Pipe-and-Tube-Welding,

SOLUTIONS with Effective, Powerful Advice

Pipe-and-Tube-Welding: Pipe Groove Welding Test Positions

Four main Pipe-and-Tube-Welding positions are used in pipe welding tests.

They are known as:

• (1G) the horizontal rolled flat position
• (5G) the horizontal fixed position
• (6G) the pipe inclined fixed position
• (2G) the pipe vertical, horizontal weld position .

• Find Specific information on Pipe-and-Tube-Welding in this page.
• Click-on links to Pipe-and-Tube-Welding requirement sources
  
• If you are involved in Pipe-and-Tube-Welding, you will find here practical know-how and further reference for assuring success in your job performance.

	Web www.welding-advisers.com

See our New Page on Metals Knowledge for assembling at no cost an Encyclopedia Online, a rich collection of valuable information on Metals, from expert Internet sources.

See the updated page now including detailed descriptions of suggested Welders suitable for covering a wide range of practical welding needs. Click on Arc Welding Equipment.

Processes

Almost all processes can be used for Pipe-and-Tube-Welding. The selection, as usual, is based on availability, expediency and economy.

SMAW (Shielded Metal Arc Welding)(stick) and GTAW (Gas Tungsten Arc Welding)(Tig) have been in use for years with a history of success in demanding applications of Pipe-and-Tube-Welding.
GTAW has been applied for thin walls of stainless steels and special alloys tubes or, with thicker pipes, for the root pass when quality is critical.

Both the above processes need a good measure of personal experience and skill for meeting product requirements, especially for high pressure and/or high temperature applications.

Although the economic advantages of higher productivity (measured as weld metal deposition rate) Pipe-and-Tube-Welding processes like GMAW (Gas Metal Arc Welding) and FCAW (Flux Cored Arc Welding) were recognized early, their practical application has been hindered by unsuccessful applications.

According to Ed Craig (www.weldreality.com), a well known authority with vast experience of these processes (on the applications of which he devotes training aids like books, articles and video courses), the main cause for their unsatisfactory utilization is an apathetic management attitude.

For a page from the Website of Ed Craig, presenting data on Pipe-and-Tube-Welding ASTM - API Carbon & Low Alloy Pipe Steels, click on Pipe Data. Further links are available therefrom.

To readers needing specific procedures for Pipe Welding, especially for GMAW, the Chapter Twelve from page 435 to page to page 512 of Ed Craig's book:
"A Management and Engineers Guide to MIG Welding
Quality-Costs-Training"
is highly recommended. The book is available from Ed's Website at
http://www.weldreality.com

The failure to recognize that GMAW and FCAW rest on process expertise with in-depth understanding of the influence of their many parameters, and not on manipulation skills, is responsible for letting those welders, who do not know any better, to come to terms with under rated conditions they feel comfortable with. Obviously any potential advantages of the methods for Pipe-and-Tube-Welding are lost in the process.

While we cannot claim to show in a short page a complete treatise on Pipe-and-Tube-Welding, we are going to present hereafter nonetheless a few of Ed Craig's recommendations, with his kind authorization.

Root pass joint preparation for outside GMA welding in position 1G (horizontal pipe, rotated) and 5G (horizontal pipe, fixed) on pipes of various diameters, from 6 to 13 mm (0.25 to 0.5 ") thick. Preferred dimension of pipe root face or land (straight length of the original face of pipe section between inside diameter and start of bevel): between 1.6 to 2.4 mm (1/16 to 3/32"). Preferred root gap: 4 mm +0.8 (5/32" +1/32).

This joint preparation is suitable for welding the root pass in Pipe-and-Tube-Welding with GMAW in the short circuit transfer mode. If the pipe is rotated, the vertical down welding technique is recommended. With the torch fixed between 1 and 2 o'clock, this is equivalent to counter-clockwise pipe rotation.

Total bevel angle recommended is 80 to 90 degrees (instead of the more common 60 degrees) to improve the conditions for complete fusion on the sides of the joint.

The development procedure for selecting the most suitable GMAW parameters for Pipe-and-Tube-Welding is summarized hereafter. It is based on the original Ed Craig's Seven Steps Weld Process Control Program for GMAW and FCAW of Pipes. Interested readers are urged to seek the full text in the said chapter of the above mentioned book. The following discussion is centered on Pipes and Tubes made of carbon or low alloy steel.

1. Determination of process consumable sizes and parameters. This is done by selecting the most probable satisfactory conditions, by Pipe-and-Tube-Welding test pieces on tube or plate, and by testing the results by means of metallographic sections of the welds, looking for absence of weld defects and for full fusion on the sides. The most promising parameters shell be selected from this experience.

2. Selection of the optimum gas mixture. Different mixes of different energy should be tried and the results assessed. 75-80 %Argon and 25-20%CO₂ (Carbon Dioxide) can be a suitable gas mix to start with.

3. Comparison of joint preparations, weld directions, gun positions and wire stick outs. Joint dimensions can be slightly altered to compare and obtain optimum results. Weaving technique may be selected for fill passes: changes have to be implemented and their influence tested on the specimens. Torch (Gun) angles must be selected and their influence evaluated. Wire stick out permits to control the energy in the pool. Shorten to increase, lengthen to decrease.

