, while the crew remembers what went wrong.
    3. Plan shutdown jobs from the procedures, with parts and tools staged before the stop.

    Number to watch: Shutdown jobs finished on plan, and hours over plan.

    Maintenance job plan templateLockout/tagout (LOTO) procedure templateHot work permit templateConfined space entry permit template

  7. Melters, casters and crane operators close to retirement

    Melters, casters, furnace and crane operators and roll shop staff take years to learn their jobs, and many are close to retirement. When one is off, the shift runs short or someone does the job who has never done it alone.

    Lean methods

    In LeanSuite

    The skills matrix shows jobs only one person can do, so you can schedule cross-training before that person is out.

    First moves

    1. Build a skills matrix by position, and mark every job fewer than three people can do and who is close to retiring.
    2. Pair each expert with a trainee, and capture their key points as job breakdowns and one-point lessons.
    3. Sign each trainee off on the job before they run it alone.

    Number to watch: Positions with fewer than three qualified people.

    Skills matrix templateCross-training plan templateOne point lesson (OPL) templateTWI job breakdown sheet

More small fixes in the production, maintenance and safety sections of the kaizen idea bank.

Questions from the floor, answered

The questions people in these plants search for most, answered in full, with the free template for each.

Casting defects: types, causes and the first thing to check

Most casting defects come from four places: the metal (gas, oxides, temperature), the mold or die (sand, coating, temperature, venting), the way the metal fills (gating and pouring) and the way it freezes (feeding and risers). Name the defect correctly before changing anything, because gas porosity and shrinkage porosity look alike and have opposite fixes.

Sort scrap by defect type and by pattern or die, then pareto it by cost. The table gives the usual causes. Your own process sheets and customer standards decide what is acceptable.

Common casting defects with their usual causes and the first check to make
DefectWhat it looks likeUsual causesFirst check
Gas porositySmooth, round holes, often near the top surfaceMoisture in sand, cores or ladles; gas in the melt; poor ventingSand moisture, ladle and core drying, venting
Shrinkage porosityRough, jagged cavities in thick sectionsMetal shrinks as it freezes and is not fed; risers too small or badly placedRiser size and position, pouring temperature
InclusionsSand, slag or oxide trapped in the castingLoose sand, eroded molds, poor skimming, turbulent pouringMold strength, skimming and gating
Cold shut and misrunSeams where two streams did not fuse, or unfilled sectionsMetal too cold, pouring too slow, thin sections, poor gatingPouring temperature and pouring time
Hot tearsRagged cracks formed while the metal was still hotThe mold or core stops the casting shrinking; sharp cornersCore collapsibility and section changes
Sand defectsBurn-on, penetration, scabs, swells or a rough surfaceSand too coarse or weak, poor ramming, metal too hotSand tests and mold hardness
Flash and finsThin metal at the parting line or core printsMold halves or die not closing, worn patterns or diesParting line, die wear and clamping
Soldering (die casting)Metal welded to the die surfaceDie too hot, poor die spray, worn coatingDie temperature and spray pattern
Defect catalogue template with boundary samplesPareto chart templateQA matrix template5 Whys templateReduce scrap and rework

Die casting: where the time and scrap go

In high pressure die casting, molten aluminum, zinc or magnesium is injected into a steel die under pressure and held while it freezes. Cycle times are short, so most of the loss is not in the cycle itself. It is in die changes, warm-up scrap after a change or a stop, die maintenance and porosity that only shows after machining.

Lean in a die casting cell starts with three counts per machine: die change time to the first good part, castings scrapped while the die comes up to temperature, and scrap by defect after trimming and machining. Preheating the next die outside the machine and keeping die spray and temperature to a standard attack all three.

Step by step

  1. Log every die change with its time to the first good casting and its warm-up scrap.
  2. Preheat the next die and stage the tools, hoses and lifting gear before the stop.
  3. Set a standard for die temperature and spray, and check it at the start of each shift.
  4. Record porosity found at machining against the die and the date it was cast, so it reaches the cell that made it.
SMED changeover worksheetChangeover checklistDefect check sheet

A 90-day starting plan

One line or product family, two problems, measured before and after. The point of the first 90 days is a result the plant believes and a method it can repeat, not a plant-wide program.

