PRECISION takes top priority

Circular saws are at work in a wide range of different areas, such as metalworking, stone and marble work, woodworking, the food industry and many more. They require speeds of up to 6,000 rpm.

The saw blades used in the machines are made from alloyed steels that have to be wear-resistant and safe from material damage. They also require cross-sections with the narrowest tolerances in order to avoid undesirable imbalances and therefore uncontrollable machine movements and material losses.

Thanks to various conversion and modernization measures, the Salzgitter Flachstahl GmbH (SZFG) hot-rolling mill can manufacture a range of current material thicknesses and tolerances that are not inferior to cold-rolled or medium-wide strip qualities and are much narrower than required by current standards. The materials employed include chrome-alloyed special steel grades such as 51CrV4 or high-carbon steels (C67 – C80) with high surface and purity requirements.

In this case, a thickness tolerance of a maximum of 50 µm (0.050 mm) between the two strip edges along the hot-rolled strip width must be complied with. This corresponds roughly to half the thickness of a human hair or 10% of a standard bell wire.

This is only possible with cutting-edge systems and processing technology as well as highly qualified employees. The hot-rolling mill relies on CVC (Continuous Variable Crown) technology in all equipment in the finishing train, where the two working rolls can be pushed against each other as required. Rolling forces of up to 4,000 tons per machine and speeds of up to 20 metres per second (around 70km/h) are not unusual for such steels.

The coils delivered by Salzgitter Flachstahl are annealed and slit lengthways after pickling.

Circular saw diameters of 720 to 900 millimeters can no longer be made as single-core medium-wide strips (w ≤ 720 mm) and cannot yet be rolled by Salzgitter Flachstahl as hot-rolled strips (w ≥ 900 mm).

Salzgitter Flachstahl supplies double-width coils for these dimensions, e.g. 1500 millimeters. The strip profile must therefore be as "box-shaped" as possible in order to ensure that there are two split strips after the slits without any wedges.