difference in welding rotating and stationary equipment 2

[electricpete]

Hello. Long-time eng-tips poster, first-time weld/bond/fastener forum poster!

I see that American Welding Society Publishes a 244 page ANSI-approved standard entitled AWS D14.6M:2005 "Specification for Welding of Rotating Elements of Equipment".

So some questions:
1 - What's different about welding rotating equipment than stationary equipment.
2 - If nothings different, why is there a standard?

Thanks in advance for any comments to help a non-welding guy understand this.

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[metengr]

I just purchased ($63 US dollars) this specific Standard the other day for an upcoming job regarding replacement of our induced draft fan rotors at one of our Power Generating Stations. The difference between this AWS Specification and let us say D1.1 is in the range of materials that are covered for procedure qualification, bend test requirements for specific materials, and range of essential welding variables for AWS D14.6.

AWS D14.6 also provides more information regarding NDT requirements. Some of the same information remains the same regarding responsibility of the Engineer, Fabricator and Manufacturer.

 

[stanweld]

The great difference with regard to welding is the need to properly address fatigue as a failure mode in rotating equipment. Welding residual stress must be minimized and the location of welds subject to cyclic loading must be properly designed to preclude premature failure.

We have recently developed and qualified welding procedures for repair of rotating equipment utilizing the guidelines in the AWS specification. The guidelines incorporate many known but not necessarily well published methods to limit residual stress.