US1565755A - Method of treating ingot molds - Google Patents

Description

Patented Dec. 15, 1925. 1,555,755

unit-ED PATENT OFFICE.

W'ILLIAMHAIG RAMAGE, on GIRARD, OHIO.

amnion or TREATING meow MoLns. Ro Drawing. i al-sea filed at, 1924. Serial m. 716,180.

1 v steel, in the use of the molds in casting in- Be it known that I, VViilLrMr HAI RAM- gets, the molten steel tends to bite into the AGE, a citizen of the United statespigesiding wall of the mold and absorbs the laminar or at Girard, iii the county of Trumbull, State plate graphite, thus shortening the useful 5 of Ohio, have invente'd certain new and uselife of the mold. Furthermore, the sand ful Improvements in Methods of Treating which sticks to the molds under the old Ingot Molds, of which the following is a practice becomes contaminated with iron e ifi atio I q particles and general foreign matter so that The present invention relates broadly to a considerable portion ofthis sand is lost. metallurgy, and iiioreespecially to a method It also frequently happens that the sand of treating ingot molds, aiid the ingot mold will tend to fuse to the sides or inner walls e lti f o the t t t of the molds and therefore a workman is re- Heretofore in the art of manufacturing quired to go over all the molds to be sure ingot molds it hasbeen the'pra'ctice after that all of the sand is free from th e mold the iii'olds were cast and sufficiently cool to Walls. Since the matrix portion is formed be safely handled to strip the ingot molds by the inner walls of the mold, the most inif m the b e b nd flask, allowing as port-ant surfaces are the least accessible. much molding sand as possible to remain on The present invention comprises a method the mold, and then the hot molds were of treating ingot molds to overcome the 20 Stacked a ile, k w as a h t il diiliculties of the known prior art, to effect The molds in the hot pile were permitted to economics and to produce a novel and better gradually cool, after which they are lifted ingot mold. llroadly, tliepresent method from the pile and shipped to their destinacollipl'lses stripping the mold f o th iion. It is the practice in some plants to molding sand, completely cleaning all sur- 25 ierniit the core bars to remain in the ingot -BS, of the moldsi g file surfaces mold til th ld ii-Q3 1 i rde t slightly, and then ehclosin'g the molds in a further facilitate the cooling gradually, but chamber having heat insulating walls so this treatnient ties up quipiiien't and is not h t t e heat given out by the hot molds atisfactory, This custom of the prior art Wlll be conserved and will produce an at iii making a hot pile is intended to permit mosphere in which the molds are very slowth .jld t 1 1-1 r dually a d th reby ly cooled by substantially uniform radiation become annealed to relieve any stresses or infrom' all surfaces thereof, it being under tmal m h g a ha e d h gd stood that if the remaining or residual heat duringthe g. Operations nd gtaL in the molds is not sufficient to complete ing of; th gml fr iflg It ill the annealn g operation, that additional pear that the molds placed in the hot pile heat may be introduced into the chamber to first wereth'ose which were removed last, b ain the desired result. p and that the molds which were placed last in lVhile the present method may be carried the hot pile Werethose which were removed Out in different specific ways, the preferred first. The ascendingheat currents over the procedure is to pick up the molds by the hot pile causes a draught of coldair toward stripping lugs, or in any other convenient the hot pile which strikes the molds on Way, as soon as the molds are sufficiently 9 the outside of the pile. and subjects theni Cooled to permit handling without injury to to the most severe cooling conditions. It the molds. The core bar is removed from will be observed that from this old procedure the mold, and when the mold is stripped it is impractical and impossible to subject from the sand of the flash, the mold is each mold to the same heat treatment conseplunged into a water bath or other cooling quently no two molds will come out of the liquid. The water or cooling liquid penepile in exactly thes'ame annealed condition. trates through the sand adhering to the sur- This old practice furthermore tends to perfaces of the mold both interior and exterior, init the carbon to precipitate out as laminar and forms steam which literally blows or or plate forn of carbon, and when such blasts the sand from the metal, sothat the molds are subjected to the heat of molten mold comes out of the bath entirely cleaner To all rv/2.0m it may concern:

of sand. The plunge of the mold in the cooling liquid is of short duration and the mold is then carried to a suitable annealing oven having heat insulating walls, and which may comprise a closed chamber in which suitable openings are provided for the introduction and removal of molds. The molds may be arranged in the annealing oven in any convenient manner, but preferably each mold is set vertically upon its own base or bottom. Usually the residual heat of the molds is sufficient to perform the annealing operation, but under other conditions, it is desirable to add suflicient heat to the annealing chamber to raise the temperature of the molds to the critical point, which is that temperature which will release the stresses and strains set up in the mold during the preceding treatments. After the mold has been subjected to the annealing operation for a sutiicient period of time to completely release the stresses and strains set up in the mold, the heat is allowed to gradually radiate and dissipate so that the mold is gradually cooled down, after which the mold is ready for disposal as an article of commerce.

