Neutron Radiographic Study of the Effect of Heat-Driven Water Transport on the Tensile Strength of Bentonite-Bonded Moulding Sand
Neutron Radiographic Study of the Effect of Heat-Driven Water Transport on the Tensile Strength of Bentonite-Bonded Moulding Sand
复制标题
热驱动水传输对膨润土结型砂抗拉强度影响的中子射线研究
DOI：
10.1007/s11242-017-0968-z
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发表时间：
2018
影响因子：
2.7
通讯作者：
Schmahl W.W.
中科院分区：
文献类型：
--
作者：
Schiebel K;Jordan G;Kaestner A;Schillinger B;Boehnke S;Schmahl W.W.
湿拉伸试验是评估膨润土粘结型砂稳定性的常用方法。对于湿拉伸测试，首先从上方加热样本，以模拟铸造过程引起的热驱动水分传输。然后，施加拉伸应力直到断裂。在这项研究中，中子射线照相成像施加到型砂在原位加热和湿拉伸试验，以调查水运动学的抗拉强度的影响。中子射线照相允许破裂面的本地化和定量测定的局部水含量与亚毫米分辨率。定量的温度在断裂平面和试样内的热运动学是通过温度测量原位和非原位。通过这种方法，首次获得了湿抗拉强度与型砂在断裂面处的特定条件相关的实验数据。进行了一系列不同初始砂含水率的试验。结果表明，砂剖面内的最弱位置可以被精确定位在蒸发和冷凝区之间的界面处（即在100 C等温线处），在该界面处，水开始蒸发并且连接砂粒的水桥坍塌。如果破裂面处的局部水含量在5重量%和9重量%之间，则该最弱位置具有最大强度。水的减少导致湿拉伸强度的大幅下降。更多的水需要高于5重量%的初始水含量，这导致未加热砂的抗拉强度降低。
Wet tensile testing is a common method to assess the stability of bentonite-bonded moulding sands. For wet tensile testing, a specimen is first heated from above in order to simulate heat-driven moisture transport induced by the casting process. Then, tensile stress is applied until rupture. In this study, neutron radiography imaging was applied to moulding sands in situ during heating and wet tensile testing in order to investigate the effects of water kinematics on the tensile strength. Neutron radiography allowed the localization of the rupture plane and the quantitative determination of the local water content with sub-mm resolution. Quantification of the temperature at the rupture plane and of the heat kinematics within the specimen was accomplished by temperature measurements both in situ and ex situ. In this way, experimental data correlating the wet tensile strength with the specific conditions of moulding sands at the rupture plane were obtained for the first time. Series of experiments with different initial sand moisture contents were conducted. The results show that the weakest location within a sand profile can be pinpointed at the interface between evaporation and condensation zone (i.e. at the 100C isotherm), where water vaporization starts and the water bridges connecting the sand grains collapse. This weakest location has maximum strength, if the local water content at the rupture plane is between 5 and 9 wt.%. Less water leads to a strong decrease of wet tensile strength. More water requires an initial water content above 5 wt.%, which leads to a decrease of the tensile strength of the unheated sand.
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DOI：
10.1016/j.nima.2011.08.022
发表时间：
2011-12-11
影响因子：
1.4
作者：
Kaestner, A. P.;Hartmann, S.;Lehmann, E. H.
通讯作者：
Lehmann, E. H.
用于伊本比伦煤矿液压密封的高密度双峰膨润土混合物
影响因子：
1.5
作者：
F. Wolters;W. Baille;K. Emmerich;Evan Schmidt;C. Wolters;F. Königer;J. Kunz;V. Krase;M. Schellhorn
通讯作者：
M. Schellhorn
DOI：
--
发表时间：
2006
期刊：
影响因子：
--
作者：
R. Hassanein
通讯作者：
R. Hassanein
DOI：
--
发表时间：
2013
期刊：
影响因子：
--
作者：
̆. IvANVANICEḰ
通讯作者：
̆. IvANVANICEḰ
通过中子射线照相可视化脱水期间和脱水后石膏板中的水分释放和迁移
DOI：
--
发表时间：
2013
期刊：
影响因子：
--
作者：
M. Sedighi;K. G. Wakili;M. Koebel;E. Hugi;S. Carl;E. Lehmann
通讯作者：
E. Lehmann