US2283749A

US2283749A - Fine texture casting

Info

Publication number: US2283749A
Application number: US317578A
Authority: US
Inventors: Mcbride Samuel Ross
Original assignee: H L F Co
Current assignee: H L F Co
Priority date: 1940-02-06
Filing date: 1940-02-06
Publication date: 1942-05-19
Anticipated expiration: 1959-05-19

Description

May 19, 1942- v s. R. M BRIDE FINE TEXTURE CASTING Filed Feb 6, 1940 INVENTOR.

I 1 SAMUEL ROSS McBRIDE BY 0%,KW? 0x4 ATTORNEYs Patented May 19, 1942 EEQE FINE TEXTURE CASTING Application February 6, 1940, Serial No. 317,573

11 Claims.

This invention relates to casting, and more particularly casting of metals which are prone to offer difiiculty from tendencies to uneven grain formation in the product; and it is among the objects of the invention to provide procedure and means for handling and setting the molten metal to form products with highly desirable and uniform grain structure and with clear finish.

To the accomplishment ofthe foregoing and related ends, the invention, then, comprises the features hereinafter fully described, and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative however, i

of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing- Fig. l is a vertical sectional view of-a mold in accordance with the invention; Fig. 2 is a transverse section taken on a plane substantially indicated by line IIII, Fig. 1; Figs. 3 and 5 are side elevational views of modifications ;'and Fig. 4 is a transverse section taken on a plane substantially indicated by line IV-IV, Fig. 3.

Referring more particularly to the drawing,

there is shown in Figs. 1 and 2 a mold, in vertically divided

sections

2, 2, which mate together and are held by convenient means, such as a recessed foundation of corresponding size, or by clamps etc., as may be desired. Within is a mold-filling well 5, and one or more mold cavities 6 as desired. The inlet 1 to the filling well vmay be flared to facilitate use with a metal charger. Proceeding from the filling well 5 to the mold cavities are a plurality of vertically spaced openings 9, Ill, etc. And, these expand outwardly and also downwardly to the mold cavities. With the arrangement of a mold-filling well and plurality of vertically spaced openings therefrom to the moldcavities, it becomes possible to simultaneously cast articles of dissimilar crosssection such as could not otherwise be practiced on account of the metal of one size tending to freeze up prematurely before that of the other. The material of the mold sections may be of permanent character, as for instance cast iron, for the casting of certain alloys, or it may be of baked sand or of like character, for relatively high temperature usage, being backed by shell backing 3. At the bottom of the central passageway 5 is a settling cavity I l to collect foreign particles which otherwise might be swept into the mold cavities with rush of the pouring metal. By having a metal bottom piece [5, even where the mold surface is of sand, abrasion of the surface upon which the metal falls isavoided.

The bottom of the mold cavities is formed preferably of metal blocks I6, and where cores are desired these may have core-holding recesses ll whereby a core [3 may be positioned. .A recessed metal block 20 may correspondingly form the topof the mold cavity, and a recess 2| therein similarly may position the upper end of the core. The material of the cores may be metal, as for instance steel, or sandcores may be employed. Where desired, the cores may have a slight taper. By the use of the recessed metal blocks for the core positioning, cores of different sizes can be put into the assembly, at will. By providing the top mold block with a rebate 22 whereby the block may fit into the mold cavity as far as the shoulder, particular accuracy of positioning and durability is assured. The top block further may have a projecting ledge 25 to facilitate lifting off by suitable tongs or other instrument.

In the process of casting, the molten metal is poured in through the inlet 1, and fillsthe set tling chamber l4 and thence overflows through thereby preventing detrimental jet-eifects into the mold. .A particularly efficient distribution is rapidly attained without excessive turbulence. Rapidly welling on up into the mold cavities, metal overflow next takes place through. the openings iii, and then in succession the openings .9; and so on, the number of these in any case depending upon the size and height of the casting.

'As a furtherrefinement, I provide a particular relationship between the dimensions of the opening and the section of the mold cavity. That is, the inlet l3, etc., of the opening .to the mold cavity is of vertical dimension between one-third and one-fourth the diameter of the mold cavity, 5

and the vertical dimension of the opening is also approximately one-half the vertical dimension of the mold wall intervening'between openings. As

a result of .7 the relationship established, it is separated and the cores removed, and on re-assembling, the mold is ready for the next pour.

When very long cores are involved, additional core-adjusting means may be provided, and this may be in the form for instance of a guide 21, Fig. 3, as a ring or partial ring, adjusted by a screw-threaded stem 28 extending therefrom through a bracket 29 attached to the mold shell, and having adjusting nuts 30. The lower end of the core may be centered by the end block 3|.

Gas vent ways are desirably provided between the mold shell sections and the sand liner, such as ducts 33, Fig. 4, within the

shell sections

2a, 2a.

By means of hinges, the mold sections shown in all of the figures may be connected together so as to match accurately and conveniently, and thus hinge members 35 may be secured to the opposed shell sections. For locking the sections at the other side, lugs 31 may be carried by the sections and have a screw-threaded take-up means coacting therewith, and which, for instance, may be a screw-threaded stem 38 extending from one lug through an opening in the other and into a screw-threaded barrel 39 having a turning handle 40.

