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Structural changes of radial forging die surface during service under thermo-mechanical fatigue

Nematzadeh, F ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.msea.2009.07.068
  3. Abstract:
  4. Radial forging is one of the modern open die forging techniques and has a wide application in producing machine parts. During operation at high temperatures, severe temperature change associated with mechanical loads and the resultant wearing of the die surface lead to intense variation in strain on the die surface. Therefore, under this operating condition, thermo-mechanical fatigue (TMF) occurs on the surface of the radial forging die. TMF decreases the life of the die severely. In the present research, different layers were deposited on a 1.2714 steel die by SMAW and GTAW, with a weld wire of UDIMET 520. The microstructure of the radial forging die surface was investigated during welding and service using an optical microscope and scanning electron microscope. The results revealed that, after welding, the structure of the radial forging die surface includes the γ matrix with a homogeneous distribution of fine semi-spherical carbides. The weld structure consisted mostly of columnar dendrites with low grain boundaries. Also, microstructural investigation of the die surface during operation showed that the weld structure of the die surface has remained without any considerable change. Only dendrites were deformed and broken. Moreover, grain boundaries of the dendrites were revealed during service
  5. Keywords:
  6. Thermo-mechanical fatigue ; UDIMET 520 ; Columnar dendrites ; Die surface ; High temperature ; Homogeneous distribution ; Machine parts ; Matrix ; Mechanical loads ; Microstructural investigation ; Open die forging ; Operating condition ; Optical microscopes ; Radial forging ; Structural change ; Temperature changes ; Weld structure ; Weld wires ; Carbides ; Dendrites (metallography) ; Forging machines ; Forgings ; Grain boundaries ; Grain size and shape ; Machinery ; Microscopes ; Microstructure ; Neurons ; Scanning electron microscopy ; Surface structure ; Thermal effects ; Thermomechanical treatment ; Upsetting (forming) ; Welding ; Welds ; Dies
  7. Source: Materials Science and Engineering A ; Volume 527, Issue 1-2 , 2009 , Pages 98-102 ; 09215093 (ISSN)
  8. URL: https://www.sciencedirect.com/science/article/pii/S0921509309008454