Abrasion Strength Research Articles

An attempt to simulate structure and realistic images of scratches on rough polymeric surfaces

AbstractNumerical simulation of scratching has been shown to exhibit many advantages in material development and surface design and can provide detailed information associated with the scratch structure. However, the visual appearance of simulated scratches in real‐world scenarios has seldom been studied. This study simulates the structure and visual appearance of scratches on rough polymer surfaces by combining the finite element method (FEM) with computer imaging (CI) techniques. FEM modeling of scratching incorporates a wide range of microgeometries in rough surfaces to ensure that the resulting scratch surfaces contain all features, regardless of whether they are visible to the human eye. Computer graphics produce realistic images of numeric scratch surfaces in real‐world lighting conditions. This method demonstrates the advantages of easily simulating scratches on rough surfaces and assessing both abrasion strength and visual scratch resistance. Scratch tests on commercial polymer surfaces at different scratch forces demonstrate that the method can satisfactorily predict the structures and scales of scratches. The simulated images correlate closely with camera‐acquired photographs in terms of the visual appearance of scratch surfaces, effect of lighting conditions, and dependence of the visual width of scratches on the scratching force, material, pigment, and additive in the material.

STUDY OF BENTONITE USAGE IN ENVIRONMENTALLY FRIENDLY CONCRETE

Production of cement generates a huge amount of carbon dioxide emissions into the environment, utilization of pozzolanic materials in concrete is a better solution for this environmental problem. Several studies are conducted for using of pozzolanic materials such as fly ash, ground granular blast furnace slag, and silica fume as a pozzolanic material in concrete. A few studies were available on using bentonite in concrete. Bentonite is mainly clay contains rich amount of silicain which obeys the pozzolanic properties. The objective of present study is to find out the effectiveness of using bentonite and waste rubber crumb in the design mix of concrete. An experimental investigation is performed on concrete mixtures to study the effect of using bentonite as a partial replacement of cement and conducting an environmentally friendly concrete using crumb rubber in the concrete mixtures as a partial replacement of fine aggregates. Cement is partially replaced by volume (2%, 5%, 10%, 15%, 20%) with Bentonite and fine aggregate is partially replaced (5%, 20%, 25%, 30%, 40%) with crumb rubber. Slump tests were conducted to evaluate the workability of fresh concrete. Compressive strength of cubes at 7days and 28 days, splitting strength and abrasion strength at 28 days are studied and compared with conventional concrete. A part of research work addresses the effect of using bentonite and waste rubber crumb on durability of concrete. For this purpose, specimens were submerged in solution containing 50 g/l of NaOH and H2SO4. Based on the test results, the ideal percentage of mix which shows maximum compressive strength is identified. The results showed that the compressive strength of the concrete was generally increases when bentonite replaced a part of the cement and decreases with the replacement of fine aggregates by the waste crumb rubber. Although the using of bentonite and crumb rubber decreases the compressive strength. The optimal mixture from the laboratory experimental investigation is 5% reduction of cement content and 20% of fine aggregates replacement that exhibited a compressive strength of 30 MPa at 28 days. The test results substantiate the feasibility to develop environmentally friendly concrete using bentonite and crumb rubber in the concrete mixtures. فى هذا البحث ،تم دراسة استخدام البنتونیت کبدیل جزئی للأسمنت ومخلفات المطاط کبدیل جزئى للرکام الناعم فى الخرسانة الصدیقة للبیئة، تم مقارنة نتائج إختبارات قابلیة التشغیل ومقاومة الضغط و مقاومة الشد الغیر مباشر (الانفلاق) ومقاومة البرى والإستدامة بالخرسانة التقلیدیة.أوصت الدراسة بإمکانیة إستخدام البنتونیت حتى 5% کبدیل للأسمنت وإستخدام مخلفات المطاط حتى 20% کبدیل للرکام الناعم فى الخلطات الخرسانیة.