The 90 days, with the gate that ends each stage

  1. Days 1 to 30Baseline the pacing equipmentDone when: The board shows baseline numbers and two problems each have an owner.
  2. Days 31 to 60Attack the top stop and the top defectDone when: Each fix has a written standard and a before-and-after number.
  3. Days 61 to 90Hold the gains and protect the know-howDone when: The gains have held for a month and the next area has its baseline.
Move to the next stage only when the gate is met, even if a stage runs past its 30 days. The cards below say what to do inside each stage.

  1. Days 1 to 30

    Baseline the pacing equipment

    Pick the furnace, caster, mill or molding line that sets the pace, and measure it before changing anything.

    • Choose the equipment that holds up the most metal when it stops, and name an owner and a sponsor.
    • Measure for two weeks: downtime by cause, scrap by defect type, change times and warm-up scrap.
    • Start a short meeting at a board on the floor at the start of each shift.
    • Walk the area with operators, maintenance and quality, and list what slows them down.
    • Choose the two biggest losses to work on first.

  2. Days 31 to 60

    Attack the top stop and the top defect

    Fix the biggest cause of downtime and the costliest defect, and prove both with numbers.

    • Start the daily care routine on the pacing equipment and tag what the operators find.
    • Analyse the longest breakdowns with maintenance and fix their causes.
    • Run a fishbone and a trial on the costliest defect on the top part.
    • Write each new method down as a standard or one-point lesson as soon as it works.

  3. Days 61 to 90

    Hold the gains and protect the know-how

    Keep the new standards on every shift, and start writing down what only a few people know.

    • Audit the new standards on every shift and act on every gap.
    • Run a SMED workshop on the most frequent die, roll or pattern change.
    • Build the skills matrix and pair each retiring expert with a trainee.
    • Compare scrap, downtime and good castings per tonne poured with the baseline, and pick the next area.

The KPIs to track

Track them per line and shift, on a board the team sees every day. Set targets from your own baseline, not from someone else's plant.

KPIs for steel mills, metals plants and foundries: what each tells you and how to measure it
KPIWhat it tells youHow to measure itFree help
Good castings per tonne pouredHow much of the metal melted ends up as product you can ship, after gating, risers and scrap.Weight of good castings shipped divided by weight of metal poured, per day or week. Mills use prime tonnes per tonne cast.Scrap rate calculator
Scrap percentageThe share of castings or tonnes that are scrapped, and which defect causes most.Scrapped castings or tonnes divided by castings or tonnes made, by defect type.Scrap rate calculatorDefect catalogue template with boundary samples
Utilization and OEEHow much of the time the pacing equipment could run it made good product at its rated rate.Availability times performance times quality on the furnace, caster, mill or molding line, per shift.OEE calculator
Energy per good tonneWhat each tonne you can sell costs in electricity or gas, including the metal melted twice.Melt energy in kWh divided by good tonnes, not by tonnes melted.Energy use and EnPI tracker
Mean time between failuresHow long the pacing equipment runs between breakdowns, and whether it is getting better.Running hours divided by the number of breakdowns in the same period.MTBF and MTTR calculator
Recordable injury rateHow often people are hurt badly enough to record, on a scale you can compare across years and plants.Recordable cases times 200,000 divided by hours worked.TRIR and DART rate calculator

Illustrative: a foundry's yield and energy per good tonne

These numbers are made up to show the method. A foundry melts and pours 20,000 kg of iron a day. Of that, 7,000 kg is gating and risers that go back to the furnace, and 650 kg of castings are scrapped.

Melting uses 11,600 kWh a day.

The calculation, step by step

Example numbers

  1. Good castings per tonne poured = good casting weight ÷ weight poured

    Gating and risers and scrapped castings both go back into the melt.

