First of all, you have to look at all the details of the WPS(you mentioned part of it-no. of passes) such as interpass temperature maximum. I assume you have backing gas so it takes time to pre-purge before welding (time factor), is grinding neccessary between passes(?).
If I have a dewar as a gas supply, I can weld a 12"-sch-20 joint in about 1hr & 15 min., But it would be safer to say 1 1/2 hours. An 8" sch-40 joint (4-passes) would take about 1 hr 10 min.and only if there is no interpass temperture maximum.
The WPS defines rate of travel......you can use the mean (travel speed) as a starting point, but if the welder's travel rate is within the range specified by the Welding Specification Proccedure than it is unwise for the supervisor to ask a welder to increase his rate of travel because he does not technically have to.
I do not Believe welding speed has any effects on the mechanical properties of 304L-ss as long as an inner purge is maintained and the weld is not visibly contaminated. Again, you would certainly be limitted by the WPS as there would be a maximum amperage setting allowed which controls travel speeds.
That's my take on that, but remember that we are human and everyone is different. I have been at it for 20+ years so I would guess that I can weld faster than someone at it for 4 years, so there's a variable that makes it hard to say how fast someone should be capable of doing something. If you push someone to get it done faster, than there should be incentive for him/her to go faster or it just ain't happening.

If the foreman can demonstrate a way to weld faster using the parameters that the individual can work with then a little help may be in order.

The arc time is a VERY small part of field fabrication of piping. Even in a jackstand. Break the process down into several smaller processes from cutting/squaring, alignment, purge setup, tacks, root/fill/cap, and final QC. See what time those tasks take, and see where the tasks can be made more efficient.

On smaller and thinner stainless it is easier to make a nice looking weld the lower you keep the interpass temp. As the mass ofmetal goes down, the easier it is to weld without the bead sagging. Stainless is a poor conductor of energy and cools down slower. Because it cools down slower it also takes heat away while welding slower. The longer the puddle stays "HOT"the more time it has to sag and oxidize as the shielding blanket leaves.

Welding in a range that keeps the SS hot for a longer period of time at a certain temp (950DEg f ? or something) can reduce the corrosion resistance.

I know this didn't give you any numbers but I hope it helps some.

Gerald Austin
http://www.weldinginspectionsvcs.com

An option for increasing production rates is to do your root and hot pass with GTAW and your fill and cap with GMAW or FCAW.
Once you get over the hurdle of new procedure and qualification testing, I'm sure you'll find that it pays of in the long run as you can eliminate 1 or 2 of the passes.
I've found that GMAW SS with 98% Argon - 2% Oxygen sheilding gas puts down a nice bead.

Good Luck,
Tim

Hi there
This is Frank writing to you.
We are a manufacturer of GTAW cold wire feeding systems.
We know the problems of time and TIG quality.
You can increase the welding speed up to GMAW speed but GTAW qualitiy.
Please browse our web site to find out more about us.
We would be glad to help you.
Frank
www.theweld.com