US2392281A - Method of making welded blade structures - Google Patents

Description

I Jan. 1,'1946. R. c. ALLEN I 9Z,281

METHOD OF MAKING WELDED BLADE STRUCTURES Original Filed July o, 1941 WWW w i Patenta& Jan. 1946` UNITED STATES PATENT OFFICE METHOD OF MAKING WEL'DED BLADE STRUCTURES Robert C. Allen, Wauwatosa, Wis., assignoto Aliis-Chalmers Manufacturing Company,' Milwaukee, Wis., a corporation of Delaware Original application July 10, 1941, Serial No.

401,'726. Divided and this application Feb-u ary 19, 1942, Serial No. 131,469

claims. (Cl. 29-156.8)

I parts are claimed and also fuliy disclosed in application Serial No. 401,'726, filed July 10, 1941, of which this application is a division.

'An object of this invention is to provide an improved method of forming a blade assembly 'in which the blades are secured to a turbine disk or the like solely by weld metal.

Another object of this invention is to provide an improved method of forming a blade assembly in which blades having an approximately smooth base portion are rigidly Secured to a turbine disk ?r the like presenting a similar peripheral surace.

Still another object of this invention is to provide an improved method oi' forming a blade' assembly which is relatively inexpensive and which can be readily employed for reblading turbine rotors with a minimum of time and e'xpense.

A further object of this invention is to provide an improved method of forming the improved blade assemblies hereinabove mentioned.

The -invention accordingly consists of the method hereinafter more fully set forth in the appended claims and in the detailed description, in which:

Fig. 1 is a side elevation of a blade assembly embodving the invention;

Fig. 2 is a perspective view of the form of blade employed;

Flgs. 3-6, incluslve, illustrate various stages in the oonstruction of a blade assembly made in accordance with the invention; and i Fig. "l is a section through a blade taken on line VII-VII of Fig. 5; and

Fig. 8 is a section through a series of blades taken on line VIII-VIII of Fig. 5.

Referring to the drawing. and particularly Figs. 1, 2,'6. 7 and 8, it is seen that the bladeassembly I. which represents a portion of a circumferential blade row, comprises a spindle or rotor disk member z, a series of impulse type blades 3 having integral shroud and base portions 4 and 6, respectively, and weld metal 'l forming the sole connection between the base 6 of each blade 3 and the periphery of the disk 2. The shroud and base portions on adjacent blades are disposed in abutting relation (see Figs. 1 and 8) to form therebetween the fluid conning passages 8. The disk 2 and the blades 3 are preferably shaped to surfaced base ends, respectively; i. e., a surface which is free of any proiection or recess abruptly interrupting the continuity of the surface. and

therefore the expression "single surface? as herein used includes surfaces which are either plane or curved, these surfaces being either perpendicular or oblique relative to the edges and to the side surfaces of a blade base or to the side surfaces of a spindle disk or the like. as this type of construction materially reduces costs.

The blade assemblies are preferably formed by placing a chill ring member 9 of inverted T-shape in cross section and the blades 3 on a suitable iig II (the particular form and the detailed construction of the jig are not essential features of this invention) and manipulating and clamping means |2 provided thereon to securely hold the blades 3 and the ring member 9 thereon in the relation shown whereupon the assembly comprisgo ing the jig Il, the blades 3 and ring member 9 is then associated with the disk 2 in the manner shown in Fig. 3 and Secured in this position by any suitable means (not shown). The chill ring member 9 in addition to the usual functions of such members also acts to correctly position the blades 3 relative to the peripheral surface on the disk 2; i. e., the chill ring member 9 which preferably covers approximateiy one-half of the width 1 of the peripheral surface on the disk 2 and which is engaged by a corresponding portion of the un Vderside surface of the blade base 8, maintains opening channel or space !3 which is defined by the exposed portion of the underside surface of the blade base 6, the exposed portion of the peripheral surface on the disk 2, and the adjacent edge of the chill ring member 9. The weld metal l, which substantially fills the channel l3. securely unites the bases 6 of the blades 3 with the peripheral surface of the diskz and with the ad jacent edge of the chill ring member 9; the weld metal fusing with the conflning surface portions of the blade base 6, the chill ring 9 and the disk 2 to produce a bond of weld metal having the cross sectional configuration shown in Fig. 4. Next the clamping means |2 is released, the jig withdrawn and the chill ring member 9 removed by asuitable machining or grinding operation,

present a single surfaced periphery and single which may be performed with the structure in 2 aseazs any desired position, to provide the circunferentially extending channel or space ll shown in Fig. 5. In this connection, the cross sectional configuration of the channel N formedby the removal of the chill ri'ng 9 is immaterial and may 6 be formed with one beveled side wall surface as shown in Fig. or otherwise shaped as necessitatedby the tool selected for performing the machining or grinding operation. The channel ll is then filled with weld metal 'l in accordance 10 with the procedure described with ,respect to the channel |3 to provide the structure shown in Fig. 6. The remaining operations are to remove the excess weld metal in any suitable manner such as by machining or 'grinding and then to heat treat the entire assembly including the blading and spindle or rotor disk member to secure the requisite or desired physical properties.

