scholarly journals Sheet metal with variable mechanical properties over its thickness

2019 ◽  
Vol 62 (8) ◽  
pp. 587-593
Author(s):  
A. B. Maksimov ◽  
I. P. Shevchenko ◽  
I. S. Erohina
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Rupture Strength ◽  
Strength Properties ◽  
Deformation Resistance ◽  
Strength Characteristics ◽  
Load Application ◽  
Bending Test ◽  
Accelerated Cooling ◽  
The Impact

The influence of one-sided accelerated cooling of A32 plate shipbuilding steel with thickness of 10·10–3 m on structure and mechanical properties was investigated. As a result of such cooling, continuous spectrum of microstructures from ferrite-bainite on the rapidly cooled surface to ferrite-perlite on the opposite surface is formed along the billet thickness. Therefore, over the billet thickness strength properties are reduced from rapidly cooled surface to the opposite one. Thus, the gradient of strength characteristics (hardness, yield strength and rupture strength) along the billet thickness is directed to rapidly cooled surface. For comparative analysis, other batches of billets were subjected to normalization and hardening with high tempering. The analysis of mechanical properties has shown that strength and plastic properties of the samples at unilateral accelerated cooling are at level of heat-strengthened state. Testing on impact strength of the samples with variable distribution of mechanical properties over their thickness has shown that the impact depends on correlation of gradient directions of strength properties and load application. In impact bending test at the temperature of –40 °C, if the direction of load application is opposite to gradient of strength properties, the impact work was more than 300 J (the sample did not collapse). At coincidence of directions of the gradient deformation resistance and load, energy of the blow was 262 J. Thus, if the direction of deformation resistance gradient coincides with the direction of external applied load, then it leads to an increase in plasticity of steel. It is shown that, knowing distribution of strength characteristics over the sample thickness, it is possible to calculate integral values of yield strength and rupture strength of the sample. Value of relative through-thickness elongation increases from the rapidly cooled surface to the opposite one. Integral elongation of the billet is less than the smallest relative through-thickness elongation. With changing thickness strength of the billet during bending, displacement of the neutral deformation line relative to the geometrically average line in the direction of the strength properties gradient is inevitable. The position of neutral line of deformation during bending is proposed to be determined by the value of experimental integral yield strength (rupture strength).

scholarly journals Mechanical Properties of Spruce Wood Extracted from GLT Beams Loaded by Fire

2021 ◽  
Vol 13 (10) ◽  
pp. 5494
Author(s):  
Lucie Kucíková ◽  
Michal Šejnoha ◽  
Tomáš Janda ◽  
Jan Sýkora ◽  
Pavel Padevět ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Cross Section ◽  
Negative Impact ◽  
Tensile Tests ◽  
Thermal Recovery ◽  
Bending Test ◽  
Small Scale ◽  
Spruce Wood ◽  
The Impact

Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual bending strength. A negative impact of high temperature on residual strength has also been observed from simple tensile tests, although limited to a very narrow layer adjacent to the charring front not even exceeding a typically adopted value of the zero-strength layer d0=7 mm. On the contrary, the impact on stiffness is relatively mild supporting the thermal recovery property of wood.

scholarly journals Microstructure and Mechanical Properties of Modern 11%Cr Heat-Resistant Steel Weld Joints

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3430
Author(s):  
Grzegorz Golański ◽  
Jacek Słania ◽  
Marek Sroka ◽  
Paweł Wieczorek ◽  
Michał Urzynicok ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Welded Joints ◽  
Martensitic Steel ◽  
Base Material ◽  
Hardness Measurement ◽  
Power Industry ◽  
Strength Properties ◽  
Typical Structure ◽  
Δ Ferrite ◽  
The Impact