Effect of weave type on abrasive strength of cotton fiber

Abrasion has a strong relationship with the overall performance of fabrics. There are number of factors that have an impact of abrasive strength of textile materials. These include type of fiber, nature of yarn, yarn number, weave structure and type, number of interlacing in warp and weft. Abraded fabrics look bad in appearance and they no longer can be able to give required service for which they are intended to provide. This study aimed at determining the effect of various weave types on abrasive strength of cotton fabric. The fabric was manufactured through ring spinning technique with three weave structures such as plain, twill and satin. Manufactured fabrics were evaluated for their abrasive strength by following ASTM 4966 test standard. These were evaluated at various laundering intervals such as at 0, 5, 10 and 15. The mass loss in percentage of was then calculated. It was concluded that plain weave structure was the most strongest in terms of its abrasive strength followed by twill and satin. Small floats helped to make the fabric hold components yarns together and provide cohesion to the finished product. It is important for the textile manufacturers and fashion designers to look for various weave structures and their impact on products in order to make creative variations to attract their customers. Keywords: Abrasion; Plain; Satin; Twill; Washing Cycles; Weave http://dx.doi.org/10.19045/bspab.2020.90192

INFLUENCE OF SILICA NANOPARTICLES ON THE PROPERTIES OF PAINT-AND-VARNISH COATING MADE OF PERCHLORVINYL ENAMEL

Effect of nanosized silicon on mechanical properties, texture, and structure of a polymer paint-and-varnish coating made of gray KhV-16 enamel based on perchlorovinyl and glyphthalic resins is studied. It is established that the abrasion strength, hardness, and elastic modulus are larger than in the case of the original coating. Various methods are used to analyze the structure of the resulting samples of paint-and-varnish coatings. It is established that the structure changes and the mechanical properties of the coatings improve because of the formation of new structure-forming centers in the composite coating due to the addition of nanosized silica.

Effect of Natural Rubber Compound (NRC)/ Methyl Methacrylate (MMA) Coating on Abrasion and Hardness, Adhesive and Shear Properties for Pavement Surface

The efficiency of the modify natural rubber (NR) combination with methyl methacrylate (MMA) monomer for pavement surface was studied. The modified coating for pavement surface consisted of MMA resin and natural rubber compound (NRC) at the weight ratio of 70:30, 60:40, 50:50, 40:60 and 30:70, respectively. The effect of rubber in MMA was studied in terms of hardness (shore A and pencil tests), adhesive, abrasion and shear strength. The results showed that hardness (shore A) and adhesion of the compound coating slightly decreased with addition of NRC. Abrasion, hardness pencil tests and shear strength notably reduced as decreasing MMA and increasing NRC concentration. The most optimum sample satisfing the pavement surface standard is M7N3 consisting of MMA:NRC of 70:30.

Effect of FLUMAG M flux on strength properties of iron ore pellets

Currently, the most common fluxing additive to pellets is d mite CaCO 3 ·MgCO 3 , in which the content of magnesium oxide can be from 17 to 22 %. But if it is necessary to increase magnesium oxide in pellets, it is necessary to increase the dosage of dolomite, and thus the iron content decreases, which entails a decrease in yield ratio at subsequent processing. One of the fluxes containing magnesium is brucite. Compared with dolomite, magnesium oxide content in pure brucite is more than 3 times higher. The basis of FLUMAG M flux is brucite. The content of magnesium oxide in it is not less than 55 %. The paper presents series of laboratory studies on the effect of FLUMAG M flux dosage on pelletizing ability of the charge and such properties of iron ore pellets as compressive, impact and abrasion strength. We have made the tests on raw and fired pellets with FLUMAG M flux. The comparative analysis of strength properties of the pellets obtained with the use of FLUMAG M and limestone was performed. Content of the binder – bentonite and magnetite concentrate for all experiments remained unchanged. The results of these experiments indicate that FLUMAG M does not interfere with charge pelletizing ability. The strength of raw pellets for discharge and compression with FLUMAG M flux has small deviations from the pellets with the addition of limestone. Roasted pellets with the addition of FLUMAG M flux have higher strength than ones with limestone. The higher difference in strength properties is observed at the flux content of 2 %.

