<p>A composite side dam for a continuous twin roll caster includes a substrate made of a refractory material capable of withstanding casting temperature and having edge portions adapted to engage casting rolls and having a nip portion adjacent a nip between casting rolls and upper portions extending across the side dam to form a lateral restraint for a casting pool, an insert of at least 10 mm in thickness positioned in a pocket in the substrate and extending to engage the molten metal and extending from the upper portions of the substrate and positioned in the pocket to within 30 mm from the nip portion by insertion adjacent the upper portions of the substrate. The insert is adapted to fit into the pocket of the substrate to form a side dam formed of a refractory material having consumption rate less than 10 mm per hour. The material forming the insert may be between 40 and 60% a SiAlON material. The remainder of the material may be a hBN material. The material may be a mullite material having between about 60 and 63 mole percent A1203. The remainder of this material may be Si02. The material may be a fused silica, such as between 40 and 60% fused Si02 and the remainder a hBN material.</p>
