Phone:

281-255-4775

877-466-0055 (toll free)

Fax:

281-516-7878

www.vulcanfinnedtubes.com

1.0

SCOPE

1.1

This specification governs materials, fabrication, tolerances, and testing (where required) applicable to helical serrated finned tubes fabricated by Vulcan Finned Tubes, L.P. (“Vulcan”).

1.2

Where the term “tube” is used herein, the specification also applies to tubular goods normally designated as “pipe”.

2.0

TUBE SPECIFICATIONS

2.1

The base tube may be supplied by the customer or by Vulcan, as agreed between the two parties.

2.2

Mill test reports or other acceptable manufacturer’s certification shall be provided to the customer for all tubes supplied by Vulcan.

2.3

Length tolerance for tubes cut to length by Vulcan shall be as follows:

2.4

Tube ends shall be square-cut or beveled, as specified by the customer.  If beveled ends are specified, the bevel angle shall be 37-1/2 degrees, with a 1/16 inch land at the tube inside diameter.

3.0

FIN STRIP SPECIFICATIONS

3.1

Fin strip material shall be compatible with and suitable for gas metal arc (GMAW) welding to the specified tube material.

3.2

If requested by customer at time of order, Vulcan shall furnish mill test reports or other acceptable manufacturer’s certification for fin strip materials.

3.3

Fin strip thickness tolerance, measured before the strip is serrated and formed around and welded to the tube, shall be as follows:

4.0

FABRICATION

4.1

Before applying the fins, the tube outside surface shall be properly prepared to ensure that the fin-to-tube weld is sound.

4.2

Before being formed around and welded to the tube, the fin strip shall be cut, or serrated, at equally-spaced intervals across all but 1/4 inch of its height.  The serrations shall extend from the outside edge of the fin strip to a point 1/4 inch from the base of the fin strip.  The segment width, or distance between each serration, shall be approximately 0.32 inch.

4.3

The fin strip is helically wound on edge around the outside surface of the tube and attached to the tube with a continuous fillet weld.  The weld attaching the fin to the tube shall be by gas metal arc (GMAW) using the proper wire and gas combination for the tube and fin materials.

4.4

Inclination or “dishing” distortion of the fin resulting from forming the fin around the tube shall not exceed 10 degrees from the vertical.

4.5

The fin is considered to be non-load bearing and non-pressure containing.  The fin-to-tube weld is not considered a load-bearing or pressure-containing weld. 

4.6

Interruptions in the fin-to-tube weld are permissible, provided that the total length of any such interruptions on a finned tube does not exceed 2.5% of the total length of fin-to-tube weld on that finned tube.

4.7

Fin height after welding shall be as specified by the customer, plus or minus 1/32 inch, as measured from the outside diameter of the tube to the outside edge of the fin.

4.8

The number of fins per any 12-inch length of tube shall be as specified by the customer, within a tolerance of plus 5% and minus 2%.

4.9

Lateral warping of finned tubes shall not exceed 3/16 inch of lateral displacement in any 10-foot section of tube.

4.10

Length of any unfinned (bare) sections on the finished finned tube shall be as specified by the customer, within the following tolerances:

4.11

Any changes in hardness, grain structure, or other properties that occur in the weld-affected zone in the fin or tube wall shall be considered permissible.  Postweld heat treatment is not required.

5.0

INSPECTION

5.1

Upon receipt at Vulcan’s shop, tubes shall be visually inspected to verify dimensions and material specification and to ensure no obvious defects.

5.2

Prior to fabrication on the tube, fin material shall be visually inspected to verify dimensions and material specification and to ensure no obvious defects.  Fin material having any defects that may affect weld quality will not be used.

5.3

When the fin strip is interrupted during the finning process (for example, when a reel of fin material is finished and a new reel started), the new section of fin strip shall be placed end-to-end with the previously welded section, and the welding process continued.

5.4

All finned tubes shall be visually inspected after fabrication and prior to shipment.  All finned tubes shall have a workmanlike finish and be free from obvious defects.

6.0

MATERIAL TRACEABILITY

Traceability on tube material shall be maintained throughout the fabrication process.  For each length of tube/pipe, the operator shall record the heat number on a “Heat Sheet” before the tube/pipe is run through the abrasive sander in preparation for welding.  After each length of tube/pipe has been finned an adhesive trace label shall be attached near one end of the tube/pipe.  Trace labels shall report customer name, customer purchase order number, tube size, tube grade, and tube heat number.

7.0

PREPARATION FOR SHIPMENT

The Shop Order shall be packaged for shipment according to customer requirements.  Packing shall consist of either a metal banded crate constructed of plywood and 2x4 lumber; or “collars” consisting of at least two (depending on tube/pipe length) 2x4 metal banded frames.