In addition to good high-temperature creep resistance and adequate heat resistance, steels for the power industry must have, among other things, good weldability. Weldability of such steels is one of the criteria determining whether or not the material is suitable for applications in the power industry. Therefore, when materials such as martensitic steel Thor 115 (T115) are introduced into the modern power industry, the quality and properties of welded joints must be assessed. The paper presents the results of metallographic and mechanical investigations of T115 martensitic steel welded joints. The analysis was carried out on joints welded with two filler metals: WCrMo91 (No. 1) and EPRI P87 (No. 2). The scope of the investigations included: microstructural investigations carried out using optical, scanning and transmission electron microscopy and mechanical testing, i.e., Vickers microhardness and hardness measurement, static tensile test and impact test. The macro- and microstructural investigations revealed correct structure of the weld, without welding imperfections. The microstructural investigations of joint No. 1 revealed a typical structure of this type of joint, i.e., the martensitic structure with numerous precipitates, while in joint No. 2, the so-called Nernst’s layers and δ-ferrite patches were observed in the weld fusion zone as well as the heat affected zone (HAZ). The mechanical properties of the test joints met the requirements for the base material. A slight influence of the δ-ferrite patch on the strength properties of joint No. 2 was observed, and its negative effect on the impact energy of HAZ was visible.

Effect of Tempering Time on Microstructure and Mechanical Properties of SA738 Gr.B Steel

2021 ◽  
Vol 1016 ◽  
pp. 1739-1746
Author(s):  
Yan Mei Li ◽  
Shu Zhan Zhang ◽  
Zai Wei Jiang ◽  
Sheng Yu ◽  
Qi Bin Ye ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Yield Strength ◽  
Microstructure Evolution ◽  
Impact Energy ◽  
Nuclear Power ◽  
Microstructure And Mechanical Properties ◽  
The Impact ◽  
Tempering Time

The effect of tempering time on the microstructure and mechanical properties of SA738 Gr.B nuclear power steel was studied using SEM, TEM and thermodynamic software, and its precipitation and microstructure evolution during tempering were clarified. The results showed that SA738 Gr.B nuclear power steel has better comprehensive mechanical properties after tempering at 650 °C for 1h. With the extension of the tempering time, M3C transformed into M23C6 with increasing size, which affected the yield strength and impact energy. When the tempering time is 8h ~ 10h, due to the transformation of M3C to M23C6, the composition of matrix around the carbide changed, causing the temperature of Ac1 dropped, forming twin-martensite which deteriorated the impact toughness of the steel.

scholarly journals Microstructure and mechanical properties of HR6W alloy dedicated for manufacturing of pressure elements in supercritical and ultrasupercritical power units

2019 ◽  
Vol 82 ◽  
pp. 01005 ◽  
Author(s):  
Grzegorz Golański ◽  
Agata Merda ◽  
Adam Zieliński ◽  
Paweł Urbańczyk ◽  
Jacek Słania ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Yield Strength ◽  
Base Alloy ◽  
Strength Properties ◽  
Laves Phase ◽  
Plastic Properties ◽  
The Matrix ◽  
Isothermal Ageing ◽  
Nickel Base

The article presents the results of research on the microstructure and selected mechanical properties of HR6W nickel-base alloy. The test alloy was subjected to isothermal ageing at 700°C and for up to 10000h. The tests of the HR6W microstructure were performed using the scanning electron microscopy (SEM) and the transmission electron microscopy (TEM). The performed microstructural tests of the HR6W alloy showed that in the as-received condition it was characterised by the structure of nickel austenite with numerous primary precipitates of NbC and TiN. Ageing of the investigated alloy contributed to the precipitation of numerous particles of varying morphologies inside the grains and at the grain boundaries, as well as at the boundaries of twins - they were the secondary precipitates of M23C6 and Laves phase. The number of the particles precipitated at the boundaries was so large that they formed the so-called continuous grid of precipitates. Inside the grains, the presence of compound complexes of precipitates was observed. These complexes consisted of the TiN particles, as well as the M23C6 carbides and Laves phase nucleating on them. The tests of the mechanical properties of HR6W alloy showed that in the as-received condition the alloy showed high plastic properties, with relatively low strength properties - in particular, the yield strength. Ageing of the HR6W alloy, as a result of precipitation of numerous particles in the matrix, through the strengthening with the precipitation mechanism, resulted in a considerable growth of the strength properties - inter alia the yield strength by over 60%, with the reduction of the plastic properties - elongation decreased by around 40%. Similar growth in the test alloy was observed for hardness.

