Inertia welding of blades to rotors

A method for manufacturing an integrally bladed rotor includes fixturing a plurality of blade blanks having radially inwardly facing blade conical surfaces into a segmented blade ring assembly circumscribed around an axis. A rotor ring having a radially outwardly facing ring conical surface circumscribed around the axis is rotated to a contact speed. The rotor ring is fictionally engaged under an axially applied weld load with the blade ring assembly to effect a conical inertia weld along the mating blade conical surfaces and ring conical surface. The integrally bladed rotor includes a plurality of airfoils circumferentially distributed about and integral with a rim. The airfoils extend radially outwardly from respective airfoil bases on a radially outer flowpath surface of the rim to airfoil tips. A conical inertia weld is located between the airfoil tips and a radially inwardly facing rim surface of the rim.

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

The present invention relates generally to construction of gas turbine engine integrally bladed rotors and, more specifically, to inertia welding of blades to gas turbine engine rotors.

Fan, compressor and other gas turbine engine rotors may have a BLISK or a BLUM. BLISKS have blades that are integral with a disk and BLUMS have blades that are integral with a drum. Conventionally, BLISKS and BLUMS are made by machining an airfoil shape (using conventional machining or ECM/EDM processes) from a forged disk. Linear and angularly reciprocating friction welding methods have been under development for manufacturing BLISKS and BLUMS for gas turbine engine rotors. Angularly reciprocating friction welding includes the disc or drum rotor being angularly reciprocated while the airfoils or blades are pressed radially against the disk or rotor circumference. Linear reciprocating friction welding includes linear reciprocating airfoils or the blades as they are pressed radially against the disk or rotor circumference.

In friction welding, the disk is clamped, a blade is clamped in a reciprocating head of a machine, and the blade is rubbed against a surface of the disk in a reciprocating motion to generate frictional heat at an interface between the disk and the blade. When a predetermined loss of length is achieved, the blade is brought suddenly to a halt at a precisely defined location on the disk and is pressed against the disk for a short time to create the weld. When the blade and disk assembly has cooled flash at the interface is removed and any required machining operations are carried out.

One drawback to using BLISKS and BLUMS is the high manufacturing cost. The manufacturing processes described above are expensive and complex to perform on airfoil shapes, particularly, the complex shapes used today and being developed for future use. Additionally, the disk material and the airfoil material must meet different design requirements. Machining the blisk from one piece often requires compromises in the part design or material selection.

BRIEF DESCRIPTION OF THE INVENTION

A method for manufacturing an integrally bladed rotor includes fixturing a plurality of blade blanks having radially inwardly facing blade conical surfaces in a segmented blade ring assembly circumscribed around an axis. A rotor ring is rotated to a contact speed. The rotor ring has a radially outwardly facing ring conical surface circumscribed around the axis and mates to the blade conical surfaces. The rotor ring and the segmented blade ring assembly are frictionally engaged under an axially applied weld load to effect a conical inertia weld therebetween along the mating blade conical surfaces and ring conical surface. In one embodiment, each of the blade blanks includes an airfoil portion extending radially outwardly from an annular base portion and the base portion includes the mating blade conical surfaces. The base portion includes a radially outer conical surface parallel to the blade conical surface and the conical inertia weld passes through the airfoil portion. Completed airfoils and radially outer flowpath surface are formed by machining excess stock from the base portion and the rotor ring after the welding. Materials of the blade blanks and the rotor ring may be two different alloys.

In another embodiment, each of the blade blanks includes a rim portion of the integrally bladed rotor and the conical inertia weld is between the rim portions and a conical rotor ring. Holes may be machined in an annular region of the rim. The holes may be circumferentially evenly distributed within the annular region and centered along radii passing through interfaces the blade blanks.

The invention includes the integrally bladed rotor and the airfoils circumferentially distributed about and integral with the rim. The airfoils extend radially outwardly from respective airfoil bases on a radially outer flowpath surface of the rim to airfoil tips. A conical inertia weld is located between the airfoil tips and a radially inwardly facing rim surface of the rim.

DETAILED DESCRIPTION OF THE INVENTION

Illustrated in FIG. 1 is a portion of gas turbine engine integrally bladed rotor 10 . The portion may be from a fan or compressor and may be part of a BLISK or a BLUM. BLISKS have blades that are integral with a disk and BLUMS have blades that are integral with a drum. The integrally bladed rotor 10 includes a hub 80 , a web 82 extending radially outwardly from the hub to an annular rim 59 and circumscribed around an axis 22 . A plurality of airfoils 52 extend radially outwardly from, are circumferentially disposed about, and integral with the rim 59 . The airfoils 52 extend radially outwardly from respective airfoil bases 57 on a radially outer flowpath surface 44 of platforms 47 formed in the rim 59 to airfoil tips 61 . Forward and aft axial extensions 71 and 73 may be arms of a disk or annular rotor sections of a drum. The airfoils 52 include radially inner and outer sections 63 , 65 bonded together along a conical inertia weld 30 radially located between the bases 57 and the tips 61 . The inertia weld 30 is generally located between the tips 61 and a radially inwardly facing rim surface 60 of said rim 59 . The airfoils 52 and the rim 59 may be made from two different alloys.

