How to make controlled welding defects

[gdmystno]

Hello everyone!

I’m a student of university of technology and to my master thesis I must make some samples of weld with intend (controlled) welding defects, which I can detect by NDT: VT, RT, UT, MT, PT.
Type of steel (but it will be carbon steel) and weld (BW, FW) is irrelevant, I wonder how to do such a controlled defect.

I came up with ideas:
1. Lack of fusion and incomplete penetration - melt part of edge withTIG, rest part – MIG with solid wire
2. Bonding (?) - after welding MIG with cored wire don’t remove the slag, then put another weld layer (stitch?), reduce the welding current for the moment)
3. Gas inclusion - impose grease between layers
4. Inclusions of tungsten - piece of the TIG electrodes put to the lake
5. Cracks - little piece of copper put in welding lake

Maybe you have some other ideas, suggestions?
If I used the wrong terms (words) then I'm sorry
Regards

 

[TechnicAl]

for cracks look up TEKKEN tests

 

[StickNtig]

We've worked with a couple of idiots over the years who could do all those defects for you, probably in one butt, not on purpose, they were just s**t!

 

[Lewis Medlock]

Go to your local college, we produce a skip full of that stuff every wednesday afternoon!

Lack of fusion- Mig fillet, aim the wire just away from the centre of the joint
Bonding (slag inclusion?)- MMA, don't chip all the slag between runs
Gas inclusion (porosity?)- MIG cut shielding gas for a small portion
Tungsten inclusion- grind tungsten to a fine point then touch down
Cracks- copper inclusion will give nice transverse cracks, weld cast material for longditudinal cracks

I'm getting quite good at producing weld defects these days, let us know how you get on

Jim