Net Energy Input vs Heat/Arc Energy Input

Date 12-31-2008 22:12

Heat/Arc Energy Input - Heat (joules/inch) = E (volts) X I (Amperes) X 60 divided by the V (travel speed in inches per minute). - vs - Net Energy Input - f1 (heat transfer efficiency (assumed to be approximately 0.9)) X E X I divided by V. Question; Has/does D1.1 or any other code require f1 as part of the calculation for heat/arc energy in weld procedure qualifications? Please quote chapter and verse of applicable code(s). thank you. Happy New Year!!

By MBSims

Date 01-01-2009 00:34

No one is using heat transfer efficiency in any Codes I am familiar with. As long as the welding process doesn't change, there is no need to factor in heat transfer efficiency. The main concern in the Codes is a "change" in heat input. If the process used in the PQR does not change, then there is negligible change in heat transfer efficiency due to other variables. The negligible difference does not appear to be enough to cause concern to the Code bodies.

By MBSims

Date 01-01-2009 16:48

As an afterthought, it would not be practical for a typical fabricator to measure thermal efficiency. It is usually done in a lab using a calorimeter or other very expensive equipment. That's probably the biggest reason it is not included in Code requirements.

By kipman

Date 01-05-2009 19:44

Check out EN 1011-1 section 19. 0.9 is not an efficiency factor listed for any welding process.
Mankenberg

By 357max

Date 01-05-2009 21:29

Correct, .9 was used as an example thanx

By MBSims

Date 01-05-2009 22:44

Here are some typical ranges:

By dmilesdot (**)

Date 01-09-2009 18:31

The New York State Steel construction manual has a minimum heat input requirement for A709-50W of 35 kilojoules per inch for material from 3/8" to 3/4" and 50 kilojoules p/i for material over 3/4". HPS70W has a minimum of 40 and a max of 90 regardless of thickness.