scholarly journals Possibility of Utilization of Gate Geometry to Modify the Mechanical and Structural Properties of Castings on the Al-Si Basis

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3539
Author(s):  
Jan Majernik ◽  
Stefan Gaspar ◽  
Jan Kmec ◽  
Monika Karkova ◽  
Jozef Mascenik
Keyword(s):  
Mechanical Properties ◽  
Permanent Deformation ◽  
Surface Hardness ◽  
Eutectic Structure ◽  
Structural Parameter ◽  
Mutual Correlation ◽  
Metallographic Examination ◽  
Gate Structure ◽  
The Individual ◽  
Die Castings

The mechanical properties of die castings correlate with the inner structure of a casting, distribution of the eutectic phases, and with the content and distribution of porous cavities in the casting volume. This submitted paper deals with the issue of the possibility to influence the basic parameters affecting the quality of castings through structural modifications of the gating system. The structural parameter under assessment is the gate height. In the case of the diverse height of the gate, five sets of castings were produced. The individual sets of castings were subjected to examination of selected mechanical properties, i.e., of permanent deformation and surface hardness. At the same time, the individual sets of castings were subjected to metallographic examination of the eutectic structure of the casting. It was proved that the gate height influences the aforementioned properties of the castings and significantly affects the ratio of the eutectic phases in the volume of the casting. The conclusion describes the mutual correlation between the gate structure, the mechanical properties of the casting, and its structural composition.

scholarly journals Influence of Gating System Parameters of Die-Cast Molds on Properties of Al-Si Castings

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3755
Author(s):  
Štefan Gašpár ◽  
Tomáš Coranič ◽  
Ján Majerník ◽  
Jozef Husár ◽  
Lucia Knapčíková ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Computer Modelling ◽  
Permanent Deformation ◽  
Surface Hardness ◽  
Technological Parameters ◽  
Inlet System ◽  
Die Cast ◽  
Key Factor ◽  
Fine Grained Structure ◽  
Design Solutions

The resulting quality of castings indicates the correlation of the design of the mold inlet system and the setting of technological parameters of casting. In this study, the influence of design solutions of the inlet system in a pressure mold on the properties of Al-Si castings was analyzed by computer modelling and subsequently verified experimentally. In the process of computer simulation, the design solutions of the inlet system, the mode of filling the mold depending on the formation of the casting and the homogeneity of the casting represented by the formation of shrinkages were assessed. In the experimental part, homogeneity was monitored by X-ray analysis by evaluating the integrity of the casting and the presence of pores. Mechanical properties such as permanent deformation and surface hardness of castings were determined experimentally, depending on the height of the inlet notch. The height of the inlet notch has been shown to be a key factor, significantly influencing the properties of the die-cast parts and influencing the speed and filling mode of the mold cavity. At the same time, a significant correlation between porosity and mechanical properties of castings is demonstrated. With the increasing share of porosity, the values of permanent deformation of castings increased. It is shown that the surface hardness of castings does not depend on the integrity of the castings but on the degree of subcooling of the melt in contact with the mold and the formation of a fine-grained structure in the peripheral zones of the casting.

Fracture Analysis on the Input Shaft of Coal Pulverize of Supercritical Unit

2014 ◽  
Vol 1033-1034 ◽  
pp. 1331-1333
Author(s):  
Shuang Liu ◽  
Kai Guo
Keyword(s):  
Mechanical Properties ◽  
Brittle Fracture ◽  
Chemical Elements ◽  
Low Cycle Fatigue ◽  
Surface Hardness ◽  
Fracture Analysis ◽  
Cycle Fatigue ◽  
Metallographic Examination ◽  
Input Shaft ◽  
Macroscopic Examination

The input shaft of coal pulverize reducer happened fracture after 3 months in operation. The metallographic examination, composition of chemical elements, mechanical properties, macroscopic examination and SEM of the fractured shaft were investigated. The result showed the metallographic and composition of chemical elements of input shaft complied with relative technique requirements. The fracture was typical brittle fracture; the fracture mode was low cycle fatigue brittle fracture. As the input shaft of surface was not required for carburization, the surface hardness was low; extension strength and yield strength were below the requests of product quality certificate, the crack source generated in the stressed side of keyway. The position design of keyway was not suitable which accelerated the fracture.

scholarly journals Effect of Lycra Percentages and Loop Length on the Physical and Mechanical Properties of Single Jersey Knitted Fabrics

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Eman Eltahan
Keyword(s):  
Mechanical Properties ◽  
Permanent Deformation ◽  
Physical And Mechanical Properties ◽  
Knitted Fabric ◽  
Loop Length ◽  
Knitted Fabrics ◽  
Fabric Hand ◽  
Knit Fabrics ◽  
The Individual ◽  
Single Jersey