Influence Study of Plasticizer Compatibility on Strength Properties of Ethylene-Vinyl Acetate

2018 ◽  
Vol 935 ◽  
pp. 79-83
Author(s):  
A.N. Volotskoy ◽  
Yuriy V. Yurkin ◽  
V.V. Avdonin
Keyword(s):  
Mechanical Properties ◽  
Vinyl Acetate ◽  
Ethylene Vinyl Acetate ◽  
Dynamic Mechanical Properties ◽  
Strength Properties ◽  
Polymer Materials ◽  
Strength Characteristics ◽  
Actual Problem ◽  
Urgent Task ◽  
Wide Range

This research is devoted to the actual problem of the development of damping polymer materials which are effective in a wide range of temperatures and having satisfactory strength characteristics. There are many works devoted to the study of dynamic mechanical properties of filled composites, but most do not take into account the influence of plasticizer on the strength properties of the polymer, as they change its characteristics for the worse. In this respect, the study and comparison of the mechanical properties of the polymer base with the introduction of different types and concentrations of plasticizers is an urgent task. According to the received regularities it was possible to define the type, concentration and boundaries of the polarity of the plasticizer, which reduces the strength characteristics of ethylene-vinyl acetate to a lesser degree.

scholarly journals Data Mining Methods for Prediction of Multi-Component Al-Si Alloy Properties Based on Cooling Curves

2019 ◽  
Vol 28 (12) ◽  
pp. 7431-7444 ◽  
Author(s):  
Krzysztof Regulski ◽  
Dorota Wilk-Kołodziejczyk ◽  
Tomasz Szymczak ◽  
Grzegorz Gumienny ◽  
Zenon Pirowski ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Data Mining ◽  
Strength Properties ◽  
Cooling Curve ◽  
Cooling Curves ◽  
Alloying Additives ◽  
Statistical Relationships ◽  
Alloy Properties ◽  
Short Time ◽  
The Impact

AbstractThe paper concerns the mechanical properties of hypoeutectic Al-Si alloy (silumin) with the addition of Cr, Mo, V and W. Changes in microstructure under the impact of these elements result in a change in the mechanical properties. Crystallization of Al-Si alloys determines grain size reduction, which causes a significant increase in their strength properties. Crystallization subjected to modifications through the influence of alloying additives can be described by the cooling curve run. Statistical relationships between the characteristic values of cooling curves and mechanical properties are investigated with data mining techniques of regression, especially regression trees. Such knowledge could provide an ability of a property prediction on the basis of cooling curves in terms of the benefits of a short time of the curve registration.

High Temperature Mechanical Behavior of Some Advanced Ni3Al

1986 ◽  
Vol 81 ◽  
Author(s):  
S. E. Hsu ◽  
N. N. Hsu ◽  
C. H. Tong ◽  
C. Y. Ma ◽  
S. Y. Lee
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Yield Strength ◽  
Mechanical Behavior ◽  
Single Phase ◽  
Rupture Strength ◽  
Strengthening Mechanisms ◽  
High Temperature Mechanical Properties ◽  
Higher Temperature

AbstractHigh temperature mechanical properties of various Zr and Cr strengthened single phase Ni3Al are investigated, with emphasis on the ability of each element to elevate Tp, the temperature corresponding to the peak yield strength. It is observed that Zr is a very effective strengthener, more so below Tp than above it, while a combination of Cr and Zr is capable of shifting Tp to a higher temperature. The combination results in an effective improvement of the rupture strength of Ni3Al. The strengthening mechanisms of each element will be discussed in this paper.

