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Join Date: May 2015
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Possible Cold Lap?

05/17/2015 2:10 AM

During a welding process and after quenching this crack appeared, could it be possibly a cold lap? the pipe is a 15" dm 20.1 thickness seamless carbon steel with 0.8 carbon.

any comment would be greatly appreciated

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#1

Re: Possible cold lap?

05/17/2015 3:18 PM
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#2

Re: Possible Cold Lap?

05/17/2015 4:15 PM

It appears that this pipe has been in service. How long and what service?

There also appears to be another anomaly near the bottom of the picture. Another crack? Has any NDT been performed?

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#3

Re: Possible Cold Lap?

05/17/2015 11:16 PM

Why would you quench with such a high carbon content. It is very likely to create brittleness in the heat affected zone. Also, you don't mention any preheat, post heat, interpass temperature etc. Examine your WPS

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#8
In reply to #3

Re: Possible Cold Lap?

05/18/2015 3:27 AM

As per Minmi post above "what he said" ,

cold lap ? NO

Quench ? why ?

it looks like the area around the crack has previously been repaired (poorly) and shows grind marks , was the crack repaired to hide impact damage during transit maybe or material defect ?

is this a liquid pipeline or a structural pipe ?

what part of the world is it ??

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#12
In reply to #3

Re: Possible Cold Lap?

05/18/2015 11:25 AM

I agree with Minmi. Why quench? And with that high carbon content, pre & post heating via a WPS will be necessary. If you don't want it to crack, you need to think "anti-quench".

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#17
In reply to #3

Re: Possible Cold Lap?

05/21/2015 7:06 AM

I agree with Minmi. Why quench? And with that high carbon content, pre & post heating via a WPS will be necessary. If you don't want it to crack, you need to think "anti-quench".

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#4

Re: Possible Cold Lap?

05/17/2015 11:17 PM

Here is alink that will teach you a lot more about cold laps that you ever wanted to know.

Then you can decide for yourself.

http://www.diva-portal.org/smash/get/diva2:402293/fulltext02

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#5

Re: Possible Cold Lap?

05/18/2015 12:11 AM

It looks like a crack.

http://www.thefabricator.com/article/arcwelding/cracking-down-on-weld-cracks

I suspect it to be another defect as the crack is perpendicular to the weld.

However you name it that crack is nothing you want in your pipe.

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#6
In reply to #5

Re: Possible Cold Lap?

05/18/2015 1:24 AM

"that crack is nothing you want in your pipe"

Unless it's a crack pipe?

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#7
In reply to #6

Re: Possible Cold Lap?

05/18/2015 1:37 AM

Hmmh aha uhu!

I did not think of that one!

You are a cracker!

I spare you the talk of the ID and OD as it leads to the question where the hole is...

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#9

Re: Possible Cold Lap?

05/18/2015 5:21 AM

You said it appeared after quenching. It happened because the quenching caused the metal to contract too fast. I would call it a quenching crack.

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#10

Re: Possible Cold Lap?

05/18/2015 9:31 AM

The picture indicates damage to the pipe from improper pre-heat treatment of the weld area of the pipe prior to the welding being performed and improper or no annealing heat treatment of the pipe at the weld area site after the welding was completed.

Following proper "pre" and "post" heat treatment procedures for performing welding and cutting of metal is critical for maintaining structural integrity.

Quenching of a fresh weld joint in pretty much any metal will cause immediate or delayed cracking and/or failure at the joint or in the immediate surrounding areas.

Some metals allow ambient temperature cooling within a certain temperature range while other metals require timed, particular, detailed procedures in combination with special heat treatment equipment.

It is imperative all personnel that perform welding know and follow all required heat treatment procedures for the material they are welding on.

Please review the AWS procedure for the material you are welding and follow it closely if you want to avoid future cracking and/or pipe failure.

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#11

Re: Possible Cold Lap?

05/18/2015 9:40 AM

Why in the hell would you quench a weld on that size of pipe?

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#15
In reply to #11

Re: Possible Cold Lap?

05/19/2015 3:00 AM

Its the so called "Bucket quench" on steel pipe - local quenching for better cracking!

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#18
In reply to #15

Re: Possible Cold Lap?

05/22/2015 4:56 PM

Its the so called "Bucket quench" on steel pipe - local quenching for better cracking!
LOL!!!Good one! May I use it sometime?

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#19
In reply to #18

Re: Possible Cold Lap?

05/27/2015 7:49 AM

Permission granted!

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#13

Re: Possible Cold Lap?

05/18/2015 3:19 PM

We have had plates crack with .4 C just trying to flatten them. Quench , are you kidding?

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#14

Re: Possible Cold Lap?

05/19/2015 2:12 AM

I'd call that "scrap". Then, I'm funny that way.

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#16

Re: Possible Cold Lap?

05/19/2015 3:08 AM

15 inch diameter. Are you sure??????

" the pipe is a 15" dm"

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bigg (1); Crabtree (1); HeadsUp (1); HiTekRedNek (1); IdeaSmith (4); lyn (1); Massey (2); minmi (1); Original_Macgyver (2); SHOCKHISCAN (1); SolarEagle (1); StandardsGuy (1); texasron (1); Whitephone (1)

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