Aluminium 6061 - Performance Qualification Record - AWS D1.2 - Table 3.2

[Mateus_R]

Hello,

I'm not a welding specialist and for a PQR with base metal Al 6061 T6 (plate), I have a question about the AWS D1.2 requirement for tensile test.

Table 3-2 presents as minimum tensile strength 24 ksi, but the Al6061 T6 ruled by ASTM B209 defines as min. Yield Strength 35ksi and Tensile Strength as 42ksi.

If the specimen fails at the base metal (hypothesis), why the tensile requirement is different? Why 24ksi instead of 42ksi?

My opinion is that the material fails near the HAZ where the heat treatment was affected, and the AWS considers this effect. Is it reasonable?

Thank you for the support.

 

[gtaw]

The mechanical properties of 6061 are degraded due to overaging. The longer the material is held at high temperature, the greater the degradation. If a welded specimen reaches a TS of 24 ksi, it is considered "good enough"

When multiple passes are required to fill the groove, cool the coupon between each weld bead and what ever you do, don't preheat the aluminum before welding.

Best regards - Al

 

[Mateus_R]

Thank you gtaw for your comment!

Best regards.
Mateus