Heat number
The melt lot the bar came from. It is stamped, inked or tagged on the stock and printed on the report. No match, no traceability.
How we value · Mill certs & heat numbers · Solids only
Do mill certs raise the offer on your drops?
For melt scrap, a cert rarely moves the price. For a remachinable drop, bar end or plate cutoff, it often does. A mill test report (MTR) with a matching heat number on the piece lets the next shop use that metal on a job that needs traceable material. This page covers what a cert proves, how to keep it with your remnants, and what happens to stock that has none.
What a mill cert actually proves
The MTR comes from the mill that made the metal. The bar on your rack is only tied to it by the heat number.
Spec and grade
The standard the material was made to and its grade or temper, for example 6061-T651 plate or 316/316L bar.
Chemistry
The measured composition for that heat, which is what lets a buyer trust the grade without testing it.
Mechanical results
Usually tensile, yield and elongation, and sometimes hardness. These are what an XRF reading cannot give you.
Why a cert moves the offer on solids, not on melt
Going to melt
- The yard prices the chemistry by the pound.
- It sorts or tests the load anyway, so paperwork saves it little.
- A cert can help a yard trust the grade, but the piece's shape doesn't matter.
Going back on a rack as stock
- The next machinist buys a grade, not "some metal."
- Many customer and aerospace-style jobs require traceable material, and a cert with a matching heat number is what makes a drop usable there.
- Without it, the same piece may only fit non-critical work, which narrows who can use it.
That is why our grade table puts segregated, known-alloy, cert-backed solids in grade A, and clearly marked solids with gaps in the docs in grade B.
How to keep certs with your remnants
Most certs get lost at the saw, not in the office. A few habits keep a drop sellable as stock.
1. Transfer the heat number
When you cut a bar or plate, mark the heat number and grade on the drop with a paint marker before it goes back on the rack.
2. File certs by heat
Keep a copy of each MTR where you can find it by heat number or PO, not only in the job folder that shipped.
3. Don't mix heats in a bin
One grade and, where you can, one heat per bin or bundle. A mixed bin turns every piece into "probably."
4. Know whose metal it is
Customer-furnished material may not be yours to sell. Clear that first; we require ownership certification on every lot.
Selling metal without mill certs
You can still sell it. What matters next is how clearly the pieces identify themselves.
Still reviewed for reuse
- Mill stamps or printed grade on the stock.
- Original tags, color-code ink or a supplier's label.
- A pack slip or invoice naming the grade.
- One grade per bin, kept apart from everything else.
Likely ID hold or decline
- No marks at all, or marks that disagree.
- Mixed grades in one bin.
- Specialty metals (titanium, nickel alloys, tool steel) with no marks. See specialty solids.
An XRF reading can help an unmarked lot get out of ID hold by confirming the grade family. It doesn't give you a heat number, so it doesn't stand in for a cert on jobs that need traceability. We will not guess an alloy or grade for you. Checks you can run yourself first: how to identify unmarked drops.
What to send so the cert counts
1. The marks
A close-up of the heat number and grade on a few pieces.
2. The cert
A photo or PDF of the MTR, with the heat number readable. Pricing on it can be covered.
3. The lot
A wide shot, rough sizes and a piece count or weight. No scale? See how to weigh and measure a drop.
4. The form
On the sell form, set certs to Yes, Partial or No and add the heat/lot if you have it. Or call/text 508-343-1219.
Mill cert FAQ
Grades A to D and the ID hold are explained on how we value. What we buy is on solids.
Do mill certs increase the value of scrap or drops?
For melt scrap, usually not much, because a scrap yard prices chemistry by weight and sorts or tests it anyway. For remachinable solids, yes. A drop or bar end with its mill cert and a matching heat number can go into another shop's job as stock, and many jobs require traceable material. That traceability is what the next buyer pays for, so certified, clearly marked lots get our strongest offers after review.
What is a mill cert or MTR?
A mill test report (MTR), also called a mill cert or material cert, is the document from the mill that made the metal. It lists the heat number, the spec and grade, the chemistry, and usually mechanical test results such as tensile and yield. The heat number stamped or printed on the bar ties that piece back to the report.
Can I sell metal without mill certs?
Yes. Clearly stamped or labeled solids in a known grade still get reviewed for reuse, just below a cert-backed lot. Unmarked, conflicting or uncertain material may get a lower offer, an ID hold until identity is clear, or a decline. We will not guess an alloy or grade for you.
Does a cert still count if the drop was cut from a longer bar?
It can, if the heat number traveled with the drop. A cert only covers the pieces you can tie back to it, so mark the heat number on each drop when you cut it and keep the cert copy with the lot. A cert with no matching marks on the pieces helps much less.
Is an XRF test the same as a mill cert?
No. An XRF gun reads surface chemistry and can confirm a grade family, which helps unmarked stock get out of ID hold. It does not give you the heat number or the mill's mechanical test results, so it does not replace the cert for jobs that need traceability.