US1387291A

US1387291A - Method and means tor billet-casting

Info

Publication number: US1387291A
Authority: US
Publication date: 1921-08-09
Anticipated expiration: 1938-08-09

Description

C. S. MORSE.

METHOD AND MEANS FOR. BILLET CASTING.

APPLICATION FILED JUNE 8, I920.

1,387,29 1 v Patented Aug. 9, 1921.

//v YEN TOR C fcczrles 8'. Mo rse BY H/S A TTORNEY.

UNITED STATES PATENT OFFICE.

CHARLES S. MORSE, OF ROLAND PARK, MARYLAND, ASSIG-NOR TO BALTIMORE TUBE COMPANY, INCORPORATED, A CORPORATION OF VIRGINIA.

METHOD AND MEANS FOR BILLET-CASTING.

Specification of Letters Patent.

Application filed June 8, 1920. Serial No. 387,348.

To all whom it may concern:

Be it known that I, CHARLES S. MORSE, a citizen of the United States, residing at B0- land Park, in the county of Baltimore, State of Maryland, have invented a new and useful Method and Means for Billet-Casting, of which the following is a specification.

My invention relates to hollow billet casting. The object is to provide method and means for casting hollow billets for metal working.

The invention comprises improved method and means for forming or casting a hollow billet, for example in form most desirable for tube making, at minimum expense of labor and material, and with a minimum 0 defects or imperfections.

The invention is especially adapted for metals and metal alloys of copper, brass and the like, but is applicable also to other metals.

The method now generally employed of casting hollow billets of the alloys above mentioned, is to use a core of yielding mate rial, such as a combination of sand and other substance, so that, as the metal casting cools and contracts, the core will yield sufiiciently to permit such contraction, without cracking or other injury to the casting; This practice has many disadvantages; for example, this core is difficult and expensive to make and is easily damaged, which results in many defective castings.

In accordance with the present invention the casting is made about a rigid metallic, perfectly formed core, which may be used many times without injury thereto, and is as indestructible as the iron mold itself.

The following method is provided for allowing the contraction of the casting without injury thereto.

The amount of contraction of the molten metal forming the casting, as it cools sufficiently to permit the withdrawal of the core, is calculated, having regard to the mass or volume of metal in the casting and to the composition of the alloy; and the core is so tapered and is withdrawn at a rate of speed corresponding to or compensating for the degree of contraction. That is to say, the larger end of the core is the first part withdrawn from the casting, so that the part of the core within the casting becomes smaller and smaller in cross-section as the casting is poured and contracts, thus permitting the natural contraction of the casting without injury thereto, and the inner surface of the casting is maintained perfectly smooth and without blemish.

It should also be noted that when the molten metal comes into contact with the core, which is comparatively cool, the engaging surface of the casting hardens sufficiently to hold the body of the casting until it solidifies. This permits of a slight leeway in withdrawing the core.

The following factors therefore enter into a successful practice of my method. 1. The volume of metal forming the casting.

2. The composition of the alloy.

These two factors determine the amount or coefficient of shrinkage or contraction in diameter of the inner wall of the casting.

3. The taper of the core.

4. The speed of withdrawal of the core:

These two factors are co-related with the amount of said contraction. That is to say, the degree of taper of the core and the speed of its withdrawal are dependent, in their calculation, upon said degree or coeflicient of contraction of the metal of the casting.

Referring to the drawings, which illustrate merely by way of example, suitable means for effecting my invention Figure 1 is a view in longitudinal section, showing the parts in position at the beginning of the casting operation.

Fig. 2 is a similar view with the core partially withdrawn.

Fig. 3 is a longitudinal section of the mold element with the billet or casting now ready, to be ejected.

Similar numerals refer to similar parts throughout the several views.

The mold element 7 is shown mountedon trunnions 8, adapted to be supported by any suitable means. The tapered core 9 is movably supported therein. The mold element? is provided at the top with the removable pouring funnel 10, and at the bottom with the removable block 12, locked in place by the bolt 13. I Y

The core 9 is mounted on or disengageably secured to the rod 14 connected with a piston or plunger 15 operating in the hydraulic cylinder 16. This cylinder is provided with the usual two-way regulating Patented Aug. 9,1921.

valve 17 or other suitable means for controlling the speed and direction of movement of the plunger 15 and core 9, as required.

