Effect of Microstructural Variation of a Martensitic Stainless Steel on High Temperature Degradation Behavior
Giselly Bandeira Gomes Dias De Lima,
Marcio Roberto Da Rocha
Issue:
Volume 10, Issue 6, November 2021
Pages:
129-133
Received:
17 September 2021
Accepted:
14 October 2021
Published:
23 November 2021
Abstract: Martensitic stainless steels are chromium steels with a small addition of Ni. They have a good combination of mechanical properties and corrosion resistance, due to their Cr content [12]. The degradation processes are present in several industrial equipments and, generate repair or replacement actions in a periodic way. In an attempt to minimize these problems, several studies have been developed with this purpose. However, due to the several variables involved in the process, both in design and equipment operation, there is still a fertile field for an effective understanding of these degradation problems. For example, one can cite the effects that the different microstructures developed in martensitic stainless steels, materials commonly used in severe service conditions, present on the behavior of resistance to oxidation of the material. And, also, the environment in which the material is inserted. In a high-temperature environment, impurities are found, among them, compounds such as vanadium pentoxide, which act vigorously in the progression of the oxidation process. Oxidation tests are necessary to relate the behavior and influence exerted on the oxide layer by grain refinement. Thus, the present work aims to analyze the influence of the microstructure of the martensitic stainless steel AISI 420, with application of different treatments. The behavior of this steel was evaluated under different oxidation conditions, in contact with a solution containing Vanadium Pentoxide, and as a control parameter the mass variation of the samples. Analysis of the microstructures and the corrosion/oxidation products were carried out via Optical Microscopy, Scanning Electron Microscopy. As result it was verified the importance of the microstructure in the material's resistance to the action of degradation by oxidation, and its influence on the oxide layer formation process.
Abstract: Martensitic stainless steels are chromium steels with a small addition of Ni. They have a good combination of mechanical properties and corrosion resistance, due to their Cr content [12]. The degradation processes are present in several industrial equipments and, generate repair or replacement actions in a periodic way. In an attempt to minimize th...
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Experimental Testing and Fabrication of Metal Matrix Composite for Automotive Applications
Alie Wube Damtew,
Raja Thiyagarajan
Issue:
Volume 10, Issue 6, November 2021
Pages:
134-140
Received:
24 November 2021
Accepted:
14 December 2021
Published:
23 November 2021
Abstract: Cold compaction behaviour, hardness, and micro-structural behavior of aluminium–boron carbide composites with variable boron carbide content for several composite systems, including Al-5 percent B4C, Al-10 percent B4C, Al-15 percent B4C, and Al-20 percent B4C, were all evaluated. Powder metallurgy was used to create the particle reinforced composite, with aluminum particles measuring 75 microns and boron carbide particles measuring 150 microns. The compacts were made using a universal testing machine (UTM) with a 60-ton capacity and the appropriate punch and die set assembly. After the green compacts were prepared, they were sintered in an electric furnace at 550°C for 120 minutes. The compacts are then allowed to cool in the furnace to room temperature. Cold compaction and axial pressing were used to study densification tendencies. The link between applied pressure and density, as well as between applied pressure and relative density, was established. The percentage of B4C reinforcement was used to boost the hardness and compressive strength of various composite samples. Scanning electron microscopy (SEM) images were used to investigate microstructural phenomena. The final solution was compared to that of Cam, an existing car component. It's made of a metal matrix composite of Al-SiC. Because the Al-B4C composite has a lower density than the Al-SiC composite, it allows for the most weight reduction in the product. The samples' weights have been reduced, resulting in a higher strength-to-weight ratio. In both cases, the material cost evaluations were substantially identical. It's simple to automate the fabrication process.
Abstract: Cold compaction behaviour, hardness, and micro-structural behavior of aluminium–boron carbide composites with variable boron carbide content for several composite systems, including Al-5 percent B4C, Al-10 percent B4C, Al-15 percent B4C, and Al-20 percent B4C, were all evaluated. Powder metallurgy was used to create the particle reinforced composit...
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