Re: [MW:12328] Code Explanations

Hi bros Philip,

 

Point 1. extension to what Rems has lucidly explained, I need to add few vital points in this more from practical point of view. 

Selection of consumable with adequate low temp CVN values.

Root need to be done lower dia. consumable(here Electrodes I understand.)

Maintaining Heat input to a minimum.( I mean justifiably lowest dia., less weaving bead-preferably more towards stringer as much as possible. But strictly Stringer for the root and hot/stablizing runs) - Even to an extent that you have to strictly monitor run wise - to get thru the Root CVN(- 40degC) and equally when CTOD is needed, (check client specs.).

Point 3.  apart from complying the 2t requiment as correctly mentioned byRems, it is very important to understandhere and honour that the specific requirements are different for different codes. Please donot mixthis.

Lets say a case: When a PQR is welded & then sent for testing, we need to specify the code to be followed. So once the report is written by the Lab with a note/declaration that the results have been observed as per a certain code. Then we cannot use that specified lab report for any other code application. More so it will not be acceptable if the vessel is a Coded one(Coded Stamped) if the reporting is as per AWS.

So, way forward:

a)we need to specify the Lab to furnish us two reportings, each shal mentionin the note below either codes respectively, for the same testing performed.

b)necessarily we need to prior intimate the TPI who will witness the Lab test as well to the ASME-AI and the Client Inspector/appointed TPI too who is going to witness while PQR coupon welding, itself.

c) necessarily one need to write the same WPS in two different code specific formats and judiciously assign a common WPS no, assigning a tag with the code followed ( ASME or AWS )- this is because one has to specify/intimate the WPS no., to the testing lab - who inturn writes the WPS no. in the test report sheet.

 

Only then it is justified to attachthese respective reports ( report as per ASME and report as peer D1.1) with the code specific PQR format, to enable us to say the same PQR is applicable to both the codes.

 

cheers,

DEBASISH

ex. Technical Manager, Dormanlong Engg. Ltd.,Lagos.

presently as a Factory Manager at Dubai.

+971504349936

 

 

  

 

On Tue, Aug 30, 2011 at 1:28 PM, Rems Okonkwo <rems.okonkwo@gmail.com> wrote:

Philip,

I just finished working on a project with the same material specification (USAN Project)

You did not mention the welding process you intend to use as that will determine the choice of consumable. API 2W Gr. 50 (TMCP) is design to have an improved Impact property at low temperature.

With reference to your query,

1.      The thickness combination especially the T1 (Bevelled) will be selected in other to cover the thickness ranges in production. If the project specification refers you to AWS D1.1 code as a reference code without additional conditions, then refer to AWS D1.1 table 4.2 for your thickness selection. Using the standard pipe 8" sch. 80/sch. 140 (refer to figure 4.27) will qualify tubular diameter of 4" and above with thickness of 5mm to unlimited, but i know that your client specification might over ride this clause. Note that the thickness selected has little to do with the impact property but rather, your choice of consumable and the welding parameters will greatly influence the Impact values. AWS D1.1 clause 5.8 state that PWHT shall be carried out when required by contract document and clause 3.14 (2) stated that PWHT shall not be carried out on TMCP materials.

Note also that according to API 2W paragraph 1.2 stated "Due to the inherent characteristic of TMCP method, plates manufactured to this spec cannot be form or Post weld heat treated at temperatures above 1100°F (595°C) without some risk of sustaining irreversible and significant losses in strength and toughness".

2.       YES, this qualification will qualify welding on API 2MT1 gr. 50 because, they are both in the same group AWS D1.1 table 3.1 and their delivery condition is the same (TMCP). Both also have same weldability.

3.      Yes you can use a lower thickness. Note that according to ASME sec IX, the weld metal thickness t deposited during qualification qualified for 2t in production.

 

Regards,

Rems Okonkwo

Welding Engineer

Nigerdock Nig. PLC-FZE

Snake Island Integrated Free Zone

Apapa, Lagos, Nigeria

On Mon, Aug 29, 2011 at 10:16 AM, Philip, Taiye (Lagos) <Taiye.Philip@deltaafrik.com> wrote:

Hello Gents,

 I want to  carry out  a welding  procedure qualification testing for  welding jackets structural members, the applicable construction code is AWS D1.1. Project  material is API 2W Gr 50 pipe rolled from TMCP plates, and job  maximum thickness is 76.2mm,and project  requires  CVN testing at (-40°C).

1.      What will  be  the best combination of thickness ( T1 & T2 )for the pipes  to produce a TKY joint that will pass CVN testing at the above job required CVN testing temperature ?  will PWHT be applicable as per code? Also specify code references.

2.      Will these qualification qualifies welding on API 2MT1 Gr 50  pipes rolled from TMCP plates  with thickness 50.8mm with CVN requirement of (-30°C).

3.       I am required to make  a procedure for welding pressure vessel of thickness 75mm as per ASME VIII DIV 1,  project material is ASTM A 516 Gr 70 N  and project requires cvn testing at (-30°C), will it be possible  to qualify these procedure with a lesser thickness of the same material, will it  meet  the impact requirement  as per applicable  code? Please help with your contributions and provide applicable code references

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