New Technologies Development and Equipment for Local Shape-Forming of the Complicated Parts Made of Heat-Resistant Alloys under Superplastic Deformation Conditions

2016 ◽  
Vol 838-839 ◽  
pp. 615-620 ◽  
Author(s):  
Farid Utyashev ◽  
Radik Mulyukov ◽  
Rafael Sukhorukov ◽  
Vener Valitov

The results of development of new resource-saving technologies of local shape-forming under superplastic deformation conditions (SP) by means of roll-forming and rotary swaging are presented. These technologies are efficient for fabrication of discs, shells, rings up to 800 mm in diameter, as well as hollow shafts made of heat-resistant nickel-, titanium-and iron-based alloys that are used in aircraft engines and ground power installations. In particular, to implement innovative technologies a universal SRZhD-800 roll-forming mill has been developed for discs roll-forming made of heat-resistant alloys under SP. An efficiency of using of semi-finished products with prepared ultrafine grained (UFG) structure for generating precise complex geometry profile parts both homogeneous and regulated structure that changing in the radial direction of the disc and for obtaining high mechanical properties that are optimized taking operational conditions into account is proved. The technological process of rotary swaging under SP conditions has been developed for fabrication parts made of high alloy heat-resistant alloys using demountable mandrels. This method allows to obtain precise complex geometry profile parts such as disc with a thin cone flange which is characterized by homogeneous structure and high mechanical properties.

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2239
Author(s):  
Nicholas Rodriguez ◽  
Samantha Ruelas ◽  
Jean-Baptiste Forien ◽  
Nikola Dudukovic ◽  
Josh DeOtte ◽  
...  

Recent advances in additive manufacturing, specifically direct ink writing (DIW) and ink-jetting, have enabled the production of elastomeric silicone parts with deterministic control over the structure, shape, and mechanical properties. These new technologies offer rapid prototyping advantages and find applications in various fields, including biomedical devices, prosthetics, metamaterials, and soft robotics. Stereolithography (SLA) is a complementary approach with the ability to print with finer features and potentially higher throughput. However, all high-performance silicone elastomers are composites of polysiloxane networks reinforced with particulate filler, and consequently, silicone resins tend to have high viscosities (gel- or paste-like), which complicates or completely inhibits the layer-by-layer recoating process central to most SLA technologies. Herein, the design and build of a digital light projection SLA printer suitable for handling high-viscosity resins is demonstrated. Further, a series of UV-curable silicone resins with thiol-ene crosslinking and reinforced by a combination of fumed silica and MQ resins are also described. The resulting silicone elastomers are shown to have tunable mechanical properties, with 100–350% elongation and ultimate tensile strength from 1 to 2.5 MPa. Three-dimensional printed features of 0.4 mm were achieved, and complexity is demonstrated by octet-truss lattices that display negative stiffness.


Author(s):  
Dhia Charni ◽  
Svetlana Ortmann-Ishkina ◽  
Marius Herrmann ◽  
Christian Schenck ◽  
Jérémy Epp

AbstractThe radial infeed rotary swaging is widely used as a diameter reduction forming process of axisymmetric workpieces, improving the mechanical properties with excellent near net shape forming. In the present study, rotary swaging experiments with different parameter setups were performed on steel tubes and bars under different material states and several resulting property modifications were investigated such as stress-strain curve, hardness, fatigue strength and surface residual stresses. The results show a significant work hardening induced by the rotary swaging process and an improvement in the static and dynamic mechanical properties was observed. Furthermore, the hardness distribution was homogenous in the cross section of the rotary swaged workpieces. Moreover, depending on the process conditions, different residual stresses distribution were generated along the surface.


1971 ◽  
Vol 3 (8) ◽  
pp. 997-999
Author(s):  
G. V. Kulygin ◽  
V. A. Bespyatyi ◽  
L. I. Tuchinskii ◽  
V. A. Samgin ◽  
N. N. Pis'mennyi

2013 ◽  
Vol 592-593 ◽  
pp. 643-646 ◽  
Author(s):  
Marko Šori ◽  
Tomaž Verlak ◽  
Srečko Glodež

Low cost, low material waste and good accuracy in components with complex geometry are the main reasons for powder metallurgy to be considered as a promising manufacturing process for the future. Like wrought steel, sintered steel can also be heat treated to increase surface hardness and to improve strength. This paper compares mechanical properties of the hardened sintered steel with the sintered steel of the same powder metal SINT D30. Firstly, the static strength of both samples is determined by quasi-static tensile tests. Results are compared in stress strain diagram and they show that the tensile strength of the hardened sintered steel SINT D30 can surpass 700 MPa. The main focus of this study is however fatigue behaviour of the sintered steel. Both sets of samples are tested on a pulsating test machine with the load ratio of R = 0. The first sample is subjected to a load that corresponds to 90 % of the yield strength and is then gradually lowered to achieve one million stress cycles without breakage. Obtained results are then presented as Wöhler curves and compared in S-N diagram.


2007 ◽  
Vol 49 (6) ◽  
pp. 702-707 ◽  
Author(s):  
A. V. Okotrub ◽  
N. F. Yudanov ◽  
V. M. Aleksashin ◽  
L. G. Bulusheva ◽  
O. A. Komarova ◽  
...  

2015 ◽  
Vol 662 ◽  
pp. 115-118 ◽  
Author(s):  
Zdeněk Česánek ◽  
Jan Schubert ◽  
Šárka Houdková ◽  
Olga Bláhová ◽  
Michaela Prantnerová

Coating properties determine its behavior in operation. The simulation of future operational conditions is therefore the best quality test. The evaluation during operation is usually not possible to perform, and the coatings are therefore frequently characterized by their physical or mechanical properties. This text deals with the high temperature corrosion of HVOF sprayed Stellite 6 coating and with changes of its local mechanical properties before and after the corrosion testing. High temperature corrosion is defined as a corrosion in the presence of molten salts. In this case, the mixture of salts in composition of 59% Na2(SO)4 with 34.5% KCl and 6.5% NaCl was used. Two exposure temperatures 525 °C and 575 °C were selected and the tests for both temperatures were performed in the time interval of 168h in the autoclave. The coating with salt mixture layer was analyzed using scanning electron microscopy and nanoindentation. The high temperature resistance of Stellite 6 coating was evaluated according to the changes in the coating surface and by the occurrence of individual phases formed on the coating surface during the test. Generally, it can be said that the Stellite 6 alloys deposited by HVOF technology show selective oxidation under the salt film. This fact was also proved in this study. Furthermore, the nanoindentation measurements of Stellite 6 coating were performed before and after the corrosion testing. These measurements were used to evaluate the change of local mechanical coating properties.


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