Determination of the relationship between the Los Angeles abrasion values of aggregates and concrete strength using the Response Surface Methodology

The present study aims to determine the relationship between aggregate abrasion strength and concrete strength considering water-to-cement and aggregate-to-cement ratios. For this purpose, concrete mixtures with different water-to-cement ratios (0.38, 0.40, 0.42, 0.45, 0.50, 0.55 and 0.60) were prepared with different aggregate types (basalt, marble, limestone, and natural aggregates). Hardened concrete properties of the prepared specimens were determined. Also, the abrasion tests were performed for each aggregate used in the experiments to determine the Los Angeles abrasion values of the aggregates. Using the experimental data, the compressive strength and splitting tensile strength values of the concrete specimens with dimensionless parameters such as water-to-cement ratio, aggregate-to-cement ratio, and Los Angeles abrasion loss value were analyzed using the Response Surface Methodology. Thus, two new models were developed with a multi-purpose optimization method. The compressive strength and splitting tensile strength can be calculated with high accuracy for different mixture designs with these models using the aggregate abrasion loss value, water-to-cement ratio, and aggregate-to-cement ratio. In conclusion, savings in labor and time, and economic profit are expected by designing a concrete mixture in this way.

Effect of Flumag M Flux on Strength Properties of Iron Ore Pellets

Currently, the most common fluxing additive to pellets is dolomite CaCO3 · MgCO3, in which the magnesium oxide content can form from 17 to 22%. If the magnesium oxide in pellets increases, then it is necessary to increase the dolomite dosage. Thus, the iron content decreases, which entails a decrease in yield ratio at subsequent processing. One of the fluxes containing magnesium is brucite. Compared with dolomite, magnesium oxide content in pure brucite is more than 3 times higher. The basis of Flumag M flux is brucite. The magnesium oxide content in it is not less than 55%. The paper presents a series of laboratory studies on the Flumag M flux dosage effects on the pelletizing ability of the charge and such properties of iron ore pellets as compressive, impact and abrasion strength. We have made the tests on raw and fired pellets with Flumag M flux. The comparative analysis of strength properties of the pellets obtained with the use of Flumag M and limestone was performed. The binder content, bentonite and magnetite concentrate, for all experiments remained unchanged. The experiment results indicate that Flumag M does not interfere with charge pelletizing ability. The strength of raw pellets for discharge and compression with Flumag M flux has small deviations from the pellets with the addition of limestone. Roasted pellets with the addition of Flumag M flux have higher strength than ones with limestone. The higher difference in strength properties is observed at the flux content of 2%.

Öğütülmüş Kolemanit Minerali İkameli Beton Yollardaki Aşınma Kaybının Araştırılması

With the increase in population, the density of the existing roads increases and therefore new roads are needed. However, road construction and maintenance costs are quite high. In addition, the long service life of the road structure is very important for both safety and economic. Concrete roads come to the forefront especially because of their economic and long service life in recent years. Wear from concrete road damages is dangerous for the long service life of the road structure. In this study; The raw milled colemanite mineral was used as a substitute in 1%, 2%, 3%, 4% and 5% by weight of cement. The abrasion resistance of the concrete samples produced was determined by Bohme test and also a relationship between Bohme test results and Schmidt hammer, the non-destructive test method, results was investigated. As a result, it was observed that colemanite substitution increased the wear amount (day 7 and 28), but with increasing hardening age (90th day), the colemanite substitution decreased the amount of wear of concrete samples up to 3%. When the approximate compressive strength obtained from Schmidt hammer was examined, it was found that the effect on the strengths measured on the 7th and 28th days was irregular, and besides on the 90th day the strength value was lower with 5% colemanite substitution compared to the reference. According to the experimental results, the use of colemanite mineral substitution up to 3% was concluded to be effective in increasing abrasion strength and Schmidt hammer (approximate compressive strength) values.

