Microscopic Evaluation of a Damaged Press Casing and Analysis of Failure by Finite Element Method

Abstract:

The paper presents an instance of a failure of the casing of a press used to make hexagonal clamps on tubes used in power engineering. The failure occurred during the press operation. The results of microscopic investigations of the cracked area show that the crack was initiated by excessive accumulation of sulfide inclusions with an unfavourable banded structure that formed in the steel. An EDS analysis identified MnS involved in the crack mechanism.Moreover, an FEM simulation of the pressure distribution and an annulus model of axial loading were used to analyse the stress and strain values arising in the press casing under compression. It was found that normal compressive stresses in direction Z were much larger in the region where the crack occurred, which means that the press casing mechanical manufacturing process creates the largest stresses in the fillet radius area. On the other hand, the effect of sulphide inclusions in the material were also considered as a cause of failure.It is concluded that both these factors – equivalent stresses and the high level of sulphide inclusions in the steel structure have an impact on the press casing failure.

• Periodical: Materials Science Forum (Volume 891)
• Pages: 278-283
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.891.278
• Online since: March 2017
• Authors: Janusz Juraszek*, Zbigniew Jurasz
• Keywords: FEM Analysis, Forged Steel, Fracture, Microstructure

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