In operation, the metal is poured through funnel 10 into the space 11, between mold 7 and core 9, and the core is withdrawn from the mold by operating the plunger 15, at a speed fixed as above described. The core is made longer than the mold, so that the entire casting is poured and completed before the top of the core drops below the top of the mold. After the core has been withdrawn entirely from the mold 7, and the casting has sufficiently cooled, the funnel 10 and block 12 are removed from the mold element 7, and the casting is then ejected therefrom.

The core is preferably permitted to cool before it is again used, in order that the molten metal, when it comes in contact with the core, will harden, as to its contacting or inner surface, sufficiently to hold the body of the casting after the core is withdrawn therefrom, and until the body of the casting solidifies. The core being made of iron or of some metallic compound can be inserted in the mold at a desirable temperature much warmer in fact than can be obtained from a sand core, for the reason that a sand core varies in dampness and temperatures as well as having other undesirable qualities. The iron core can be dressed or coated with a prepared compound the same as the inside surface of the mold, thereby insuring a better surface on the inside of the hollow billet than can be obtained from a sand core. This is particularly true with some of the copper alloys that are used in seamless tubing in large quantities.

While I have described and illustrated, in the foregoing example given, as suitable means for effecting my invention, a stationary mold and movable core, it will be obvious that the core may be stationary and the mold movable for securing the withdrawal of the core from the mold, without depart ing from thespirit of my invention as defined in the claims.

What I claim is 1. The method of casting hollow billets which consists in introducing the molten metal into the space formed between a mold element and a separable tapered core element and withdrawing the core element from the mold element while pouring, the degree of taper of the core element and the speed of its withdrawal being dependent upon the degree of contraction of the metal of the casting in the process of cooling.

2. The method of casting hollow billets which consists in introducing the molten metal into the space formed between a mold element and a separable tapered core element and withdrawing the core element from the mold while pouring element, the

degree of taper of the core element and the time required in its withdrawal being dependent upon the degree of contraction of the metal of the casting in the process of cooling.

3. The method of casting hollow billets which consists in introducing the molten metal into the space formed between a mold element and a separable tapered core element and withdrawing the core element from the mold element while pouring, the degree of taper of the core element and the speed of its withdrawal being dependent upon the degree of contraction of the metal of the casting in the process of partial cooling.

4. The combination of a mold element, a cooperating tapered core element, and means for withdrawing the core element from the mold element while pouring, the degree of taper of the core element and the time of operation of the withdrawing means being dependent upon the degree of contraction of the body of metal cast in the mold, during the process of cooling.

5. The combination of a mold element, a cooperating tapered core el ment, and means for withdrawing the core element from the mold, element while pouring, the degree of taper of the core-element and the time of operation of the withdrawing means being dependent upon the degree of contraction, of the body of metal cast in the mold, during the process of cooling of its inner surface sufliciently to hold the body of the metal.

6. The combination of a mold element, a cooperating rigid tapered core element, and means for withdrawing the core element from the mold element while pouring, the degree of taper of the core element and the 105 time of operation of the withdrawing means being dependent upon the degree of contraction, of the body of metal cast in the mold, during the process of cooling.

7.. The combination of a mold element, a 110 cooperating tapered core element, and means for withdrawing the core element from the mold element while pouring, the degree of taper of the core element and the time of operation of the withdrawing means being 115 dependent upon the coefiicient of contraction, of the body of metal cast in the mold, during the process of cooling.

8. The combination of a mold element, a cooperating tapered core element, longer 120 than the mold element and adapted, in initial position, to project above the top of the mold element, and means for withdrawing the core element from the mold element, the degree of taper of the core element and 125 the time of operation of the withdrawing means being relative to the degree of contraction of the body of metal cast in the mold, during the process of cooling.

9. The combination of a mold element, a 130 cooperating tapered core element, and means the core passes below the top of the mold, the for causing the Withdrawal of the core eledegree of taper of the core element and the ment from the mold element through the time of operation of the Withdrawing means 10 lower end of said mold element, said withbeing relative to the degree of contraction 5 drawing means operating in such relation to of the body of metal cast in the mold, durthe pouring of the metal into the mold, that ing the process of cooling. the pouring is completed before the top of CHAR ES S. MORSE.