Undesired bonding between two parts under pressure
Undesired bonding between two parts under pressure
(OP)
Is anybody out there expert on unwanted bonding between surfaces of parts coupled under force or pressure?
I'd like to find out all major parameters, for example surface finishing, geometry, etc.
I'm also interested in mechanical literature about.
Thanks
I'd like to find out all major parameters, for example surface finishing, geometry, etc.
I'm also interested in mechanical literature about.
Thanks





RE: Undesired bonding between two parts under pressure
RE: Undesired bonding between two parts under pressure
RE: Undesired bonding between two parts under pressure
Is this what happens when you wring gage blocks together????
RE: Undesired bonding between two parts under pressure
RE: Undesired bonding between two parts under pressure
the surface finish the greater
the bonding. Just a guess.
RE: Undesired bonding between two parts under pressure
RE: Undesired bonding between two parts under pressure
http://www.tribtech.com/app.1.htm
http://www.tribology-abc.com/sub1.htm
RE: Undesired bonding between two parts under pressure
The case I'm studying now regards still parts, both made of steel, coupled on a conical surface, altough it could be affected by vibrations.
Temperature is about 50 C, more or less (probably more).
Think of a brake, working on a conical surface and not on a disc.
RE: Undesired bonding between two parts under pressure
RE: Undesired bonding between two parts under pressure
steel screws spontaneously welding solid...
<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032
RE: Undesired bonding between two parts under pressure
RE: Undesired bonding between two parts under pressure
Parts processed with shot peening proved to be better, from this specific point of view.
Following the theory of cold welding, it could be due to a decrease of areas in contact, I think.
RE: Undesired bonding between two parts under pressure
The "pick up" to which you refer is the same as galling for threaded fasteners. It is due to small-scale fracture and re-welding of the surface.
cicciazzo,
Shot peening improves performance by increasing the surface hardness, thereby making it less prone to deformation.
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Undesired bonding between two parts under pressure
As the spindle is spun up to speed, often up to 20000 RPM, the nose of the machine tool taper begins to deform outward. As this occurs, there is a constant force along the axis of the toolholder that retains it in the spindle.
The combination of deformed spindle nose, the axial force for toolholder retention, and less than 'ideal' mating between the two tapers, often makes the toolholder 'stick' or wedge into the mating taper surface. The stick is one or both of the surfaces deforming and then being forced into the other taper. This can be observed by running at high speeds for an extended period and then removing the tool from the spindle. A distinctive 'POP' can be heard as the tool is removed from the spindle.
For this reason CAT 40 or CAT 50 tapers are not usually used on spindles that run at greater than 20000 RPM. HSK style toolholders perform much better at these higher speeds.
RE: Undesired bonding between two parts under pressure
RE: Undesired bonding between two parts under pressure
The reason galling occurs is due to the thickness of the oxide film on SS. The film is so thin that as two parts are placed into contact and moved the film fractures exposing surfaces of unoxidized steel. These then weld together. This also happens with Al alloys and Ti. I guess you could say that it has something to do with the "stainless" properties. Mainly since the film is generally so thin that its easy to break.
nick
RE: Undesired bonding between two parts under pressure
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.