waiting period between welding and NDT

[Ali Aghajafari]

Hi all,

Is there a waiting period between welding and NDT in the ASME Code in order to find cold cracking. Material is SA 182 Gr. F12

Thanks for your answers

[Mtho Kana]

Recommended is anything from 12 to 24 hours.

Best Regards

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[Vignesh Manoharan]

24hrs for GTAW and 48hrs for SMAW. 

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[Prathab P]

Sir Where it is mentioned?

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[Vinoth Rajendran]

Hi,

As per,

AWS D1.1 NDT performed not less than 48hrs. After completion of welds

BS EN 1011-2 for 16 hrs.

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[Amol Betkar]

Dear,

In ASME Boiler and Pressure Vessel Code Section VIII, Division 1, and Section IX, there are no specific waiting periods mandated between welding and non-destructive testing (NDT) for the purpose of detecting cold cracking. However, the potential for cold cracking, especially in materials like SA 182 Grade F12, which is a low alloy steel typically used in high-temperature applications, is a significant concern.

Cold cracking, also known as hydrogen-induced cracking (HIC) or delayed cracking, can occur in certain materials, including low alloy steels like SA 182 Grade F12, when they are subjected to hydrogen embrittlement. Hydrogen from various sources, such as moisture or contaminants in the welding process, can diffuse into the material during welding and cause cracking.

To mitigate the risk of cold cracking, several measures are typically taken:

1. Preheating: Preheating the base metal and maintaining interpass temperatures during welding can help reduce the risk of cold cracking by slowing down the cooling rate and allowing hydrogen to diffuse out of the material more effectively.

2. Post-weld Heat Treatment (PWHT): Performing a post-weld heat treatment can help relieve residual stresses, promote hydrogen diffusion, and reduce the risk of cold cracking. The specific PWHT requirements for SA 182 Grade F12 are typically specified in the applicable welding procedure specification (WPS) or project specifications.

3. Control of Hydrogen: Implementing proper welding practices, such as using dry electrodes and ensuring a clean welding environment, can help minimize the introduction of hydrogen into the weld metal and base metal.

While ASME codes do not prescribe a waiting period between welding and NDT specifically for detecting cold cracking, it's essential to follow industry best practices and project-specific requirements to minimize the risk of cold cracking and ensure the integrity of welded components, especially in critical applications like pressure vessels and piping systems.

Consulting the welding procedure specification (WPS) and project specifications, as well as engaging with qualified welding engineers and inspectors, can provide valuable guidance on the appropriate welding procedures, pre- and post-weld heat treatments, and NDT practices to detect and mitigate the risk of cold cracking in materials like SA 182 Grade F12.

Regards,

AB

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Best regards,

Amol K.B

B.E(Mech), CSWIP 3.2.2, NACE CIP 1 & ASNT LII(4M)

[pradip kumar Sil]

In my understanding, the code  is silent. Check client spec

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