Reclamation of Green Sand Containing Hot-Box Resin Sand and its Application

The green sand containing hot-box resin sand was reclaimed by the process of calcination followed by mechanical reclamation. The reclaimed sands were reused in the hot-box process. The grain size distribution, the shape factor, the clay content and the acid demand value were determined. The results show that the acid demand value of the reclaimed sand is higher than that of the base sand. Compared with the base sand, the grain size of the reclaimed sand is almost no difference. It can also be observed that the tensile strength of the molding sand is influenced by the acid demand value and clay content, but the reclaimed sand can still meet the casting process needs. In addition, the reclaimed green sand is satisfactory for hot-box process.

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Effect of Different Processing on Properties of Silica Sand

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.139-141.528 ◽

2010 ◽

Vol 139-141 ◽

pp. 528-531

Author(s):

Qing Zhou Sun ◽

Rong Fu Xu ◽

Zhong Kui Zhao ◽

Pu Qing Zhang ◽

Wei Liu

Keyword(s):

Grain Size ◽

Tensile Strength ◽

Size Distribution ◽

Grain Size Distribution ◽

Downward Trend ◽

Silica Sand ◽

Test Results ◽

Molding Sand ◽

Physical Chemical ◽

Chemical Attributes

This paper will cover some processing routes along with grading and physical/chemical attributes of silica sand. The silica sand in this experiment was divided into four lots, and each of them was processed by the methods of calcining, scrubbing, mulling or rubbing respectively. The test results show that the sand grains which processed by different processing methods are irregular, the acid demand value of sand is lower than that of the base sand, and the grain size distribution of sand is similar to that of the base sand. However, the SiO2 content of processed sand is increased, the impurities content has a downward trend. Compared with the base sand, it can be found that the tensile strength value of molding sand prepared using the processed sands is higher and the bench life is almost no change.

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Effect of Combined Electromagnetic Fields on Microstructure and Properties of Large-Sized Ingot of 2219 Aluminum Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.993.287 ◽

2020 ◽

Vol 993 ◽

pp. 287-293

Author(s):

Hao Dong Zhao ◽

Zhi Feng Zhang ◽

Yang Qiu ◽

Bao Li ◽

Ming Wei Gao

Keyword(s):

Grain Size ◽

Aluminum Alloy ◽

Size Distribution ◽

Grain Size Distribution ◽

Electromagnetic Fields ◽

Casting Process ◽

Microstructure And Properties ◽

Aluminum Ingot ◽

2219 Aluminum Alloy ◽

Dc Casting

Large-sized 2219 aluminum alloy ingot has wide application prospect in aerospace and military fields. Severe defects, such as coarse grain, the inhomogeneity of structure and macrosegregation occurred in large-sized aluminum ingot produced by normal DC casting. The application of a single magnetic field in DC casting process cannot solve these defects. In this paper, a new method with the combination of electromagnetic fields imposed on bulk melt treatment during DC casting was proposed. And a φ508 mm ingot of 2219 aluminum alloy was prepared in this method. Compared with the normal DC casting, the effect of the combined electromagnetic fields on the microstructure and properties was studied. The experimental results demonstrate that the application of the combined electromagnetic fields significantly refines the grains, and the grain size distribution on the cross section of the ingot tends to be more uniform as well as the mechanical properties are significantly improved. The microstructure and grain size distribution can be significantly affected by different combined electromagnetic fields. It is considered that the appropriate combined electromagnetic fields parameters play an important role in controlling the homogeneity of large-sized ingots.

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Effects of rotational disruption on the evolution of grain size distribution in galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa793 ◽

2020 ◽

Vol 494 (1) ◽

pp. 1058-1070 ◽

Cited By ~ 2

Author(s):

Hiroyuki Hirashita ◽

Thiem Hoang

Keyword(s):

Grain Size ◽

Tensile Strength ◽

Size Distribution ◽

Galaxy Evolution ◽

Grain Size Distribution ◽

Extinction Curve ◽

Short Time Scale ◽

Dust Grains ◽

Grain Production ◽

Dust Temperature

ABSTRACT Interstellar dust grains can be spun up by radiative torques, and the resulting centrifugal force may be strong enough to disrupt large dust grains. We examine the effect of this rotational disruption on the evolution of grain size distribution in galaxies. To this goal, we modify our previous model by assuming that rotational disruption is the major small-grain production mechanism. We find that rotational disruption can have a large influence on the evolution of grain size distribution in the following two aspects especially for composites and grain mantles (with tensile strength ∼107 erg cm −3). First, because of the short time-scale of rotational disruption, the small-grain production occurs even in the early phase of galaxy evolution. Therefore, even though stars produce large grains, the abundance of small grains can be large enough to steepen the extinction curve. Secondly, rotational disruption is important in determining the maximum grain radius, which regulates the steepness of the extinction curve. For compact grains with tensile strength ≳109 erg cm −3, the size evolution is significantly affected by rotational disruption only if the radiation field is as strong as (or the dust temperature is as high as) expected for starburst galaxies. For compact grains, rotational disruption predicts that the maximum grain radius becomes less than 0.2 $\rm{\mu m}$ for galaxies with a dust temperature ≳50 K.

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Geotechnical Aspects of Explosive Compaction

Shock and Vibration ◽

10.1155/2016/6719271 ◽

2016 ◽

Vol 2016 ◽

pp. 1-14 ◽

Cited By ~ 6

Author(s):

Mahdi Shakeran ◽

Abolfazl Eslami ◽

Majid Ahmadpour

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Field Tests ◽

Clay Content ◽

Silty Sand ◽

Fine Content ◽

Explosive Compaction ◽

Ground Modification ◽

Earthquake Effects

Explosive Compaction (EC) is the ground modification technique whereby the energy released from setting off explosives in subsoil inducing artificial earthquake effects, which compact the soil layers. The efficiency of EC predominantly depends on the soil profile, grain size distribution, initial status, and the intensity of energy applied to the soil. In this paper, in order to investigate the geotechnical aspects, which play an important role in performance of EC, a database has been compiled from thirteen-field tests or construction sites around the world, where EC has been successfully applied for modifying soil. This research focuses on evaluation of grain size distribution and initial stability status of deposits besides changes of soil penetration resistance due to EC. Results indicated suitable EC performance for unstable and liquefiable deposits having particle sizes ranging from gravel to silty sand with less than 40% silt content and less than 10% clay content. However, EC is most effective in fine-to-medium sands with a fine content less than 5% and hydraulically deposited with initial relative density ranging from 30% to 60%. Moreover, it has been observed that EC can be an effective method to improve the density, stability, and resistance of the target soils.

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