disbonding - crack problem CoCr-A welding on F6a material

Question

disbonding - crack problem CoCr-A welding on F6a material

35jacob35 (Petroleum)

(OP)

26 Jun 24 05:57

I apply stl6 HFO with PTa on f6a material.
After machining the weld surface, there is no problem. weld surface checked with UT and liquid penetrant method
but after 3-4 days the all weld disbond from surface or seen big cracks.
do you have any suggest.

SWComposites (Aerospace) · Answer 1 · 2024-06-26 13:19:58

stl6?
HFO?
PTa?
f6a?

contamination?
residual stresses?

a picture or two (directly embedded not linked) might help

r6155 (Mechanical) · Answer 2 · 2024-06-26 16:40:52

RE: disbonding - crack problem CoCr-A welding on F6a material

r6155 (Mechanical) 26 Jun 24 16:40

Thickness?
Code?
General dimensions?

Regards

mfgenggear (Aerospace) · Answer 3 · 2024-06-26 18:19:07

After welding prior to any machining must be done penetrant , radiographic , then repeat
After machining then penetrant radiographic, and UT. Depending on the calibration method and the calibration defect UT will or could not detect slight subsurface defects. Most likely but not definitely
The grain structure change to fast and distorted.
Causing cracks. Was there a post weld stress relief. PWHT. Were the parts pre heated, was the recipe for gas purging was correctly processed.
Was there weld and mfg engineer review.

TugboatEng (Marine/Ocean) · Answer 4 · 2024-06-26 19:02:32

RE: disbonding - crack problem CoCr-A welding on F6a material

TugboatEng (Marine/Ocean) 26 Jun 24 19:02

Is this on the ID, OD, or face?

EdStainless (Materials) · Answer 5 · 2024-06-29 15:53:42

Surface texture?
Preheat?
Have you tried various deposition settings?
You are not using HVOF?
How thick of a layer and what contours?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

mfgenggear (Aerospace) · Answer 6 · 2024-06-29 16:02:34

The condition of material ? And type ?
Is it annealed or core harden ,what percentage of carbon. Op can't answer the questions

gtaw (Structural) · Answer 7 · 2024-07-05 17:29:49

Base metal designations that I'm not familiar with, likewise, I'm not familiar with the filler metal designation.

Best regards - Al

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disbonding - crack problem CoCr-A welding on F6a material