Bend Test Failure in parent material

[krishh07]

Dear Experts,

We have done a welding procedure qualification with mig wire ER70S6on SA516Gr70 plate,16mm,

1)tensile test - passed

2)Bend test done at 1T and observed sample cracked away from weld - is the test accepted,if yes as per which ASME IX clause?

mks07

 

I've had that happen to me with cast materials, but I will need to see a picture to comprehend how this could happen in PV plate away from the weld.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[DAVIDSTECKER]

Make sure that the RADIUS of the bend fixture is equal to the material thickness.
We had a lab miss that and failed us 3 or 4 times until I noticed the extremely tight inside bend on the test bars.

 

[CWEng]

Why are you bending at 1T? Per ASME IX, radius should be 2T (or Diameter at 4T).

 

[dhengr]

Krishh07:
Also, you might pay particular attention to the direction of rolling of the plate. Plate always bends with less problems and tighter radii when the bend is perpendicular to the direction of the plate rolling. When the bend line is parallel to the direction of rolling there is more likelihood of cracking. It is an orientation of the grain in the plate problem, and a slightly inferior mechanical props. condition in the orientation perpendicular to the grain.

 

[weldstan]

As per CWEng, why 1T? was the weld even in the bend radius? And no you cannot accept. Reperform the bends at 2T and they will no doubt be acceptable per ASME IX.









t

 

[Don56]

DHENGR are you sure about that?

 

[gtaw]

The plate was 16 mm thick, the yield strength was 70 ksi. So, the sample should have been cut so side bends could be performed. the thickness of the samples should have been 10 mm. As noted, the direction of roll does make a difference when performing the guided bend tests because of the anisotropic properties of hot rolled materials. To ensure the guided bend tests are oriented correctly the weld groove should be oriented perpendicular to the direction of roll. The bend radius should have been 2T or in this case 20mm.

A wrap around bend fixture is my preference, but if you use a plunger and die type bending unit make sure to grease the shoulders of the die.

Good luck.



Best regards - Al