Welding SMAW without interrun cleaning 5

[sayee1]

When welding the piles offshore one of the main criteria is the welding productivity. To decrease the time of welding(Horizontal position with 15 Deg bevel on lower tubular and 30 Degree Bevel on the upper tubular), upto 6.3mm electrodes are used effectively. Now, I have seen welders doing it in other positions and would like to know the nuances and precautions as well as the adv/disadv of using what some people call "slag welding". What it means is that for each layer, no cleaning of the slag is done in between runs . But by the welders' skill the slag is broken down and the turbulence of the weld metal and the arc force bring the slag back to the top(The slag cannot be remelted by the welding arc). Then after the completeion of each layer, the slag is wire brushed. What this would mean is that the cleaning time after every run can be avoided and cleaning time thus minimized. Anyone having any feedback/experience/comments please?

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
End of all knowledge is the attainment of immortality!

 

[sayee1]

JTMcC, Gerald and Jeffery
The point here is like JTMcC said, the welding of offshore related work like say for piles is entirely dependent on welders skills and less on the WPS developed for the process. The PQR might have been qualified in an ideal condition in the workshop but hardly replicating the conditions the welders are working in while offshore. The key there is to have the joint welded between two pile sections as quickly as possible and ready for hammering in. The point to be noted is as a welding engg with a little less than 10 years experience in welding in various industries including aerospace and with materials from Ti to Al to CIs has hardly prepared me to argue with the welder in this particular case. The welders for offshore understandably might be paid more than me only because so much hinging on their experience to get the welding right as there is hardly any time for repair of welds. I have seen welders successfully using this technique and would hardly question their criteria when welding a 50"+ dia and a 2"+ WT because I want to speed up welding too. I cannot use a higher deposition rate process like FCAW because of the welding conditions and that is why the welders even end up using 8.00 mm electrodes in this type of welding. I have run procedures replicating this technique which has been successfully tested for mechanical properties & even impacts. What I wanted to discuss in this forum is the +es and -es of such a technique which I can use as an arguement to clients in case they have some objection which I got from all your replies.

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
End of all knowledge is the attainment of immortality!

 

[MURZ]

Sayee:
I am the author of the spreadsheet that you downloaded from Gerald’s web site. Since you seem to like the sheet and use it extensively, I would like to give you the full version. This full version is quite a bit more extensive than the one you have and is about 4 MB long. Let me know where I can e-mail it to you. Thanks for the feedback.

Mark

 

[Rjeffery]

JTMcC,

I am not casting doubt towards the truth of your tale nor towards the skill and perseverance of your welding friend. I have seen welders working in many awkward positions, and having the weld pass after working in the position you describe is more than remarkable it is admirable!

I, on the other hand, am not as slick as your friend is. I could not have accomplished what HE did. (Please de-increment your slick welder count by 1) No way, not on my best day. I am Joe Journeyman, the average (and I may be over evaluating that!) welder that the procedure is written for.

If every welder had the same level of skill, knowledge and experience as your welding friend then the skill of the welder would not be a wildcard in the quality equation. If he and I were side by side in the same bobbing boat trying to weld the pile splices, even in a calm sea state, he would weld rings (pun intended) around me.

The WPS was developed in the shop where the floor does not move, the walls do not sway and the wind does not blow your shielding gas away. It was designed to give a welder, at any skill level, the essential variables to perform the welding with a reasonable expectation of producing a sound weld. Reasonable expectation I think is the key. Those ‘welders’ that do not have the skill set (yet) will fail. But with experience… But again, that is in the shop and not onboard ship, 15 stories in the air or leaning over the gunnels of a boat trying to weld piles.

When I proctor welding exams, I want every welder to pass. I do all I can to ensure that happens. I would never suggest that the slag not be cleaned out of the toes of the weld or that the next pass will burn out the slag. I would never annotate the welder’s record indicating that he (or she) could, in fact, produce a sound weld coupon without interpass cleaning of the stringers.

Yes it is a pain in the a$$ to have to clean the stringers between passes. If cleaning them will help guarantee the weld will pass then I’ll clean them. If the time it takes to weld, then clean maybe then a welding helper/laborer should be employed to clean them while the welder welds? “Pay me now or pay me later,” said the Piper. Short cuts may save time, now and then but they can kill more than reputations. To get quality one must be prepared to pay for quality.

As you have correctly pointed out it seems to be common practice not to clean the stringers between passes. Just because it is commonly done doesn’t mean it is proper or correct and I feel any one who does not clean their welds are taking an unnecessary chance.

Again, I did not mean to intimate that you were being untruthful in any way. Nor did I intend to besmirch the talent and skill of the welder you related the story about. I only intended to make the point that over looking or encouraging a welder to eschew cleaning of his stringers between passes is asking for inclusions and should be avoided.

 

[JTMcC]

Rjefery,
Fair enough!
It was a calm day on a small lake, Lake Las Vegas, if you ever go to the casino built on the bridge over the lake, on the north side, that's where my man made his world famous splice! : )
We'll just have to differ on the one point.

regards,
JTMcC.

 

[sayee1]

A star each for JTMcC and Jeffery for making my day with your humour

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
End of all knowledge is the attainment of immortality!

 

[sayee1]

MURZ (Materials) Sayee:
"I am the author of the spreadsheet that you downloaded from Gerald’s web site. Since you seem to like the sheet and use it extensively, I would like to give you the full version. This full version is quite a bit more extensive than the one you have and is about 4 MB long. Let me know where I can e-mail it to you."
If this is just a part of the actual spreadsheet, I'd love to have the whole spreadsheet. My email id is spraghunathan@mcdermott.com


Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
End of all knowledge is the attainment of immortality!