    1. Castings poured =20,000 − 7,000= 13,000 kg
    2. Scrap rate =650 ÷ 13,000= 5.0%
    3. Good castings =13,000 − 650= 12,350 kg
    4. Yield =12,350 ÷ 20,000= 61.8%
    Good castings per tonne poured618 kg

  2. Energy per good tonne = melt energy ÷ good tonnes

    Dividing by tonnes melted hides the metal that is melted twice.

    1. Per tonne melted =11,600 ÷ 20= 580 kWh
    2. Per good tonne =11,600 ÷ 12.35= 939 kWh
    3. Scrap halved to 325 kg =11,600 ÷ 12.675= 915 kWh
    Energy per good tonne today939 kWh
Only 618 kg of every tonne melted is sold, so each good tonne carries 62% more melt energy than the per-tonne-melted figure shows. Halving scrap saves about 24 kWh per good tonne at the same melt; gating and risers, at 7,000 kg a day, are the bigger lever, and that is a methods job.

By the numbers

Public figures for this industry or for the wider sector it belongs to, each linked to the report or government table it comes from and checked against it on October 9, 2026. More in our lean manufacturing statistics and benchmark charts.

Injury and illness rate by industry, 2024

  1. Motor vehicles5.6
  2. Beverage and tobacco3.7
  3. Furniture3.5
  4. Food3.3
  5. Primary metals3.3This industry
  6. Nonmetallic mineral products, incl. glass3.3
  7. Fabricated metal products3.2
  8. Transportation equipment3.2
  9. Motor vehicle parts2.9
  10. Plastics and rubber products2.8
  11. HVAC and refrigeration2.4
  12. Paper2.4
  13. Machinery2.3
  14. All private industry2.3
  15. Electrical equipment and appliances2.0
  16. Printing1.6
  17. Chemicals1.6

Total recordable cases per 100 full-time workers, 2024: Motor vehicles 5.6, Beverage and tobacco 3.7, Furniture 3.5, Food 3.3, Primary metals 3.3, Nonmetallic mineral products, incl. glass 3.3, Fabricated metal products 3.2, Transportation equipment 3.2, Motor vehicle parts 2.9, Plastics and rubber products 2.8, All manufacturing 2.7, HVAC and refrigeration 2.4, Paper 2.4, Machinery 2.3, All private industry 2.3, Electrical equipment and appliances 2, Printing 1.6, Chemicals 1.6.

Total recordable cases per 100 full-time workers, U.S., 2024 data, from the BLS Survey of Occupational Injuries and Illnesses. This industry's rows are in yellow; the dark mark on each bar is all manufacturing, at 2.7.

Free templates, calculators and buyer's guides

Templates (27)

Calculators (9)

Buyer's guides

LeanSuite pages for these problems

How LeanSuite handles each of these is on the page for steel mills, metals plants and foundries.

Whirlpool tackled project visibility and continuous improvement across 14 manufacturing plants with LeanSuite. Read the Whirlpool case study.

FAQ

Lean in steel mills, metals plants and foundries: common questions

  1. Yes, but it starts with the equipment and the metal, not with takt time. Keep the pacing equipment running with operator care and breakdown analysis, and cut scrap at the step that makes it. Then shorten die, roll and pattern changes, and write down the jobs only a few people know. Flow tools such as kanban matter less where the process is continuous.

  2. With the defect that costs most on the part that runs most. Record every scrapped casting with its defect type and the step that made it for two weeks. Rank the defects by cost, and work on the top one with the melt, molding and finishing crews. Track good castings per tonne poured to see the result.

  3. Good castings or prime tonnes per tonne poured, scrap percentage by defect, utilization or OEE on the pacing equipment, energy per good tonne, mean time between failures and the recordable injury rate. Track them per shift on a board the crew sees.

  4. Melt less metal twice. Every kilogram of gating, risers and scrap goes back into the furnace, so better yield and less scrap lower energy per good tonne. Add fewer furnace delays and holding at temperature, and charge scrap that is dry and sized for the furnace.

See LeanSuite on your furnace, caster or molding line

Bring the routine you want to fix first. We will show you how LeanSuite handles it and what a 90-day pilot would cover.

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