US2743509A

US2743509A - Method of making compressor blades

Info

Publication number: US2743509A
Application number: US328604A
Authority: US
Inventors: Robert G Friedman
Original assignee: National Machinery Co
Current assignee: National Machinery Co
Priority date: 1952-12-30
Filing date: 1952-12-30
Publication date: 1956-05-01
Anticipated expiration: 1973-05-01

Description

y 1956 R. G. FRIEDMAN 2,743,509

METHOD OF MAKING COMPRESSOR BLADES Filed Dec. 30, 1952 3 Sheets-Sheet l 15 7 Ploanzssslvz HEA DE/Z f i g i%o j l/VDULT/ON 12 HEATER 2:,113

4 1 47%? 2/10 PROGRESSIVE 1 r HEADER IN VEN TOR. ROBERT 6. FRIEDMAN EICHEX, w 7T6 06m am lvz/v/vr ATrozalvgY-s May 1, 1956 R. G. FRIEDMAN 2,743,509

METHOD OF MAKING COMPRESSOR BLADES Filed Dec. 30, 1952 3 Sheets-Sheet 2 IN VEN TOR. ROBE/27" 6. FRIEDMAN May 1, 1956 R. G. FRIEDMAN METHOD OF MAKING COMPRESSOR BLADES 3 Sheets-Sheet 3 Filed Dec. 30, 1952 INVENTOR.

ROBE/27' G. FEM OMAN United States Patent METHOD OF MAKING COMPRESSOR BLADES Robert G. Friedman, Tiflin, Ohio, assignor to The lfla tional Machinery Company, Tiflin, Ohio, a corporation of Ohio Application December 30, 1952, Serial No. 328,604

2 Claims. (Cl. 29-1563) This invention relates to the forging of metal articles having enlarged sections and more particularly to the forging of compressor blade blanks wherein large variations in cross section are necessary.

Great difiiculties have been encountered when attempting to forge articles having large variations infcross section and it has been necessary in the past to provide numerous anneals to prevent fractures and adhesions. Difficulty has particularly been present in attempts to form compressor blade blanks, since such articles require a large root section and a relatively small stem.

An important object of this invention is to provide a method for forging articles wherein large variations in cross section are necessary.

Another object of this invention is to provide a method which combines hot and cold forging in the forming of articles having large changes in cross section.

It is still another object of this invention to provide a method of forging compressor blade blanks wherein it is necessary to upset a large root section while mantaining a relatively small stem section.

A still further object of this invention is to provide a method of forging articles combining cold extrusion of a portion of a blank, heating of the unextruded portion, and hot upsetting of the heated portion of the blank.

The foregoing and other objects and advantages will become apparent in view of the following description taken in conjunction with the drawings, wherein:

Fig. l is a schematic view of the entire apparatus preferably employed in forging a compressor blade-blank according to this invention;

Fig. 2 shows the blank before working;

Fig. 2a is an end view of the blank;

Fig. 2b shows the blank after cold extrusion;

Fig. 2c is an end view of the blank of Fig. 2b;

Fig. 2d shows an extruded blank partially hot forged;

Fig. 2e is an end view of the blank of Fig. 2d;

Fig. 2 shows the completed compressor blade blank;

Fig. 23 is an end view of the blank of Fig. 2f;

Fig. 3 is a cross sectional view showing the die arrangement in the first header;

Fig. 4 is a schematic view of a preferred apparatus utilized for transferring the blank from the first header to the second header; and

Fig. 5 is a cross sectional view of the die arrangement utilized in the second header.

In a preferred embodiment of this invention, stock is selected having a cross section larger than the desired cross section of the stem portion of 'the compressor blade blank and smaller than the cross section of the root section in the finished compressor blade blank. This permits the reducing of the cross sectional area of the stock to form the stem section of the blank and subsequently upsetting the large root section from stock having a cross section substantially larger than the cross section of the stem section. By employing this method it is possible to reduce the amount of upsetting necessary in the formation of the root section.