Bainitic Cast Irons with Nanosized Particles

In the present study austempered ductile irons (ADI) with lower bainitic structure are investigated. Nanosized particles (50nm) of titanium carbonitride + titanium nitride TiCN+TiN and titanium nitride TiN are added to the casting volume. The samples microstructure is studied by optical metallography and X-Ray analysis. The influence of the nanosized additives on the kinetics of the bainitic transformation and on the morphology of the bainitic structure is investigated. The abrasive wear testing, hardness measurements and impact strength are carried out. It is established that the presence of nanoadditives in the bainitic cast irons leads to the changes in their microstructure which increases their mechanical characteristics and abrasive wear resistance. The studied nanocomposite materials expand the potential for new ADI applications in the industry.

Estimating the Optimal Mixture Design of Concrete Pavements Using a Numerical Method and Meta-heuristic Algorithms

Designing the optimal mixture proportion of concrete pavements has been a significant concern. Classical methods are not proficient to spot the optimal mixture design, and they may not consider all of the vital characteristics. Hence, in this investigation, a novel method is developed to predict the optimal mixture proportion, which enhances fundamental characteristics of concrete, including flexural strength, abrasion strength, slump, drying shrinkage, and freezing–thawing resistance, and its unit cost. Considering these six objectives make the model NP-hard. Accordingly, four robust algorithms such as interior-point optimizer (IPOPT), genetic algorithm, particle swarm optimization, and differential evolution are used to scrutinize the model and to solve the multi-objective problem. The outcomes of this model reveal that the performance of IPOPT is considerably better than those of heuristic algorithms. Moreover, the performance of mixtures designed by all algorithms is much better than the performance of initial specimens designed by experimental tests. By virtue of multi-objective optimization, the average of abrasion strength, drying shrinkage, freeze and thaw resistance, flexural strength and cost in the introduced model are improved 18%, 12%, 5%, 4%, and 1%, respectively. However, the average of slump deteriorates 9%.

Synthesis of Selective Sorbent LiCl ⋅ 2Al(OH)3 ⋅ nH2O

A synthesis process of selective layered sorbent LiCl ⋅ 2Al(OH)3 ⋅ nH2O from a mixture of LiCl + AlCl3 + NaOH + H2O solutions with the formation of NaCl solutions in the final suspension with a concentration ranging from 0.5 to 4.0 mol/dm3 has been studied. The effect of various factors exerted on the chemical composition of the sorbent in the course of its synthesis has been analyzed. It is shown that the abrasion strength of the sorbent depends on the amount of NaCl impurities therein. Practical recommendations for the synthesis of the sorbent are given.

Strain-Rate-Dependent Deformation Behavior of High-Carbon Steel under Tensile–Compressive Loading

High-carbon low-alloy steels with a dual-phase structure of austenite and martensite are widely used for cutting tools and in mining industries due to their excellent abrasion resistance and strength properties. The aim of this paper is to critically assess the tension–compression asymmetry behavior over a wide range of quasistatic strain rates. Experiments were conducted at four different strain rates (2.56 × 10−4/s to 2.56 × 10−1/s) under uniaxial tensile and compressive loading. The experimental results indicated an increasing trend in the yield strength in tension and compression as the strain rate was increased. It was observed that the influence of the strain rate on the phase transformation behavior had no significant effect on the tensile-loaded specimens. On the other hand, the martensitic transformation was found to be rate dependent in the compression-loaded specimens. Electron backscatter diffraction studies indicated an increase in the grain average misorientation values with an increase in the strain rate. The fracture surface revealed the presence of transgranular and intergranular cracks for the samples deformed at low (2.56 × 10−4/s) and high (2.56 × 10−1/s) strain rates during compressive loading. On the other hand, ridges and cleavage steps were found for the samples deformed under tensile loading. Transmission electron microscopy revealed the formation of dislocation cells and discontinuous blocks of martensite for tensile-loaded specimens, whereas formation of subgrains and a decrease in the lath martensite with an increase in the strain rate were found to be the dominant features for the compressive-loaded specimens.

Dermal Denticles of Three Slowly Swimming Shark Species: Microscopy and Flow Visualization.

