Lubrication-free piece for a railway device

Abstract

The disclosure relates to a lubrication-free piece having a friction surface that rubs against a second surface, the lubrication-free piece having at least one structure made from spheroidal graphite cast iron or steel, the external surface of the piece including at least one layer of lubricating thermoplastic polymers, wherein the lubrication-free piece includes a nickel/aluminium-based intermediary layer between the spheroidal graphite cast iron or steel structure and the layer of lubricating thermoplastic polymers.

1 . A lubrication-free piece for a railroad device comprising:
 a friction surface that rubs against a second surface;   a spheroidal graphite cast iron or steel structure, with an external surface of the lubrication-free piece having at least a layer of lubricating thermoplastic polymers; and   a nickel-aluminum based intermediate layer between the spheroidal graphite cast iron or steel structure and the layer of lubricating thermoplastic polymers.   
     
     
         2 . The lubrication-free piece or part according to  claim 1 , wherein a surface of the spheroidal graphite cast iron or steel structure onto which is arranged the nickel-aluminum based intermediate layer, produces a relief that is at least partially filled by the nickel-aluminum based intermediate layer. 
     
     
         3 . The lubrication-free piece according to  claim 1 , wherein the nickel-aluminum based intermediate layer produces an isolation of spheroidal graphite particles. 
     
     
         4 . The lubrication-free piece according to  claim 1 , wherein the lubricating thermoplastic polymers include at least a thermostable semi-crystalline thermoplastic. 
     
     
         5 . The lubrication-free piece according to  claim 1 , wherein the lubricating thermoplastic polymers include at least a polyether ether ketone. 
     
     
         6 . A joint forming a sliding assembly comprising: the lubrication-free piece having a friction surface according to  claim 1 . 
     
     
         7 . A treatment process of a surface of a spheroidal graphite cast iron or steel structure for achieving a reduction of friction resistance and obtaining a lubrication-free piece according to  claim 1 , the treatment process comprising:
 smoothing the surface to be treated;   cleaning the smoothed surface;   projecting a nickel-aluminum based composition onto the smoothed surface;   impregnating a liquid or powder thermoplastic polymer onto the nickel-aluminum based surface; and   heating the impregnated nickel-aluminum based surface.   
     
     
         8 . The treatment process of a steel surface according to  claim 7 , further comprising, prior to the aforementioned steps:
 degreasing the spheroidal graphite cast iron or steel surface;   smoothing the spheroidal graphite cast iron or steel surface; and   thermal spraying at least a substratum comprising nickel and aluminum.   
     
     
         9 . The treatment process of a steel surface according to  claim 7 , further comprising:
 abrading the steel surface by corundum spraying until a surface is obtained with a specific relief;   cleaning the abraded steel surface.   
     
     
         10 . A component for railroad applications comprising the lubrication-free piece according to  claim 1 .