CA1229227A - Composite metal anchor for refractory linings - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Disclosed is a composite metal anchor for securing castable refractory materials to structural supporting members wherein the anchors are constructed such that their tine section is comprised of an oxide dispersion strengthened alloy which is butted to a lower shank section comprised of an austenitic or ferritic alloy.

Description

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2 The present invention relates to a composite

3 metal anchor member for securing a cartable refractory

4 to structural supporting member, such as the interior wall of a high temperature reaction vessel.

7 There are many metal components, such as 8 reaction vessels and piping, used in the petroleum and 9 petrochemical industries which are employed in eon-erosive or erosive environments, or both, at elevated 11 temperatures and pressures. Because such environments 12 are deleterious to the surfaces of metal components, 13 the metal surfaces are generally protected with one or 14 more layers of refractory materials the refractory material is conventionally held in place by metal 16 anchoring members which are usually butt welded to the 17 metal surfaces. The refractory material is then 18 applied, usually gunned, over the surface of the metal 19 of sufficient thickness to cover the anchoring mom-biers.

21 Examples of refractory anchoring members 22 conventionally employed can be found in So Patent 23 No. 2,525,821, as well as the following publications:
24 Cut Installed Cost With Stud Welded Refractory Anchors, by H. A. Chambers, Hydrocarbon Processing, 26 December 1971; and Metal Anchors For Refractory Con-27 Crete by M. S. Rowley, Ceramic Bulletin, Vol. 45 No.
28 7, 1966.

~ZZ92;;:7 1 Although some of the conventional refractory 2 metal anchoring members have met with various degrees 3 of success, all such anchoring members are subject to 4 corrosion at sections which are closest to the front, or hot face, of the refractory lining. That is, the 6 temperature at the hot face area of the lining is 7 generally very high and corrosive moieties of the 8 process stream will diffuse through the refractory g material and attack the metal anchoring member. Cons-quaintly, the anchoring system is weakened, leaving Thea refractory layer subject to spelling.

13 In accordance with the present invention, 14 there is provided composite Y-shaped metal anchor 15 members for anchoring cartable refractory material to 16 a structural supporting member. The anchor members are 17 constructed such that their tine section, and at least 18 some upper portion of their shank section, are come 19 prosed of an oxide dispersion strengthened alloy which is butted to a lower shank section comprised of an 21 austenitic or ferritic alloy.

22 In one preferred embodiment of the present 23 invention, the shopped metal anchor members are of 24 circular cross-section and the oxide dispersion 25 strengthened alloy is an iron, nickel, or cobalt based 26 alloy containing yttria as its dispersed oxide.

27 In other preferred embodiments of the pros-28 en invention, the anchor members are employed for 29 securing a cartable refractory to a high temperature 30 reaction vessel or high temperature piping.

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BRIEF DESCRIPTION OF THE FIGURES
_ Figure 1 is a vertical, cross-section view of a typical reaction vessel embodying the invention;
Figure 2 is a vertical plan view of a preferred embodiment of metal anchoring member in accordance with the invention;
DETAILED DESCRIPTION OF THE INVENTION
-Referring to the drawings, particularly Figure 1, a reaction vessel generally indicated at 10 includes an outer metal shell 12 having an inlet flange 14 and an outlet flange 16. The inner wall of the metal vessel includes a plurality of the Y-shaped metal anchor members 22 of the present invention. The anchor members are typically butt welded at the ends of their outer shank to the inner wall of the vessel.
Contiguous to the inner wall of the vessel and super-imposed over the anchoring members is a refractory insulating layer 18 which is of a sufficient thickness to completely cover the anchoring members. The refractory insulating layer I may be comprised of any conventional cartable refractory material suitable for thermal insulation purposes. These are usually materials having a relatively low density Referring more particularly to Figure 2, a composite Y-shaped metal anchor member generally indicated at 22 includes a tine section 24 which also includes a shank section which is jutted to a lower shank section 26. The tine section 12 is comprised of r ~L~229227 1 an oxide dispersion strengthened alloy based on a 2 metal selected from the group consisting of iron, 3 nickel, and cobalt. Such alloys are dispersion 4 strengthened by the uniform dissemination of a rota-lively large number of discrete sub-micron sized no-6 factory particles throughout the metal matrix. The 7 refractory particles, in this case oxides, serve to 8 stabilize the matrix micro structure at elevated them-g portrays, thereby increasing its tensile strength and 10 stress rupture life at elevated temperatures. These 11 alloys, as well as their preparation, are described in 12 US. Patent No. 3,591,362 issued July 6, 1971 to Into 14 By employing an oxide dispersion strength-15 eyed alloy in the tine section of the anchor members 16 of the instant invention the anchor members will have 17 a substantially greater life expectancy when used for 18 securing cartable refractory materials to metal sup-19 port members when such support members are subjected 20 to high temperature corrosive environments. That is, 21 the tine section being the upper most section of the 22 anchor member, will be more resistant to corrosion in 23 the event that corrosive moieties diffuse through the 24 protective refractory layer.

