What Is a Heat Number on Steel?
If you’ve noticed numbers or letters marked on steel, you may have been looking at a heat number.
What Is a Steel Heat Number?
A heat number is a unique identification number assigned to a batch of steel produced from a single melt at the mill.
One simple way to think about it is as a serial number for the steel. It provides a way to identify and trace material back to the batch it came from.
Steel produced from the same heat shares a common production history, which is why the heat number is useful when material needs to be identified or verified.
Where Can You Find a Heat Number?
Heat numbers can be found on many types of steel, including beams, plate, pipe, tubing, and other products.
Depending on the material and mill, the number may be painted, stamped, printed, or otherwise marked directly on the steel.
These markings help keep the material identifiable as it moves through distribution and fabrication.
Why Are Heat Numbers Important?
The main purpose of a heat number is traceability.
For projects with specific material requirements, it may be necessary to verify that the steel meets a certain grade, specification, or standard. The heat number provides the link needed to trace that material back to its production records.
This can be especially important in structural, industrial, energy, and other applications where material documentation is required.
How Does a Heat Number Relate to an MTR?
A heat number connects the physical piece of steel to its Mill Test Report (MTR).
The MTR contains more detailed information about that heat of steel, which can include its grade, chemical composition, yield strength, tensile strength, and other test results.
In simple terms, the heat number identifies the batch, while the MTR provides the documentation and test information for that batch.
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