Surface of hot-rolled steel sheets in accordance with DIN EN 10163

The surface of hot-rolled steel sheets is much more than just a visual feature. It affects further processing, coating quality, and the material’s subsequent usability.

Various surface imperfections arise during the manufacturing process. These must be evaluated in practice.

What types of surface imperfections are found on hot-rolled steel sheets?

DIN EN 10163 describes typical surface imperfections in hot-rolled sheets.

These include:

• Impressions and Impressions
• Scratches and Scrapes
• Fire-setting roll-ins
• Cracks and Shells
• Bubbles or sandy spots

Not every irregularity is an error. What matters is its impact on usability.

Permitted or not permitted?

The DIN EN 10163 standard distinguishes between different types of imperfections.

Permissible Deviations

Indentations, marks, scratches, and scuffs are usually not a concern. They occur during the manufacturing process. Sheet metal may be shipped if:

• the specified thickness is still achieved
• the permissible coverage area is not exceeded.

Sharp-Edged Imperfections

Cracks, chips, or chipped strips are considered critical. They must be recorded and addressed.

Typically:

• Sanding Down the Defects
• Inspection and, if necessary, repair by welding.

For orders in accordance with EN 10163 B3, the following applies: Welding for repair purposes is not permitted.

Why do errors only become apparent later?

Rolling scale can conceal surface defects. These defects often become visible only after blasting or descaling.

That is why surface preparation is crucial—especially when the surface will be coated later or subjected to heavy use.

UnionStahl’s Commitment to Quality

UnionStahl generally orders steel sheets in accordance with DIN EN 10163-B3.

This means:

• strict surface requirements
• Critical defects such as cracks or chips are not permitted
• Welding repairs are not permitted.

Conclusion

The surface of a hot-rolled steel sheet is a key quality factor.

Those who properly assess defects can identify risks early on—and ensure that components perform reliably in service.