Generally this kind of defects found in Carbon steel..
Pock marks are depressions in the weld metal surface and happened due to gas bubbles. These gas bubbles ( Oxygen & Carbon monoxide) forms in a weld puddle and escape thro the slag to atmosphere
To avoid/Reduce
1. Increase voltage
2. Decrease travel speed
3. Decrease Current
4. Decrease stick out
5. Reduce flux burden
THANKS & BEST REGARDS
KG.PANDITHAN, AWS-CWI, CSWIP 3.1
CONSULTANT-WELDING & QUALITY
On Mon, Jun 16, 2014 at 8:35 AM, pgoswami <pgoswami@quickclic.net> wrote:
Hi Mohit ,Please seethe attached paper on SAW , which gives a small hint to this problem. Also similar query was discussed in this forum earlier. Such uncharacteristic surface finish may happen with SAW fluxes containing lass Ca-fluorides, which adds to fluidity of the flux.Uneven grain size, excess flux burden (flux feed) during ,delayed freezing all leads to this defect. Typically the flux burden, 1" or a little more, so as to generate, thin beads would not cause this problem. Again this problem may vary from flux to flux. You need to get flux manufacturer's recommendation also. What was the flux used in this case? You may reply in my personal email if you wish so.Also see the earlier Q&A on the same topic posted in this group.ThanksPradip Goswami, P.Eng,IWEWelding & Metallurgical SpecialistOntario, Canada
From: Prakash Hegde [mailto:pb.hegde@yahoo.com]
Sent: Saturday, June 14, 2014 10:52 AM
To: materials-welding@googlegroups.com
Cc: pgoswami
Subject: Re: [MW:21113] Poke Mark observed in thin wire SAWSome time excessive Flux burden height also causes poke mark ,lease checki) Baking of Flux and its temp (You may have to increase by about 25C than recomendation)ii) Location of nozzle(Wire) on cirseam It should be about 25-50mm offset To maintain proper flux burden heightiv) Excessive currentRegardsHegde P.B.Kindly use baked flux....> To unsubscribe from this group, send email to mailto:materials-welding%2Bunsubscribe@googlegroups.com
On 14-Jun-2014 2:08 pm, "Mohit Aggarwal" <aggarwalmohit05@gmail.com> wrote:
>
> Respected Experts,,
> We are doing thin wire SAW ON Ss material pipe to pipe joint observing poke mark often. Kindly let me know how can it be eliminated because it effecting over all.productivity due to grinding of poke marks observed in weld metal layer!!
>
> Best Regards
> Mohit Aggarwal
>
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