Steel coated metal structures and methods of fabricating the same

Abstract

An elongated hollow component includes a body extending from a first end to a second end and defining a longitudinal axis. The body includes a plurality of layers each circumscribing the longitudinal axis. The plurality of layers include a base layer formed of a first steel material, an inner surface layer formed of a second steel material and coupled directly to the base layer such that the base layer circumscribes the inner surface layer and the inner surface layer is exposed to an interior cavity of the elongated hollow component. An outer surface layer formed of the second steel material is coupled directly to the base layer such that the outer surface layer circumscribes the base layer. The first steel material has a chromium content of less than 10.5% by mass and the second steel material has a chromium content of at least 10.5% by mass.

What is claimed is: 
     
         1 . A method of fabricating an elongated hollow component, said method comprising:
 providing a first layer formed of a first steel material;   coupling a second layer to the first layer to form a plurality of layers, the second layer formed from a second steel material; and   rolling the plurality of layers to form a tubular body of the elongated hollow component, such that the plurality of layers each circumscribe a longitudinal axis extending from a first end to a second end of the body, and the second layer is on a radially inner surface of the first layer and exposed to an interior cavity of the elongated hollow component.   
     
     
         2 . The method in accordance with  claim 1 , wherein said providing the first layer formed of said providing the first layer formed of the first steel material comprises first steel material comprises providing the first layer as a sheet of the first steel material. 
     
     
         3 . The method in accordance with  claim 1 , wherein said coupling the second layer to the first layer comprises at least one of diffusion bonding and annealing. 
     
     
         4 . The method in accordance with  claim 1 , wherein the first steel material has a greater surface roughness than the second steel material. 
     
     
         5 . The method in accordance with  claim 1 , wherein the second steel material has a higher chromium content than the first steel material. 
     
     
         6 . The method in accordance with  claim 1 , wherein the interior cavity is configured to receive a liquid fluid flow therein and the second layer is configured to direct the liquid fluid flow within the interior cavity between the first end and the second end. 
     
     
         7 . The method in accordance with  claim 6 , wherein the second steel material, after said coupling and before said rolling, has material properties configured to reduce friction of the liquid fluid flow in the interior cavity and inhibit corrosion caused by the liquid fluid flow in the interior cavity. 
     
     
         8 . The method in accordance with  claim 1 , wherein the first steel material has a chromium content of less than 10.5% by mass and the second steel material comprises a chromium content of at least 10.5% by mass. 
     
     
         9 . The method in accordance with  claim 1  further comprising coupling a third layer to the first layer opposite the second layer, wherein the third layer is formed from a third steel material. 
     
     
         10 . The method in accordance with  claim 9 , wherein said coupling the third layer to the first layer comprises at least one of diffusion bonding and annealing. 
     
     
         11 . The method in accordance with  claim 1  further comprising:
 stamping the first layer to cut the first layer from a coil, wherein said stamping further comprises defining an aperture extending through the first layer and the second layer, the aperture located intermediate the first end and the second end, wherein the aperture is sized, after said rolling, to receive another elongated hollow body into flow communication with the interior cavity. 
 
     
     
         12 . The method in accordance with  claim 1 , wherein, prior to said rolling, the first layer extends laterally between a first edge and a second edge, wherein said rolling the plurality of layers further comprises rolling the first layer such that the first edge is opposed to the second edge, said method further comprising welding the first edge to the second edge to define a longitudinal seam in the tubular body. 
     
     
         13 . An elongated hollow component comprising:
 a body extending from a first end to a second end and defining a longitudinal axis, said body comprising a plurality of layers each circumscribing said longitudinal axis, said plurality of layers comprising:
 a base layer formed of a first steel material; 
 an inner surface layer coupled directly to said base layer such that said base layer circumscribes said inner surface layer and said inner surface layer is exposed to an interior cavity of said elongated hollow component, said inner surface layer formed of a second steel material; and 
 an outer surface layer coupled directly to said base layer such that said outer surface layer circumscribes said base layer, said outer surface layer formed of said second steel material, wherein said first steel comprises a chromium content of less than 10.5% by mass and said second steel material comprises a chromium content of at least 10.5% by mass. 
   
     
     
         14 . The elongated hollow component in accordance with  claim 13 , wherein said first steel material comprises a black steel material and said second steel material comprises a stainless steel material. 
     
     
         15 . The elongated hollow component in accordance with  claim 13 , wherein said second steel material comprises a decreased surface roughness relative to said first steel material. 
     
     
         16 . The elongated hollow component in accordance with  claim 13 , wherein said second steel material comprises an increased corrosion resistance relative to said first steel material. 
     
     
         17 . A fire suppression sprinkler system comprising:
 a plurality of pipes, each of said pipes comprising a body extending from a first end to a second end and defining a longitudinal axis, said body comprising a plurality of layers each circumscribing said longitudinal axis, said plurality of layers comprising:
 a base layer formed of a first steel material; 
 an inner surface layer coupled directly to said base layer such that said base layer circumscribes said inner surface layer and said inner surface layer is exposed to an interior cavity of said pipe, said inner surface layer formed of a second steel material; and 
 an outer surface layer coupled directly to said base layer such that said outer surface layer circumscribes said base layer, said outer surface layer formed of said second steel material, wherein said first steel material comprises a chromium content of less than 10.5% by mass and said second steel material comprises a chromium content of at least 10.5% by mass; and 
   at least one sprinkler head coupled in flow communication to said plurality of pipes.   
     
     
         18 . The fire suppression sprinkler system in accordance with  claim 17 , wherein said system is configured to maintain stagnant liquid in said pipes when said system is not being tested or used to suppress a fire. 
     
     
         19 . The fire suppression sprinkler system in accordance with  claim 17 , wherein said system is configured to maintain said pipes substantially empty of liquid when said system is not being tested or used to suppress a fire. 
     
     
         20 . The fire suppression sprinkler system in accordance with  claim 17 , wherein said second steel material comprises a decreased surface roughness relative to said first steel material.