TS EN 10049

TS EN 10049 is a standard focused on the measurement conditions for two key surface texture parameters on metallic flat products: the roughness average Ra and the peak count RPc. In practice, these parameters are used to describe the surface condition of flat sheet and strip products, helping users understand not only how rough a surface is on average, but also how densely surface peaks are distributed.

According to the supplied scope, the standard applies to uncoated metallic flat products, including cold-rolled and hot-rolled pickled steel, as well as products with metallic coatings such as zinc, aluminium, tin and chromium. Its role is to define a common measurement environment for these product groups so that results can be compared consistently. This is a measurement standard, not a general manufacturing specification; it addresses how the roughness parameters are measured rather than all aspects of product quality.

What Ra and RPc tell you

In general technical use, Ra is the arithmetic mean roughness and is one of the most widely used indicators of surface texture. It gives a compact numerical summary of the profile’s departures from the mean line. RPc, by contrast, describes the number of peaks along a measured length, so it adds information about the frequency of surface asperities. That distinction matters for metallic flat products because two surfaces may have a similar Ra value while behaving differently in coating adhesion, friction, appearance or forming operations.

Why measurement conditions matter on flat metal products

Flat metal products are used in processes where surface condition can influence downstream performance, such as painting, coating, roll forming and pressing. A shared measurement framework helps ensure that roughness results are not dominated by differences in setup or interpretation. By focusing on measurement conditions for Ra and RPc, this standard supports more consistent communication between mills, processors and users who need surface texture data in a comparable form.