Patent Publication Number: US-3880550-A

Title: Outer seal for first stage turbine

Description:
United States Patent 1 Corey et al.  
 .[ Apr. 29, 1975 1 OUTER SEAL FOR FIRST STAGE TURBINE [75] Inventors: Arthur F. Corey. Glastonbury:  
 Bruce E. Snyder. South Windsor. both of Conn.  
 [731 Assignee: The United States of America as represented by the Secretary of the Air Force, Washington. DC.  
 [22] Filed: Feb. 22, 1974 [21] Appl. No.: 445.047  
 [52] US. Cl 415/174; 277/96 [51] Int. Cl. F0ld 11/00 [58] Field of Search 415/174&#39;, 277/96 [56] References Cited UNITED STATES PATENTS 2.742224 4/1956 Burhans 415/174 3.092.306 6/1963 Edcr 415/174 3.291.382 12/1966 Blackhurst et 415/174 3.537.713 11/1970 Matthews et al. 415/174 Primary E.\&#39;uminerRobert 1. Smith ASS/Mil!!! E.\&#39;aminerRobert 1. Smith Allvrney. Agent. or Firm-Harry A. Herbert, Jr.; Richard J. Killoren [57] ABSTRACT An outer air seal for the first stage turbine of an engine having the seal segments made of a high strength base material with a highly oxidation-corrosion resistant abradable alloy layer bonded to the surface thereof on the side adjacent the rotor blade. Another embodiment having an abrasive layer bonded to the high strength base material with the abradable layer being bonded to the abrasive layer.  
 4 Claims, 3 Drawing Figures OUTER SEAL FOR FIRST STAGE TURBINE RIGHTS OF THE GOVERNMENT The invention described herein may be manufactured and used by or for the Government of the United States for all governmental purposes without the payment of any royalty.  
 BACKGROUND OF THE INVENTION The outer air seals for the first stage turbine of the TF30 engine and the JT9D engine use a single material for the seal segments. The material is selected with a compromise between strength and corrosion resistance. In the past, abradable surfaces on the seals have prior art structure except the seal 14.  
  The seal segments 16, one of which is shown in FIG. 2, have a base member 24 of a material PWA 647 or PWA 663 with highly oxidation-corrosion resistant abradable layer 26 of PWA 1045 NiCrAlY diffusion bonded to the base material by heating for 1 hour to between 1,300 and 1.400F in a vacuum at a pressure between 145 and 275 meganewtons per square meter and then postheating two hours to between 1,900 and 2,l50F at a pressure of about 15 meganewtons per square meter. Before bonding the surfaces are cleaned by sanding and then either chemical polishing or electropolishing. The material PWA 662, PWA 647 and PWA 1045 will be described in greater detail below.  
 been used but these have been unsuccessful since a A modlficatlon of the devlce of FIGS. 1 and 2 compound of sufficient abradabihty without undesirshown in FIG. 3. In this device. the seal segments 16 able side effects, such as corrosion, had not been have a layer 28 of abrasive material WS-6 bonded to found. Thus, abradable surfaces were eliminated and the desi n returned to sin le material se&#39;tl se ments the base member wlth the abradable layer 26 of PWA g g g 1045 being bonded to the abrasive layer 28. This will BRIEF SUMMARY OF THE INVENTION allow incrusion of the moving rotor blade tip into the A I abradable layer until it reaches the abrasive layer Ccor mg to f bed g are T whereupon some machining of the blade tip by the vlded for the outer seal of the first stage turbine abrasive laygr would occur wherein a highly oxidation-corrosion resistant abradas The Composition f the materials PWA 1045 PWA able alloy 15 bonded to a strong high temperature alloy, 661 PWA 647 d W5 5 are given i h f ll i thus eliminating the property compromise necessitated table wherein the parts by weight given are of 100 total by the use of a single alloy. In another embodiment, an parts.  
 PWA 1045 PWA 663 PWA 647 WS 6 Aluminum 55 6.0 Bismuth 0.5 PPM max Boron 0.003 max 0.015 0.01 max Carbon 0.05 0.1 1 0.6 0.9 Chromium 16.00 8.0 23.4 25.0 Cobalt 10.0 Remainder Remainder Columbium 0.10 max 1.0 Iron 0.75 max 0.35 max 1.50 max 1 0 Lead 10 PPM max Manganese 0.50 max 0.20 max 0.10 max Molybdenum 6.0 Nickel Remainder Remainder 10.0 15.0 Phosphorous 0.015 max Silicon 0.40 max 0.25 max 0.40 max Sulfur 0.015 max 0.015 max 0.015 max Tantalum 4.25 3.5 2.75 Titanium 1.0 0.2 0.9 Tungsten 0.10 max 7.0 7.75 Yttrium 0.2 Zirconium 0.075 0.45 0.4  
 abrasive material is bonded to the high strength mate- The terms PWA 1045, PWA 663, PWA 647 and rial with the highly oxidation-corrosion resistant layer S-6 as us d in th specification and clalms will Indibeing bonded to the abrasive material. Cate the Composition as given in thls table- In some applications, other alloys than those given IN THE DRAWING may be used for the base member 24. FIG. 1 is a partially schematic cut away sectional Them 15 thus provldefi an P Outer Seal of view of the first stage turbine of an engine with the the first slage Ofa turbme engmeouter air seal of the invention. We  
  1. An outer seal for the first stage of a turbine engine,  
  FIG. 2 is an elongated sectional view of an outer air seal of the device of FIG. 1.  
  FIG. 3 is an enlarged sectional view of an outer air seal for the device of FIG. 1 according to another embodiment of the invention.  
 DETAILED DESCRIPTION OF THE INVENTION Reference is now made to FIG. 1 of the drawing which shows the first stage rotor assembly 10 having rotor blades 12, one of which is shown. positioned adjacent the outer air seal 14. The outer air seal 14 has a plurality of segments 16 positioned around the rotor assembly. The segments 16 are supported on support elements 18 and 20 on a support member 21 which are supported on the outer case 22. All of this structure is comprising an annular seal segment support member surrounding the blades of the first stage of the turbine engine; a plurality of seal segments supported on the seal segment support member; said seal segments having a layer of PWA 1045 sheet material bonded to a high strength Nickel-Chrominum alloy base material.  
  2. The device as recited in claim 1 wherein the high strength base material is PWA 663.  
  3. The device as recited in claim 1 wherein the high strength base material is PWA 647.  
  4. The device as recited in claim 1 wherein an abrasive layer of WS-6 is bonded to the high strength base material between the base material and the sheet of PWA 1045.