Page 71 - Pipeline Rules of Thumb Handbook

58 Pipeline Rules of Thumb Handbook

Lens shade selector

Operation Shade No. Operation Shade No.

Nonferrous
Soldering 2
Gas Tungsten-Arc Welding
Torch Brazing 3 or 4
Gas Metal-Arc Welding
1/16, 3/32, 1/8, 5/32 inch electrodes 11
Oxygen Cutting
up to 1 inch 3 or 4 Ferrous
1 to 6 inches 4 or 5 Gas Tungsten-Arc Welding
6 inches and over 5 or 6 Gas Metal-Arc Welding
1/16, 3/32, 1/8, 5/32 inch electrodes 12
Gas Welding
Shielded Metal-Arc Welding
up to 1/8 inch 4 or 5
3/16, 7/32, 1/4 inch electrodes 12
1/8 to 1/2 inch 5 or 6
5/16, 3/8 inch electrodes 14
1/2 inch and over 6 or 8
Atomic Hydrogen Welding 10 to 14
Shielded Metal-Arc Welding
1/16, 3/32, 1/8, 5/32 inch electrodes 10 Carbon-Arc Welding 14

Reprinted with permission—Tube Turns, Inc.

PIPELINE WELDING

Meeting Today’s Quality Requirements For Manual Vertical Down Techniques

Pipelines are inspected more critically than ever before years ago. Therefore, it will take a change in the attitude of
and today’s radiographic equipment and techniques produce the welders and everyone else involved if this new level of
clearer radiographs with greater sensitivity than in the past. quality and workmanship is to be met. In turn, a commitment
Although codes have not changed drastically, interpretation to new methods, equipment and theory will be required by
standards have been upgraded. The combination of more all concerned.
rigorous inspection, better testing methods, and high accept-
ability standards often approaches an attitude requiring zero
Importance of joint preparation
defects.
This poses some serious problems because the job of
It must be recognized that all joint preparation details
welding cross-country pipelines under typical conditions has
(Figure 6) are critical and any variation could directly con-
always been an extreme challenge requiring specialized and
tribute to rejected welds.
highly developed skills. Now that the demands are greater,
Without good cooperation from those who prepare the pipe
even the best welding operators are having trouble.
edges and the line-up crew, the welder has very little chance
Rejectable defects usually require cutting out the entire weld.
of meeting today’s rigid inspection requirements. Too often
This is expensive and can cost competent pipeline welders
the attitude exists that variations in fit-up and joint prepara-
their jobs.
tion are permissible and that the welder can compensate for
The purpose of this bulletin is to discuss some of the more
them. This attitude cannot be tolerated. It puts too much
common reasons given for rejecting a pipeweld and to suggest
responsibility on the welder and inevitably leads to rejects.
what may be done to correct some of these conditions.
Recommended procedures for properly
Change in attitude cleaning pipe
Any discussion on this subject should begin by accepting For lowest cost and highest quality, careful attention to the
the fact that the standards are higher than they were a few cleaning of pipe joint surfaces is critically important. Today’s