Single jersey knitted fabrics are generally used to make underwear and outerwear such as T-shirts. Knit fabric can more easily deform or stretch by compressing or elongating the individual stitches that form the fabric. Cotton yarns, which are not elastomeric, do not have the ability of recovery to rearrange the stitches. As a consequence, single-knit fabrics may have permanent deformation. To improve the recovery performance of circular single-knit fabrics, it is now a common practice to knit a small amount of spandex fiber or yarn with companion cotton yarn. In this study the physical, dimensional, and mechanical properties of back plaited cotton/spandex single jersey knitted fabrics were investigated and the results are compared with knitted fabrics made from 100% cotton and the effect of spandex percentage was also studied. It was found that as the loop length increases, the wales density was not affected and specific fabric hand and extension increased, but bursting strength and fabric recovery decreased. The presence of Lycra in single jersey knitted fabric increases of course density, fabric thickness, and knitted fabric recovery, while fabric width, fabric porosity, and extension were decreased.

Effect of silver nitrate on some mechanical properties of heat polymerizing acrylic resins

2019 ◽  
Vol 14 (1) ◽  
pp. 110
Author(s):  
Assiss. Prof. Dr. Sabiha Mahdi Mahdi ◽  
Dr. Firas Abd K. Abd K.
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Silver Nitrate ◽  
Surface Hardness ◽  
Mechanical Tests ◽  
Hardness Tester ◽  
Acrylic Resins ◽  
The Difference

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.

Severe plastic deformation of Al-1%Cu Alloy processed by a Simple Cyclic Extrusion Compression technique

2018 ◽  
Vol 1 (1) ◽  
pp. 77-90
Author(s):  
Walaa Abdelaziem ◽  
Atef Hamada ◽  
Mohsen A. Hassan
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Deformation Behavior ◽  
Cast Alloy ◽  
Surface Hardness ◽  
Grain Structure ◽  
Compression Technique ◽  
Cu Alloy ◽  
Cyclic Extrusion Compression

Severe plastic deformation is an effective method for improving the mechanical properties of metallic alloys through promoting the grain structure. In the present work, simple cyclic extrusion compression technique (SCEC) has been developed for producing a fine structure of cast Al-1 wt. % Cu alloy and consequently enhancing the mechanical properties of the studied alloy. It was found that the grain structure was significantly reduced from 1500 µm to 100 µm after two passes of cyclic extrusion. The ultimate tensile strength and elongation to failure of the as-cast alloy were 110 MPa and 12 %, respectively. However, the corresponding mechanical properties of the two pass CEC deformed alloy are 275 MPa and 35%, respectively. These findings ensure that a significant improvement in the grain structure has been achieved. Also, cyclic extrusion deformation increased the surface hardness of the alloy by 49 % after two passes. FE-simulation model was adopted to simulate the deformation behavior of the material during the cyclic extrusion process using DEFORMTM-3D Ver11.0. The FE-results revealed that SCEC technique was able to impose severe plastic strains with the number of passes. The model was able to predict the damage, punch load, back pressure, and deformation behavior.

scholarly journals Analysis of Mechanical Properties and Mechanism of Natural Rubber Waterstop after Aging in Low-Temperature Environment

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2119
Author(s):  
Lin Yu ◽  
Shiman Liu ◽  
Weiwei Yang ◽  
Mengying Liu
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Energy Dispersive Spectrometry ◽  
Permanent Deformation ◽  
Test Chamber ◽  
Accelerate Aging ◽  
Aging Mechanism ◽  
Temperature Environment ◽  
Freezing Test ◽  
Temperature Water

In order to elucidate the aging performance and aging mechanism of a rubber waterstop in low-temperature environments, the rubber waterstops were placed in the freezing test chamber to accelerate aging, and then we tested its tensile strength, elongation, tear strength, compression permanent deformation and hardness at different times. Additionally, the damaged specimens were tested by scanning electron microscope, Fourier transform infrared spectroscopy and energy dispersive spectrometry. The results showed that with the growth of aging time, the mechanical properties of the rubber waterstop are reduced. At the same time, many protrusions appeared on the surface of the rubber waterstop, the C element gradually decreased, and the O element gradually increased. During the period of 72–90 days, the content of the C element in the low-temperature air environment significantly decreased compared with that in low-temperature water, while the content of O element increased significantly.

