Methods of testing plastics. Mechanical properties determination of charpy impact resistance of rigid plastic and ebonite (charpy impact flexural test)

1977 ◽  
Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4057 ◽  
Author(s):  
Izabela Maria Barszczewska-Rybarek

Material characterization by the determination of relationships between structure and properties at different scales is essential for contemporary material engineering. This review article provides a summary of such studies on dimethacrylate polymer networks. These polymers serve as photocuring organic matrices in the composite dental restorative materials. The polymer network structure was discussed from the perspective of the following three aspects: the chemical structure, molecular structure (characterized by the degree of conversion and crosslink density (chemical as well as physical)), and supramolecular structure (characterized by the microgel agglomerate dimensions). Instrumental techniques and methodologies currently used for the determination of particular structural parameters were summarized. The influence of those parameters as well as the role of hydrogen bonding on basic mechanical properties of dimethacrylate polymer networks were finally demonstrated. Mechanical strength, modulus of elasticity, hardness, and impact resistance were discussed. The issue of the relationship between chemical structure and water sorption was also addressed.


2017 ◽  
Vol 756 ◽  
pp. 52-59 ◽  
Author(s):  
Ľudmila Dulebová ◽  
František Greškovič ◽  
Janusz W. Sikora ◽  
Volodymyr Krasinskyi

The paper deals with the influence of environmental degradation on the change of the mechanical properties of polymer nanocomposites. The tested material was polyamide (PA) filled with nanoclay fillers Cloisite 30B, Cloisite 93A and Cloisite Na + in a volume of 2, 4 and 6 wt%. Test samples were produced by injection molding and were subjected to 540 hours and 1080 hours of UV radiation. The change of mechanical properties of PA6/MMT nanocomposite systems after the ageing in the UV chamber was studied by tensile test and Charpy impact resistance test. Article also compares structure of PA6/MMT nanocomposite.


2013 ◽  
Vol 32 (2) ◽  
pp. 163-169
Author(s):  
Josip Brnic ◽  
Goran Turkalj ◽  
Sanjin Krscanski

AbstractThis paper presents and analyzes the responses of non-alloy structural steel (1.0044) subjected to uniaxial stresses at high temperatures. This research has two important determinants. The first one is determination of stress-strain dependence and the second is monitoring the behavior of materials subjected to a constant stress at constant temperature over time. Experimental results refer to mechanical properties, elastic modulus, total elongations, creep resistance and Charpy V-notch impact energy. Experimental results show that the tensile strength and yield strength of the considered material fall when the temperature rises over 523 K. Significant decrease in value is especially noticeable when the temperature rises over 723 K. In addition, engineering assessment of fracture toughness was made on the basis of Charpy impact energy. It is visible that when temperature raises then impact energy increases very slightly.


2021 ◽  
Vol 8 (5) ◽  
pp. 836-851
Author(s):  
Hiremath Pavan ◽  
◽  
M. C. Gowrishankar ◽  
Shettar Manjunath ◽  
Sharma Sathyashankara ◽  
...  

<abstract> <p>Steel is a versatile metal, got a wide range of applications in all the fields of engineering and technology. Generally, low carbon steels are tough and high alloy carbon steels are hard in nature. Certain applications demand both properties in the same steel. Carburization is one such technique that develops hard and wear resistant surfaces with a soft core. The objective of this work is to study the influence of post carburizing treatment (normalizing) on three grades of steels (EN 3, 20MnCr5, and EN 353). Post carburizing treatments are necessary to overcome the adverse effects of carburization alone. Here carburization was carried out in the propane atmosphere by heating the gas carburizing furnace to 930 ℃ for more than a day. Normalizing was carried out at 870 ℃ for 1 h and cooled in air. Tensile, hardness, Charpy impact tests along with SEM (scanning electron microscopy) and EDAX (energy dispersive X-ray analysis) were conducted to analyze the phase transformation, failure mode analysis in all the samples. Carburized steels displayed the formation of ferrite, pearlite, and sometimes bainite phases in the core and complete coarse pearlite in the case regions, whereas in the post carburized steels, increased amount of ferrite, fine pearlite, and bainite in the core and fine pearlite with traces of bainite in the case region was observed. Normalizing also refines the grain with increased UTS (ultimate tensile strength), hardness, and impact resistance. EN 353 showed higher UTS among the steels with 898 MPa after carburization and 1370 MPa after normalizing treatment. Maximum hardness of 48 HRC was observed in 20MnCr5 and toughness was superior in EN 3 with energy absorbed during test i.e., 8 and 12 J before and after normalizing treatment. Based on the fracture surface analysis, in EN 353 steel, a finer array of dimples with voids and elongated bigger clustered dimples containing ultrafine dimples array are observed in the core and case respectively during carburizing whereas, more density of river pattern and cleavage failure (brittle) are observed in the core and case respectively after post carburizing (normalizing) treatment. There is a reduction in the ductility of the steels after post carburizing treatment. It was observed that normalizing treatment produces superior mechanical properties in the carburized steels by grain refinement and strong microstructures like bainite. Normalizing as post carburizing treatment can be recommended for engineering applications where ductile core and hard surface are of great importance.</p> </abstract>


