In steel production and quality control, Heat Number and Batch Number are distinct but related identifiers critical for traceability. For S275JR, adhering to EN 10025, this traceability is mandatory.
Heat Number (or Melt Number, Furnace Number, Cast Number):
Definition: A unique alphanumeric code assigned to all steel originating from a single primary melting process in a steelmaking furnace (e.g., Basic Oxygen Furnace, Electric Arc Furnace).
Purpose: It is the fundamental unit of chemical identity. All slabs, billets, and subsequently rolled products (plates, beams) from the same heat share an identical chemical composition (within the allowed ladle analysis tolerances). It is the primary key for tracing a material's origin.
Format: Typically includes codes for the plant, year, furnace number, and a sequential serial number for that melt (e.g., AB23045001).
Importance for S275JR: When conducting mandatory chemical analysis or checking Carbon Equivalent for weldability, the results are linked to the Heat Number.
Batch Number (or Lot Number, Rolling Batch Number):
Definition: A unique identifier for a specific quantity of product (e.g., a set of H-beams) that has been produced under essentially the same conditions.
Purpose: It is the fundamental unit for testing mechanical properties and dimensional checks. A batch groups together products that are expected to have uniform properties because they share the same heat number, product form (H-beam), size (e.g., HEB 340), rolling process parameters, and heat treatment condition (in this case, as-rolled).
Creation: A single Heat Number can be rolled into multiple Batches (e.g., different sections or rolled on different days). Conversely, a standard batch for plates is often defined as material from one heat, one thickness, one rolling practice, and a maximum tonnage (e.g., 60 tons).
Importance for S275JR: The mandatory tensile and impact tests specified in EN 10025-2 are performed on samples taken from a defined Batch. The test results reported on the mill certificate are valid for all products within that Batch number.
In practice, on a material certificate or shipping tag, you might see "Heat/Batch No." or simply a number that serves both purposes if the entire heat was processed as one lot. The batch number is crucial for incoming inspection at a construction site or fabricator, as mechanical test reports are associated with it.