US3248926A - Device for determining the shearing strength of the bordering layer of sand molds and cores - Google Patents

Device for determining the shearing strength of the bordering layer of sand molds and cores Download PDF

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Publication number
US3248926A
US3248926A US327341A US32734163A US3248926A US 3248926 A US3248926 A US 3248926A US 327341 A US327341 A US 327341A US 32734163 A US32734163 A US 32734163A US 3248926 A US3248926 A US 3248926A
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United States
Prior art keywords
test body
sand
annular member
shearing
ring
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Expired - Lifetime
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US327341A
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English (en)
Inventor
Szatmari Ferenc
Kern Franz
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Georg Fischer AG
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Georg Fischer AG
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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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces

Definitions

  • the present invention relates to a method of and device for determining the strength of the bordering layer below the surface of unilaterally highly heated compacted foundry or molding sand.
  • the sand and core surfaces of the mold and core wall are very quickly heated by direct contact with liquid metal or by heat radiation therefrom.
  • an object of the present invention to provide a method and an apparatus which will make it possible, in a simple manner, to determine the shearing strength in the border layer when a sand skin is formed.
  • FIGURE 1 illustrates the forming of a test body according to the present invention on a compacting device
  • FIGURE 2 shows an enlarged section of the testing body
  • FIGURE 3 illustrates partly in side view and partly in section a shearing strength testing device and the testing body, as well as a heating source arranged above the testing body and in operative condition;
  • FIGURE 4 is a top view of FIGURE 3 with the heating source moved out of alignment with the testing body.
  • a test body provided at one end with two rings arranged one upon the otheris manufactured in a manner known per se and disclosed, for instance, in German Industrial Standards DIN 52401.
  • any desired compact as it may occur in practice can be produced in the mold or core.
  • the cylindrical inner surfaces of the two rings are provided with a rough surface in order to prevent any accidental slipping of the rings from the testing body.
  • the test body inserted into the hollow cylinder is placed on a support of the shearing stress testing apparatus.
  • This apparatus is composed primarily of three functionally cooperating structural units arranged on a common bottom plate. These three units are: a heating source, a hydraulically operable shearing strength testing device, and a support for receiving the test body.
  • the test body is, by means of a heating source, heated quickly and to a high temperature, and subsequently is immediately subjected to a testing operation by the shearing strength testing apparatus, the ring arranged at the upper end of the testing body being sheared off from the test body.
  • the thickness of the ring being sheared off from the test body corresponds approximately to the thickness of a sand skin as it forms in sand forms and cores under the influence of the casting heat.
  • test body For carrying out the method according to the present invention, first with a tamping 0r compacting device of any standard type, there is prepared a test body from J) foundry sand, the volume, weight and composition of said test body being predetermined.
  • the device shown in the drawing comprises a base 1 having connected thereto a bottom plate 2 with recesses 3 and 4 (see FIG. 2) for receiving a hollow cylinder 9 and two rings 6 and 5. Between ring 6 and hollow cylinder 9 there is provided a slight distance in order to make sure that ring 6, during the shearing test, will not rest against the edge of hollow cylinder 9. Ring 5, resting on ring 6 will, during the shearing test, eliminate the frictional resistance which otherwise, if ring 5 were not provided, would have to be overcome by the sand adhering to one side of ring 6.
  • Rings 5 and 6 are mounted on surface 8 of bottom plate 2, and a predetermined quantity of foundry sand was poured into the inner chamber for producing the test body 11, said inner chamber being confined by surface 8, the recesses for rings 5 and 6, and the inner wall of the hollow cylinder 9.
  • the driver or compacting piston 10 in a manner known per se, three driving strokes are carried out for compacting the loose sand.
  • the compacting piston 10 occupies its upper position, the hollow cylinder 9 together with the now completed test body 11 and with rings 5 and 6 is lifted out of the recesses 3 and 4 of the bottom plate 2, and for further processing is placed with its upper side upon a support 13 firmly connected to a bottom plate 12 (FIG. 3).
  • a short cylindrical body 14 For purposes of connecting the hollow cylinder 9 there is provided a short cylindrical body 14 forming a unit with the support 13. On one side of the body 14 there is provided a groove-shaped recess 15 whereby, when slipping hollow cylinder 9 over the cylindrical body 14, the air will be allowed to escape from the chamber between the cylindrical body 14, the test body 11 and the inner wall of the hollow cylinder 9.
  • the test body 11 is, by means of a suitable heating source, heated up by heat radiation or by heat conduction.
  • the heating unit consists of a base plate 40, a pipe 41 with an adjusting screw 42, a bar 43 vertically displaceable in pipe 41 and tiltable, and a heating body 44 which, provided with a heating plate 45, is suspended on an upper bent portion of bar 43.
  • the heating unit is connected to the bottom plate 12 by means of screws and is so placed that when tilting or moving in the heating body 44, the test body 11 will be completely covered by the heating plate 45.
  • the heating body 44 above the test body is tilted outwardly, and the shearing strength of the test body 11 is measured by means of a suitable, for instance hydraulic, shearing strength testing device.
  • the testing device diagrammatically illustrated in the drawing is connected to a stand 16. Stand 16, in its turn is firmly connected to the bottom plate 12 by means of screws 37.
  • the testing device proper consists of two parts detachable from each other. One of said parts contains the pressure cylinder 31, whereas the other part contains the working cylinder 22.
  • the sleeve 17 containing the working cylinder 22 is provided with a thread 18 which threadedly engages a corresponding threaded bore in stand 16.
  • Piston rod 34 passes through a bore 21 of a closing plate connected to sleeve 17.
  • the end of piston rod 34 has connected thereto a plate which, for better guiding ring 6, is provided with a guiding path 46 (FIG. 4) in conformity with the outer diameter of the ring.
  • a threaded bore arranged coaxially with regard to the working cylinder 22. The threaded bore is engaged by a sleeve 25 with the corresponding thread 23 while a sealing ring or gasket 38 is interposed between sleeve 25 and sleeve 17.
  • Sleeve 25 confines a pressure cylinder 31 which, through a bore 32, communicates with the cylinder 22.
  • a pressure piston 3t Displaceably arranged in cylinder 31 is a pressure piston 3t) which is adapted to be actuated by means of a hand wheel 28 on one end of a spindle 27 having its other end connected to piston 30.
  • Spindle 27 is provided with a thread 29 threadedly engaging the closure plate 26 connected to sleeve 25.
  • the surface of pressure piston 30 is five times greater than the surface of piston 33 in order to be able better to measure by means of a pressure gauge 36 the forces required for shearing the hard crust off the test body 11.
  • the scale of the pressure gauge 36 has been so designed that there can be read on the same the pressure exerted upon ring 6 and also the pressure exerted by the pressure piston 30.
  • sleeve 17 may be replaced by another sleeve confining a larger or smaller diameter cylinder.
  • the method according to the present invention makes it possible, in a simple manner, to ascertain the shearing strength of the bordering layer when a hard crust is formed in the sand.
  • an apparatus for use in connection with a test body made up of foundry sand to be investigated and comprising an annular member confining an end layer of said test body which includes: holding means forming a chamber for receiving and holding said test body while leaving a portion thereof projecting from the holding means disposed in said annular member with the end surface layer thereof exposed, heating means movable selectively into close relationship with said exposed end surface of said test body for subjecting said end surface to sudden heat of at least 1067 F.
  • power operable means operable to engage and move said annular member in its own plane and in a direction lateral to the test body so as to shear off the portion of the test body within said annular member from the remainder of said test body, and force-responsive means operatively connected to said power operable means for measuring the force required for said shearing-off operation.
  • an apparatus for ascertaining the border layer strength below the surface of unilaterally highly heated compacted foundry sand which includes: tubular holding means for receiving therein and holding a test body made up of the foundry sand to be investigated with a portion of the test body projecting upwardly from the tubular holding means, ring meanssurrounding said projecting portion and leaving exposed an end surface of said projecting portion of said test body when the latter is received by said holding means, heating means having a heating surface substantially transverse to the axis of said tubular holding means and movable selectively into substantially axial alignment with said tubular holding means and close to one end thereof above said ring so as to be inheat transfer relation tosaid end surface of said projecting portion of the test body, and power operable means arranged at the level of said ring means and movable transverse to the longitudinal axis of said tubular holding means and operable for moving at least an axial portion of said ring laterally of said holding means for 5 6 shearing-oif the said projecting portion of the test
  • ring means comprises a first ring extending partly into said tubular holding means and thus held stationary thereby, RICHARD QUEISSER, Examine"- and a second ring resting on said first ring and forming DAVID SCHONBERG, Examiner that portion of said ring means Which is moved by said power operable means. 10 I C. GOLDSTEIN, Assistant Examiner.

