Hot-rolled steel foam and method for manufacturing hot-rolled steel foam

Abstract

A steel foam sheet and a method of producing a hot-rolled steel sheet, wherein a steel slab is prepared by casting molten steel, the steel slab including a plurality of interconnected pores that form a substantially uniform pattern within the steel slab, wherein the steel slab is cooled, reheated, and hot rolled at a starting temperature of between 1050 degrees Celsius and 1230 degrees Celsius to form the steel slab into the hot-rolled steel sheet. The plurality of interconnected pores can be flattened during hot rolling. The hot-rolled steel sheet can also be cooled and heat treated.

What is claimed is: 
     
         1 . A method of producing a hot-rolled steel foam sheet, the method comprising:
 preparing a steel foam slab by sand casting molten steel, the steel foam slab including a plurality of interconnected pores that form a substantially uniform pattern within the steel foam slab;   cooling the steel foam slab;   reheating the steel foam slab;   hot rolling the steel foam slab at a starting temperature of between 1050 degrees Celsius and 1230 degrees Celsius to form the steel foam slab into the hot-rolled steel foam sheet, wherein the plurality of interconnected pores is flattened during hot rolling;   cooling the hot-rolled steel foam sheet; and   heat treating the hot-rolled steel foam sheet.   
     
     
         2 . The method of  claim 1 , wherein the steel foam slab has a thickness, and wherein hot rolling includes reducing the thickness of the steel foam slab between 25% and 75%. 
     
     
         3 . The method of  claim 2 , wherein the thickness of the steel foam slab is within a range of 1 inch to 2 inches, and wherein reducing the thickness of the steel foam slab includes reducing the thickness to within a range of 0.25 inches to 0.75 inches. 
     
     
         4 . The method of  claim 1 , further comprising applying an antiscale coating to the steel foam slab. 
     
     
         5 . The method of  claim 4 , wherein applying the antiscale coating includes applying a coating to reduce scaling of the plurality of interconnected pores. 
     
     
         6 . The method of  claim 1 , wherein hot rolling further includes passing the steel foam slab through hot rollers between two and six times. 
     
     
         7 . The method of  claim 1 , further comprising soaking the steel foam slab at the starting temperature for at least 1.0 to 1.5 hours per inch of thickness of the steel foam slab. 
     
     
         8 . The method of  claim 1 , wherein heat treating the hot-rolled steel foam sheet includes heat treating the hot-rolled steel foam sheet subsequent to cooling the hot-rolled steel foam sheet to achieve a hardness in a range of 150 BHN to 400 BHN 
     
     
         9 . The method of  claim 1 , wherein heat treating the hot-rolled steel foam sheet includes quenching and tempering the hot-rolled steel foam sheet or normalizing and tempering the hot-rolled steel foam sheet. 
     
     
         10 . The method of  claim 1 , wherein preparing the steel foam slab further includes forming the plurality of interconnected pores as a plurality of spheres and cylinders. 
     
     
         11 . The method of  claim 10 , wherein hot rolling further includes flattening the plurality of pores such that at least some of the plurality of pores have substantially oval-shaped cross-sections. 
     
     
         12 . The method of  claim 1 , wherein preparing the steel foam slab further includes providing the steel foam slab with a chemical composition including, by mass %: C: 0.10% to 0.35%, Si: 0.2% to 0.8%, Mn: 0.5% to 1.5%, P: 0.00% to 0.025%, S: 0.00% to 0.025%, Al: 0.01% to 0.08%, Ni: 0.00% to 2.00%, Cr: 0.00% to 1.5%, Mo: 0.00% to 0.50%, and a balance including Fe and incidental impurities. 
     
     
         13 . The method of  claim 1 , wherein preparing the steel foam slab further includes forming the plurality of interconnected pores to represent at least 20% of a total volume of the steel foam slab. 
     
     
         14 . A hot-rolled steel foam sheet comprising:
 a steel body having a chemical composition including, by mass %: C: 0.10% to 0.35%, Si: 0.2% to 0.8%, Mn: 0.5% to 1.5%, P: 0.00% to 0.025%, S: 0.00% to 0.025%, Al: 0.01% to 0.08%, Ni: 0.00% to 2.00%, Cr: 0.00% to 1.5%, Mo: 0.00% to 0.50%, and a balance including Fe and incidental impurities,   the steel body including a plurality of interconnected pores forming a substantially uniform pattern within the body, wherein each of the plurality of interconnected pores have a flattened profile when viewed in a cross-sectional plane that is perpendicular to a thickness of the steel body.   
     
     
         15 . The hot-rolled steel foam sheet of  claim 14 , wherein the plurality of interconnected pores form at least 20% of a total volume of the steel body. 
     
     
         16 . The hot-rolled steel foam sheet of  claim 14 , wherein at least some of the plurality of interconnected pores have substantially oval-shaped cross-sections. 
     
     
         17 . The hot-rolled steel foam sheet of  claim 14 , wherein the plurality of interconnected pores does not extend through an entirety of the steel body such that at least a portion of the steel body is solid. 
     
     
         18 . The hot-rolled steel foam sheet of  claim 14 , wherein the steel body has a hardness in a range of 150 BHN to 400 BHN. 
     
     
         19 . The hot-rolled steel foam sheet of  claim 14 , wherein the steel body is no greater 0.75 inches 
     
     
         20 . The hot-rolled steel foam sheet of  claim 14 , wherein the steel foam body comprises a first portion having the plurality of interconnected pores, and a second portion having another plurality of interconnected pores with a density different from the density of the first portion.