What controlled rolling does for S355J2WP

Finer grain size. Typical grain size: ASTM 8–10 (vs. 5–7 for as-rolled). Finer grains mean better toughness, especially at -20°C.

Improved impact toughness. Controlled-rolled S355J2WP often delivers 40–60J at -20°C—well above the 27J minimum.

Better through-thickness properties. More uniform mechanical properties from surface to center.

Reduced segregation. Controlled rolling minimizes centerline segregation, which improves weldability.

Higher yield strength. Sometimes allows thinner sections for the same load capacity.

When to specify controlled rolling.

Controlled rolling isn't always necessary. But here are the situations where it's worth specifying:

Heavy plates (over 30mm). As-rolled plates thicken, grain structure becomes coarse. Controlled rolling restores properties.

Cold-climate structures. Bridges, railcars, and offshore structures facing -20°C or lower benefit from the improved impact toughness.

High weldability demands. Controlled-rolled steel has cleaner internal quality and less segregation, making welding more consistent.

When standard rolling can't meet impact requirements. For thick plates, as-rolled Charpy values may dip below the 27J minimum. Controlled rolling solves this.