Heat Input - ASME VS EN

[AllanEjames]

Good morning,

As the title suggests is there a general consensus on whether or not Thermal Efficiency (E) being factored into the heat input equation produces a more accurate joules reading? If so why has ASME/AWS not adopted this into their equations as of yet? Please see below.

Typical ASME/AWS - (V)x(I)x(60)/Travel Speed

EN 1011-1 - (V)x(I)x(60)x(E)/Travel Speed

Thank you
Allan James

 

[metengr]

There is no consensus at the moment, just two different calculation methods. Both methods are proven for what is intended. From the ASME side, welding arc efficiency is considered as 1, versus other factors less than 1. The bottom line is you are obtaining a heat input value and this value, however calculated (EN versus ASME) achieves the necessary result - it is a maximum heat input value for weld procedure qualification purposes.

This is no different than comparing design or fabrication practices between EN and ASME. Both are acceptable and achieve the necessary results.

 

[DekDee]

Allan,
Probably because EN 1011-1 will be superceded by something else next week and then two weeks later another new specification will come out.
Sorry for being blunt but the amount of "standards" produced by the British / European committees is a joke.

Regards,
Shane

 

[CWEng]

It doesn't matter unless you are comparing processes. Per ASME Section IX, since changing processes is an essential variable, there is no need to account for process efficiency. If you are comparing for instance, GMAW heat input vs GTAW heat input for non-qualification reasons, the EN equation would give you a better result. So the ASME equation is perfectly good for what it is intended to do. I'm not sure what the EN equation is intended to do, because you would have to reference at least 3 other EN standards to figure it out.