WELDING OF STRIPS AND OR PATCHES ON A COLD FORMED DISHED END

[KAUSTUBH12]

A STAINLESS STEEL DISHED END OF 2 M DIA AND 4MM THICKNESS WAS COLD FORMED BY GRADUAL LOAD APPLICATION. DEFORMATON WAS OBSERVED NEAR SKIRT. DISHED END WAS FORMED WITH ONE LONG SEAM SINGLE V FULLY FUSED, BACK CHIPPED AND WELDED FROM OTHER SIDE. DUE TO THE DEFORMATION, NEAR THE SKIRT IN THE FORM OF A CRIMPING ON THE SKIRT, A STRIP (500 mm X 90 mm)OF THE DISH WAS REMOVED AND A FLAT STRIP SHAPED BY COLD HAMMERING WAS WELDED TO THE DISH. SUBSEQUENTLY THE WELDED SEAM WAS RADIOGRAPED AND PROFILE CHECKED AND FOUND ACEPTABLE. IS THIS PROCEDURE ACCEPTABLE?

 

[KAUSTUBH12]

WHAT IS THE STRIP ORIENTATION? ALONG THE LONG SEAM A T- JOINT WAS MADE AND RADIOGRAPED

 

[bmoorthy]

As per UG 80/UG 81 of ASME sec VIII div 1 the shape of the formed item can be made by any process which does not affect the property of the material.

Now coming to good engineering practice,
What you have described is nothing but Black Smithy.
Is it ok to hammer out a component to the required shape? (say cold forge) check your quality/Manufacturing manual (if you have one).

It is also observed the pressure could be much less (deduced from the thk and Dia you have given),SS material might have been chosen by the designer due to corrosive service.

If the hardness has increased, then Solution Annealing is recommended. (235BHN is our practice)

After having decided to hammer out the shape why bother too much about the orientation of the patch. Orientation of Patch coinciding with Long seam is less bad (Although not prohibited) as compared to hammering.

Patch work is not unacceptable.

Patch coinciding with Long seam is also not Unacceptable.

Hammering (You could atleast bend form) is objectionable but not unacceptable.

Think about your "U" stamp (if you have one) if this is a "U" stamp job.

 

[bmoorthy]

You may take a strip, hammer it out, then cut it to required shape, test the balance for Physical properties and IGC pr E (this is to proove your self that the property of the material is still ok for useage).

If you decide to sol anneal then you have to have WPS supported by appropriate PQR (Where test coupon must have been Sol Annealed).

 

[bmoorthy]

You may take a strip, hammer it out, then cut it to required shape, test the balance for Physical properties and IGC pr E (this is to proove your self that the property of the material is still ok for useage).

If you decide to sol anneal then you have to have WPS supported by appropriate PQR (Where test coupon must have been Sol Annealed).

Also refer UHA of ASME for further info.

 

[bmoorthy]

Refer to UHA 44 and table UHA 44 for the post fabrication Strain limits and required heattreatment.