Stainless Steel Strip Coated with a Metallic Layer

Abstract

A coated high strength stainless steel strip product with a dense and evenly distributed metallic layer on one side or both sides of said strip is provided. Said layer consists of essentially pure gold, copper, nickel, cobalt, molybdenum, silver, tin or tungsten or alloys of at least 2 of these metals, the thickness of said layer is preferably maximally 15 μm, the tolerance of said layer is maximally +/−30% of the layer thickness, the Cr content of the steel strip substrate is at least 10%, and that the layer has such a good adhesion so that the coated steel strip can be uniaxially stretched to fracture by tensile testing without showing any tendency to peeling, flaking or the like. The metal-coated strip product is suitable for use in applications that are load carrying and is able to transfer electrical currents to a contacting surface without an electrical conductivity drop at the interface between the surfaces.

1 . A coated stainless steel strip product with a dense and evenly distributed layer on one side or both sides of said strip wherein said layer consists essentially of one or several of the metals gold, copper, nickel, molybdenum, cobalt, silver, tin or tungsten, that the wherein a thickness of said layer is preferably maximally 15 μm, wherein a tolerance of said layer is maximally +/−30% of the layer thickness, wherein a Cr content of the steel strip substrate is at least 10%, and wherein the layer has an adhesion to the strip that the coated steel strip, under uniaxial stretching to fracture by tensile testing, does not show any tendency to peeling or flaking.  
   
   
       2 . Product according to  claim 1  wherein the thickness of the strip substrate is between 0.015 mm and 3.0 mm.  
   
   
       3 . Product according to  claim 1 , wherein said strip includes a substrate of austenitic stainless steel, or duplex stainless steel, or hardenable martensitic chromium steel, or precipitation hardenable stainless steel, or maraging steel with a minimum tensile strength of 1000 MPa in the cold rolled or heat treated condition.  
   
   
       4 . Product according to  claim 1 , wherein the layer has a multi-layer constitution of up to 10 layers.  
   
   
       5 . Product according to  claim 4  wherein each individual layer has a thickness of between 0.05 to 15 μm.  
   
   
       6 . Product according to  claim 4  wherein each individual layer has a thickness of between 0.05 to 11 μm.  
   
   
       7 . Product according to  claim 4  wherein each individual layer has a thickness of between 0.05 to 5 μm.  
   
   
       8 . Product according to  claim 5 , wherein the layer has a multi-layer constitution of individual layers of different metallic coatings.  
   
   
       9 . Product according to  claim 8 , wherein the layer consists of alloys of at least 2 elements selected from the group consisting of gold, copper, nickel, molybdenum, cobalt, silver, tin and tungsten.  
   
   
       10 . A product according to  claim 1 , wherein the product is suitable for use in load carrying applications where a low contact resistance at the surface is advantageous.  
   
   
       11 . A product according to  claim 1 , wherein the product is suitable for the production and use of spring elements is in switches, connectors, or metallic domes.  
   
   
       12 . Method of manufacturing a coated stainless steel strip product according to  claim 1 , comprising producing the coated stainless steel strip product in a continuous roll-to-roll process included in a strip production line using electron beam evaporation comprising an etch chamber in-line.  
   
   
       13 . Product according to  claim 8 , wherein the different metallic coatings are selected from the group consisting of Ag, Ni, Mo, Co, Au, Mo, W and Sn.