How to trace a casting back to its heat

A heat number must exist before the first charge goes in. Print or write it on the melt card, and keep one sequence for the whole foundry. Do not restart it by furnace unless the furnace letter is part of the number.

Record the charge mix, the additions, the tap temperature and the time. Add the spectrometer reading from the test spoon. If a second spoon is taken after correction, log it as a second reading on the same heat. Never overwrite the first.

A heat with no chemistry attached is only a label. Nothing more. Make the reading a required field before the ladle may be released.

One heat never fills one mould. A heat is tapped into one or more ladles, and each ladle pours a run of moulds. Give every ladle a sub-number such as the heat number plus a letter.

Pouring is where metal meets pattern. The pourer or line leader notes the ladle against the first and last mould number it filled. That note is the link most foundries lack. Write it down.

Where a ladle is topped up from a second heat, record both. Rare. Still real. When a mixed ladle happens, the record must say so.

The mould log already shows the pattern, the line and the cavity count. Add the ladle sub-number to each row. Now every mould points to a heat.

Castings come out of the mould in a lot. Cast or stamp a lot code or a mould number on each piece where the drawing allows. For small parts, tag the tub or tray and keep the tag with the lot until the end.

Codes get ground off. Do not rely on one surviving shot blasting and grinding. Record the lot when pieces leave shake-out, and again when they enter fettling.

Fettling, machining, heat treatment and inspection are where lots get split and mixed. Each move needs a count in and a count out, with the lot code written on both entries.

When a lot is split into two trays, each tray keeps the parent lot code and adds a suffix. When two lots merge for a heat treatment batch, record the batch with every lot it contains.

Scrap needs the same code. Rework does too. A rejected casting with a known heat tells you whether the problem sits in the melt or in the moulding.

Pick a casting from last month’s dispatch. Start from the customer’s invoice and walk back to the heat card. Time it. If you need more than a few minutes, find the missing link.

Now reverse it. Pick a heat with an off-grade reading and list every casting it poured. That is the exercise you would need in a recall.

Run the trial every quarter and keep the notes. Short and dull is fine. A foundry system helps most here, because it joins heat, ladle, mould and lot without anyone leafing through melt cards.