Papers by Author: Xue Dong Xu

Abstract: In this paper, theoretical and experimental researches were done to find the repeated cracking reason of stuffing box in a super hyper pressure compressor. The mathematical expression of the assembly pressure was deduced in interference fit. From macro and micro perspectives, residual stresses were measured by X-ray diffraction in typical position of stuffing box when the packing box in combination and separation states. Besides, metallography and fracture examinations were carried out. The results showed that the real magnitude of shrink range of the failed stuffing box was only account for 12% of the designed size requirements, however, under this working condition this stress was not sufficient to cause cracking; Unqualified smelting process and tensile stress concentration in tank caused micro crack, which finally results in fracture of the stuffing box under fatigue mode.

Abstract: Comprehensive residual stress of a 1500m3 liquefied petroleum gas spherical vessel was measured and analyzed after many cracks arised. The results show that the general residual stress was at a high level in the field with cracks as well as the field without cracks. Furthermore, the measurements were taken at the same place to evaluate the effect of the heat treatment after this spherical vessel was re-welded and the integral heat treatment was performed. Meanwhile, the measurement to the stress in the vertical direction with X-Ray was finished after a set of special treatments in the outfield.

Abstract: YBa2Cu3O7-δ(YBCO) films with highly biaxial textures were deposited on SrTiO3 single crystal, textured polycrystalline Ag and NiO/Ni substrates using pulsed laser deposition, metal-organic decomposition and ultrasonic spray pyrolysis method. The microstrains in different specimens with strong textures were measured using x-ray diffractometer and were compared each other.