01.12.07
New generation of levelers tame high-strength steels
Sascha Becker

The material requirements in the stamping industry have changed to meet industry demands. The increasing use of high-tensile-strength materials, mainly in the automotive industry, makes leveling more essential than ever. To obtain adequate flatness in high-strength steel (HSS) coil, higher leveling forces and new concepts are needed.
Why are next-generation levelers required to tame HSS? To understand this connection, it is necessary to understand coil defects. Cold-rolled strip defects are coil set, cross-bow, twist, and edge camber.

Defects

Coil set and crossbow occur as a result of the strip-coiling process. Coiling causes a lengthwise stretching of the inside surface relative to the outside surface of the stock. The lengthwise stretching causes a widthwise contraction, resulting in crossbow. Other defects are twisted strip and edge camber. Generally, edge camber occurs only in narrow strips.
Defects in wide strips are wavy edges, coil breaks, and center buckles, although wavy edges and center buckles can occur in the strip also. As the material is cold-rolled, deflections in the rolling mill thin some areas of the strip cross section more than others. This also elongates those thinner areas of the strip, causing a waviness in the longer areas. To remove these material tensions, leveling is needed.

...

Artikel anfordern

Download

zurück