Stainless flux core problems.

[Hood]

Thanks for the Esab info. I see it does mention porosity and worm holes due to moisture so it is certainly looking like that is the issue.
The Bohler spec sheet I posted says bake for 24hrs at 150°C, looks like I am going to have to get the seals for the oven door

 

[Liquid Metal]

Might be a bit off of the mark here, but di you allow it a while to cool off between welds? Might it be a case of too hot of an inter-pass temperature affecting the weld??

 

[Hood]

Might be a bit off of the mark here, but di you allow it a while to cool off between welds? Might it be a case of too hot of an inter-pass temperature affecting the weld??

Yes, was letting them cool a bit between welds.

 

[Liquid Metal]

Fair do's, only a thought lol. Think the other guys above are closer to the mark though, a lot more experience with the stuff than me lol

 

[Hood]

All thoughts are welcome as I have never used it before so know absolutely nothing about it. All of my stainless welding is either stick or tig so this is new to me and I am only trying it because I got the wire for free.

 

[oliwb]

Sounds like moisture.... But if you try that & it didn't work we had a sort of similar problem with a Bohler flux core wire (Ni-alloy 625 - can't remember their name for it). Ours didn't look as bad as yours but we had worm tracks all over it. We spoke to Bohler about it (they'd lent us the roll for a procedure qualification so we didn't have to buy a full 15kg) & they said something along the lines of "we've seen this before, keeping the interpass down will help, but what you're looking at isn't actually porosity it's indentations on the surface of the deposited metal caused by a very fast freezing flux on that wire". In the end we didn't fancy putting the samples in at great expense to fail so we changed over to a solid wire. It did pass....

This was probably 2-3 years ago. No idea if it extends to your grade... Could be worth calling Bohler, but I still think it sounds like moisture. 24 hours in the oven seems unnecessary to me....

 

[Hood]

Thanks for the info, it was definitely porosity in a lot of it but with the second roll it was possibly more like you mentioned as it did seem to be more dips in the surface.
Not had a chance to haul out the oven yet but will give it a go next week and see.
It is not really a big deal for me as I was only wanting to try it out as I got it free. As most of my stainless welding is outside on boats I tend to just use stick.

 

[Hood]

This was the first run with the second reel, after that I was getting feeding issues due to the damaged reel.

 

[oliwb]

What we had was not as deep and was all over the surface rather than a straight line down the centre of the bead. They were also not as long and were curved. But it is similar. I'd definitely bake it and try again. They assured us that it wasn't porosity and would pass x-ray but we didn't fancy chancing it at ~£2k per qualification test!

 

[Brad93]

What we had was not as deep and was all over the surface rather than a straight line down the centre of the bead. They were also not as long and were curved. But it is similar. I'd definitely bake it and try again. They assured us that it wasn't porosity and would pass x-ray but we didn't fancy chancing it at ~£2k per qualification test!

Where were you sending your test pieces. Even TWI aren’t that expensive.

 

[oliwb]

Code-a-weld... They sub-con the x-ray inspection out and it included a salt spray test. So yeah - expensive!

 

[Brad93]

Code-a-weld... They sub-con the x-ray inspection out and it included a salt spray test. So yeah - expensive!

You need to try a different ndt outfit.

 

[Jim Davey]

Is the Bohler stainless wire seamless?

 

[Hood]

No idea, never looked that closely.

 

[Brad93]

Seamless wire doesn’t pick up moisture

 

[Hood]

Seamless wire doesn’t pick up moisture

In that case it can't be then or there would be no reason for them to state the redrying procedure.

 

[Richard.]

The seamless wire has a higher level of hydrogen control but they’ll all pick up moisture if not stored or looked after probably.

 

[Hood]

The seamless wire has a higher level of hydrogen control but they’ll all pick up moisture if not stored or looked after probably.

And I can assure you I have definitely not looked after this properly

 

[oliwb]

Could be the Aberdeen-oil-bubble effect but Element (formerly Exova - or maybe it's the other way round) quoted virtually the same price. There's a lot of testing involved with this one though as it was a dual ASME / ISO with corrosion testing.

 

[backpurge]

As has been said, volts too high, the slag is freezing before all the gas has had chance to escape so it runs longitudinally along the surface of the weld, usually only a surface defect that will pass most NDT