Stainless steel performance test fail

[sftyvlv1]

Can excessive amperage used while stick welding 309l cause failure of a guided bend test when using carbon steel pipe? Interpass temp to high? Degredation of electrode coating when using to high an amperage?

 

[weldstan]

It could. Excessive dilution with the base metal. It appears that fracture initated at or near the fusion line and into the weld metal itself. There may also be some weld flaws which contributed to failure.

 

[EdStainless]

What was the filler?
Excessive dilution was my first thought.
But as Stan said you need to first rule out simple weld defects (porosity, lack of fusion, contamination, etc).

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P.E. Metallurgy, consulting work welcomed

 

[sftyvlv1]

In performing this test Lincoln excalibur 309L-15 3/32 dia stick electrode 70amps dcep with a "stiff" arc force setting.
After failing this test with same parameters but different electrode manufacturer and suffix -17 the test passed.
This only occured on the face bends as the root bends were done with Gtaw and an F6 filler w/out purge.
Since then others have failed tests using the above electrode and our test shop super will not use it any longer.

 

[jessieleo99]

It is very likely.
Excessive current can overheat the weld, causing a wider and more fluid weld pool. This can lead to poor fusion, undercutting, or excessive penetration, all of which weaken the joint and may cause failure in a bend test.

The interpass temperature for 309L electrodes is typically around 150-200°C. If it gets too high, it can cause grain growth in the heat-affected zone (HAZ), reducing toughness and ductility, which makes the joint more likely to fail during a bend test.

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