Mechanical Properties of Fibre-Metal Composites Connected by Means of Bolt Joints

2013 ◽  
Vol 837 ◽  
pp. 296-301
Author(s):  
Sławomir Zolkiewski
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Polyester Resin ◽  
Steel Plate ◽  
Fibrous Composite ◽  
Laminate Plate ◽  
Strength Properties ◽  
Fibre Metal Laminates ◽  
Fibre Metal ◽  
The Impact

The fibre-metal laminates made of a steel plate and fibreglass laminate plate were tested in the special laboratory stands. Epoxy resin and polyester resin were used as matrix to fabricate the composites. The fibre-metal laminates combine advantages of metals and laminates. These materials have very good force versus displacement characteristics and overall mechanical properties. They are very popular and widely applied in technical systems. They can be put to use in connecting materials made of various fabrics, connecting high number layer laminates and most of all connecting metals and laminates. In this paper there are the results of testing fibrous composite materials connected in bolt joints presented. Composite materials reinforced with fiberglass, carbon and aramid fibers are considered. The impact of number of applied bolts in a joint on strength properties was investigated. The connections by means of eight or sixteen bolts were compared. A major problem of modelling the composites is assuming physical and material parameters of the analyzed elements.

scholarly journals Effect of repeated disinfections by microwave energy on the physical and mechanical properties of denture base acrylic resins

2009 ◽  
Vol 20 (2) ◽  
pp. 132-137 ◽  
Author(s):  
Rafael Leonardo Xediek Consani ◽  
Douglas Duenhas de Azevedo ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
Paulo César Saquy
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Flexural Strength ◽  
Physical And Mechanical Properties ◽  
Knoop Hardness ◽  
Microwave Energy ◽  
Bending Test ◽  
Denture Base ◽  
Acrylic Resins ◽  
The Impact

The present study evaluated the effect of repeated simulated microwave disinfection on physical and mechanical properties of Clássico, Onda-Cryl and QC-20 denture base acrylic resins. Aluminum patterns were included in metallic or plastic flasks with dental stone following the traditional packing method. The powder/liquid mixing ratio was established according to the manufacturer's instructions. After water-bath polymerization at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling and finished. Each specimen was immersed in 150 mL of distilled water and underwent 5 disinfection cycles in a microwave oven set at 650 W for 3 min. Non-disinfected and disinfected specimens were subjected to the following tets: Knoop hardness test was performed with 25 g load for 10 s, impact strength test was done using the Charpy system with 40 kpcm, and 3-point bending test (flexural strength) was performed at a crosshead speed of 0.5 mm/min until fracture. Data were analyzed statistically by ANOVA and Tukey's test (α= 0.05%). Repeated simulated microwave disinfections decreased the Knoop hardness of Clássico and Onda-Cryl resins and had no effect on the impact strength of QC-20. The flexural strength was similar for all tested resins.

scholarly journals The effect of rubber on the mechanical properties of epoxy and carbon fiber (Review)

2020 ◽  
Vol 1 (312) ◽  
pp. 11-21
Author(s):  
M. N. Meiirbekov ◽  
◽  
M. B. Ismailov ◽  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Carbon Fiber ◽  
Impact Strength ◽  
Yield Strength ◽  
Strength Properties ◽  
Carboxyl Groups ◽  
Published Data ◽  
Hydroxyl Groups

The paper presents published data on the effect of rubber elastomers on the strength properties of epoxy resin (ES) and carbon fiber. The introduction of 10% rubbers into ES ED-20 leads to an increase in compressive strength by 50%, tensile strength by 51%, impact strength by 133% and elongation by 128%. The optimal content of rubber with carboxyl groups for the OLDEN mixture was 10-12.5%, while the increase in compressive strength was 48%, impact strength - 73% and elongation - 187%. For DER 331 resin, the study was conducted with two hardeners Piperidine and DETA. The best results for Piperidine hardener were obtained on rubber with hydroxyl groups, with its optimal content of 2.5%, impact strength increased by 170%. For the hardener DETA, the best results were obtained on rubber with carboxyl groups at its optimal content of 10%, the increase in impact strength was 66%. When modifying carbon fiber with rubbers, it leads to a significant increase in the yield strength in tension by 42%, the modulus of elasticity in bending by 63%, and with a slight loss of impact strength.

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