Dear All,
This is just my view and my experience.
If the weld bead width (weaving) is more
Then the profile of the weld bead will become concave at the center of the weld, and this type of shape is not suitable / recommendable for any of the Coating systems.
Because air will entrap in that location at the time of Joint coating and will effect adversely on the coating system.
All this phenomena is because of more width of the weld bead, and as per practice condition and previous experiences 3 times of the electrode dia weaving bead will not produce such kind of concaveness.
Hence this practice has implemented in welding – Especially in Coating required pipelines(Cross country / Onshore / Offshore / Subsea)
Engineers who had worked in pipelines will treat this is a major point and started putting this general statement in WPS – Which in not that much big Issue and will not affect any parameter
Thanks & Regards
Lakshman kumar.B | Manager - QA/QC | LANCO INFRATECH LIMITED
www.lancogroup.com
Go Green |The future will thank you
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Ahmed Husain
Sent: Tuesday, April 05, 2011 4:03 PM
To: materials-welding@googlegroups.com
Subject: Re: [MW:10599] Weaving
Dear Mr Rogers,
First, If weaving has so critical effect on welding, then why its limitation is not stated in Codes.
Second, on what basis, anyone decide that weaving above 3 times of electode dia will affect the grain structure and impact value of weld metal, and below that will produce satisfactory weld metal property.
Third, different material have different impact toughness requirement, but generally WPS for all materials requires weaving limitaion.
Ahmed Husain
Mob-0547170325
From: Geoff Rogers <gbr476@gmail.com>
To: materials-welding@googlegroups.com
Sent: Tue, April 5, 2011 12:44:22 PM
Subject: Re: [MW:10598] Weaving
The amount of weaving directly affects the heat input since the wider the weave the slower the travel speed. With a slower travel speed the greater the heat input which will affect the weld and HAZ grain structure. This typically leads to lower impact toughness values and increased hardness. Typically the tensile strength is not affected by the extent of weave. Also, the width of the weave affects how well the weld pool is protected by the shielding and how well the weld metal will fuse to the base metal. A max weave of 3 times electrode diameter for SMAW and 5mm for GMAW is typically specified since it produces the best overall weld quality and mechanical properties for the productivity achieved.
Geoff Rogers
Welding Engineer
Houston, TX
On Tue, Apr 5, 2011 at 2:42 AM, Ahmed Husain <ahmraha@yahoo.com> wrote:
Dear All,
Almost all SMAW WPS prepared in accordance to ASME IX, I have seen, it specify maximum weaving 3 times the electrode dia. But I am unable to co-relate this WPS requirement to any ASME code or Client (ARAMCO) requirement . If weaving 3 times electrode dia is not stated in ASME codes, then why does it is mentioned in WPS?
Kindly share some information on this subject.
Ahmed Husain
Mob-0547170325
From: ramu ramalingam <ramu.srivi@gmail.com>
Sent: Fri, April 1, 2011 9:49:05 AM
Subject: Re: [MW:10554] Weaving
Hai,
If they want to weave more than 3 times of electrode/filler wire dia, better to make new WPS and proof all the necessary requirement to meet with old WPS.
Because,when we weave more, in production weld that time heat input will be increased and its fail in tenstile test. The heat inputput should not be more than 3 KJ/min for each process.
Regards,
RR
On Wed, Mar 23, 2011 at 11:31 PM, Sampath Kumar <skthatham@gmail.com> wrote:
Dear Friends,
WPS says the weaving is allowed/permitted 3times the diameter of the electrode.Please tell me wheather we can allow if the weaving is more than the allowable limit.If it can be allowed.What is the reasons and on what basis it is allowed?If it can not/should not be allowed.Why and what is the reasons?
My opinion is that it should not be allowed.[1]Because it deviates from the WPS.[2]properties may vary because of the excess heat In put due to excess weaving.
The contractor is of opinion that they will change the WPS to suit excess weaving.It is not an essential variable,hence it can be allowed.To substantiate their claim they say they will change the WPS and they will perform Hardness Test to prove that the properties were not changed.
With Best Regards
Sampath
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