Volume-II - GAIL
Volume-II - GAIL
Volume-II - GAIL
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6.2.6.2<br />
(New)<br />
6.2.7<br />
(New)<br />
6.2.7.1<br />
(New)<br />
6.2.7.2<br />
(New)<br />
extraction shall be as per Figure 6.2.6.1 of this specification. The specimen shall be suitably<br />
ground, polished and etched to reveal the microstructure. The specimen shall be visually<br />
examined using a minimum 10X magnification to provide evidence that proper fusion has<br />
been obtained for full thickness and there is proper interpretation of passess , their alignment<br />
and texture of weld zone. In case defects are observed, it will become a cause of reevaluation<br />
of welding parameters and heat treatment as deemed necessary by Purchaser's<br />
Representative.<br />
For EW Pipes<br />
Vickers hardness tests shall be carried out on each specimen taken for macroscopic<br />
examination in accordance with ASTM E-92, at locations indicated in figure 6.2.6.2 (a) of this<br />
specification. The resulting Vickers hardness value at any point shall not exceed 248 HV10. The<br />
maximum difference in hardness between the base material and any reading taken on the<br />
weld or heat affected zone shall be less than 80 HV10 . Modalities of retest shall be in<br />
accordance with para 9.12.2 of API Spec. 5L.<br />
For SAW Pipes<br />
Vickers hardness tests shall be carried out on each specimen taken for metallographic<br />
examination in accordance with ASTM E-92, at locations indicated in figure 6.2.6.2 (b) of this<br />
specification. Indentation in the Heat Affected Zone (HAZ) shall start as close to the fusion line as<br />
possible. The resulting Vickers hardness value at any point shall not exceed 248 HV10. Modalities<br />
of retest shall be in accordance with para 9.12.2 of API Spec. 5L.<br />
Reverse Bend Test (For EW Pipes only)<br />
Reverse bend test shall be executed with the same number of tests and retests<br />
specified for flattening tests in para 9.3.2 of API Spec. 5L. Ring Specimen of width 100mm to<br />
115mm shall be taken from the pipe and tested in accordance with the procedure given below<br />
and Fig 6.2.7 of this specification.<br />
Selection of Mandrel<br />
The reverse bend test shall be carried out with a mandrel, whose radius (R), or width (A) shall<br />
be calculated for any combination of diameter, wall thickness and grade with the following<br />
formula.<br />
1.4 ( D – t ) t<br />
A = 2R = ------------------------ - t<br />
e ( D - 2t ) - 1.4t<br />
Where<br />
D - Specified Outside diameter of pipe, mm<br />
t - Specified Wall thickness of pipe, mm<br />
1.4 - Peaking factor<br />
e - Strain<br />
Minimum values of `e' shall be as follows :<br />
Grades of Steel Min `e' value<br />
Gr.B : 0.1425<br />
X-42 : 0.1375<br />
X-46 : 0.1325<br />
X-52 : 0.1250<br />
X-60 : 0.1125<br />
<strong>GAIL</strong> (INDIA) LIMITED CARBON STEEL LINE PIPES <strong>GAIL</strong>-TS-LINEPIPE-CS<br />
Page 8 of 37
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