Fatigue Assessment of 17-4 PH Stainless Steel Notched Specimens Made by Direct Metal Laser Sintering

Author(s):  
Filippo Berto ◽  
Ali Fatemi ◽  
Nima Shamsaei ◽  
Seyed Mohammad Javad Razavi
Author(s):  
Rupinder Singh ◽  
Rishab ◽  
Jashanpreet S Sidhu

The martensitic 17-4 precipitation-hardenable stainless steel is one of the commercially established materials for structural engineering applications in aircrafts due to its superior mechanical and corrosion resistance properties. The mechanical processing of this alloy through a conventional manufacturing route is critical from the dimensional accuracy (Δ d) viewpoint for development of innovative structural components such as: slat tracks, wing flap tracks, etc. In past two decades, a number of studies have been reported on challenges being faced while conventional processing of 17-4 precipitation-hardenable stainless steel for maintaining uniform thickness of aircraft structural components. However, hitherto little has been reported on direct metal laser sintering of 17-4 precipitation-hardenable stainless steel for development of innovative functional prototypes with uniform surface hardness (HV), Δ d, and surface roughness ( Ra) in aircraft structural engineering. This paper reports the effect of direct metal laser sintering process parameters on HV, Δ d, and Ra for structural components. The results of study suggest that optimized settings of direct metal laser sintering from multifactor optimization viewpoint are laser power 100 W, scanning speed 1400 mm/s, and layer thickness 0.02 mm. The results have been supported with scanning electron microscopy analysis (for metallurgical changes such as porosity (%), HV, grain size, etc.) and international tolerance grades for ensuring assembly fitment.


Author(s):  
Genrik Mordas ◽  
Ada Steponavičiūtė ◽  
Aušra Selskienė ◽  
Jurijus Tretjakovas ◽  
Sergejus Borodinas

Additive manufacturing (AM) is a type of manufacturing technologies whereby the material is added a layer upon layer to produce a 3D object. Produced 3D parts are applied in such industry sectors as space, aviation, automotive, building and has excellent future promises. Ourdays, the commercialy promised technique for metal manufacturing is Direct Metal Laser Sintering (DMLS). Our study concentrated on the investigation of the mechanical properties of produced17-4H (stainless steel) parts using DMLS. The effect of the DMLS process parameters (laser power, scanning speed and energy density) on the ultimate strength, yield strength and Young’s modulus was determined. We showed an evolution of the microstructure. The detected defects were classified. This study allowed to determine the optimal regimes of DMLS for SS 17-4H and describe mechanical properties of the produced parts as well as helped to show future possibilities of DMLS development.


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