What Is a Heat Number in Steel? Traceability After Cutting

A heat number in steel is an identification code that links the material to the relevant production heat. In English-language documents, it is commonly referred to as a “heat number.” It does not mean the same thing as the steel grade: the grade defines a technical classification, while the heat number identifies a specific production record. The purpose of traceability is to link material in storage or production back to the correct documentation. If this link is established at delivery but lost after cutting, maintaining a certificate archive alone is not sufficient.

Heat Number, Batch Number, and Order Number

The identification numbers commonly encountered during steel procurement and production and their primary functions are as follows:

These numbers are not expected to be identical. A single order may contain material from multiple heats, while material from the same heat may be allocated to different work orders. The company’s records should show these relationships in a way that can be understood and verified later.

Where Is Traceability Most Commonly Lost?

When a bundle is opened, the identity of all the bars may remain only on the bundle label. This method becomes unreliable when individual bars are moved to different storage racks or when materials from different heats are placed together in the same area.

Short cut pieces and remnants stored for future use are also common points where traceability can be lost. For this reason, the traceability process should not end when “the label reaches the warehouse.” A defined method should be used to transfer material identification through bundle opening, cutting, intermediate storage, and release to production.

How Is Material Identification Maintained After Cutting?

The following steps can help maintain material identification after cutting:

• Link to the work order: Match the identification of the bar being cut with the relevant work order.
• Identify cut pieces: Establish suitable identification at container, pallet, or individual part level.
• Record remnants: Record both the remaining length and identification of the parent bar.
• Keep heats separated: Separate parts from different heats in a way that prevents unintended mixing.
• Verify during transfer: Confirm that the traceability link remains intact when the material is transferred to the next production stage.

The marking method should be suitable for the material surface and its intended use. When choosing between labels, barcodes, or other identification methods, factors such as readability, processing temperature, oily surfaces, and cleaning processes should be considered. Methods that leave permanent marks on the surface should be evaluated against the applicable technical requirements.

How Can a Simple Traceability Record System Be Established?

A basic internal traceability record can include the following information:

• Supplier and heat number
• Steel grade and delivery condition
• Cross-section and remaining length
• Storage rack location
• Certificate file

The objective is not to implement a complex software system, but to create a consistent link between the physical material and its records. For example, separate inventory sub-records can be created for two different heats of the same steel grade. The quantity consumed during each cutting operation can then be deducted from the corresponding sub-record.

This allows bars with the same diameter and steel grade to appear together in commercial inventory reports while remaining distinguishable in their production and traceability records.

What Should Be Checked When Matching Material Certificates?

A link should first be established between the heat or batch identification on the certificate and the product label. The steel grade, delivery condition, product description, and scope of testing required by the purchase order should then be verified.

The presence of a heat number alone does not demonstrate that the product meets all technical requirements. To better understand the scope of inspection certificates, you can review our EN 10204 inspection documents guide. For purchasing and supplier evaluation, see our steel supplier selection criteria.

Can Steel with a Missing Label Be Used Immediately?

No. The traceability link should first be re-established. The company’s internal records should be reviewed to determine whether the material can be reliably identified. Visual appearance, approximate hardness, or proximity to other material on a storage rack should not be considered sufficient evidence on their own.

If the traceability link cannot be restored, any additional verification requirements and decisions regarding the material’s use should be handled according to the applicable quality procedure.

Conclusion

A heat number is a key identification code that links steel material to its production record and corresponding certificate. Traceability should be maintained not only at delivery but throughout bundle opening, cutting, remnant storage, and release to production, supported by a simple but consistent record-keeping system.

To define your labelling and documentation requirements in advance, you can submit your technical requirements to Uyar Çelik through our contact page.