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  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Biochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Ceramic Engineering (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
US327341A 1962-12-07 1963-12-02 Device for determining the shearing strength of the bordering layer of sand molds and cores Expired - Lifetime US3248926A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1445262A CH402460A (de) 1962-12-07 1962-12-07 Verfahren und Vorrichtung zur Bestimmung der Grenzschicht-Abscherfestigkeit bei der Schalenbildung von oberflächlich hocherhitzten Giessereisandformen und -kernen

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US3248926A true US3248926A (en) 1966-05-03

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US327341A Expired - Lifetime US3248926A (en) 1962-12-07 1963-12-02 Device for determining the shearing strength of the bordering layer of sand molds and cores

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US (1) US3248926A (de)
CH (1) CH402460A (de)
DE (1) DE1473428A1 (de)
GB (1) GB1025007A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3353407A (en) * 1964-08-24 1967-11-21 Dietert Co Harry W Granular material testing apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4312938A1 (de) * 1993-04-21 1994-10-27 Eirich Maschf Gustav Vorrichtung zur Charakterisierung von Gießereiformsand

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2491512A (en) * 1946-05-16 1949-12-20 Meehanite Metal Corp Process for testing molding sand and apparatus therefor
US2660051A (en) * 1951-05-15 1953-11-24 Rock Island Millwork Company Device for testing hot flow

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2491512A (en) * 1946-05-16 1949-12-20 Meehanite Metal Corp Process for testing molding sand and apparatus therefor
US2660051A (en) * 1951-05-15 1953-11-24 Rock Island Millwork Company Device for testing hot flow

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3353407A (en) * 1964-08-24 1967-11-21 Dietert Co Harry W Granular material testing apparatus

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Publication number Publication date
GB1025007A (en) 1966-04-06
CH402460A (de) 1965-11-15
DE1473428A1 (de) 1968-10-31

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