Material flow of a warm formed profile considering the pre-treatment of the material

Rolled profiles for special purposes are mostly manufactured in multiple stand rolling mills and a downstream grinding process. Usually those mills consist of a pay off reel, heating equipment, a two high stand, a cooling device, several universal mill stands and a coiler. Basic products are coils of rolled or drawn wire with diameters of about O 10 till O 12 mm. The material is mostly high speed steel or cold working steel. With respect to an accurate groove filling the initial diameters of the rolling stock must be defined very precisely. If the grooves are not fully filled the product must be scraped. If the grooves are overfilled the grinding costs will increase. However, not only the initial diameter plays a decisive role but also the pre-treatment of the initial material. If the initial material is rolled and annealed its deformability behaviour is different from a material which has additionally been drawn after annealing. To compare the characteristics of these two different starting materials practical tests have been performed. Thereby we came to the conclusion that – under the same rolling conditions – the spread of a drawn wire is higher than the spread of a rolled wire.