17-7 stainless steel weld certification 1/8x3x8 plates for butt weld

by PLT
(Lompoc CA)

We have to cert. on 17-7 stainless steel at work. FAA required. We all know 17-7 is a bear. We have a good fixture at work already. What I am looking for is a little advice on technique. The problem is we either get a nice crown on the weld and not much penetration or a low crown and nice penetration. It's pretty difficult to get somewhere in between. We've done it before but we only do this every 5 years. Any advice would be appreciated. And of course we are using a trailing shield and backing gas. Thank you for input.

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It depends on the wps and test supervisor etc.

but if you have the leeway, why not use 2 passes.

the first pass concentrate on penetration and dont worry about underfill.

let cool completely and then put the 2nd pass on not worrying about penetration.

if thats not allowed then a small addition of helium or using n argon hydrogen mix with 2.5% hydrogen works too.

if thats not allowed either and you just have to fight with a single pass , then you might try using a forward and back technique.

move the electrode forward and watch for the sink.
then back up and add rod making sure you get it crowned.

thanks for the post.

jody