Need X-ray or Ultrasonic spec suggestion 1

[mfgenggear]

I need to x-ray & /or Ultrasonic test some parts made from Carburized AISI 9310 steel, 3 of 5 parts had heat treat cracks.
I need to verify the two parts do not have cracks below sub-surface. any recommendations?

parts past mag particle insp,but I want to make sure there are no defects at the center.

Thanks
Mfgenggear

 

[Duwe6]

Unless your parts are thicker than about 2-inches, or have a convoluted geometry, Wet Fluorescent Fully-rectified DC mag-particle will find your subsurface problems. The MT is what you will get in a 'bench MT booth'. Not really possible to duplicate it 'in the field'.

Otherwise, have them UT scanned using 70-degree and 45-degree transducers "Client info -- No Cracks"

 

[mfgenggear]

Duwe6

I not sure I under stand your statement

Yes the MPI was done with an fully rectified Mag. Isso Approved.

My understanding is Mag will detect surface defects same as
penetrant. X-ray & ultrasonic will detect sub surface defects. I am a levell II except I have not been in practice for xx number of years.

no X-ray? why please advise.

Mfgenggear

 

[ndeguy]

mfgenggear

If the 3 parts were rejected due to surface-breaking heat treat cracks, why should you suspect the other 2 parts(already succesfully passed the MPI) have sub-surface cracks i.e. not heat treatment.

As your sector is aerospace I would guess part geometry may be complex and to PROVRE no sub-surface cracks present you will need to perform extensive NDT, both UT and RT as you have no idea of defect location. An odd random X-ray or a few UT scans will not guarantee freedom from haphazardly oriented cracks. That is process quality control's responsibility.

Talk to your Level III or approach Level III consultants.

 

[mfgenggear]

NDEguy

we have a level 3 only in mag & temper etch,
we normally send out all x-ray or UT to an out side source.
hence I need a spec that details the actual procedure.
I no longer due NDT I am now an Mfg Engineer.

any suggestions

Mfgenggear

 

[ndeguy]

So if you send the 2 parts out to your local RT/UT shop with the instruction find all sub-surface cracks without limitations on size, position or orientation, you will be offering them a blank check! And as for a guarantee you will only ever be relying on what your NDT shop determines as sufficiently comprehensive examination.

If failure analysis of the 3 cracked parts reveals the reason for the failure then you can perhaps understand why the other 2 parts did not fail and if there is any reason to suspect the internal quality of the material.

I dont feel this helps you much because its the old NDT bind - how much work and money is justifiable for the desired end result of a "No significant defect" report. Basically, what are the parts worth to you?

 

[mfgenggear]

NDE Guy

I understand

There is a in-process failure analysis for the corrective action from our Heat Treating Vendor.
To my experience it is very rare for 9310 steel to crack.

But I have two possible good parts that where acceptable to MPI. and that is all I am required by contract (ASTM E1444)&
Mil-Std-1907 Grade A except no Indications permitted.

base on that criteria could I apply it to X-ray ?
is there an equivlant ?

Thanks
Mfgenggear

 

[Duwe6]

mfgenggear: DC MT will reveal subsurface defects. There is a limit to the size of defect detectable, depending on how deep that defect is. Google "Ketos Ring". You may be thinking of AC MT. The AC magnetic field makes it a "skin effect" and will only detect defects open to the surface.

As to "no x-ray / RT": crack orientation is very critical for detectability, and each RT costs money. Taking RT 'shots' every few degrees in a full 360-deg circle will be VERY costly. UT scanning is MUCH faster, thus much cheaper. Additionally, it is MUCH easier to find tight cracks using UT versus RT.

 

[mfgenggear]

Duwe6

Very well thanks

Mfgenggear