Thirty years of systematic research by SAAR-Hartmetall und Werkzeuge to perfect  the adjustment of the WC-volume, the WC-grain structure and the composition of the binder contect have resulted in a wide range of different tungsten carbide grades for the hot deformation of steel. Today, our high wear resistant SARAMANT grades can be used economically at rolling speeds from 2-120 m/sec in intermediate and finishing stands of bar mills, in high speed wire rod and sizing units and in tube mills.

The tougher tungsten barbide grades with a binder rate of 25-30% have been developed for lower speeds in the intermediate stands (speed 2-15 m/sec). For the higher speed range of 10-50 m/sec TC grades with a higher hardness and a higher wear resistance (17-25% binder) are used for the rolling of small wire sections. In the last 2 stands of the wire rod and sizing blocks, where there is a requirement of tight tolerances during a long rolling time at a low reduction, the wear resistant SARAMANT tungsten carbide grades with a hardness of 860-1200 HV 30 (7-17% binder) are successfully used. 

There are special technical requirements for the ribbed rolls in the last stand of wire rod blocks or in the finishing stand of bar mills for rolling rebar. Due to the notching effect of the ribs in the passes and the much better machinability of the rolls, the SARAMANT grades 
VG 627 and VN 77 with 30% binder are the appropriate choice. 

Generally, all tungsten carbide roll rings are ground with diamond wheels to the required dimensions. Alloys in a hardness range of 600-800 HV30 can be machined with CBN tools. 

A preselection of the differenct TC grades is done according to the technical information above. In view of the latest rolling results, higher  wear resistant or tougher TC grades can be used later in accordance with the experience of the rollers. 

It should be borne in mind that tungsten carbide has a relatively low toughness and special care is therefore necessary when transporting, stocking, mounting and clamping the rolls.

Tungsten carbide, due to its hardness and its thermal shock sensitivity, requires intensive cooling immediately after the contact of the roll with the hot material. For the cooling parameters in the different stands refer to the listing below.