×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Is 24 hour cool down necessary for non exotic welding before MPI

Is 24 hour cool down necessary for non exotic welding before MPI

Is 24 hour cool down necessary for non exotic welding before MPI

(OP)
Is it necessary to let steel sea fasting brackets (S355) fastening containers to a ship’s deck cool down before MPI?.

Would DNV insist on it, it is a DNV registered vessel?

Thanks

RE: Is 24 hour cool down necessary for non exotic welding before MPI

yes they can 72 hours or 24 hours

RE: Is 24 hour cool down necessary for non exotic welding before MPI

Denlow,
Can you please note where this requirement is stated ?
I would have thought the answer is no.
Regards,
DD

RE: Is 24 hour cool down necessary for non exotic welding before MPI

DekDee,

can you show me where it is written that it is no

Regards,

Denlow

RE: Is 24 hour cool down necessary for non exotic welding before MPI

(OP)
I've mobilised many vessels over the last decade and have never came across this requirement, a particular ship yard has said this is a requirement. If it's a mandatory we can pass this in to our client but he will be paying £100k plus / day vessel rate. If it's not the fabricator is trying to have our eyes out!

RE: Is 24 hour cool down necessary for non exotic welding before MPI

Thank you for the information denlow

RE: Is 24 hour cool down necessary for non exotic welding before MPI

For certain steels delayed NDT is mandated to check for hydrogen cracking in weldments and the base metal heat affected zone.

RE: Is 24 hour cool down necessary for non exotic welding before MPI

EN 1090 is not applicable in this case.
I fully agree with the logic behind it, for the reasons metengr explained above.

@ escapizm, you'll have to ask them for a reference.

RE: Is 24 hour cool down necessary for non exotic welding before MPI

(OP)
Thanks all, is this even when proven and tested weld procedures are used for same materials and techniques?

Perhaps we've been cutting corners all these years but I've never come across it before.

RE: Is 24 hour cool down necessary for non exotic welding before MPI

escapizm,
I initially thought DNV would refer to EN 1090-2 as posted by denlow so I didn't respond further.
However, having a quiet day at work so thought I would investigate further

DET NORSKE VERITAS

RULES FOR CLASSIFICATION OF
Ships / High Speed, Light Craft and
Naval Surface Craft

PART 2 CHAPTER 3

Fabrication and
Testing of Ships
JULY 2013

SECTION 7 NON DESTRUCTIVE TESTING OF WELDS

For detection of surface imperfections the following methods applies: Visual testing (VT), Magnetic particle testing (MT) and Penetrant testing (PT).

202 For NV 420 grades and higher, final inspection and NDT shall not be carried out before 48 hours after completion unless heat treatment has been carried out.

NV 420 is steel with a minimum yield of 420 mpa and as you are using S355 (minimum yield 355 mpa) the hold period for NDT is not applicable to you,
Regards,
DD

RE: Is 24 hour cool down necessary for non exotic welding before MPI

(OP)
Thanks dekdee you nailed it there! Thanks again.

RE: Is 24 hour cool down necessary for non exotic welding before MPI

Quote (escapism)

is this even when proven and tested weld procedures are used for same materials and techniques?
yes, delayed hydrogen cracking can always occur on a later time. Even with correct PQR and WPS

RE: Is 24 hour cool down necessary for non exotic welding before MPI

Define "non exotic"

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

RE: Is 24 hour cool down necessary for non exotic welding before MPI

Hi escapizm,
I write in connection to thread1083-344803: Complex Hydraulic Synchronising Problem, about the hydraulic synchronizing problem you solved last year (I am asuming everything went reasonably well, at least you had dealt with many contingencies). As it happens, I am working in a different company, which has larger machines that can manufacure the parts for a very large anular cylinder. We are now working with a project for a 1,200 ton force cylinder for R4 mooring chain, the central hole is 400 mm and stroke is 600 mm, equal to the length of each link.
We feel the anular cylinder you initially considered (with longer stroke) can be built and operated reliably, at reasonable cost. You can imagine: the guys in production are OK, the guys in engineering are excited, but the guys in finance are, as usual, skeptic. So, escapizm, I would need to ask if you think there would be demand for such a product, I can only guess it would be used for tensioning of FPSO mooring lines. Would you have been interested in such a product 18 months ago? Would you have rented it for maybe $30,000/month? Do you think other pros in the offshore industry would?
Your views are extremely valuable, and very much appreciated!
Aarne

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources