scholarly journals Mechanical and Thermal Influences on Microstructural and Mechanical Properties during Process-Integrated Thermomechanically Controlled Forging of Tempering Steel AISI 4140

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5772
Author(s):  
Bernd-Arno Behrens ◽  
Kai Brunotte ◽  
Tom Petersen ◽  
Julian Diefenbach

Thermomechanical treatment (TMT) describes the effect of thermal and mechanical conditions on the microstructure of materials during processing and offers possible integration in the forging process. TMT materials exhibit a fine-grained microstructure, leading to excellent mechanical properties. In this study, a two-step TMT upsetting process with intermediate cooling is used to demonstrate possibilities for a process-integrated treatment and corresponding properties. A water–air-based cooling system was designed to adjust different phase configurations by varying the target temperature and cooling rate. Four different thermal processing routes and four combinations of applied plastic strains are investigated in standardized mechanical tests and metallographic analyses. The applied TMT results in a finely structured bainitic microstructure of the investigated tempering steel AISI 4140 (42CrMo4) with different characteristics depending on the forming conditions. It can be shown that the demands of the standard (DIN EN ISO 683) in a quenched and tempered state can be fulfilled by means of appropriate forming conditions. The yield strength can be enhanced up to 1174 MPa while elongation at break is about 12.6% and absorbed impact energy reaches 58.5 J without additional heat treatment when the material is formed after rapid cooling.

2009 ◽  
Vol 6 (S1) ◽  
pp. S314-S320 ◽  
Author(s):  
Luciano Dutrey ◽  
Evangelina De Las Heras ◽  
Hernán G. Svoboda ◽  
Pablo A. Corengia

2005 ◽  
Vol 101-102 ◽  
pp. 131-134 ◽  
Author(s):  
Henryk Dybiec ◽  
Paweł Kozak

The paper presents results of mechanical tests and grain structure investigation of aluminium wires obtained by plastic consolidation of aluminium powders produced by atomisation from liquid state. The powders produced by this method could be potentially adopted to obtain ultra fine/nano structured materials by rapid solidification. Conversion of material from powder to bulk state with retaining of powders fine structure and minimizing of porosity are crucial for technological route of sub-micron grained materials production. An influence of condition of plastic consolidation by hot extrusion on mechanical properties of consolidated products is a main target of presented investigation. The standard mechanical properties of extrusion products have been determined and grain structure has been inspected. The results have been compared to extrusion products of conventional bulk aluminium. It has been stated substantial increase of properties and refining of grain structure in materials consolidated from powders.


2020 ◽  
Vol 995 ◽  
pp. 174-179
Author(s):  
Sathyashankara Sharma ◽  
B.M. Gurumurthy ◽  
U. Achutha Kini ◽  
M.C. Gowrishankar ◽  
Y.M. Shivaprakash

The present investigation intended to analyse the mechanical properties of medium carbon low alloy steel (AISI 4140) under dual phase heat treatment condition. Formation of dual phase, ferrite and martensite (F+M) from normalized condition followed by heating in the intercritical temperature range to form different volume fractions of ferrite and martensite alters tensile, hardness and impact strength of medium carbon steel. Effect of alloying elements in dual phase treatment will change the mechanical properties. Tensile strength and hardness of austempered steel shows higher value followed by dual phase condition. Ductility of normalized shows better as compared to as bought and dual phase, but austempered shows almost similar to normalized result. Impact strength of the austempered is excellent followed by dual phase condition. Heat treated specimen microstructures reveal the different phase’s present.


2019 ◽  
Vol 14 (1) ◽  
pp. 110
Author(s):  
Assiss. Prof. Dr. Sabiha Mahdi Mahdi ◽  
Dr. Firas Abd K. Abd K.

Aim: The aimed study was to evaluate the influence of silver nitrate on surfacehardness and tensile strength of acrylic resins.Materials and methods: A total of 60 specimens were made from heat polymerizingresins. Two mechanical tests were utilized (surface hardness and tensile strength)and 4 experimental groups according to the concentration of silver nitrate used.The specimens without the use of silver nitrate were considered as control. Fortensile strength, all specimens were subjected to force till fracture. For surfacehardness, the specimens were tested via a durometer hardness tester. Allspecimens data were analyzed via ANOVA and Tukey tests.Results: The addition of silver nitrate to acrylic resins reduced significantly thetensile strength. Statistically, highly significant differences were found among allgroups (P≤0.001). Also, the difference between control and experimental groupswas highly significant (P≤0.001). For surface hardness, the silver nitrate improvedthe surface hardness of acrylics. Highly significant differences were statisticallyobserved between control and 900 ppm group (P≤0.001); and among all groups(P≤0.001)with exception that no significant differences between control and150ppm; and between 150ppm and 900ppm groups(P>0.05).Conclusion: The addition of silver nitrate to acrylics reduced significantly the tensilestrength and improved slightly the surface hardness.


Author(s):  
Georgel MIHU ◽  
Claudia Veronica UNGUREANU ◽  
Vasile BRIA ◽  
Marina BUNEA ◽  
Rodica CHIHAI PEȚU ◽  
...  

Epoxy resins have been presenting a lot of scientific and technical interests and organic modified epoxy resins have recently receiving a great deal of attention. For obtaining the composite materials with good mechanical proprieties, a large variety of organic modification agents were used. For this study gluten and gelatin had been used as modifying agents thinking that their dispersion inside the polymer could increase the polymer biocompatibility. Equal amounts of the proteins were milled together and the obtained compound was used to form 1 to 5% weight ratios organic agents modified epoxy materials. To highlight the effect of these proteins in epoxy matrix mechanical tests as three-point bending and compression were performed.


Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 293
Author(s):  
José M. Acosta-Cuevas ◽  
José González-García ◽  
Mario García-Ramírez ◽  
Víctor H. Pérez-Luna ◽  
Erick Omar Cisneros-López ◽  
...  

Photopolymerized microparticles are made of biocompatible hydrogels like Polyethylene Glycol Diacrylate (PEGDA) by using microfluidic devices are a good option for encapsulation, transport and retention of biological or toxic agents. Due to the different applications of these microparticles, it is important to investigate the formulation and the mechanical properties of the material of which they are made of. Therefore, in the present study, mechanical tests were carried out to determine the swelling, drying, soluble fraction, compression, cross-linking density (Mc) and mesh size (ξ) properties of different hydrogel formulations. Tests provided sufficient data to select the best formulation for the future generation of microparticles using microfluidic devices. The initial gelation times of the hydrogels formulations were estimated for their use in the photopolymerization process inside a microfluidic device. Obtained results showed a close relationship between the amount of PEGDA used in the hydrogel and its mechanical properties as well as its initial gelation time. Consequently, it is of considerable importance to know the mechanical properties of the hydrogels made in this research for their proper manipulation and application. On the other hand, the initial gelation time is crucial in photopolymerizable hydrogels and their use in continuous systems such as microfluidic devices.


2019 ◽  
Vol 36 ◽  
pp. 112-120 ◽  
Author(s):  
Ömer Üstündağ ◽  
Sergej Gook ◽  
Andrey Gumenyuk ◽  
Michael Rethmeier

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