4. Initial weld procedure is almost ready. It should be tested by welding three real pipe coupons, and cross sectioning the welds every 25 mm (1"), polishing and etching for regular macro examination. If results are satisfactory, five coupons should then be welded by each of two welders, with the approved parameters.

   All the ten specimens should be x-ray inspected and then cross checked by ultrasonic testing. Finally the specimens shall be cut for side bend test and for further macro examinations.

   Documentation of all the results should be organized in a professional Report, with identification of the test pieces to be stored for documentation.

5. With the derived weld data, the Shop Pipe Weld Procedure should be established, with positive identification of the tolerances for each one of the parameters. It should be stressed to the workers that setting parameters outside the approved ranges is strongly forbidden.

   In the Weld Qualification Procedure all data previously collected demonstrating the compliance to requirements shall be organized and supplemented by non destructive and destructive test reports, with reference to radiographic films and to identified physical samples.

6. Establishment of Welder Training with Management concurrence, to make sure that every welder understands the importance of sticking to the approved parameters and moreover that all involved are sensitive to the potential for lack of fusion.

7. Establishment of practical, routine Quality Control procedures for determining that the production procedures are adhered to and that the results are constantly acceptable in time.

Several GMAW and FCAW procedure examples are given at the end of Chapter 12 on Pipe-and-Tube-Welding in the above recommended book from Ed Craig. Whoever is facing daily problems with the subject matter will gain much needed process expertise from learning at the source.

Materials:

Some of the most common pipe steels are reported hereafter.

ASTM A 53/A 53M
Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless
ASTM International
01-Oct-2004
22 pages
Click to Order.

ASTM A106/A106M-04b
Standard Specification for Seamless Carbon Steel Pipe for High-Temperature Service
ASTM International
01-Oct-2004
8 pages
Click to Order.

ASTM A381-96(2001)
Standard Specification for Metal-Arc-Welded Steel Pipe for Use With High-Pressure Transmission Systems
ASTM International
10-Sep-1996
5 pages
Click to Order.

Specifications.

ANSI/API STD 1104
Welding Pipelines and Related Facilities - 19th Edition - Includes errata dated October 31, 2001
American Petroleum Institute
01-Sep-1999
57 pages
Click to Order.

BS EN 288-9:1999
Specification and approval of welding procedures for metallic materials. Part 9.
Welding procedure test for pipeline welding on land and offshore site butt welding of transmission pipelines
British Standard / European Standard
15-Aug-1999
22 pages
Click to Order.

BS EN 287-1:2004
Qualification test of welders. Fusion welding. Steels
British Standard / European Standard
10-Mar-2004
42 pages
Click to Order.

ANSI/AWS D10.12M/D10.12-2000
Guide for Welding Mild Steel Pipe
American Welding Society
01-Jan-2000
48 pages
Click to Order.

ASME B31.1-2004
Power Piping
American Society of Mechanical Engineers
01-Sep-2004
328 pages
Click to Order.

For Standards and information on the Boiler and Pressure Vessel Industry, click on this Library. Special selections available of individual volumes and of packages from the ASME Boiler and Pressure Vessel Code. With a purchase, one gets 60 minutes of free online access to the Interpretations Database for the ASME Code.

For Standards and information on the Energy and Petrochemical Industry click on this Library.

For Standards and information on the Water and Wastewater Industry click on this Library.

An article on Pipe Welding was published in the Issue No. 11 of Practical Welding Letter for July 2004. Reference to different standards (also reported here) are given and also URLs (Internet addresses) to articles on particular aspects of the same subject, available online. To see the article click on PWL#011.

Another article on Parameters for GMA Welding Pipes (IV), complementary to this Web Page, was published in the Issue No. 26 of Practical Welding Letter for October 2005. To see the article click on PWL#026.

A short note on grinding (gouging) of the root pass of welds in thick Pipes was included in the Q&A department of Issue No. 13 of Practical Welding Letter for September 2004. Practical tips on welding thick wall pipes are included. To see the article click on PWL#013.

A short note on Orbital Tube Welding reviewing mechanized systems dedicated to perform circumferential welds of stationary tube ends was included in Department 9.2 of Issue No. 05 of Practical Welding Letter for January 2004. To see the article click on PWL#05.

An Article on Orbital Welding was published in Issue 51 of Practical Welding Letter for November 2007. Click on PWL#051 to read it.

To read all the Issues of Practical Welding Letter as they are published, please Subscribe.

So, if you are interested, we offer a opt-in no-cost subscription to our Practical Welding Letter and a book in pdf format to be made available for download to your computer on
PRACTICAL HARDNESS TESTING MADE SIMPLE. Please Subscribe.

To reach a Guide to the collection of the most important Articles from Past Issues of Practical Welding Letter, click on Welding Topics.

Any questions or comments or feedback? Write them down and send them to us by e-mail. Click on the Contact Us button in the NavBar at top left of every page.

Back Home
Site Map
to look for an updated Index of Subjects dealt with in this Website.

POWERED BY:

Click on this Logo NOW!

Copyright (c) 2005, 2006, 2007
by Elia E. Levi and
www.welding-advisers.com
All Rights Reserved

Pipe-and-Tube-Welding is an industrial activity very important for any economy. It pays to do it well. Read here how to...