US2348155A - Mold-facing sand - Google Patents

Description

Patented May 2, 1944 Connor B. Shanley, Kirkwood, Mo.

No Drawing. Application November 30, 1942,

- .Serial No. 467,387

3 Claims. (Cl. 22-189) This invention relates to a certain useful improvement in mold-facing sands.

My invention has for its object, and resides in, the provision of a mold-facing sand characterized by its ability to withstand relatively high temperatures and to enable the economic, facile production of clean, uniform castings weighing up to approximately six thousand pounds.

The present sand, briefly described, comprises as its chief ingredients, elements, or constituents, a preferably sharp or unbonded sand, bentonite, pitch, and sea-coal, in preferably the following approximate proportions, namely, sand, 80%,

V bentonite, 12%. pitch, 4%, and sea-coal, 4%.

Preferably the bentonite, the pitch, and the seacoal are each in the form of a dry powder of.

relatively fine mesh,'while the sand is of a socalled sharp type possessing a high degree of reiractoriness to withstand varying metal temperatures up to approximate y 3000". F. and having a mesh or grain size ranging from 69 to 40 grain fineness according to the metal and thickness of the particular casting.

The sand is first disposed in a muller, and to the sand in the approximate proportions named, and with any selected unit as a base quantity, I add the dry bentonite powder, the dry pitch powder, and the sea-coal dry powder, with a small quantity, say, approximately 3% as a maximum, of water for effecting sand adherence or so-called plasticity during ramming.

'I'he several constituents are'then' thoroughly mixed and mulled from two to five minutes, depending upon the stiffness required in the final product, in which the bentonite functions as a bond, the pitch functions in protecting the casting from sand-cutting, and the sea-coal vents the sand and assists the sand in pulling off the casti s, so that a clean, smooth surface results.

The product may be emciently rammed hard in the mold and poured with hot metal without any preliminarymold -drying and without any resu1ting scabs or'cutting oi' the sand by-the metal, and

enables the production of fine, easily cleaned, and

uniform castings.

The rammed product air-dries very readily, and, if necessary, coal-oil or blacking mixtures with an oilbase may be employed in moistening the mold surface, without any injury or demise to the metalorsand. i

new and The product maybe cheaply manufactured and efllciently fulfills in every respect the object stated.

It should be understood that minor changesin the ingredients or constituents of the facing sand and in their relative proportions and manner of mixing may be made and substituted for those herein set forth without departing from the nature and principle of my invention.

Having thus described my invention, what claim and desire to secure by Letters Patent is:

1. A mold-facing sand having.the characteris-.

tics and properties described and comprising, as its constituents, sand, and bentonite, pitch, and sea-coal in the following approximate proportions, namely, sand bentonite 12%, pitch 4%, and sea-coal 4%, the bentonite, the pitch, and the sea-coal being each in the form of a dry powder or relatively fine mesh and the sand beins oi sharpv type possessing a degree of refractorlness for withstanding metal temperatures up to approximately 3000' F.

2. A mold-facing sand having the characteristics and properties described and comprising, as its constituents. sand, and bentonite, pitch, and sea-coal in the following approximate proportions, namely,sand 80%, bentonite 12%, p tch 4%, and sea-coal 4%, the bentonite, thepitch, and the sea-coal being each in the form of a dry powder of-relatively fine mesh and the sand being of sharp type possessing a degree of refractoriness for withdrawing metal temperatures up to approximately 3000 F; and having a grain size ranging from 69 to 40 grain fineness according to the metal and thickness of the particular casting.

3. A mold-facing sand having the characteristics and properties described and comprising, as its constituents, sand, bentonite, pitch, and seacoal in the following approximate proportions, namely, sand, 80%, bentonite, 12%, pitch, 4%, and sea-coal, 4%, and water, approximately 3% as a maximum, sufiicient for plasticity during ramming, the bentonite, pitch, and sea-coal being in powder form of relatively fine mesh, and the sand being of sharp type possessinga degree of refractoriness for withstanding metal temperatures up to approximately 3000 F.

' CONNOR B. smmnr.