Multiple specimen - Tensile test location - ASME SEC IX - QW 151- Sub clause - c , d,
Vishwas Keskar Welding Manager Pune India
40 mm thk pipe test coupon of PQR was welded using GTAW + SMAW process .For tensile test specimens,test pieces are required to draw as Multiple specimens to represent full thickness .The specimen locations were marked on the pipe as per ASME Figure.
While drawing the specimens , the specimens were machined from the marked locations on pipe . However it is observed that the specimen(Top and Bottom ) are not got machined exactly one below each other but a little offset.The bottom specimen is a little offset to Top side specimen.
The Top side specimen thickness was 25 mm and bottom side specimen was also 25 mm .But inactual the thickness of the test pipe is 40 mm .
.In total , full thickness representation shall not be more than 40 mm . Actually it 25 + 25 = 50mm. So the query.
But at the outset ,Collectively , the full thickness tensile testing is achieved as per Code
(Two location - One set - Top tensile 1 , Bottom Tensile 1 -
Other set - One set - Top tensile 2 , Bottom Tensile 2
Side bends are satisfactory as per Code
Question :
Is the intent of the Code that the specimen shall be drawn exactly one below each specimen(Bottom side specimen exactly below the top side specimen) to represent the full thickness or some offset is acceptable to represent the full thickness as mentioned above
.
Regards
navnitkumar parikh
Dear Sir,
According to QW-151.2(d),
when multiple specimens are necessary, the entire thickness shall be mechanically cut into a minimum number of approximately equal strip of a size that can be tested in the available equipment.
So in your case Pipe thickness is 40 mm so size of multiple specimen shall be 20 mm (Top) and 20 mm (bottom)
Regards,
Navnitkumar Parikh
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Nilesh Pathare
Dear Mr. Keskar,
As per code requirements ideally we should test the full thickness specimen for tensile test. But due to the limitations of Universal Testing Machine code has given permission for testing multiple samples and it should represent the same cross section of thickness. Code allows the lesser thickness after addition
Of multiple specimen thicknesses. As per your mail if sample thickness is 25 mm for both samples then these samples are machined side by side and not from one location. So in my opinion these samples are not meeting the code requirements.
Pls. Refer QW 151.2 C "All of the specimen required to represent the full thickness of weld at one location shall comprise a set".
Regards,
Nilesh Pathare.