The case of unsucceful repair welding of a treiber roll

Abstract

Presented in this paper is the case of unsuccessfully performed repair welding of the upper treiber roll in the „Topla Valjaonica“ facility within the Železara Smederevo, currently known today as Hesteel ltd. Inadequate and improperly performed welding technology resulted in the occurrence of a large number of cracks, with the possibility of their propagation to the parent material. The upper and lower treiber roll are parts of the installation whose purpose is to fold the rolled strip and then send it to be further machined. The parent material used for the upper treiber roll was the structural steel S235J0. Repair welding was the consequence of damage that occurred during the exploitation of the roll. Shown in the paper are some of the cracks detected on the welded surface of the upper treiber roll. The analysis of the reasons behind the occurrence of these cracks is presented, and machining was recommended for the purpose of removing of these cracks, along with the use of certain NDT methods.