Shark skin has for many years inspired engineers to produce biomimetic structures reducing surface drag or acting as an anti-fouling layer. Both effects are presumed to be consequences of the structure of shark skin that is composed of arrays of so-called dermal denticles. However, the understanding of the full functional role of the dermal denticles is still a topic of research. We report optical microscopy and scanning electron microscopy of dermal denticles from three slowly swimming shark species for which the functional role of the dermal denticles is suggested as one of defense (possibly understood as anti-fouling) and/or abrasion strength. The three species are Greenland shark (Somnosius microcephalus), small-spotted catshark (Scyliorhinus canicula) and spiny dogfish (Squalus acanthias). Samples were taken at over 30 different positions on the bodies of the sharks. In addition, we demonstrate that the flow pattern near natural shark skin can be measured by micro-PIV (particle image velocimetry). The microfluidic experiments are complemented by numerical flow simulations. Both visualize unsteady flow, small eddies, and recirculation bubbles behind the natural dermal denticles.

Technical study on the production of blocks with composites of cement-wooden wastes from pallets of Pinus sp

A composite between particles obtained residual pallets of Pinus sp and cement was manufactured. Also, three methods were performance for wood particles: hot water washed, unwashed and unwashed with calcium carbonate (CaCO3). Different concrete-wood particle ratios were tested. Curing time was evaluated with ultrasonic pulse velocity (USV) and density of composites. Water absorption, module of rupture (MOR) in flexion, abrasion strength and resistance to decay by fungi attack were too determined. Results showed that using USV and density, curing occurs within 8 days. Moisture absorption ranges15 and 22% and decreases with decreasing of the amount of particles. MOR ranged from 0.40 a 1.23 MPa and the blocks with unwashed wooden particles and with CaCO3 addition had the greatest significant differences. In abrasion strength, blocks with unwashed wooden particles reported the best results. Finally, it was concluded that mixture with proportion of 60:40 (concrete:wood) and CaCO3 had the best performance and were not attacked by fungi decay.

SANDVIK APM 2730

Abstract Sandvik APM 2730 is a powder metallurgical alloyed hot-isostatic-pressed high-speed tool steel with abrasive wear resistance and high-compressive strength. This datasheet provides information on composition, physical properties, and elasticity. It also includes information on heat treating and machining. Filing Code: TS-763. Producer or source: Sandvik Steel Company.

SANDVIK APM 2723

Abstract Sandvik APM 2723 is a powder metallurgical alloyed hot-isostatic-pressed high-speed tool steel with abrasive wear resistance and high-compressive strength. This datasheet provides information on composition, physical properties, and elasticity. It also includes information on heat treating. Filing Code: TS-758. Producer or source: Sandvik Steel Company.

Estimation of application efficiency of “Flumag M” magnesia flux in agglomeration and BF production.

To decrease viscosity of BF slag and improve its desulfurization ability during hot metal production a magnesia oxide is used, which is introduced into a blast furnace, as a rule, within iron ore sinter, as well as in the form of a fluxing additive. Dolomite, sometimes iron ore materials with increased magnesia content (for example, Kovdor concentrate, raw or roasted Bakal siderite) as well as magnesia-contained wastes, most often BOF slag, are usually used as a main source of magnesia oxide during iron ore sinter production. Brucite, which is widely used abroad, mainly in Japan during iron ore sinter production, is a very prospective magnesia flux. However, brucite was never used in sinter production in Russia. Main parameters and efficiency of its application were obtained under Japan raw materials conditions. However sinter chemical and mineral compositions at Russian and Japanese sinter plants considerably differ. In this connection studies on influence of the magnesia flux “Flumag M”, which is identical by its composition to brucite, on the process parameters of sinter burden sintering and pellets production were carried out. The estimation of application efficiency of “Flumag M” magnesia flux was made during typical sintering of NLMK sinter burden. It was determined, that partial and complete substitution of dolomite by the “Flumag M” magnesia flux in the NLMK sinter burden results in an increase of specific productivity of sintering process by 10–20% (comparative) and the sinter strength by 3–5% (comparative) correspondently. Laboratory experiments on “Flumag M” magnesia flux application, carried out in STI NITU “MISiS”, showed, that raw pellets with magnesia flux additives have higher compressive strength comparing with the pellets having dolomite additives. Impact strength and abrasion strength of roasted pellets is higher, comparing with those with dolomite. Optimal content of “Flumag M” flux in the pellets burden is 2%. The application of “Flumag M” magnesia flux enables to remove burden from the burden and increase strength of roasted pellets.

