Acceptance criteria for root oxidation

[pradip kumar sil]

Dear experts,
As per ASME B 31.3 what is the acceptance criteria for the root
oxidation in M catagory fluid.
Thanks in advance.
Regards
Pradip

[Shashank Vagal]

Such welds will be rejected for having failed to meet WPS requirements, to say the least. --- On Wed, 30/5/12, pradip kumar sil <prad...@gmail.com> wrote:

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[César Alexis Viteri Pérez]

I forgot to attach the file, sorry
 

---

From: alexis...@hotmail.com
To: material...@googlegroups.com
Subject: Filler metal with lower strength thsn base metal
Date: Thu, 31 May 2012 08:10:26 -0500

Dear Experts,
 
Could you please share your criteria/experiencie regarding procedures that are qualified (API 1104 or ASME IX) with filler metals with lower strength than base metal, for instance, e6010 (SY 48 KSI / SUT 60 KSI) used to weld API X52 (SY 52 KSI  / SUT 66KSI).
According to the document attached it could be a choice, but i don't understand very well why the tensile test was cleared and how this fact could impact in a gubernamental audit.
 
Thanks and regards
Alexis

[jignes...@linde-le.com]

Dear Mr. Pradip,

The straight forward answer is - There is no acceptance criteria in ASME B 31.3 for root oxidation for category M fluid.

No code has identified it is as a defect and so called acceptance / rejection criteria not defined. However, process licensor / consultants have defined various criteria for oxidation of the weld based on expected corrosion resistance of the weld.

In fact, this has been considered as inherent control of a welding process .Weld gets oxidised due to inadequate / improper shielding or contaminated shielding gas. So first remedial action would be to provide the condition, which eventually will results in proper shielding of the weld joint.

Further , when weld gets oxidised, there may be detrimental effect on the weld metal properties. For procedure qualification, the oxidised weld results in failure of bend test also. These oxide layers may be removed by mechanical grinding / pickling passivation etc.

For low and moderate corrosion, for stainless steel, heat tint upto yellow is acceptable. For severe corrosion conditions, the bright shinny (no discoloration) weld is required.

I fully agree with Mr. Vagal's opinion, regarding acceptance standard as WPS to minimum. However, process licensor / consultants recommendations to be followed for rejection of the weld.


With Best Regards,

Jignesh R Rana
Manager - Materials Technology, QA/QC & Standards+

Linde Engineering India Pvt. Ltd.
'Linde House'
Opp: VUDA Office, VIP Road, Karelibaug,Vadodara - 390018, India.
Tel.: +91 265 3056789, Fax: +91 265 2335213 , Mobile: +91 90999 86019
jignes...@linde-le.com, www.linde-india.com

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Shashank Vagal ---05/31/2012 10:50:20 AM---Such welds will be rejected for having failed to meet WPS requirements, to say the least. --- On Wed

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[sudhakar kuppuswamy]

Hi César Alexis Viteri Pérez

Greeting for the day!

E 6010 electrodes are normally used for root pass welding in cross country pipeline construction,can also be used for structure application where back chipping is not possible,deep penetration is required and HIC is not a major concern.

The reasons for using E 6010 in pipelines are as follows.

1. Usually the root pass speed determines the speed that the pipeline may be constructed.

2. Can be welded by vertical-down progression, which is the traditional and most popular method and offers the fastest welding speeds and can even accommodate poor joint fit-up

3. E 6010 contains titanium coating, which helps in good arc stability and easy slag removal during root pass welding.

To achieve the required joint strength, further passes shall be made with low hydrogen electrodes with matching electrodes with proper precautions like preheating if required, proper heat input & Inter pass temperature control. 

regards,

Sudhakar