|
5985 |
|
Wednesday, May 22, 2019, Saal Brüssel 11:00 AM Properties of brazed joints 2 |
|
Thermal fatigue of steel joints brazed with various NiCrSiB filler metals |
|
A. Abramov* / National Research Nuclear University, Germany Boris Kalin / National Research Nuclear University, Russia Oleg Sevryukov/ National Research Nuclear University, Russia Alexander Ivannikov/ National Research Nuclear University, Russia Alexei Suchkov/ National Research Nuclear University, Russia Diana Bachurina/ National Research Nuclear University, Russia Eugene Abramov/ National Research Nuclear University, Russia |
|
Demands on the properties of constructions are constantly being increased and the technology of producing permanent joints is crucial for advancement of the high-tech industry. This investigation focuses on thermal fatigue of austenitic steel joints, brazed with NiCrSiB filler metals. This type of fatigue has nonmechanical origin and arises from the cyclic variation of thermal stresses with temperature changes. For investigation selected temperature range is: from room temperature to 450 °C (low-cycle fatigue). Due to inhomogeneous thermal expansion or compression during thermal fatigue, thermal stresses and deformation arise and lead to microstructural changes in the joint zone. This can have a strong effect on the mechanical characteristics of the joint. Therefore, it is important to investigate the properties of the brazed seam after thermal cycling. In this work samples brazed various filler metals before and after thermocycling were evaluated using various methods. The microstructures were investigated and micro-X-ray spectral analysis of the diffusion zone was carried out using electron microscope. The main regularities of the structure-phase state formation studied using electron backscatter diffraction (EBSD). Standard tests for the tensile strength of the samples were carried out. The result of this research is the prediction of the durability and reliability of brazed steel constructions operating under conditions of low-cycle temperature changes. |