Tube and a method of manufacturing a tube

Patent metadata

Field	Value
Publication number	US-11446722-B2
Application number	US-201616093679-A
Country	US
Kind code	B2
Filing date	Nov 14, 2016
Priority date	Apr 22, 2016
Publication date	Sep 20, 2022
Grant date	Sep 20, 2022

Abstract

A high temperature iron-chromium-aluminium (FeCrAl) alloy tube extending along a longitudinal axis, wherein the tube is formed from a continuous strip of a high temperature FeCrAl alloy and comprises a helical welded seam. The high temperature FeCrAl alloy tube is manufactured by feeding a continuous strip of the high temperature FeCrAl alloy toward a tube shaping station, helically winding the strip such that long edges of the strip abut each other and a rotating tube moving forward in a direction parallel to its longitudinal axis is formed, and continuously joining said abutting long edges together in a welding process directly when the tube is formed, whereby a welded tube comprising a helical welded seam is obtained.

First claim

The invention claimed is:

1. A high temperature iron-chromium-aluminium alloy tube extending along a longitudinal axis, comprising a helical welded seam,
wherein the tube has an inner diameter that is constant or almost constant along the longitudinal axis of the tube,
wherein the tube is formed from a continuous strip of an iron-chromium-aluminium alloy, and
wherein the iron-chromium-aluminium alloy comprises:
5-25 wt. % Cr,
4-6 wt. % Al,
0-5 wt. % Mo,
0.01-0.60 wt. % Y, and
the balance being Fe and normally occurring impurities, and
optionally other intentionally added alloying elements, and

wherein the high temperature iron-chromium-aluminium alloy tube is annealed.

2. The high temperature iron-chromium-aluminium alloy tube according to claim 1 , wherein the tube has a wall thickness of 0.5-7.5% of an inner diameter of the tube.

3. The high temperature iron-chromium-aluminium alloy tube according to claim 2 , wherein the tube has a wall thickness of 0.5-4.5% of an inner diameter of the tube.

4. The high temperature iron-chromium-aluminium alloy tube according to claim 1 , wherein the helical welded seam extends at a helix angle of 1 to 89° with respect to the longitudinal axis of the tube.

5. The high temperature iron-chromium-aluminium alloy tube according to claim 4 , wherein the helical welded seam extends at a helix angle of 40-70° with respect to the longitudinal axis of the tube.

6. The high temperature iron-chromium-aluminium alloy tube according to claim 1 , wherein the iron-chromium-aluminium alloy comprises:
9-25 wt. % Cr;
4-6 wt. % Al;
0-5 wt. % Mo;
0.05-0.60 wt. % Y;
the balance being Fe and normally occurring impurities, and
optionally other intentionally added alloying elements.

7. The high temperature iron-chromium-aluminium alloy tube according to claim 1 , wherein content of Cr in the iron-chromium-aluminium alloy is 11 to 17 wt. %.

8. The high temperature iron-chromium-aluminium alloy tube according to claim 1 , wherein content of Cr in the iron-chromium-aluminium alloy is 5 to 15 wt. %.

9. The high temperature iron-chromium-aluminium alloy tube according to claim 1 , wherein content of Cr in the iron-chromium-aluminium alloy is 20.5 to 25 wt. %.

10. The high temperature iron-chromium-aluminium alloy tube according to claim 1 , wherein content of Mo in the iron-chromium-aluminium alloy is 1 to 4 wt. %.

11. The high temperature iron-chromium-aluminium alloy tube according to claim 1 , further comprising 0.1 to 3 wt. % Si.

12. The high temperature iron-chromium-aluminium alloy tube according to claim 1 , wherein the alloying elements include one or more elements selected from:
0.01-0.40 wt. % Zr;
0.05-0.50 wt. % Hf;
0.05-0.50 wt. % Ta;
0-0.10 wt. % Ti;
0.01-0.05 wt. % C;
0.01-0.06 wt. % N;
0.02-0.10 wt. % O;
0.05-0.50 wt. % Mn;
0-0.08 wt. % P;
0-0.005 wt. % S.

13. The high temperature iron-chromium-aluminium alloy tube according to claim 1 , wherein the alloying elements include one or more elements selected from:
0.01-0.1 wt. % C;
0.001-0.1 wt. % N;
0.02-0.10 wt. % O;
0-0.01 wt. % B;
0-0.5 wt. % Mn;
0-0.2 wt. % total of Sc+Ce+La;
0-1.7 wt. % Ti;
0-0.4 wt. % Zr:
0-0.4 wt. % Nb:
0-0.1 wt. % V:
0-0.3 wt. % total of Hf+Ta+Th.

14. The high temperature iron-chromium-aluminium alloy tube according to claim 11 , wherein content of Si in the iron-chromium-aluminium alloy is 0.5 to 3 wt. %.

15. The high temperature iron-chromium-aluminium alloy tube according to claim 11 , wherein content of Si in the iron-chromium-aluminium alloy is 0.10-0.70 wt. %.

16. A method of manufacturing an high temperature iron-chromium-aluminium alloy tube having almost a constant or almost constant inner diameter extending along a longitudinal axis, comprising the steps of:
preheating a continuous strip of an high temperature iron-chromium-aluminium alloy;
feeding the preheated continuous strip of the high temperature iron-chromium-aluminium alloy toward a tube shaping station;
helically winding the strip in the tube shaping station such that long edges of the strip abut each other and a rotating tube moving forward in a direction parallel to its longitudinal axis is formed;
continuously joining said abutting long edges together in a welding process directly when the high temperature FeCrAl alloy tube is formed, whereby a welded high temperature FeCrAl alloy tube comprising a helical welded seam is obtained; and
annealing the formed high temperature FeCrAl alloy tube,
wherein the iron-chromium-aluminium alloy comprises:
5-25 wt. % Cr,
4-6 wt. % Al,
0-5 wt. % Mo,
0.01-0.60 wt. % Y, and
the balance being Fe and normally occurring impurities, and
optionally other intentionally added alloying elements.

17. The method according to claim 16 , wherein the welding process is selected from a fusion welding process or a solid state joining process.

18. The method according to claim 16 , wherein the welding process is selected from one of a tungsten inert gas welding process, a metal inert gas welding process, a laser welding process, and a plasma arc welding process.

19. The method according to claim 16 , wherein a shielding gas is used during the welding process, wherein the shielding gas is an inert gas.

20. The method according to claim 19 , wherein the shielding gas consists of Argon, Helium, or a mixture thereof.

21. A heating device comprising a radiant tube, wherein the radiant tube is the high temperature iron-chromium-aluminium alloy tube according to claim 1 .

Assignees

• Sandvik Intellectual Property

Inventors

• Wickman Krister

Classifications

• C21D8/10

  during manufacturing of tubular bodies · CPC title

• B21C37/12 Primary

  Making tubes or metal hoses with helically arranged seams · CPC title

• B23K26/302

  of helicoidal seams · CPC title

• B23K2103/02

  Iron or ferrous alloys · CPC title

• C21D9/08

  for tubular bodies or pipes · CPC title