Effect of N2 Ion Bombardment on Optical and Mechanical Properties of Ultra-High Molecular Weight Polyethylene (UHMWPE)

2013 ◽  
Vol 341 ◽  
pp. 169-180 ◽  
Author(s):  
A.M. Abdul-Kader ◽  
Y.A. El-Gendy ◽  
Awad A. Al-Rashdi ◽  
A.M. Salem
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Ion Beam ◽  
Surface Hardness ◽  
Conjugation Length ◽  
High Fluences ◽  
Pristine Sample ◽  
Optical And Mechanical Properties ◽  
Ultra High Molecular Weight

The effect of ion beam bombardment on the optical and mechanical properties of ultra-high molecular weight polyethylene (UHMWPE) was investigated. UHMWPE polymer samples were bombarded with 150 keV N2ions under vacuum at room temperature to high fluences ranging from 1x1016to 2x1017ions cm-2. The untreated as well as treated samples were investigated by ultraviolet-visible (UV-Vis) spectrophotometer and Vickers micro-hardness techniques. The direct and indirect optical band gap decreased from 2.9 and 1.65 eV for pristine sample to 1.7 and 1 eV for those bombarded with N2ion beam at the highest fluence, respectively. With increasing ion fluence, an increase in the number of carbon atoms per conjugation length, N and number of carbon atoms per cluster, M in a formed cluster were observed. A significant improvement in surface hardness was obtained by increasing the ion fluence.

Heat Treatment Effects on Static and Dynamic Mechanical Properties of Sintered SINT D30 Powder Metal

2013 ◽  
Vol 592-593 ◽  
pp. 643-646 ◽  
Author(s):  
Marko Šori ◽  
Tomaž Verlak ◽  
Srečko Glodež
Keyword(s):  
Mechanical Properties ◽  
Complex Geometry ◽  
Low Cost ◽  
Surface Hardness ◽  
Load Ratio ◽  
Tensile Tests ◽  
Test Machine ◽  
Strain Diagram ◽  
Powder Metal ◽  
Sintered Steel

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.

Effects on the microstructure and mechanical properties of Sn-0.7Cu lead-free solder with the addition of a small amount of magnesium

2016 ◽  
Vol 23 (6) ◽  
pp. 641-647
Author(s):  
Her-Yueh Huang ◽  
Chung-Wei Yang ◽  
Yu-Chang Peng
Keyword(s):  
Mechanical Properties ◽  
Aging Process ◽  
Intermetallic Layer ◽  
Eutectic Structure ◽  
Contact Angles ◽  
Solidification Structure ◽  
Lead Free Solder ◽  
Bulk Alloy ◽  
Scanning Calorimetry ◽  
Free Solder

AbstractThe influence of a small amount of magnesium (only 0.01 wt.%) added to the Sn-0.7Cu solder alloy during the aging process of microstructural evolution is studied along with the mechanical properties of the alloy. The experimental results indicate that the addition of magnesium decreases the tensile strength of the solders but improves their elongation. The solidification structure of eutectic Sn-0.7Cu consists of β-Sn, and the eutectic structure, which has extremely fine intermetallic nodules, Cu6Sn5, is located in the interdendritic region. When the magnesium is added to the Sn-0.7Cu alloy, the Sn dendrites become slightly coarser; in comparison, the melting point of the Sn-0.7Cu-0.01Mg alloy decreased by 2°C for the differential scanning calorimetry results of bulk alloy samples. Sn-0.7Cu-0.01Mg exhibits the lowest contact angles and the widest spreading areas. After aging, the Sn-0.7Cu and Sn-0.7Cu-0.01Mg solders show significant changes in strength, mainly because of the obvious increase in the thickness of the Cu6Sn5 intermetallic layer.

scholarly journals The effects of welding current and purging gas on mechanical properties and microstructure of tungsten inert gas welded aluminum alloy 5083 H116

2018 ◽  
Vol 197 ◽  
pp. 12007 ◽  
Author(s):  
Ekak Novianto ◽  
Priyo Tri Iswanto ◽  
Mudjijana Mudjijana
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Salt Water ◽  
Surface Hardness ◽  
Welding Process ◽  
Welding Current ◽  
Inert Gas ◽  
Aluminum Alloy 5083 ◽  
Welding Sequence ◽  
Weld Current

Aluminum alloy 5083 H116 has an exceptional performance in extreme environments, moderately high strength, outstanding corrosion resistance in salt water and high impact strength at cryogenic temperature. In the present study, Aluminum alloy AA 5083 H116 plates were joined by tungsten inert gas (TIG) process by single and double sided welding. Welding current used was 53 A and 80 A with the addition of purging gas during welding process. The effects on micro structure and mechanical properties like surface hardness and tensile strength of the welded region were studied. The results have shown that optimum current out of the two weld current used is 53 A. Better microstructures, tensile and hardness were found in the welded joint for the weld current 53 A where the tensile obtained in the softened zone was approximately 87% than that of the base metal (BM). With increasing of TIG current, the width of PMZ increased. In addition, the doubled sided welding sequence also produced broader PMZ area.

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