METHOD OF TUBING MANUFACTURING
A method of tubing manufacture comprising forming a tube having an internal artifact projecting radially inward from a tube inner surface, retaining the tube in a fixture, broaching an end of the tube to remove a longitudinal portion of the internal artifact which longitudinal portion is less than a total length of the tube, finishing the radius of the internal artifact so it is substantially equal to a radius (R1) of the adjacent inner surface, and forming a single flare on the end of the tube.
The invention relates to a method of tubing manufacturing, and more particularly, to a method of tubing manufacturing comprising broaching a tube to remove a longitudinal portion of an internal artifact which longitudinal portion is less than the total length of the tube, and a finished radius of the internal artifact is substantially equal to a radius of the adjacent inner surface.
BACKGROUND OF THE INVENTIONGenerally, broaching is a metal manufacturing process by which a metal blank is formed to a final or near final shape by use of a die. The metal blank can either be pressed or pulled through the die, and can move either linearly or in a rotary motion. Passing the metal blank through the die cuts the metal blank to the desired final shape.
Broaching can be used to form either an interior or an exterior surface. Forming an exterior surface of a workpiece is also called pot broaching.
Blind broaching refers to use of a broach which does not pass completely through the work piece, but instead extends only partially into the piece. Blind broaching is typically applied in situations where only a short throw is required, hence it is not used when machining multi-foot lengths of tube and pipe.
Tubing and pipe can be made using a number of methods which include seam welding. Seam welded tubing comprises rolling flat stock into a round shape, and then joining the adjacent edges by welding. The welding process will typically leave a weld bead and slag. The weld bead or slag may need to be removed depending on the intended use of the tubing. The weld bead or slag can interfere with fluid flow or the intended method of endforming terminations for joining lengths of the tubing to each other.
Endforming terminations directly on tubing allows a manufacturer to produce a leak-free connection for hydraulic systems. In order to create proper terminations, a manufacturer may create physical interferences between a punch, the tubing, and a set of clamping blocks. This reduces the cost of brazing or-welding the terminations on the tubing ends. However, while endforming is often more cost effective than welding or brazing, endforming often requires the use of drawn-over-mandrel (DOM) tubing instead of less costly non-DOM material. Non-DOM tubing is much more cost effective, but is not allowed for certain termination styles due to an internal weld seam being present. The weld seam has a negative impact on sealing performance, as the effected sealing surface may leak in the weld seam area through a weld undercut.
Representative of the art is U.S. Pat. No. 6,887,020 which discloses a device for deburring the inside of a longitudinally seam-welded pipe includes a retention arm secured outside the pipe in the area of the pipe that is not yet closed and having an end zone which is located behind the welding spot. Arranged on the retention arm is a frame part which is tiltable in longitudinal direction of the pipe about a tilt axis and provided with a scraping tool. The tilt axis of the frame part is hereby located, as viewed in advancing direction, behind the scraping point at the end of the frame part. An adjustment mechanism is provided on the forward end of the frame part for adjusting the tilt angle.
What is needed is a method of tubing manufacturing comprising broaching the tube to remove a longitudinal portion of an internal artifact which longitudinal portion is less than the total length of the tube, and a finished radius of the internal artifact is substantially equal to a radius of the adjacent inner surface. The present invention meets this need.
SUMMARY OF THE INVENTIONThe primary aspect of the invention is to provide a method of tubing manufacturing comprising broaching the tube to remove a longitudinal portion of an internal artifact which longitudinal portion is less than the total length of the tube, and a finished radius of the internal artifact is substantially equal to a radius of the adjacent inner surface.
Other aspects of the invention will be pointed out or made obvious by the following description of the invention and the accompanying drawings.
The invention comprises a method of tubing manufacture comprising forming a tube having an internal artifact projecting radially inward from a tube inner surface, retaining the tube in a fixture, broaching an end of the tube to remove a longitudinal portion of the internal artifact which longitudinal portion is less than a total length of the tube, finishing the radius of the internal artifact so it is substantially equal to a radius (R1) of the adjacent inner surface, and forming a single flare on the end of the tube.
The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the present invention, and together with a description, serve to explain the principles of the invention.
The angle α of the flare may be in the range of 35° to 90°, allowing for use in a wide range of applications. For example, a flare angle of 37° is well suited for certain coupling applications.
As shown in
A finished radius of the broached weld seam 13 is substantially equal to a radius (R1) of the adjacent internal surface 15. That is, the surface of the broached weld seam blends with the surface of the adjacent tube inner surface 15. The broach stroke is of a depth sufficient to remove the projecting weld seam plus any undercut in the weld seam which may otherwise provide a leak path.
The inventive method can be used to make tubing manufactured under SAE J356 compliant with SAE J525 for single flare use.
In an alternative method the tubing may be machined or turned using a cutting tool to remove the inward projecting weld bead up to a distance D1.
Method.
The tubing is typically manufactured according to SAE Standard J356, but may also be manufactured using any method which results in a weld bead on an inner surface. The method of tubing manufacture comprises forming a tube having an internal artifact, namely a weld bead, projecting radially inward from a tube inner surface. Tube 10 is then clamped in a fixture 400. A linear broach of the tube is performed using punch 300 to remove a longitudinal portion of the internal artifact which longitudinal portion is less than a total length of the tube. The radius of the internal artifact after the broach is substantially equal to a radius (R1) of the adjacent inner surface. A single flare is then applied to the broached end of the tube. The single flare may be used with single flare tube fittings.
All numeric values provided herein are by way of example only, and are not intended to limit the scope of the invention.
Although a form of the invention has been described herein, it will be obvious to those skilled in the art that variations may be made in the construction and relation of parts without departing from the spirit and scope of the invention described herein.
Claims
1. A method of tubing manufacture comprising:
- forming a tube having an internal artifact projecting radially inward from a tube inner surface;
- retaining the tube in a fixture;
- broaching an end of the tube to remove a longitudinal portion of the internal artifact which longitudinal portion is less than a total length of the tube;
- finishing the radius of the internal artifact so it is substantially equal to a radius (R1) of the adjacent inner surface; and
- forming a single flare on the end of the tube.
2. The method of tubing manufacture as in claim 1 comprising extending the broach within the tube for a longitudinal distance that is at least greater than a radius of the tube.
3. The method of tubing manufacture as in claim 1, wherein the internal artifact is a weld bead.
4. The method of tubing manufacture as in claim 1, wherein the broach is linear.
5. The method of tubing manufacture as in claim 1, wherein the weld bead is chamfered.
6. The method of tubing manufacture as in claim 1 comprising forming a second flare in the end of the tube.
7. A method of tubing manufacture comprising:
- forming a tube having a weld bead projecting radially inward from a tube inner surface;
- retaining the tube in a fixture;
- broaching the tube a longitudinal distance at least greater than a radius of the tube to remove a longitudinal portion of the weld bead, which longitudinal portion is less than a total length of the tube;
- finishing the radius of the weld bead so it is substantially equal to a radius (R1) of the tube; and
- flaring the broached end of the tube.
8. The method as in claim 7 comprising applying a second flare to the broached end of the tube.
9. The method as in claim 7 wherein the flare comprises an angle of approximately 37°.
Type: Application
Filed: Dec 19, 2014
Publication Date: Jun 23, 2016
Inventor: Patrick McNamee (Monument, CO)
Application Number: 14/577,142