The tine section 24 of the Y-shaped come 26 posit metal anchor members of the present invention 27 includes a shank section comprised of the same alloy 28 as that of the tine section and is of course molded or 29 machined from the same material. This tine section is 30 attached to a lower shank section 14 which is comprise 31 Ed of an austenitic or ferritic alloy which is prefer-32 ably weldable to the metal support member and which 33 preferably has substantially the same coefficient of 34 expansion as the metal support member. of course, ~L2~292;27 1 other suitable means for attaching the anchor members 2 to the metal support member may also be employed here-3 in. Such other suitable means would include mechanical 4 coupling.

Any suitable conventional joining method may 6 be used for joining the tine section to the lower 7 shank section of the anchors of the present invention.
8 Non limiting joining methods which may be used herein g include brazing, friction welding and mechanical coupling (threaded). Preferred is friction welding.

11 Non-limiting examples of refractory ma-12 Tories which may be used in the practice of the 13 present invention include various fire clays, dip 14 atomizes earths, magnesite, concrete, mixtures of metallic oxides and cement, diatomaceous earths and 16 cement, and the like. The refractory material, and 17 water, are prepared and pressure sprayed, gunned, or 18 troweled into place over the anchor members and 19 allowed to dry in situ. Enough refractory material is applied so that the anchor members are completely 21 covered. Preferably, enough refractory material is 22 applied such that the upper portion of the tines of 23 the anchor members are at least about 1/2 inch from 24 the hot face surface of the refractory layer.

Non-limiting examples of metal support 26 members to which the composite anchoring members of 27 the present invention may be butted include reaction 28 vessels, piping, furnace tube sheets and burner fin-29 ins.

While specific embodiments of the present 31 invention have been shown and described in detail to 32 illustrate the application of the inventive prince-12292;~7 1 pies, it will be understood that the invention may be embodied or practiced otherwise without departing from 3 such principles.

Claims (4)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A corrosion resistant composite Y-shaped metal anchor for anchoring a castable refractory ma-terial to a structural supporting member, which anchor is characterized by having: (i) its tine section com-prised of an oxide dispersion strengthened alloy; and (ii) a shank section comprised of an austenitic or ferritic alloy.

2. The anchor of claim 1 wherein the tine section is comprised of an iron, nickel, or cobalt based oxide dispersion strengthened alloy and its lower shank section is an austenitic alloy.

3. A method for anchoring a refractory material to a structural supporting member comprising the steps of fastening a plurality of Y-shaped metal-lic anchors to the interior surface of the supporting member, spraying a castable layer of refractory ma-terial onto said interior surface of sufficient thick-ness to cover the metallic anchors, wherein said anchors are characterized by having: (i) a tine sec-tion comprised of an iron, nickel, or cobalt based oxide dispersion strengthened alloy; and (ii) a lower shank section comprised of an austenitic or ferritic alloy.

4. The method of claim 3 wherein the anchors are welded to the structural support member.