Mechanical processing of high aspect ratio metallic tubing and related technology

Patent metadata

Field	Value
Publication number	US-9976675-B1
Application number	US-201715462733-A
Country	US
Kind code	B1
Filing date	Mar 17, 2017
Priority date	Jun 24, 2015
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

Tubes for use in ultrahigh pressure devices, and associated systems and methods of manufacture are disclosed herein. In one embodiment, a metal tube includes an elongate bore having a circular transverse cross-sectional shape. The metal tube also includes an elongate wall extending around the bore and having an annular transverse cross-sectional shape with an inner surface closest to the bore, an outer surface furthest from the bore, and a wall thickness extending from the inner surface to the outer surface. An inner portion of the wall is under swage-autofrettage-induced overall compressive stress.

First claim

We claim:

1. A metal tube, comprising:
an elongate bore having a circular transverse cross-sectional shape, wherein a ratio of a length of the tube to a diameter of the bore is greater than 90; and
an elongate wall extending around the bore, wherein an inner portion of the wall closer to the bore is under residual longitudinal compressive stress, and wherein an outer portion of the wall farther from the bore is under residual longitudinal tensile stress.

2. The tube of claim 1 wherein the inner portion of the wall is under residual overall compressive stress that includes the residual longitudinal compressive stress, residual tangential compressive stress, and residual radial compressive stress.

3. The tube of claim 2 wherein the residual overall compressive stress is substantially uniform throughout the length of the tube.

4. The tube of claim 1 wherein a ratio of a diameter of the tube to a diameter of the bore is greater than or equal to 2 and less than or equal to 5.

5. The tube of claim 1 wherein the tube is laterally flexible.

6. The tube of claim 1 wherein a ratio of a diameter of the tube to a diameter of the bore does not deviate by more than 15% throughout the length of the tube.

7. The tube of claim 1 wherein the residual longitudinal compressive stress is in the same longitudinal direction throughout the length of the tube.

8. The tube of claim 1 , further comprising:
first metal microstructures within the inner portion of the wall, wherein the first metal microstructures are dislocated in the same longitudinal direction throughout the length of the tube; and
second metal microstructures within the outer portion of the wall, wherein the second metal microstructures are not longitudinally dislocated.

9. The tube of claim 1 wherein the residual longitudinal compressive stress is swage autofrettage induced.

10. The tube of claim 1 , wherein a portion of the tube at a midpoint along the length of the tube is laterally displaceable relative to portions of the tube at opposite ends of the tube by a distance of at least 10% of the length of the tube without permanently deforming the tube.

11. The tube of claim 1 wherein the ratio of the length of the tube to the diameter of the bore is greater than 250.

12. The tube of claim 1 wherein the length of the tube is at least 15 feet, and wherein the diameter of the bore is at most 0.5 inch.

13. The tube of claim 1 wherein the outer portion of the wall is under residual overall tensile stress including the residual longitudinal tensile stress and residual tangential tensile stress.

Assignees

• Omax Corp

Inventors

• Raghavan Chidambaram
• Stang Darren

Classifications

• C21D9/14 Primary

  wear-resistant or pressure-resistant pipes · CPC title

• F16L9/02 Primary

  of metal (F16L9/16 - F16L9/22 take precedence) · CPC title

• B21D41/026

  by means of mandrels · CPC title

• B26F3/004

  by means of a fluid jet (methods for use of abrasive blasting for cutting B24C1/045; guns for abrasive fluid jets B24C5/02; perforating by non-mechanical means, e.g. by fluid jet B26F1/26) · CPC title

• C21D2261/00

  Machining or cutting being involved · CPC title