Patented May 1, 1956 ice A method of forming compressor blade blanks according to this invention also utilizes the processes of hot and cold forging wherein a portion of the stock is extruded cold to form the stem section of the finished blank after which that portion of the stock which is to be upset to form the root section is heated. Subsequent to the heating, hot forging is utilized to upset the root section thereby forming the finished compressor blade blank.

If articles such as compressor blade blanks were forged by cold extruding and upsetting, it would be necessary to provide interim anneals to eliminate ruptures. Such anneals are not only time consuming but result in more costly process. It is also unsatisfactory to use hot extrusion and upsetting since a small extrusion angle is required to prevent lines at the extrusion point which result in defects in the blades. To drive metal down the small extrusion angle requires such a high pressure that the hot metal which is unconfined between the dies would be upset resulting in failure of the process. By combining cold extrusion, localized heating of the unextruded portion of the blank, and hot upsetting of the heated portion of the blank it is possible to forge articles wherein large variations in cross section are present without requiring time consuming and expensive interim anneals.

Referring to Fig. l, the first phase of the forging process takes place at the first progressive header 10, similar to the header disclosed in the patent to Clause No. 2,043,- 093. In the preferred embodiment of this invention wire stock 11 is fed into an automatic cut-off in the first header 10 which supplies the individual blanks that are subsequently extruded into a first intermediate blank having a stem portion of reduced cross section. From the first progressive header 10 the first intermediate blank is automatically transferred through the second phase of the process wherein the large section of the blank is heated by an induction heater 12. It is preferred that the conveyer belt 13 utilized to transport the first intermediate blank from the first header 10 through the induction heater 12, and on to the second header 14. At the second header the first intermediate blank is forged into the final compressor blade blank by upsetting the hot portion of the blank.

Referring to Fig. 3 the wire stock 11 is fed by any conventional means through the bore 16 in the cut-off die 17 at the first station on the header and on through the bore 18 in the shearing element 19 until it engages the stock feed stop 21. The stock feed stop 21 may be constructed in any suitable manner but should be adjustable axially relative to the cut-off die 17 to permit adjustment of the quantity of metal in the blanks. The shearing element 19 then cuts the blank 22 from the wire stock by moving radially along the cut-off die 17. The amount of metal necessary to form the finished compressor blade blank and the cross section of the wire stock 11 determines the length of the blank 22. When forging a compressor blade blank according to this invention the stock 11 should be selected to have a cross sectional area larger than the stem or smallest cross section in the finished blank but smaller than the cross section of the root or largest cross section of the finished blade blank. After the blank 22 is sheared from the wire stock 11 it is positioned before the extruding die 23 at the second station of the header 10 as shown in Fig. 3. The transfer mechanism (not shown) may be of any conventional type and is not critical to this invention. The die 23 is formed with an enlarged bore portion 24 opening on the forward face of the die and a reduced bore portion 26 spaced from the face of the die and axially aligned with the bore 24. A transition section 27 is formed between the

bores

24 and 26. The bore 24 is formed having a cross section substantially equal to the cross section of the blank 22 and the bore 26 is formed having a cross section substantially equal to the cross section desired in the finished stem'of the compressor blade blank. The die breast 28 in which the extruding die 23 is mounted is provided with a bore 29 axially aligned with the bore 26 in the die 23. A reciprocating die 31 is mounted on the header slide (not shown) and is formed with a receiving bore 32 axially aligned and substantially equal in cross section to the bore 24 in the extruding die 23. A backing pin 33 is mounted within the bore 32 with a forward face 34 spaced from the forward end of the reciprocating die 31. As the header slide moves forward the blank 22 enters the bore 24 until it engages the transition section 27 and enters the bore 32 until it engages the face 34 of the pin 33. As the header slide continues to move toward the die breast 28 the blank 22 is extruded through the bore 26 forming the first intermediate blank 36 having a stem portion 37 of reduced cross section and a base section 38 having a cross section substantially equal to the cross section of the blank 22.

In the preferred embodiment the stem portion 37 of the first intermediate blank 36 is formed with a cross section equal to the desired cross section of the stem portion of the finished compressor blade blank.

