US3457769A - Testing of foundry sand - Google Patents

Testing of foundry sand Download PDF

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Publication number
US3457769A
US3457769A US527304A US3457769DA US3457769A US 3457769 A US3457769 A US 3457769A US 527304 A US527304 A US 527304A US 3457769D A US3457769D A US 3457769DA US 3457769 A US3457769 A US 3457769A
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United States
Prior art keywords
sand
spalling
testing
foundry
mould
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Expired - Lifetime
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US527304A
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English (en)
Inventor
John Miles Macnair
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Foseco Technik Ltd
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Foseco Technik Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/38—Concrete; Lime; Mortar; Gypsum; Bricks; Ceramics; Glass

Definitions

  • ABSTRACT OF THE DISCLOSURE A method for testing the propensity of a foundry moulding sand to spall which includes compacting a sand sample having a particular predetermined moisture content to a shape having a flat surface, facing the flat surface downward at a preselected distance from a source of radiant heat at a temperature sufiicient to cause spalling in a standard moulding sand under the conditions and determining the time before spalling occurs and the extent thereof.
  • This invention relates to a method of testing foundry sands and more particularly to a method of testing the propensity of a foundry sand to spall in use, giving rise to the phenomenon known as scabbing.
  • a so called green sand moulding mixture comprises natural or synthetic quartz or sand particles held together by a mixture of clay and water.
  • the clay can be either a naturally occurring impurity in the sand as excavated or an added material such as bentonite.
  • the clay and a definite amount of water are dispersed round the sand grains by a milling process and the resulting mixture, which is the moulding material, can be compacted by ramming to enable it to withstand compressive and tensile forces.
  • the moulding mixture After the moulding mixture has been moulded it may be baked to expel most of the water present and enable it to be handled and this mould is then ready to be used in a metal casting process or, alternatively, the mould can be used in its green, i.e., unbaked state.
  • the body of sand tends to shear along this plane so that the heated surface shell of the mould bends and breaks away, i.e., spalls.
  • the phenonomenon is most marked on downwardly-facing horizontal surfaces of the mould interior, these being the areas which are subjected to heat radiated from the surface of the molten metal as it rises within the mould.
  • a method of testing the propensity of a foundry moulding sand to spall which comprises compacting a "ice sample of sand to be tested at a standard moisture content, to a shape having a flat surface and of a thickness greater than any potential thickness of spall, locating the shape with a flat surface facing downwards a preselected distance above a source of radiant heat at a temperature sufficient to cause spalling in a standard foundry moulding sand under the conditions obtaining, and determining the time taken before spalling of the test sample occurs and the extent of spalling in terms of depth and area.
  • a sample of the sand mix to be tested is lightly handpressed onto a pattern plate to a depth of 5 cm. in a small moulding box 1,
  • the pattern plate, onto which the test card is moulded may be either plane or of a suitable design to artifically increase (or diminish) spalling, e.g., a corrugated, grooved or ridged pattern plate.
  • the box 1 is then filled with backing sand, and jolted for 15 seconds.
  • the box is then topped up again and jolted for a further 15 seconds, after which the surplus backing sand is removed and the surface smoothed.
  • a refractory plate 2 is electrically heated to temperature selected in the range l000 0-1500 C. and thermostatically maintained at the selected temperature.
  • the test surface of the moulded sand 3 is inverted and positioned so that an area of 23 cm. square (529 sq. cm.) of its surface, at a distance of 3.8 cm. above the heated plate 2, receives radiation from the plate in a manner similar to that encountered under casting conditions.
  • the time is measured between subjection of the test sample to radiant heat and the time wherein spalling first occurs. If no spalling has occurred at the end of 40 seconds the sample sand can be regarded as satisfactory for most foundry mould purposes. Within this period the longer time it takes for spalling first to occur the more resistant to spalling is the test sand when used in foundry practice. Furthermore, the depth and extent of the spalling provides an additional assessment of the susceptibility of the sand to cause casting defects.
  • the method of the invention closely simulates the conditions which occur in actual practical use of the sand or a sand mould and it is found that the results obtained are consistently reproducible and afford a very sound measure of the propensity of a sand mix to spalling, thus indicating the value of the sand for any particular foundry use.
  • a method of testing the propensity of a foundry moulding sand to spall which comprises compacting a sample of sand to be tested at a standard moisture content, to a shape having a flat surface and of a thickness greater than any potential thickness of spall, locating the shape with a flat surface facing downwards a preselected distance above a source of radiant heat at a temperature suflicient to cause spalling in a standard foundry moulding sand under the conditions obtaining, and determining the time taken before spalling of the test sample occurs and the extent of spalling in terms of depth and area.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Medicinal Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Ceramic Engineering (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Food Science & Technology (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials Using Thermal Means (AREA)
  • Mold Materials And Core Materials (AREA)
  • Sampling And Sample Adjustment (AREA)
  • Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
US527304A 1965-02-17 1966-02-14 Testing of foundry sand Expired - Lifetime US3457769A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB6894/65A GB1088913A (en) 1965-02-17 1965-02-17 Testing of foundry sands

Publications (1)

Publication Number Publication Date
US3457769A true US3457769A (en) 1969-07-29

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Family Applications (1)

Application Number Title Priority Date Filing Date
US527304A Expired - Lifetime US3457769A (en) 1965-02-17 1966-02-14 Testing of foundry sand

Country Status (3)

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US (1) US3457769A (da)
JP (1) JPS5132578B1 (da)
GB (1) GB1088913A (da)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2822035A1 (de) * 1978-05-20 1979-11-22 Leitz Ernst Gmbh Schaltungsanordnung zur kompensation des temperaturkoeffizienten von halbleiterstrecken
GB9314596D0 (en) * 1993-07-14 1993-08-25 Europ Economic Community A method of measuring spalling of a protective surface

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2452613A (en) * 1945-04-24 1948-11-02 Howard F Taylor Method of determining effect of mold conditions on metal castings

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2452613A (en) * 1945-04-24 1948-11-02 Howard F Taylor Method of determining effect of mold conditions on metal castings

Also Published As

Publication number Publication date
JPS5132578B1 (da) 1976-09-13
DE1573502A1 (de) 1970-04-30
GB1088913A (en) 1967-10-25
DE1573502B2 (de) 1973-01-25

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