Friction Coefficient for Steel Subsea
Friction Coefficient for Steel Subsea
(OP)
Does anyone have information on the coefficient of friction for hard steel on hard steel subsea? The steels will not be lubricated, but obviously they will be wet!
Any input or direction is appreciated.
Any input or direction is appreciated.





RE: Friction Coefficient for Steel Subsea
RE: Friction Coefficient for Steel Subsea
The tool uses four hydraulic pistons @90 degrees to push 4 'shoes' onto the surface and lock it. The clamps will be used to counteract the torque the tool will apply to the casing. The shoes will actually have a sharp facets, so in fact it will be more of a hardness/biting question; but since I have no way to analyze that mathematically, I was going to be conservative and just use a friction force.
I don't know if that changes your answer, but at least you understand the application now.
RE: Friction Coefficient for Steel Subsea
RE: Friction Coefficient for Steel Subsea
"Happy the Hare at morning for she is ignorant to the Hunter's waking thoughts."
RE: Friction Coefficient for Steel Subsea
Calculate (or even measure) the penetration depth of your gripper facets, this will give you an area. Calculate the shear at this area when you torque the tool to remove the pipe. Multiply times the number of grips.
If your pipe diameter is consistent I would think a locking tool approach might be worth looking at. Have you ever seen an automotive stud remover?
You could also take a look at a monkey wrench to see how best to take advantage of the effect.
Crashj 'on the Internet no one knows you are a monkey' Johnson
RE: Friction Coefficient for Steel Subsea
The pipe diameter will not be consistent, so the tool will need to adapt from 13" to 36" diameters. Once I have built the tool I can empirically test the grip force - measuring the penetration depth would be a good idea. The cams are also a good idea. I'll need to look at that.
I'm still not convinced though that 'wet' steel will perform similiar to 'greasy' or 'lubricated' steel. I guess I might have to do some tests and let everyone know in the future.
Thanks again.
-DeepBlues
RE: Friction Coefficient for Steel Subsea
Good luck!
Pat