Its preferred by some client and some client prefer other way. And there are reasons behind it and its all depends on the service, environment and type of fluid which comes in contact.
Generally reinforcement to be removed for the following reasons whenthe equipment in high stress and cyclic stresses ;
1) to remove the top layer of the weld which will be having the highest stresses
2) to remove the irregular surface (weld ripples) to avoid stress concentration
3) To avoid weld defects (which generally not removed by fabricators) like undercuts, overlap, concavity (which will make acute angle with base metal surface and increase stress concentrations)
4) Extra weights due to reinforcements (this is minimal but for Marine and Aerospace it becomes very much important)
Some Client want to retain the as welded surfaces because during removal of the reinforcement following would occur which may be harmful ;
1) Excess removal of weld and adjacent base material reducing thickness below design thickness (fabricators do not provide any extra thicknesses if design in their scope to avoid higher cost / gain higher margin
2) Sharp scars due to grinding will increase stresses risers again
3) Discontinuities open to surface get camouflaged during grinding operation
4) Some Customer believe that welders may deposit weld with coarse bead (to get higher productivity using bigger dia electrodes) and later on surface of welds ground so no evidence exist and this may cause failure in weld and HAZ due to coarse grains produced during solidification
I hope there are more experienced people in our group and I feel that debat on this topic shall take place in elaborative manner so that everybody will learn from others experience and that is also one of the intension to create tsuch group.
Cheers.
C. K. Purohit - Encg Tech
Sr. Welding Inspector
Generally reinforcement to be removed for the following reasons whenthe equipment in high stress and cyclic stresses ;
1) to remove the top layer of the weld which will be having the highest stresses
2) to remove the irregular surface (weld ripples) to avoid stress concentration
3) To avoid weld defects (which generally not removed by fabricators) like undercuts, overlap, concavity (which will make acute angle with base metal surface and increase stress concentrations)
4) Extra weights due to reinforcements (this is minimal but for Marine and Aerospace it becomes very much important)
Some Client want to retain the as welded surfaces because during removal of the reinforcement following would occur which may be harmful ;
1) Excess removal of weld and adjacent base material reducing thickness below design thickness (fabricators do not provide any extra thicknesses if design in their scope to avoid higher cost / gain higher margin
2) Sharp scars due to grinding will increase stresses risers again
3) Discontinuities open to surface get camouflaged during grinding operation
4) Some Customer believe that welders may deposit weld with coarse bead (to get higher productivity using bigger dia electrodes) and later on surface of welds ground so no evidence exist and this may cause failure in weld and HAZ due to coarse grains produced during solidification
I hope there are more experienced people in our group and I feel that debat on this topic shall take place in elaborative manner so that everybody will learn from others experience and that is also one of the intension to create tsuch group.
Cheers.
C. K. Purohit - Encg Tech
Sr. Welding Inspector
From: tong tong <tong2je@gmail.com>
To: materials-welding@googlegroups.com
Sent: Wednesday, 24 June, 2009 9:10:29 AM
Subject: [MW:2518] Grind Flush
Dear All
I really need your help. It is true all weld reinforcement for high pressure vessel shall be grinded flush?. What code and standard should i refer? Thank in advance for your cooperation
Regards
Tong2je
ICC World Twenty20 England '09 exclusively on YAHOO! CRICKET
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