As the header slide moves away from the die breast 28 the ejector pin 39 ejects the first intermediate blank 36 from the die 23 and the first intermediate blank is positioned by the transfer mechanism (not shown) in front of the holding die 41 at the third station in the header 10.

It should be noted that no forging takes place at the die 41 and this station is used to maintain control of the first intermediate blank 36. The punch 42 is mounted on the header slide of the header and moves the first intermediate blank into the bore 43 in the die 41. The ejector pin 44 is axially slidable in the bore 43 and ejects the blank from the bore when the punch 42 moves axially away from the die 41. The first intermediate blank 36 is then transferred by any conventional means to the conveyer belt 13 shown in Fig. 4. The transfer mechanism for transferring the first intermediate blank to the conveyer belt 13 may include a tube or slide 46. The particular conveyer belt shown in Fig. 4 is synchronized with the operation of the first header 14 and is adapted to receive the stern portion 37 of the first intermediate blank 36. The base section 38 of the first intermediate blank 36 is arranged to extend laterally relative to the conveyer belt 13.

The heater 12 is of the induction type and is arranged with an induction coil 47 arranged to surround the base section 38 as the first intermediate blank is moved from the first header to the second header. Since only the base section 38 of the blank is surrounded by the induction heating coil 47 only that portion of the blank is heated by the induction heater and the stem portion remains relatively cool. An induction heating coil is particularly well adapted to this process since it makes possible to rapidly heat a portion of the blank. When the intermediate blank reaches the slide 48 it is ejected from the conveyer belt 13 by any conventional method such as an air blast or ejector pin. The intermediate blank then slides down the slide 48 until it is received by a conventional type transfer mechanism (not shown) positioned for the second forging operation at the first station in the second header.

It is preferable to synchronize the operations of the first and second header as well as the conveyer belt so that control of the blank is maintained during the entire process to reduce the handling necessary.

Referring to Fig. 5, the first intermediate blank is aligned with the die 51 mounted in the die breast at the first station of the second header 14. The die 51 is formed with a bore 52 which is substantially equal in cross section to the cross section of the stem 37. The forward end of the bore 52 is rounded as at 53 to facilitate the upsetting of the root or enlarged section of the sec 0nd intermediate blank 54. The reciprocating die 56 is mounted on the header slide of the second header 14 and is formed with a bore 57 axially aligned with the bore 52. The bore 57 is formed having a cross sectional area substantially equal to the cross sectional area of the base section 38 and is tapered as at 58 to an enlarged mouth section having a size substantially equal to the mouth section of the die 51. The backing pin 59. is mounted in the bore 57 with its forward face 61 spaced from the mouth of the die 56. An ejector pin 62 is mounted within the bore 52 of the die 51 with its forward face 63 spaced from the mouth of the die 51. The length of the bore 52 between the face 63 and the rounded section 53 is substantially equal to the length of the stem 37 on the first intermediate blank 36. As the header slide moves the die 56 toward the die 51 the stem portion 37 of the first intermediate blank 36 slides into the bore 52 in the die 51 until the end of the blank engages the forward face 63 of the ejector pin 61. At the same time the base section 38 of the first intermediate blank slides into the bore 57 until the end engages the forward face 61 of the backing pin 59. As the header slide continues to move the reciprocating die 56 toward the die 51 the base section 38 of the first intermediate blank is upset so as to fill the dies as shown in station 1 of Fig. 5. Since the stem 37 of the blank is relatively cool and the base section 38 is heated the upsetting of the enlarged section 64 of the second intermediate blank 54 does not result in any upsetting of the stem section. As the header slide moves away from the die breast the ejector pin 62 ejects the second intermediate blank 54 into transfer fingers (not shown) which position the blank at the second station of the second header 14.

