US1929739A - Method of bronze or brass treatment and application - Google Patents

Description

Oct. 10, 1933. H, GANNETT 1,929,739

M OF RONZE 0R BRAS REATME APPLICATION Filed April 4, 1932 1711/8116? 44M Z V Patented ct. 10, 1933 PATENT OFFICE LMETHOD @F BRONZE R BRASS TREAT- MEN'E AND APPLICATION My invention relates broadly to the method of treating bronze or brass designed for use in contact members where abrasive conditions exist; the treatment being intended where the con- 6 tact members may be entirely made of bronze or brass, or where the outer contact or wear receiving surfaces of such members consist of bronze or brass which may be integrally united with the supporting metallic body portion of the members.

The object of my invention is the provision of contact members whose rubbing or contacting surfaces will be greatly hardened beyond their original hardness by mechanical or manual working and the life of the members thereby greatly enhanced.

My invention, more specifically stated, consists in subjecting a unit of bronze or brass to a mechanical or manual working, namely subjecting the bronze or brass to a compacting action either by means of suitable pressure rolls or hammer blows, whether manually or mechanically applied, whereby the hardness of the bronze or brass is greatly increased beyond its native hardness and its resistance to abrasion or wear materially increased.

As a specific embodiment or application of the invention, I have chosen to illustrate the application and use of my invention in connection with the bull-ring of a piston as employed in a locomotive cylinder; the figure in the drawing being a sectional View of a piston provided with a bullring involving the invention; the piston-rod and the usual packing rings for the piston being omitted.

In the exemplification, the main body of the bull ring 10 may be of the conventional type at present in use, with'its perimeter provided with the grooves or parallely arranged channels 11 in which the usual packing rings (not shown) which are usually sectional, are mounted andheld to provide constant and proper contact with the lining or bushing in the locomotive cylinder.

As the locomotive cylinders are generally horizontally disposed, the weight of the bull-rings causes the lower segmental portion of the ring to very quickly become worn and the usefulness of the ring destroyed, with the result that the bull-rings of locomotive cylinders require frequent periodical replacement.

In many instances, these replacements are re-' quired in periods of twenty to thirty days or so and hence entailing a great expense for railas roads both in the cost and labor'of renewal or replacement of the bull-rings as well as in the loss of service time of the locomotive.

I have found in actual practice that the life and usefulness of the bull-rings will be extended for a long period beyond the useful life thereof, 6 by building up the worn segmental portion of the bull-ring with bronze as shown at 12 in the drawing. The bronze is integrally united with the cast metal ring by welding; the bronze being autogenously applied to the ring on opposite sides of the packing-ring channels or grooves 11, in gradually increasing thickness toward the lower side of the bull-ring in keeping with: the worn condition of the ring, as for example indicated by the dotted line 13 in the drawing. 79

These sections or layers of bronze of increasing cross-sectional dimensions or thickness are separately applied to the bull-ring outer face by welding the same so as to build up the bull-ring, or the renewed segment thereof, somewhat beyond its normal circumference, say from an eighth to a quarter of an inch in thickness greater than the final diametrical thickness of the ring at this point.

After a sufficient quantity of the bronze or brass has been applied, the applied layer of the bronze is then hammered throughout its entire area for the purpose of closing the pores therein and to eradicate or compress the pockets that may be produced therein by oil or gases which ooze from the cast iron portion of the ring during the application of the bronze thereto.

The added segments of bronze are then trued down, say to within one-sixteenth of its finished size and the bronze again subjected to proper pressure, which, on a bull-ring, is best obtained by hammering the entire areas of the segments for the purpose of hardening the bronze. It has been found in practice that this is best accomplished by placing the bull-ring in a lathe where it can be rotated and an air hammer, or other power driven hammer, used so as to cause the entire body of the bronze to be compacted, namely so as to induce a hardening beneath the outer surface as well. That is to say, the bronze is subjected to sufficiently heavy blows so as to thoroughly compact its molecules. 1

The hammering of the bronze is preferably done when the bronze has cooled or is cold because the Brinnell hardness of the metal is then very materially increased and as a result the life of the bull-ring is greatly enhanced.

After the second hammering of the bull-ring segments, they are then machined'to remove the uneven surfaces produced by the action of the her.

