What's going wrong?

[Richard.]

I think the darkened ss weld is down to welding too hot/slow and it's simply cooking the cr out of the weld.

 

[James1433]

The last weld was done same amps and speed as the others only difference was with the gas lens fitted. Hopefully my technique has got a bit better too though.

 

[wheresmejumper]

I think the darkened ss weld is down to welding too hot/slow and it's simply cooking the cr out of the weld.

Yes its the porosity on mild is the concern.not the stainless finish

 

[Richard.]

The bead is certainly a lot better than the other attempts but it's still hot. The amperage may be good for what your doing but the travel speed needs picking up and matching with consistent fill. The bead is sunk and wide. It's not shiny. I'm going to put it down to heat input/arc length and inconsistency. Practice these things on a flat plate. It's easier to get to grips with technique that way and results will be more pleasing. Transfer your findings to the pipe.
I've got a few bits I stuck together many years ago kicking about when I was striving for better beads in ss I'll dig it out later and show you.

 

[Richard.]

Yes its the porosity on mild is the concern.not the stainless finish

What mild? I've only seen stainless in the thread.

 

[Richard.]

1st post. Yep sorry mate. Porosity in ms I forgot he wrote that.

 

[wheresmejumper]

What mild? I've only seen stainless in the thread.

Very first post.

 

[Richard.]

Here it is. I was learning with this trying out different techs. Fillet, butt , torch angles. I've kept it for years.

 

[James1433]

Thanks Richard will give it a go on some plate then.

 

[James1433]

Yes its the porosity on mild is the concern.not the stainless finish

Not posted any mild steel. 1st post was stainless.

 

[Richard.]

In the first post you mention your getting porosity in Ms welds.

 

[Rrunnach]

Did some SS myself last Thursday. Blanking off, 150 square box section.