US816709A - Method of forming castings. - Google Patents

Description

No. 816,709. PATENTED APR. 3, 1906. Y

W. BRINTON. I METHOD OF FORMING OASTINGS.

APPLICATION FILED APR. 8, 1902.

' TED STATES.

PATENT orEroE.

WALTER BRINTON, OF HIGH BRIDGE; NEW JERSEY. mE-i-HoDoFFoRMme oAsrmes.'

Specification of Letters Patent.

- Patented April 3,- 1906,

Application filed-April 8,1902. Serial No. 101,89?-

.To all whom it may concern.-

- Be it known that I, WALTER BRINTON, a ccitizen of the United States, residing at High Bridge, in the county of Hunterdon and State of New Jersey, have invented certain new and useful Forming Castings, of which the'following is a specification.

This invention relates to the formation of castings, the object of the invention being to provide an'improved castin such, for instance, as aroll-shell for crus ers-and to an improved method of forming the same, Whereby in the heating of such castings a more uni form expansion and in cooling a more uniform contraction thereof is obtained, thus preventing abnormal and irregular strains and'subsequent cracking of the castings.

It is frequently desirable to subject castings to heat treatment, particularly manganese-steel castings, for the purpose of toughening them. It is Well known that when a solid mass of metal, which conducts heat relatively slowly, is heat-treated the interior will be heated or cooled much more slowly than the exterior, and if rapid cooling is desired the interior will in consequence receive less'benefit than the exterior. This is particularly true of manganese steel, which to be serviceable should ordinarily be cooled rapidly and uniformly throughout the mass, this steel ordinarily tending to cool irregularly on account Y ofits extraordinary poor heat conductivity.

Therefore it is necessary to have the casting heated and cooled uniformly throughout, so that its expansion and contraction under the heating and cooling thereof, respectively, will be uniform, thereby preventing abnormal and irregular strains and subsequent cracking of the casting, and I havetdiscovered that by providing a hollow casting with an irregular surface on its interior superior results are obtained in-the heat treatment thereof. In order to get the full benefit of the treatment, manganese-steel castings after being heated are cooled quickly, generally by immersion in a coolin fluid or bath, the effect of which is to rapidly absorb the heat from the surfaces of the casting. If such casting is in the form of a ring or cylinder of the ordinary thickness of a roll-shell, such surface cooling effect causes a rapid contraction of the part so affected, while the interior body of metal I ,between the surfaces still contains a much higher degree of heat and is thereforecon- Improvements in Methods of' .tracting muchmore slowly. i It is therefore readily seen that during the whole process of a treatment the interior heat. must' be absorbed through that part of the casting which has been more directlyand rapidly afiected by the cooling contact. It is also conceded 1 that a plane inner surface of a cylindrical or circular casting forms a very rigid arch', and

as this surface is. first affected in cooling therefore a perfectly ri idarch is set u later contraction of t e interior b0 metal over said resistance of arch bein cient to cause internal strains to deve 0p in the later cooling body of steel. The resistance of the inner surface of the ring or cylin the y of der provided with corrugations or broken surfaces while in a semiheated state does not set up such a rigid arch as does the plane surface. The diffusion of the interior heat of the casting radiating through these corrugated or broken surfaces also has a tendency to assist in the distribution and better equalization of the interior heat.

In the drawings, accompanying and forming part of this specification, Figure 1 is a top View of a roll-shell for crushers with the interior surface thereof corrugated. Fig. 2 1 is a side view thereof, partly in section.

As a preface to a further description of this improved castin and the method of forming the same it wi I be understood that this method is applicable to all kinds of castings formed of man anese steel or otherwise, and it is particularfy Well adapted for roll-shellsfor crushers.

To illustratelthe resent improved method, have shown in t e drawings a roll-shell 2 for crushers, and in practice to facilitate the heat treatment and securesuperior results in the uniform expansion and contraction thereof durin the heating and cooling, I'GSPGC7. tively, 0 this shell I providesuch shell .with

an irregular surface-such, for instance, as a corrugated surface 3-th1s surface bem formed durin the castin of'the shell. This irregular su ace. is in the present instanceformed on the interior of the shell. Practical experience has demonstrated that these corrugations are advanta eous, since there is less ikelihood of interna strain setting up in the castin while it is absorbing heat and also less 1i elihood of the'easting being afiected ,by such strains while it is giving up heat or cooling, so that abnormal or irregular strains and subsequentcracking of the casting is avoided; These corrugations constitute a. V

' the cooling thereofi means, for securing 'a more thorough distribution end equalization-of the heat during the absorption thereof and fof'insfil'ing the f giving off of the heat uniformly during-the cooling of the casting. The corrugations, it" is believed, afiord increased surface exposure castings, also the givin off of the cat during ur-thermone, o to the con'ugations it is beheved that there isless rigidity of thecastin'gs at critical oeniods of e ansion and contrection'duringt e'heztt treatment, there being lesslikelihooci of rigid andintense arches of resistance settingup in the broken lines then: there wouid be in straight g mme surfaces;

sicgme form'in'whichth'e" efea; of the inner surface is ggeeter then the sree of the outer surface of: the Bod and then subjecting the body to.

heat an then cooling it. of the castings, which thus essiststhe' more equal distribution of heat throu .hout such- 21' emethod of producin'g sbody of'en- {miles section, consisting in casting it in a,

form in which the outer face is substantially circular in transverse section, and the inner f see" issubstantially sinusoidalin 'tmnsverse section, thereupon subjecting the bony to beet end then cooiingitu WALTER- BRINTQ NZ Witnesses: I I

&ebeim winner, PERGWAL YsTm,

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