Perfect Weld Requirements

A. The pipe nipples and the edges to be welded should be free from oil, grease, etc.; after they are tacked together, the root openings are inspected. During the course of welding, each layer of welded metal is checked for porosity, undercut, slag inclusion, and surface roughness. An inspector has the responsibility of terminating any particular test at any time if he finds that the operator does not have the skill required to produce satisfactory welds.

B. When a test weld is completed, further visual inspection is conducted to see that the weld is free from cracks, that there are no

arc strikes on the pipe surface, that the melt-through does not exceed Vs inch, that concavity of the root bead does not exceed ’/i6 inch, that incomplete fusion is not present, that restarts and tie-ins do not exceed Vie to у64 inch in cavity, and that the cover pass is uniform and smooth,

C. Having passed the visual inspection, four specimens are extracted from the welded pipe as shown on page 227, comprising two face bends and two root bends. Those bends must be inspected for the following:

A. Slag inclusion

B. Cracks

С Incomplete fusion between the welded metal and the base metal, and between any of the weld passes.

Bend Tests

If the welder is to pass the guided bend test, the specimen shall have no cracks or other defects exceeding % inch in any direction, with the exception of corner cracks. However, if corner cracks are caused by lack of fusion, slag inclusion, or other defects, the welded specimen can be rejected.

A complete record is kept on each welder if the specimens have passed the described test. Procedure and qualification tests for each specimen, including tensile and bend tests, are recorded in detail.

In addition, a written document is kept, showing:

A. Specification of material being welded

B. Specification of filler metal

C. Edge preparation

D. Preheat and postheat, if being used

E. Volts and amps

F. Spacing or root opening

G. Number of passes

H. Size of electrode and classification

I. Wall thickness and diameter of pipe being tested

J. The test conditions, open air or closed shop.

All this and other important information is documented and made available to supervisors and inspectors.

It is important to note that when tests are conducted on pipe with wall thickness exceeding 3/4 inch, the test specimen is sectioned out differently from those in Fig. 15-2. Bend specimens are prepared

Perfect Weld Requirements

Perfect Weld Requirements

Standard Dimensions, Inc.













A-Length of reduced

See Note 4

See Note 4

See Note 4

See Note 4



0.500 ±0.010

0.3 50 ±0.007

0.250 ±0.005

0.188 ±0.003

R - Radius of fillet

% min

Vi. min

Vie. min

V'g, min

B - Length of end

1% approx

I %, approx


У2. approx


C-Diameter of end








(1) Use maximum diameter specimen (a), (b), (c>, or (d) that can be cut from the section.

(2) Weld should be in center of reduced section.

(3) Where only a single specimen is required the center of the specimen should

be midway between the surfaces.

(4) Reduced Section "A” should not be less than width of weld plus two "D."

(5) The ends may be of any shape to fit the holders of the Testing Machine in

such a way that the Load is Applied Axially.

Fig. 15-3. Test specimens for thick*wall pipe.

in a way which allows them to be bent sideways. The tensile speci­men is also prepared differently for thick-wall pipe (Fig. 15-3).

It is also important to note that when welded specimens are being prepared for bend tests, the surface is smoothed by grinding which should be done in the direction shown in Fig. 15-4.

For information concerning The American Petroleum In­stitute Butt Weld Procedure Qualification Test (API) 1104 see the latest edition of the API Standard 1104, for sale by

Perfect Weld Requirements

Hg. 15-4. Method of grinding the weld of the test specimen.

the American Petroleum Institute, 1271 Avenue of the Americas, New York, N. Y. 10020.

The points covered in this limited discussion on Inspection and Qualification Procedures will vary over a period of time. Inspections and qualifications are changeable and kept up-to-date. Therefore, it is always necessary to consult the* approoriate code (ASME BOILER AND PRESSURE VESSEL CODE, SECTION IX).


[1] Electrodes made to the same classification but manufactured by different companies may require different current settings to liberate the same amount of heat.

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