The integrally bladed rotor 10 is manufactured in part by fixturing a plurality of blade blanks 14 into a segmented blade ring assembly 20 , illustrated in FIG. 5 , circumscribed around the axis 22 as illustrated in FIG. 6 . Rotation is effected between a rotor ring 24 and the blade ring assembly 20 such as by rotating the rotor ring 24 to contact speed for inertia welding as illustrated in FIG. 6 . The rotor ring and the segmented blade ring assembly 20 are frictionally engaged under an axially applied weld load 29 to effect the conical inertia weld 30 therebetween and along mating blade conical surfaces 18 of the blade blanks 14 and a ring conical surface 28 of the rotor ring 24 .

Referring to FIGS. 2 , 3 , and 4 , each one of the blade blanks 14 has an airfoil portion 32 extending radially outwardly from an annular base portion 34 . The base portion 34 includes the radially inwardly facing blade conical surfaces 18 and a radially outer conical surface 36 parallel to the blade conical surface 18 . The conical inertia weld 30 , illustrated in FIG. 1 , is effected between the annular base portions 34 and the rotor ring 24 . The completed airfoils 52 , the platforms 47 formed in the rim 59 , and the radially outer flowpath surface 44 are formed by machining excess stock 38 from the base portion 34 and the rotor ring 24 after the welding as illustrated in FIG. 1 . Final shapes of the airfoils 52 are machined after welding from the radially inner and outer sections 63 , 65 . Materials of the blade blanks 14 and the rotor ring 24 may be two different alloys.

Illustrated in FIGS. 7 , 8 , and 9 is an alternative embodiment of the blade blanks 14 , each of which includes a rim portion 39 used to form the rim 59 of the integrally bladed rotor 10 . The conical inertia weld 30 is formed between and bonds the rim portions 39 and a conical rotor ring 124 . The blade conical surfaces 18 are located on the rim portions 39 of the blade blanks 14 . The airfoils 52 and the rim 59 may be made from two different alloys. The integrally bladed rotor 10 is manufactured in part by fixturing the plurality of the blade blanks 14 , illustrated in FIG. 8 , into the segmented blade ring assembly 20 circumscribed around the axis 22 as illustrated in FIG. 8 . Rotation is effected between the conical rotor ring 124 and the blade ring assembly 20 such as by rotating the conical rotor ring 124 to contact speed for inertia welding as illustrated in FIG. 9 . The conical rotor ring 124 and the segmented blade ring assembly 20 are frictionally engaged under an axially applied weld load 29 to effect a conical inertia weld 30 therebetween and along mating blade conical surfaces 18 of the blade blanks 14 and a ring conical surface 28 of the conical rotor ring 124 as illustrated in FIG. 10 .

Illustrated in FIG. 11 are the completed airfoils 52 , the platforms 47 formed in the rim 59 , and the radially outer flowpath surface 44 are formed by machining the excess stock 38 from the rim portion 39 base and the conical rotor ring 124 after the welding. The rim 59 is formed from the rim portions 39 of the blade blanks 14 and the conical rotor ring 124 . The airfoils 52 extend radially outwardly of and are formed integral with a radially outer annular portion 62 of the rim 59 . The radially outer annular portion 62 has a radially inwardly facing conical boundary 64 and is formed from the rim portions 39 of the blade blanks 14 . A radially inner portion 66 of the rim 59 is machined from the conical rotor ring 124 and has a radially outwardly facing conical boundary 68 . The conical inertia weld 30 is disposed between the radially inner and outer annular portions 66 , 62 of the rim 59 along the radially inwardly and outwardly facing conical boundaries 64 , 68 .

Holes 48 may be machined in an annular region 50 of the rim 59 after the welding. The holes 48 may be circumferentially evenly distributed within the annular region 50 and centered along radii 56 passing through interfaces 58 between segments 70 of the outer annular portion 62 of the rim 59 formed by the blade blanks 14 . The annular region 50 is located in the welded together rim portions 39 and the conical rotor ring 124 .

While there have been described herein what are considered to be preferred and exemplary embodiments of the present invention, other modifications of the invention shall be apparent to those skilled in the art from the teachings herein and, it is therefore, desired to be secured in the appended claims all such modifications as fall within the true spirit and scope of the invention. Accordingly, what is desired to be secured by Letters Patent of the United States is the invention as defined and differentiated in the following claims.