The die 66 is mounted in the die breast at the second station of the second header 14 and is formed with a bore 67 having a cross section equal to the cross section of the stem of the finished compressor blade blank. At the forward end of the die 66 the bore is flared at as 68. The die 69 is mounted in the header slide of the second header 14 and is formed with a bore 71 having a cross section substantially equal to the cross section of the bore 57 in the die 56. The forward end of the bore 71 in the die 69 is flared as at 72. The flare 68 and the flare 72 are substantially similar so that the mouth size of the two dies 66 and 69 is equal. A backing pin 73 is mounted in the bore 71 with its forward face 74 spaced from the forward end of the die 69. An ejector pin 76 is mounted in the bore 67 of the die 66 with its forward face 77 spaced from the forward end of the die 66. As the header slide moves forward toward the die breast the stem of the second intermediate blank moves into the bore 67 until its end engages the forward face 77 of the ejector pin 76. At the same time the other end of the second intermediate blank moves into the bore 71 until it engages the forward face 74 of the backing pin 73. As the header slide continues to move toward the die 66 the root section 78 of the finished compressor blade blank 79 is upset thereby forming the finished compressor blade blank 79. Again, since the stem section of the second intermediate blank is relatively cool and since the large section 64 is relatively hot a large amount of upsetting may be accomplished at the root section 78 without the use of excessive pressures. As the header slide moves away from the die breast the finished compressor blade blank 79 is ejected by the ejector pin 76 thereby completing the process of forming the compressor blade blank.

Since the bore 57 in the die 56 and the bore 71 in the die 69 have a cross sectional area substantially equal to the area of the base section of the blank, a portion of the heated end of the blank is confined thereby preventing this portion of the blank from upsetting. This structure permits the upsetting of a portion of the blank spaced from the ends.

By combining the steps of reducing the cross section from stock of a larger size than the cross section desired in the stem 81 of the finished compressor blade blank, it is possible to forge an article wherein relatively large variations in cross section are present. By combining this method with the hot upsetting of the large root sections makes possible even larger variations in the cross section of the finished article.

It should be understood that although the forging method according to this invention, though particularly adapted to the formation of compressor blade blanks, is equally well adapted to the forging of other articles wherein large variations in cross section are desired.

Having completed a detailed description of a preferred embodiment of the present invention so that others skilled in the art may be able to understand and practice the same, I state that what I desire to secure by Letters Patent is not limited by said preferred embodiment but rather is defined in what is claimed.

I claim:

1. A method of extruding and forging elongated metal blanks having a stem portion of one cross section and a root section spaced therefrom of larger cross section comprising, the steps of extruding said stern portion of small cross section from a blank having substantial uniform cross section larger than said stern cross section and smaller than said large root portion, conveying said extruded blank so that the unextruded portion of the blank extends laterally from a conveyor, heating the entire unextruded portion of the blank as the conveyor moves the unextruded portion of the blank through a heating device, confining the extreme end of the heated unextruded portion of the blank in a die corresponding to the diameter of the unextruded portion, confining the extruded stern portion in a die corresponding to the extruded stem diameter, and exerting pressure longitudinally on said heated confined unextruded portion of the blank, whereby the heated unconfined portion of the unextruded portion is upset by the pressure to provide the enlarged upset root portion.

2. A method of extruding and forging elongated metal blanks having a stern portion of one cross section and a root section spaced therefrom of larger cross section comprising, the steps of extruding said stem portion of small cross section from a blank having substantial uniform cross section larger than said stem section and smaller than large root section, inserting the extruding stern portion of the blanks successively into spaced holders of a conveyor, leaving the unextruded stem portions projecting therefrom, conveying the extruded blanks through a heating zone to heat the entire unextruded portion of the blank, confining the extreme end of the heated unextruded portion of the blank in a die corresponding to the diameter of the unextruded portion, confining the extruded stem portions in a die correspoding to the unextruded stem diameter, and exerting pressure longitudinally on said heated confined unextruded portion of the blank, whereby the heated unconfined portion of the unextruded portion is upset by the pressure to provide the enlarged upset root portions.

References Cited in the file of this patent UNITED STATES PATENTS 1,430,399 Parsons et al. Sept. 26, 1922 1,668,442 Wineman May 1, 1928 1,803,803 Kaufman May 5, 1931 2,473,245 Hanna June 14, 1949 2,638,663 Bartlett et a1 May 19, 1953