As a preferred arrangement where casting certain alloys, the core l8a, Fig. 5, is connected to a fluid-operated plunger 42 so as to be withdrawable thereby, the core fitting through the metal bottom block 43, and in casting, when the metal is formed and solidifies sufficiently to stand against collapse, the cast metal is held by the bottom piece 43 while the core is drawn slidingly along the setting metal. This, I find, gives a peculiar skin-effect finish texture.

In all of the molds in accordance with the invention it is seen that there is a non-chilling or sand wall against which the molten metal contacts, but there is a chill block at the bottom. Instead of congealing the molten metal from all sides simultaneously as in the prior art practices, there is here a relationship in which the setting up of the metal is started at the bottom chill block and it can progress up, with the formation of a uniform texture in the casting.

Desirably, where using a metal core, a metal having low oxidizability is preferred, as for instance nickel chromium steels. A slight taper may be given in instances desired, such as oneeighth inch per foot, particularly where relatively long molds are involved.

Bars and hollow shapes may thus be formed in quite wide variety of dimensions, and of metals such as bronzes, copper-lead alloys, and antifriction alloys; and anti-friction castings initially formed as long hollow cylinders by use of cores can, where desired, be cut into a plurality of sections, axial and transverse, providing high uniformity of texture.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

I therefore particularly point out and distinctly claim as my invention:

1. Means for casting metal, comprising an axially sectioned metal shell, sand liner sections therein forming when assembled mold cavities and a mold-filling well therebetween, a settling chamber at the bottom of the filling well, a plurality of vertically spaced openings from said filling well to said mold cavities, said openings expanding outwardly and downwardly to the mold cavities to a substantial extent, whereby jet effects of metal flowing into said cavities are minimized, and at their entrance to the mold cavities having their vertical dimension approximately onehalf that of the intervening wall between openings and being also from one-third to onefourth the diameter dimension of the mold cavities, metal blocks at the ends of said mold cavities including core-centering means, and chill cores between said blocks.

2. Means for casting metal, comprising an axially sectioned shell, sand liner sections therein forming a mold cavity and a mold-filling well alongside, a settling chamber at the bottom of the filling well, a plurality of vertically spaced openings from said filling well to said mold cavity, said openings expanding outwardly and downwardly to the mold cavity to a substantial extent, whereby jet effects of metal flowing into said cavity are minimized, and having their vertical dimension where entering the mold cavity approximately one-half that of the intervening wall dimension between openings and being one-third to one-fourth the diameter dimension of the mold cavity, metal blocks at the ends of said mold cavity including core-centering means, and a chill core between said blocks.

3. Means for casting metal, comprising an axially sectioned shell, sand liner sections therein forming a mold cavity and a mold-filling well alongside, a settling chamber at the bottom of the filling well, a plurality of vertically spaced openings from said filling well to said mold cavity, said openings expanding outwardly and downwardly to the mold cavity to a substantial extent, whereby jet effects of metal flowing into said cavity are minimized, and having a vertical dimension into the mold cavity approximately onehalf that of the dimension of the wall space intervening between openings, and metal blocks at the ends of said mold cavity including core-centering means.

4. Means for casting metal, comprising an axially sectioned metal shell, sand liner sections therein forming a mold cavity and a mold-filling well alongside, a settling chamber at the bottom of the filling well, a plurality of vertically spaced openings from said filling well to said mold cavity, said openings expanding outwardly and downwardly to the mold cavity to a substantial extent, whereby jet effects of metal flowing into said cavity are minimized, metal blocks at the ends of said mold cavity including core-centering means, and a chill core between said blocks.

5. Means for casting metal, comprising an axially sectioned shell, sand liner sections therein forming a mold cavity and a mold-filling well alongside, a settling chamber at the bottom of the filling well, a plurality of vertically spaced openings from said filling Well to said mold cavity, said openings expanding outwardly and downwardly to the mold cavity to a substantial extent, whereby jet effects of metal flowing into said cavity are minimized, and metal blocks at the ends of said mold cavity including core-centering means.

6. Means for casting metal, comprising axially divided sections including shell sections and baked sand sections therein forming a mold cavity, hinge means for holding the sections, a taper core, core-centering means including a metal chill block in the bottom of the mold, and a plunger for moving said core through said block.

7, Means for casting metal, comprising axially metal chill block in the bottom of the mold hav- 7 ing the same outer perimeter as that of the molten metal positioning against it in the mold cavity, and vent-ways between the sand sections and, shell.

9. Means for casting metal, comprising axially divided sections forming a mold cavity and a mold-filling well alongside, a settling chamber at the bottom of the filling well, and a plurality of vertically spaced openings from said filling well to said mold cavity, said openings expanding outwardly and downwardly to the mold cavity to a substantial extent, whereby jet effects of metal flowing into said cavity are minimized.

10. A process of casting, comprising flowing the fluid metal through a vertically extending filling zone, settling out solid particles therein, passing the fluid metal thence laterally through expansion openings in progressively higher succession into a solidifying cavity to contact with sand side Walls and central and end metal chill walls.

11. Means for casting metal comprising axially divided sections, a mold cavity and a mold-filling well alongside, and a plurality of vertically spaced openings from said filling well to said mold cavity, the transverse and vertical dimensions of said openings being greater at the mold cavity than at the filling well, whereby jet effects of metal flowing into said cavity are minimized.

SAMUEL ROSS MCBRIDE.