Investigation of the Durability of the Ni3Al-Based Alloy Piercing Plug when Piercing 08Х18Н10Т-Ш Steel Bars

Abstract

The piercing plug with a diameter of the calibrated part of 30 mm for the investigation was prepared from Ni3Al-based cast alloy. The Ni3Al-based alloy piercing plug was tested when piercing 08Х18Н10Т-Ш steel bars by means of the cross-screw piercing mill (CSP-120). The crack was discovered after manufacturing of 15 rough pipes with dimensions of Ø83±0.5хØ38±0.5хL mm and a total weight of 675 kg from 08Х18Н10Т-Ш steel bars with dimensions of Ø85±1х1000±5 mm. It had excluded the possibility of further exploitation of this piercing plug. The cracks and other rolling defects were not detected as a result of the visual measurement control and the ultrasonic inspection of the produced 08Х18Н10Т-Ш steel rough pipes and the analysis of the macrostructure of the samples from these rough pipes. The question of the stability of the Ni3Al-based alloy microstructure when the bars are pierced was considered. Comparison the photographs of the metal sections of the piercing plug before use with the photographs of the metal sections of the piercing plug after use showed that the microstructures consisted of the primary doped compound Ni3Al crystals and the crystallized eutectic around these primary doped compound Ni3Al crystals. The eutectic consisted of the doped intermetallic compound Ni3Al and the Ni-based solid solution. Thus, it is established that the structure of the alloy used as the material of the piercing mandrel is stable when operating under conditions of thermo-mechanical loading.