Taking in to account the definition for "as welded" it seems they are looking for some type of thermal treatment, weld bead dressing or chemical treatment of some type. I would be reviewing my paperwork or submit a RFI to get a positive readout on what is required.
By 803056
Date 01-03-2011 05:34
Edited 01-03-2011 16:18
Joe;
I'm busting your stones a wee bit here. Don't take offence.
AWS A5.29 is the specification, but there are many electrodes of different classifications that are included in the specification.
You haven't filled us in on the details and the correct response requires the details of what is proposed by the contractor.
Welds can be in the "as welded" conditions or the "post weld heat treated" condition. As welded is just what it says, no post weld thermal treatment is applied. The PWHT condition is performed below the lower transformation temperature or above the lower transformation temperature. Below the lower transformation temperature (for carbon and high strength low alloy steels, the typical PWHT is thermal stress relief. Above the lower transformation temperature the PWHT is either normalizing or annealing. Thermal stress relief is the PWHT that is most often performed to relieve the residual stresses that develop as a result of the uneven heating and cooling that occurs during the welding or thermal cutting operations. Occasionally a tempering operation is performed at temperatures between 400 and 800 degrees F to reduce the hardness of the weld and/or the HAZ.
The electrodes listed in the footnote for the most part are not those used to match the weathering characteristics of weathering steel. You need to look at the table that lists the filler metals that provide matching weathering characteristics. Simply selecting any electrode classification included in the A5.29 specification is not necessarily going to provide the match required. While EXXT-B2L is listed in the footnote and in the matching filler metal table, it is not the only electrode classification that provides the necessary weathering characteristics of the base metal. If you look at the table “Filler Metal Requirements for Exposed Bare Applications of Weathering Steel” there are several electrode classifications that can be used that are not included in the footnote of Table 3.1.
If, as you stated, the contractor has selected a filler metal included in the footnote, the WPS must be supported by a PQR where the weld is tested in the as welded condition or PWHT is required for the WPS to be eligible for prequalified status. The A5.29 specification should be reviewed to see what PWHT conditions are applicable in addition any limitations imposed by AWS D1.1.
Keep in mind that if the application requires the base metal to be painted or if single pass groove welds or fillet welds are used, a matching filler metal is not required if the welds are small and sufficient dilution with the base metal is achieved. There are several clauses that addresses these requirements or limitations.
Under the auspices of AWS D1.1, the review and approval of the WPS is the owner’s Engineer’s responsibility, not the inspector’s responsibility. The WPS and supporting PQR (if the WPS isn’t prequalified) must be filtered through the Engineer.
Best regards – Al
Careful Joe,
Both Lawrence and I stated we didn't have books to look at and were going from the ever dangerous aspect of 'MEMORY' and thus making ASSUMPTIONS which is really a NO NO. But we both did it trying to get you something to look for just in case.
It was a Holiday Weekend and most of us were spending lots of time AWAY from WORK. No Books handy. Check out Al's comments carefully. I still don't have time to grab books this morning. Got my own work to look after for a spell. Hopefully it will all be resolved by and for you soon.
Have a Great Day, Brent