The result of the foregoing method is that the sand which is removed by the cooling fluid is clean sand, and where a water bath is used it falls to the bottom of the bath as clean washed sand. This cleaned sand may be removed therefrom by a traveling conveyor or otherwise so that the sand is saved in its best condition for reuse. This effects a considerable economy. The subjecting of the hot mold to the cooling fluid produces a dense fine grained surface on the mold. which surface effectively resists the cutting action of hot steel when the mold is in use. It appears that the majority of carbon in the metal of the mold, which is usually pig iron or blast furnace iron, remains in combined form and the graphite which is precipitated out appears to assume the spheroidal form of graphite. This tends to produce a condition of greater tensile strength in the mold and, as previously stated, tends to close the grain of the metal near and at the surface so as to produce a very smooth surface which is extremely desirable in the matrix portion of the mold in that it reproduces a similar smooth surface on ingots cast in these new molds. The annealing of the mold apparently does not destroy or change the carbon condition and does not destroy or change the hard smooth fine grained surface produced by the chill, although it does permit the stresses and strains in the mold to be equalized, so that the final product is an ingot mold having substantially uniform stress conditions throughout, or, in other words, a mold which is under neutral tension. This method of treatment not only results in an economy in manufacture, but produces a better, stronger, and longer lived ingot mold of novel characteristics.

Having thus described my invention, what I claim is:

1. The method of treating iron castings cast in sand molds, which method comprises removing the casting from the sand mold while the casting is hot; plunging the casting into a chilling bath, and subsequent ly annealing the casting.

2. The method of treating iron castings cast in. sand molds, which method. com prises removing the casting from the sand mold while the casting is hot; subjecting the casting to a chilling water bath, and subsequently annealing the casting.

3. The method of treating iron castings cast in sand molds, which method comprises removing the casting from the sand mold while the casting is hot; plunging the casting into a chilling bath, and subsequently annealing the casting in an enclosed atmesphere.

at. The method of treating iron ingot molds cast in sand molds, which method comprises removing the ingot mold from the sand as soon as the ingot mold can be safe- 1 y handled, plunging the ingot mold into a chilling bath, and annealing the ingot mold.

The method of treating iron ingot molds cast in sand molds, which method comprises removing the ingot mold from the sand as soon as the ingot mold can be safely handled, plunging the ingot mold into a chilling water bath, and annealing the ingot mold by its own heat in an enclosed quiescent atmosphere.

(3. The method of treating iron ingot molds cast in sand molds which method comprises stripping the core bar from the ingot mold and removing the mold from the sand as soon as the mold can be safely handled; quickly plunging the mold into a chilling bath capable of penetrating masses of sand adhering to the mold; removing the mold from the fluid before the mold has been substantially cooled; and annealing the mold.

7. The method of treating iron ingot molds cast in sand molds which method comprises stripping the core bar from the ingot mold and removing the mold from the sand as soon as the mold can be safely handled; quickly plunging the mold into a chilling fluid capable of penetrating masses of sand adhering to the mold; removing the mold from the fluid before the mold has been substantially cooled; and annealing the mold by preventing rapid withdrawal of the residual heat therefrom.

S. The method of treating iron ingot molds cast in sand matrices, which method comprises stripping the mold from the sand soon as the mold has cooled sufficiently to be self supporting; subjecting the stripped mold to a chilling fluid capable of penetrating adhering masses of sand and of forming an expansible'gas upon coming in contact with the hot walls of the mold to loosen said adhering masses of sand and then annealing the mold.

9. The method of treating iron ingot molds cast in sand matrices which method comprises stripping the .mold from the sand; subjecting the mold to a water bath and removing the mold therefrom before the mold has been substantially cooled; and an healing the mold.

10. The method of treating iron ingot molds cast in sand matrices which method comprises stripping the mold from the sand; subjecting the mold to a water bath; and removing the mold therefrom before the mold has been substantially cooled.

11. The method of treating iron ingot molds; which comprises chilling the surfaces only of the molds after the molds are cast and annealing the molds.

12. The method of treating iron ingot molds; which comprises casting the ingot mold in a non-chill matrix and chilling the surfaces only of the molds after the molds are cast.

13. The method of treating cast iron ingot molds, which method comprises casting the mold in a non-chill mold, and chilling the matrix wall surfaces of the ingot mold for a small depth only after the ingot mold has been cast.

14:. The method of treating cast iron ingot molds, which method comprises casting the mold in a non-chill mold, chilling the matrix wall surfaces of the ingot mold for a slight depth only after the ingot mold has been cast, and then annealing the chilled portions.

15. As an article of manufacture a cast iron ingot mold having the metal at and chilled and in substantially neutral stress COIIClllLIOH.

17. As an article of manufacture a cast iron ingot mold, having the surfaces thereof of close grained metal with the major portion of the free carbon therein in substantially spheriodal form and with the interior metal in the walls thereof in substantially neutral stress condition.

18. The method of treating ingot molds cast in sand molds, which method comprises removing the ingot mold from the sand while hot and quickly subjecting the ingot mold to a water bath to remove adhering sand therefrom.

19. The method of treating ingot molds cast in sand molds, which method comprises removing the ingot mold from the sand while hot and quickly subjecting the ingot mold to a water bath to permit water to permeate the adhering sand and to remove same by vaporizing the water therein with heat from the ingot mold.

20. The method of removing adhering sand from hot ingot molds, which method comprises quickly subjecting the mold to a water. bath, permitting the water to permeate the adhering sand, and driving the sand from the mold by vaporizing the water therein.

New York, N. Y., January 24:, 1924.

\VILLIAM HAIG RAMAGE.