preheating for interpass for welding 1

[RE52]

hello,
we did the first pass of vertical weld in storage tank but becuase of raining we stoped the work.after 2 days we started to weld the socand pass without any preheatig and the ambiente temprature was 5-10'C .our refrence standard is API650.for second pass the plates was dry.
can this sequence cuase a problem in our work and is it against the standard.

 

[JoeTank]

How thickj was the shell plate?

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[SJones]

What preheat does the WPS require and is 5 to 10 deg C within the allowable temperature variation from that qualified without having to resort to requalification?

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[RE52]

thank you for your response,the shell thk.20 mm and the preheatig temp is 30

 

[JoeTank]

afshin, I am assuming that the following post you made elsewhere also belongs herein...

You state... "addition for former questions our standard is API650 and shell thk. in first shell is 20mm and preheat temp. which is mention in WPS 30'c"

API-650 requires that welding be done above 0 degrees C; otherwise, preheat is required. Also, there are additional preheat requirements for plates above 32mm.

Since welding was done above 0 degrees C and the plate is only 20mm thick, I do not believe that you have a problem with API-650.

Notwithstanding this minimum requirement for preheat, the welding is to be performed following a WPS that meets the API minimum requirements. It sounds like the only problem you have is the the contractor did not follow his own WPS.

Hope this helps.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com