Abstract Described herein are improved methods and means for lubrication during diametral mandrel expansion of hollow couplings at cryogenic temperatures, the couplings being formed of a metal susceptible to the impartation of dimensional heat recoverability by deformation at a temperature below that at which the material undergoes a martensitic transformation. Films or fibrilous cloths of organic material are disposed between the interior wall of the part and the mandrel, the material being such as to undergo plastic deformation at the temperatures and pressures obtained during forcible expansion of the fitting internal diameter of from about 3 to about 9 percent, in order to provide roller bearing lubrication. Preferred lubricant materials are polyethylene and related linear polymers and waxes and fluorocarbon oligomers. The couplings may be formed of titaniumnickel or beta-copper alloys, stainless steels and the like.
A method according to claim 1 wherein the internal surface of the hollow coupling is provided with a plurality of radial teeth.
Claim 2
Dependent Claim
18 words
A method according to claim 2 wherein said organic material is in the form of a fibrilous cloth.
Claim 3
Dependent Claim
27 words
A method according to claim 2 wherein said cryogenic liquid is liquid nitrogen and wherein said transition point is less than about -75*C but above about -196*C.
Claim 4
Dependent Claim
27 words
A method according to claim 3 wherein said cryogenic liquid is liquid nitrogen and wherein said transition point is less than about -75*C but above about -196*C.
Claim 5
Dependent Claim
13 words
A method according to claim 1 wherein said organic material is a polyethylene.
Claim 6
Dependent Claim
13 words
A method according to claim 2 wherein said organic material is a polyethylene.
Claim 7
Dependent Claim
13 words
A method according to claim 3 wherein said organic material is a polyethylene.
Claim 8
Dependent Claim
13 words
A method according to claim 5 wherein said organic material is a polyethylene.
Claim 9
Dependent Claim
24 words
A method according to claim 3 wherein said cloth is wrapped about the tapered portion of said mandrel before insertion thereof into said coupling.
Claim 10
Dependent Claim
27 words
A method according to claim 3 wherein the interior of said coupling is lined with said cloth before insertion of the tapered portion of said mandrel therein.
Claim 11
Dependent Claim
17 words
A method according to claim 3 wherein said cloth is a high density polyethylene spun bonded cloth.