The change in the value of the breaking energy is discussed here for selected steel grades used in building structures after subjecting the samples made of them to episodes of heating in the steady-state heating regime and then cooling in simulated fire conditions. These changes were recorded based on the instrumented Charpy impact tests, in relation to the material initial state. The S355J2+N, 1H18N9T steels and also X2CrNiMoN22-5-3 duplex steel were selected for detailed analysis. The fire conditions were modelled experimentally by heating the samples and then keeping them for a specified time at a constant temperature of: 600 °C (first series) and 800 °C (second series), respectively. Two alternative cooling variants were investigated in the experiment: slow cooling of the samples in the furnace, simulating the natural fire progress, without any external extinguishing action and cooling in water mist simulating an extinguishing action by a fire brigade. The temperature of the tested samples was set at the level of -20 °C and alternatively at the level of +20 °C. The conducted analysis is aimed at assessing the risk of sudden, catastrophic fracture of load-bearing structure made of steel degraded as a result of a fire that occurred previously with different development scenarios.
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http://dx.doi.org/10.3390/ma14143922 | DOI Listing |
Materials (Basel)
January 2025
Department of Machine Design and Manufacturing Engineering, Kielce University of Technology, al. Tysiaclecia Panstwa Polskiego 7, 25-314 Kielce, Poland.
The minimum cutting thickness is a key value in machining processes, as below this value the material will only undergo elastic and plastic deformation without chip removal. Existing measurement methods require time-consuming preparation and complicated procedures. This work focuses on the development of a new, simplified method for determining the minimum cutting thickness (h) using a contact profilometer that can be used in industry.
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January 2025
Key Laboratory of Impact and Safety Engineering (Ningbo University), Ministry of Education, Ningbo 315211, China.
Obtaining reliable dynamic mechanical properties through experiments is essential for developing and validating constitutive models in material selection and structural design. This study introduces a dynamic tensile method using a modified M-type specimen loaded by a split Hopkinson pressure bar (SHPB). A closed M-type specimen was thus employed.
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December 2024
Hydrotechnical Unit, KGHM Polska Miedź S.A., Polkowicka 52, 59-305 Rudna, Poland.
The increasing challenges related to the reliability and durability of steel pipeline infrastructure necessitate a detailed understanding of degradation and failure mechanisms. This study focuses on selective corrosion and erosion as critical factors, analyzing their impact on pipeline integrity using advanced methods, including macroscopic analysis, corrosion testing, microscopic examination, tensile strength testing, and finite element method (FEM) modeling. Selective corrosion in the heat-affected zones (HAZs) of longitudinal welds was identified as the dominant degradation mechanism, with pit depths reaching up to 6 mm, leading to tensile strength reductions of 30%.
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December 2024
Istituto Universitario di Studi Superiori IUSS-Department STS, Scuola Universitaria Superiore Pavia, 27100 Pavia, Italy.
This study evaluates the API 650 design procedure for steel storage tanks, incorporating nonlinear dynamic analysis with large deformation effects. Focusing on seismic vulnerability, the case study examines storage tanks proposed for construction in Naples, Italy, assessing their performance under site-specific seismic conditions. A target spectrum and 20 earthquake records were selected to reflect regional seismic characteristics.
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December 2024
School of Mechanical Engineering and Rail Transit, Changzhou University, Changzhou 213164, China.
Variations in the microstructural morphology with building direction during selective laser melting (SLM) result in the anisotropic mechanical properties of the specimens, while heat treatment effectively reduces this anisotropy. The degree of anisotropy of the material can be assessed by calculating the variance (σ) of the mechanical properties (strength, hardness) at different building directions at different temperatures. In this work, the effects of heat treatment temperatures (450°, 750 °C, and 1050 °C) and building directions (0°, 45°, 60°, and 90°) on the microstructure, hardness, and tensile properties of selective laser melting (SLM) SS316L were investigated.
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