cracking/checking induced by turning operations
cracking/checking induced by turning operations
(OP)
I'm well aware of the possibility of creating "heat checks" when grinding iron and steel. I've even created a few.
How possible or even likely is it to create cracks/checks/indications in a steel shaft made only using turning type operations?
thanks
Dan T
How possible or even likely is it to create cracks/checks/indications in a steel shaft made only using turning type operations?
thanks
Dan T





RE: cracking/checking induced by turning operations
RE: cracking/checking induced by turning operations
http:
Maui
www.EngineeringMetallurgy.com
RE: cracking/checking induced by turning operations
depending on the configuration of the parts, heat treat condition & so on.
cracking from to high of jaw pressure, excessive feeds & speeds.
I seen parts crack because the jaw pressure was to high & the parts where thin & fragile.
Parts turned with to high of speed cracked.
rarely seen any parts over tempering but it's possible.
Mfgenggear
RE: cracking/checking induced by turning operations
RE: cracking/checking induced by turning operations
Maui
www.EngineeringMetallurgy.com
RE: cracking/checking induced by turning operations
thanks
Dan T
RE: cracking/checking induced by turning operations
look at the parent material as said above.
raw stock may have cracks.
Mfgenggear
RE: cracking/checking induced by turning operations
Along with environmental considerations, this is one of the reasons why industry is beginning to turn away from using coolants............particularly on grinding operations.
Ron Volmershausen
Brunkerville Engineering
Newcastle Australia
http://www.aussieweb.com.au/email.aspx?id=1194181
RE: cracking/checking induced by turning operations
thanks all.
Yes, we UT the shaft blanks pretty early in the process.
The current quest is to justify whether we need mag particle at the end.
Detecting induced cracking was originally considered one (theoretical) concern.
It remains legitimate, possibly. There were some bearing seats that suppliers used to finish grind.
Reports are they now turn them to within 0.002", and finish polish to size with something like this.
http://www.abs-products.com/abs_images/abs-product-images/specialty-tools/bicycle-handled-polisher.jpg
My first reaction is to be mighty suspicious of the results, especially taper, whether used on crankshafts or our bearing seats, but if the QC guys say they measure OK I guess I have no real complaint.
RE: cracking/checking induced by turning operations
Yes it does. I have seen for what ever reason, The UT NDT not detect fine defects. be it operator error or the procedure it self.
I would highly recommend Mag & Demag after finish machining. yes there could be cases where the mfg may final grind parts, straighten or could open up defects during final machining. I am on the conservative school of thought when quality is concerned.
The cost is well worth the piece of mind.
Mfgenggear