The depositing of the weld metal in the channels !3 and M can be best eflected with the structurepositioned to place the channels on the up side thereof. as indicated by Figs. 3 and 6 of the drawing. that is, with the assembly comprisin v the jig ll, the blades 3, the chill ring member 9 and the disk 2 associated as shown in Fig. 3, and

after filling the channel !3 with weld metal and removing the jig Il and chill ring 9 to produce the structure shown in Fig. 5, by then inverting said structure to place the channel H on the upper side thereof. However, it is not essential that the 3 structure be positioned to place the channels l3 and !4 on the upper side thereof and depositing the weld metal therein, as weld metal can be readily deposited in said channels when placed in a horizontal position conforming with that effected by turning the structures shown in Figs. v 3-5, inclusive, through an angle of 90". Moreover, weld metal can also be deposited in an underside or downwardly opening channel similar and means for securing blades to a turbine disk' or the like is of general application. and that therefore it is not desired to limit the invention to the exact details herein shown and described,

as various modiflcations within the scope of the appended claims, may occur to persons skilled in the art.

It is claimed and desired to secure by Letters Patent: i

1. The method of making a .bladed element for turbines and the like comprising providing an nel, substantially filling said channel with metal..

fusibly integrally uniting the channel forming portions of said base ends, chill ring structure and peripheral portion, removing said chill ring structure to form a second laterally opening oppositely facing channel formed in part by the v metal previously' deposited in said first channel; and substantially filling said second channel with metalfusibly integrally uniting the exposed wall portions thereof.

2. The method of making a bladed element for' turbines and the like comprising providing an element with a peripheral portion commensurate in width with the base ends of the blades to be attached thereto, providing blades having single surfaced base ends. partially covering said single surfaced peripheral portion with a structure-presenting a substantially fiat outer surface. posi-- to that presented by the structure When posi- 40 tioning and holding the blades in row forming.

tioned as shown in Fig. 5, although this procedure (termed overhead welding) does require considerably more time and skill than is required when the channels are placed in either of the two positions hereinbefore specified. The' correct weld- .publication, Procedure Handbook of Arc Welding Design and Practice, 1936.

It' should be particularly noted that in the lllustrated construction the area of the underside surface of the base 6 is considerably greater than the area of the blade cross section taken adjacent the base 6 as is clearly indicated 'by Fig. 7, and that therefore the effective 'bond area of the weld metal, which area is commensurate with the area of the underside surface of the blade base 6, is also materially greater than the area of the said blade section. In this connection, it is desirable although not essential in all instances to make the effective bond area of the weld metal, i. e, the cross sectional area of the weld meta taken on line A-A of Fig. 6, greater than the area of the cross section of the blade taken adjacent the base thereof.

The blades 3 are of milled Construction and the abutting surfaces of the shroud and base portlons on adjacent blades are finish machined to coact and provide in efiect a sealed fluid conning pasr sage '8. However, it should be understood that the blades 3 may be of any desired configuration and may be constructed or built-up in any de-' sired manner, that the herein disciosed manner .75

relation with their base ends abutting said s`ubstantially flat surface and forming with said structure and with the exposed part of said peripheral portion a'first laterally opening channel substantially filling said channel with metal ,fusibly integrally uniting the channel forming por-' tions of said base ends, structure and peripheral portion, removing said structure to form a second laterally opening oppositely facing channel formed in part by the metal previously deposited in said first channel, and substantially filling said second channel with metal fusibly integrally uniting the exposed wall portions thereof.

3. The method of making a bladed element for turbines and the like comprising providing an element with a single surfaced peripheral portion commensurate in width with the base ends of the blades to be attached thei-eto. providing blades having single surfacedbase ends, positioning and holding the blades in row forming relation with their base ends opposing said single surfaced peripheral portion and in part spaced therefrom so as to form therewith a first laterally opening channel 'bf less depth than the width oi-the base ends of said blades, substantially filling said' channel with metal fusibly integrally uniting the opposed channel forming wall parts of said base ends and peripheral portion, forming between the remaining opposed parts of said base ends'.

and peripheral portion, a second laterally opening oppositely facing channel having an inner wall:

:mesu

4. The method of making e bladed element tor turbines and the like comprising providing en elcrnent with single surfaced peripheral portion commensurete in width with the base ends of the blnde to be ttached thereto. providing blades dpted to be positioned in row torming relstion with their base ends opposing the peripheral portion of said elemen't,` positioning and holding the binde; in row !orning relation with portions of their base ends smedly opposing and forming with e part o! said peripheral portion, a. first latereiy opening channel ol less depth than the width of the base ends of said blade. substantially filling seid channel with metal tusibly integraly uniting the opposed channel parte of said base ends and peripherl portion. forming between the remaining opposed portions o! said base ends and peripherl portion. second lnternlly opening oppositely racing channel formed in part by the mete! previouely deposited in said nrst channel.

and substentiely filling said second channel with metal !uxibly integrily uniting the wall; denn- 5. The method of making e. bladed element !or turbines and the like eomprising providing an element with a peripheral portion commensurate in width with the base ends of the blades to be etteched thereto, providing blades having single surfaced base ends, positioning and holding the blades in row torming relation with portions of their base ends spacedly opposing and torning with a part ot said peripheral portion a first laterally opening channel o! less depth than the width of the base ends of said blades, substantially filling seid channel with metal !usibly integrly uniting the opposed channel Iorming parte of said base ends and peripheral portion. i'orming between the remaining opposed portlons of said base ends and periphera portion. a. second later- -ally opening oppositely tacing channel torned in part by the metal previously deposited in said first channel, and substantially filling said second channel with metal !usibly integrally uniting the wlls denning same.

ROBERT C. ALIEN.

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