Utilization of the prepyrolyzed technical hydrolysis lignin as a fuel for iron ore sintering

A promising direction of technical hydrolysis lignin utilization is metallurgical production, primarily iron ore preparation and blast furnace process. A significant potential is concentrated in the sintering process. In order to improve properties of lignin in the role of a fuel, and to remove, with the possibility of trapping, toxic substances, it is necessary to carry out preliminary pyrolysis. The effect of technical hydrolysis lignin of different pyrolization degrees on the iron ore sintering process and properties of the obtained sinter is experimentally studied. Initial lignin was subjected to preliminary heat treatment to the final temperature of 400, 600, 800 and 1000 ºС without air access. Sintering with the participation of pyrolyzed lignin has been carried out via lab-scale sinter pot. After sintering, the sinter strength and the macrostructure have been determined. The chemical composition of the sinter samples has been revealed by X-ray fluorescence analysis.As a result of the experiments, the possibility of replacing 25 % of coke breeze with lignin prepyrolyzed at 800 ºС has been determined. Under these conditions, the main indicators of the sintering process, such as vertical sintering rate, product yield and specific capacity of the lab-scale sinter pot, remain virtually unchanged. There is a slight decrease in the impact strengths and the abrasion strengths of the sinter. However, these figures remain at a technologically acceptable level. It should be noted that when using lignin as a sintering fuel, there is a tendency for some decrease in the iron content of the sinter produced with it. The study of the sinter macrostructure has shown an increase in the pore diameter when the partial replacement of coke breeze with lignin while with the increasing lignin pyrolysis temperature the pore volume increases.The studies has evidence the possibility of solving the urgent environmental issues of technical hydrolysis lignin utilization by applying it in the sintering process with preliminary pyrolization. A promising direction for further research is the development of methods for the preparation of technical hydrolysis lignin for the use in iron ore sintering

An Experimental Investigation on the Abrasion Strength of Aggregate: Elazığ Province Calcareous Aggregate

In order to produce quality concrete in our country which is located in the earthquake zone, it is necessary to ensure that the aggregate to be used is subjected to the necessary abrasion and strength tests and to be used in concrete production after being controlled in accordance with the concrete norms. Due to the geological structure of the country, there are different kinds of aggregates with different properties in and in very large quantities in Turkey. Therefore, it is of great importance to investigate the physical and mechanical properties of aggregates in our country to use them in different fields. The present study aims to determine whether or not this calcareous aggregate, which cannot be stored, is sufficient in terms of abrasion strength. This shows that the strength of the concrete produced by the said aggregate will be high. Thus, both the production of concrete with improved properties is provided and the environmental pollution is prevented. In addition, because it is aimed to use the available resources in the most efficient way, it is thought that evaluating this calcareous aggregate found in nature will contribute to the country’s economy found in nature. In the present study, the abrasion strength of the calcareous aggregate extracted from Elazığ province was investigated. The abrasion resistance of the said aggregate was investigated experimentally by changing the Los Angeles parameters under different conditions. In addition, the microstructural morphology of the existing calcareous aggregate was investigated. In this context, Scanning Electron Microscopy test was conducted using an EDX micro-analyzer. As a result of the tests, it was observed that the aggregate abrasion strength decreased with the increasing numbers of balls and revolutions. It was seen that the abrasion strength of the existing calcareous aggregate was higher than most of the related aggregates in the previous studies and it was found to be suitable for use in concrete.