Definition of 'flaw' and 'defect' 1

[bagnamento]

Hi all!

I would like to track down a definitive reference which states the difference between a flaw and a defect in the English language. I believe this originated in AWS somewhere.

Can anybody help?

Thanks

 

[metengr]

The only definition you need to be concerned with is how Codes and Standards bodies/organizations view flaws and defects. In ASME Boiler and Pressure Vessel code, defect is consistently used throughout the various Code book sections and is defined to be a crack, porosity, lack of fusion, incomplete penetration, etc in welds.

For base metals, Codes and Standards bodies view defects, flaws and now let me introduce imperfections as synonymous terms, and are used interchangeably.

ASME B31.1 has a specific section titled, Definitions. There is one for flaw and one for defect.

 

[stanweld]

In simplest of terms, a defect is a flaw that is defined as rejectable by a Code or Specification.

While all defects are flaws, not all flaws are defects.

 

[EdStainless]

This is also related to non-destructive testing. Your NDT only finds indications. It is up to the sester to determine if they are just flaws, or if they are defects.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[redpicker]

Just to clarify EdStainless' post (ref ASNT-TC-1A)

An "Indication" is what the specific NDT method reveals (be it an accumulation of particles, a 'blip' on the UT screen, or bleed-through with penetrant testing). The inspector first determines whether it is relevant (caused by a flaw or imperfection in the material) or irrelevant (an artifact created by the method, such as the build-up of particles on a sharp edge with Mag. Particle). If it is relevant, he then determines whether it is a defect (and, therefore rejectable), or acceptable, based on the accpetance criteria. Depending on the inspection requirements, accpetable indications may have to be recorded, but aren't cause for rejection.

rp