A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Green sand properties from compactibility control
Green sand processing in most foundries is mainly aimed at delivering sand of controlled compactibility to the molding process. The consequence of targeting a specified compactibility is properties that are largely predictable. They are measured by the usual tests for compactibility, moisture, green and dry strength, permeability, and specimen weight. From these, a variety of parameters can be calculated for comparison of a system sand with new sand mixtures of the same clay content at equal compactibility. Equations and sample calculations are provided. Green strength is limited to the 40 psi characteristic of the sodium bentonite mineral rock deposit. Dry strength is shown to decrease with increase in repetitive mulling time. Repetitive mulling of new sand mixtures ultimately ends with limiting moisture percentage and green compressive strengths for 3.0-12% MB clay levels at compactibility in the 20-60 % range. These properties are related to each other by equations provided in the text. In system sands, the same properties approach but do not reach those of the repetitively mulled new sands. Processing efficiency is presented as the percentage of approach of the system sand properties to those of the new sands. Mulling efficiency deals with comparisons that measure the extent to which the clay is being used, to produce the sand's behavior. A series of questions were posed, which stem from compactibility control. These included sand formulation, green sand property limits, permissible variation of properties, parameters that describe the property variation and link them to sand control, and prediction of the presence or absence of casting defects. Specific examples are provided of calculations and their application to answering these questions. The property of friability as related to sand surface defects confirmed that such defects were indeed predictable from certain parameters. Mold cracks and runouts were also considered. The parameters discussed can provide insight into improvement of the control process. (VDG)
Green sand properties from compactibility control
Green sand processing in most foundries is mainly aimed at delivering sand of controlled compactibility to the molding process. The consequence of targeting a specified compactibility is properties that are largely predictable. They are measured by the usual tests for compactibility, moisture, green and dry strength, permeability, and specimen weight. From these, a variety of parameters can be calculated for comparison of a system sand with new sand mixtures of the same clay content at equal compactibility. Equations and sample calculations are provided. Green strength is limited to the 40 psi characteristic of the sodium bentonite mineral rock deposit. Dry strength is shown to decrease with increase in repetitive mulling time. Repetitive mulling of new sand mixtures ultimately ends with limiting moisture percentage and green compressive strengths for 3.0-12% MB clay levels at compactibility in the 20-60 % range. These properties are related to each other by equations provided in the text. In system sands, the same properties approach but do not reach those of the repetitively mulled new sands. Processing efficiency is presented as the percentage of approach of the system sand properties to those of the new sands. Mulling efficiency deals with comparisons that measure the extent to which the clay is being used, to produce the sand's behavior. A series of questions were posed, which stem from compactibility control. These included sand formulation, green sand property limits, permissible variation of properties, parameters that describe the property variation and link them to sand control, and prediction of the presence or absence of casting defects. Specific examples are provided of calculations and their application to answering these questions. The property of friability as related to sand surface defects confirmed that such defects were indeed predictable from certain parameters. Mold cracks and runouts were also considered. The parameters discussed can provide insight into improvement of the control process. (VDG)
Green sand properties from compactibility control
Bestimmung der Nasssandeigenschaften mit einem Kompaktibilitätstest
Heine, R.W. (author)
2002
11 Seiten, 4 Bilder, 2 Tabellen, 12 Quellen
Conference paper
English
Study of Key Parameters in the Process of Aeolian Sand Compactibility
| British Library Conference Proceedings | 2014
Experimental Investigation of Bridge Grouting Compactibility
| Trans Tech Publications | 2013
Experimental Investigation of Bridge Grouting Compactibility
| British Library Conference Proceedings | 2013
Compactibility and stability of soils and gravels
| Engineering Index Backfile | 1959
Compactibility of soils by means of a pulsator
| British Library Conference Proceedings | 1998