Per: jeferson iorio tessari (arcelormittal), Matheus Rodrigues Furlani (Arcelormittal Tubarão), Henrique Severiano de Jesus (ArcelorMittal Tubarão), Estefano Aparecido Vieira (IFES)
Abstract:
The continuous casting process is currently the most important for the solidification of steels worldwide. In slab continuous casting machines (CCM), the drive rollers are usually made of forged steel, and the EN 42CrMo4 alloy is very commonly used for manufacturing. However, despite having good malleability and resistance to withstand operating conditions involving vibrations and mechanical stresses, this material is not suitable to withstand severe wear conditions under high temperatures. These situations are commonly observed, as the rollers come into direct contact with the solidified plate, whose temperature can be higher than 1000 ºC. Thus, to minimize the wear caused by friction, it is common to cover these rollers with more wear-resistant steels through welding processes. For this application, the use of martensitic ferritic steels is very common. The objective of this work was to study the microstructure formed and the hardness profiles of two rolls submitted to the coating process by welding (Submerged Arc Welding). For the present study, two ferritic martensitic stainless steels were evaluated. The first conventional alloy DIN 8555 class UP 5-GF-45-C, containing higher Ni and low Cr, the second steel DIN EN 14700 class T Fe 8 containing higher Mo and low Ni. Specimens were prepared and the hardness profile was measured as well as the microstructural characteristics. The results show that the hardness profile decreases as we approach the base material, however with distinct gradients, where the DIN EN 14700 standard presents a superior average difference of 175 Vickers HV0.5 and martensitic structures with similarity between the materials.