2021 ◽  
Vol 57 (4) ◽  
pp. 325-332
Author(s):  
Sebastian Aradoaei ◽  
Vasile Bahrin ◽  
Mihaela Aradoaei ◽  
Mirela Alina Constantin ◽  
Lucian Alexandru Constantin ◽  
...  

The study is highlighting the possibility of modeling the properties of composite materials based on recycled polypropylene (PPR), flour feathers(FF), and compatibilizers (C). The composite materials with 10% and 20% feather flour content were mixed and processed with a two-stage extruder having four heating zones between 200-230�C, in order to obtain granules. The granules were injected in various forms to evaluate the properties. The composite materials have been evaluated for determination of melt flow index (1900C; 2.16kg), density, Charpy impact, breaking strength, elongation at break, and the dielectric behavior. The results showed that the introduction of feather flour in the polymer matrix based on PPR leads to decreased flow properties as well as physical and mechanical properties. The solution in solving these deficiencies was to use compatibility agents, that would improve these properties. The physico mechanical properties were analyzed in order to identify a composite with optimal properties for industrial application.


2010 ◽  
Vol 660-661 ◽  
pp. 23-28 ◽  
Author(s):  
G.C. Nascimento ◽  
D.M. Cechinel ◽  
R. Piletti ◽  
Erlon Mendes ◽  
M.M.S. Paula ◽  
...  

The minerals powders are much applied on polymeric materials to better its properties and to promote new applications. The rice husk ash powder - RHS is a mineral compound has been applied on polymeric compounds to increase the stiffness. This work presents studies of different sizes of particles of RHS applied at different concentrations in polypropylene. To study the mechanical properties were applied techniques of Charpy Impact Resistance and Uniaxial Tensile Analysis. The morphology was observed using the optical microscope. The results showed that the CCA may be an alternative in the incorporation of mineral loads in polypropylene, since this is a waste product generated in the production of rice, thus the complete closure of the production cycle of the cereal.


2018 ◽  
Vol 115 (4) ◽  
pp. 407 ◽  
Author(s):  
Annika Eggbauer Vieweg ◽  
Gerald Ressel ◽  
Peter Raninger ◽  
Petri Prevedel ◽  
Stefan Marsoner ◽  
...  

Induction heating processes are of rising interest within the heat treating industry. Using inductive tempering, a lot of production time can be saved compared to a conventional tempering treatment. However, it is not completely understood how fast inductive processes influence the quenched and tempered microstructure and the corresponding mechanical properties. The aim of this work is to highlight differences between inductive and conventional tempering processes and to suggest a possible processing route which results in optimized microstructures, as well as desirable mechanical properties. Therefore, the present work evaluates the influencing factors of high heating rates to tempering temperatures on the microstructure as well as hardness and Charpy impact energy. To this end, after quenching a 50CrMo4 steel three different induction tempering processes are carried out and the resulting properties are subsequently compared to a conventional tempering process. The results indicate that notch impact energy raises with increasing heating rates to tempering when realizing the same hardness of the samples. The positive effect of high heating rate on toughness is traced back to smaller carbide sizes, as well as smaller carbide spacing and more uniform carbide distribution over the sample.


2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    


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