I have found in practice that manganese bronze is best adapted for this purpose, although other types of bronze or brass may be used and treated in the same manner.

While I have shown and described my invention in connection with the bull-ring of the piston for use in the steam cylinders of a locomotive, it is apparent that the application and treatment may be otherwise employed, as for example the shoes or gibs of the cross-heads of a. locomotive may be made of bronze or brass of a suitable character having the desired ingredients. The shoes, like the segmental lower portion of the bull-ring, may be welded onto the upper and lower sliding surfaces of the cross-head and hammered as heretofore described and then ma chined down to proper dimensions. The nonmagnetic bronze or brass will eliminate the wear at present encountered with cross-heads which is greatly due to the abrasive action of the fine metal particles that result from the frictional contact between the cross-head and the guidebars and which metal particles, due to the magnetic metal used, enter between the contacting surfaces of the bars and cross-head. This difiiculty can be eliminated and the life of the crosshead greatly increased. and at the same time a considerable saving in lubricant obtained.

Then, too, considerable difficulty is at present encountered with the wear and breakage of journal-box brasses and particularly the wear and breakage that now occurs at the lower or depending side portions of the brasses resulting from the lateral impacts and frictional action of the journals. This dimculty may also be eliminated by subjecting the brasses, at least the side depending portions thereof, to an ample pressure or hammer blows whereby the entire transverse area of the brass is compacted throughout its thickness.

Attempts at brazing certain elements, as for example bull-rings, have been made, but these have been found a failure, because the thin coating of bronze was not capable of withstanding ab= rasive resistance and consequently the side edges of the brazed or soldered coating, especially adjacent to the packing ring receiving grooves, would soon burr over and thereby lock the pack= ing rings against proper action and hence resulted in engine failure. On the other hand, by welding an initially large quantity of bronze or brass onto the supporting body or element and then subjecting it to proper pressure or hammer blows, the bronze or brass is brought to a hardness extremely beyond its natural hardness and. hence its use for purposes not heretofore known,

where abrasive conditions exist, is made possible.

I have defined what is believed, from actual experience, to be the best method of treatment, which has been described in terms of description and not in terms-of limitation, as certain modifications may be possible without, however, departing from the spirit of my invention.

What I claim is:

l. The herein described method and application to a horizontally disposed cast metal bullring of a steam cylinder which consists in building up the lower wear receiving segmental portion of the bull-ring by welding bronze thereon to an initial thickness greater than that of the upper cast metal segmental portion, subjecting the applied bronze portion to pressure so as to close the ports therein, truing the applied bronze to dimensions somewhat greater than the crosssectional dimensions of the intended dimensions; then again subjecting the bronze to a hardening pressure and then machining said portion.

2. The herein described method which consists in applying bronze to the wear receiving surface of a bull-ring by welding the bronze to the cast metal ring in thickness greater than the ultimate thickness of the ring; hammering the welded bronze to close the pores; truing the welded bronze down to a thickness somewhat greater than the ultimate circumferential dimensions of the ring; and again hammering the welded bronze, down to substantially the circum= ferential dimensions of the ring, to densify the molecular nature of the bronze.

3. The herein described method which consists in autogenously applying a mass of bronze to the wear receiving surface of a piston to a thickness greater than the desired ultimate thickness of the piston, and then subjecting the applied mass after it has cooled below the temperature of the autogenous application to pore-closing and densifying operations until the mass has been reduced to the desired dimensions whereby a hard wear resisting surface is provided and retained.

i. The herein described method which consists in autogenously applying a mass of bronze or brass to the wear receiving surface of a piston or piston bull-ring operable in a horizontally disposed cylinder to a thiclmess greater than the desired ultimate thickness of the piston or bullring, and then subjecting the applied mass to pore-closing and hardening pressure after the mass has cooled below the temperature of the autogenous application until the mass has been reduced to the desired dimensions whereby a hard wear resisting surface is provided and retained. HOMER E. GANNETT.

CERTIFICATE OF CORRECTION.

rmm no. 1,929,739. October 10, 1933.

HOMER E. GANNETT.

it ia hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, line 92, claim 1, for "ports" read pores; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and aealed 'thia 12th day of December, A. D. 1933.

i. M. Hopkine "(Sean Acting Commissioner of Patente.

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