Failure Analysis of small part

[M. BR]

Hey guys,

Need some help to understand the fracture surface attached (SEM images)

The part fractured during assembly, with little stress.

Inthe middle of the fracture there is this kind of inclusion, the way aroud of it looks spherical, and it possible to identify dimples.

Never seen anything like this.

The steel is SAE 1070 plate, hardeness of 45HRC.

Do you think that the fracture started at this inclusion? There is some black stinch, looking like oxidation.

Any clue will be really helpfull....

 

[rb1957]

are those striations (fatigue) on the surface ?

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[M. BR]

I dont think is fatigue striations…but maybe… if it is striations (fatigue), do you think it started on that dark area?

 

[desertfox]

Would be helpful if you could tell what the component actually is and how it’s been loaded?

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[M. BR]

See if the images help. Its a trigger bar

 

[M. BR]

to understand the function....