Inert material with increased hardness for thermally stressed parts

Abstract

A material for the manufacture of parts and tools for use at elevated temperature, comprising an iron-based alloy comprising C, Si, Mn, Cr, Ni and N in certain concentrations and being cold formed to a hardness of at least 230 HB, a process for the manufacture of the material and a hot working tool comprising the material. This abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

What is claimed is:  
     
         1 . A material for the manufacture of parts and tools for use at elevated temperature, comprising an alloy having a composition of, in % by weight, 
 Carbon (C) 0.01 to 0.25    Silicon (Si) 0.35 to 2.5    Manganese (Mn) 0.4 to 4.3    Chromium (Cr) 16.0 to 28.0    Nickel (Ni) 15.0 to 36.0    Nitrogen (N) 0.01 to 0.29    provided that the nickel content of the alloy is equal to or higher than the value formed by the chromium content plus 1.5 silicon minus 0.12 manganese minus 18 nitrogen minus 30 carbon minus the numerical value of 6:    Ni≧Cr+1.5×Si−0.12×Mn−18×N−30×C−6    with the balance iron (Fe) and accompanying elements and impurities, which material shows a hardness provided by cold forming of at least 230 HB.    
     
     
         2 . The material of  claim 1 , wherein the hardness of the material is higher than 250 HB.  
     
     
         3 . The material of  claim 2 , wherein the hardness is at least 300 HB.  
     
     
         4 . The material of  claim 1 , wherein the nickel content of the alloy is higher by not more than 4.8% than the value obtained according to the equation of  claim 1 .  
     
     
         5 . The material of  claim 1 , wherein the alloy comprises one or more elements in the following concentrations, in % by weight: 
 C 0.02 to 0.20    Si 0.50 to 2.48    Mn 0.62 to 4.05    Cr 20.1 to 27.6    Ni 16.1 to 27.3    N 0.014 to 0.23.    
     
     
         6 . The material of  claim 1 , wherein the alloy comprises one or more elements in the following concentrations, in % by weight: 
 C 0.04 to 0.15    Si 1.22 to 2.36    Mn 1.00 to 3.95    Cr 23.9 to 26.5    Ni 17.9 to 25.45    N 0.018 to 0.20.    
     
     
         7 . The material of  claim 5 , wherein the alloy comprises one or more elements in the following concentrations, in % by weight: 
 C 0.04 to 0.15    Si 1.22 to 2.36    Mn 1.00 to 3.95    Cr 23.9 to 26.5    Ni 17.9 to 25.45    N 0.018 to 0.20.    
     
     
         8 . The material of  claim 1 , wherein the alloy comprises one or more accompanying elements in the following concentrations, in % by weight: 
 Molybdenum (Mo) less than 1.0    Vanadium (V) up to 0.5    Tungsten (W) up to 0.5    Copper (Cu) up to 0.5    Cobalt (Co) up to 6.5    Titanium (Ti) up to 0.5    Aluminum (Al) up to 1.5    Niobium (Nb) up to 0.5    Oxygen (0) up to 0.05    Phosphorus (P) up to 0.03    Sulfur (S) up to 0.03.    
     
     
         9 . The material of  claim 5 , wherein the alloy comprises accompanying elements in the following concentrations, in % by weight: 
 Mo less than 1.0    V up to 0.5    W up to 0.5    Cu up to 0.5    Co up to 6.5    Ti up to 0.5    Al up to 1.5    Nb up to 0.5    O up to 0.05    P up to 0.03    S up to 0.03.    
     
     
         10 . The material of  claim 6 , wherein the alloy comprises accompanying elements in the following concentrations, in % by weight: 
 Mo less than 1.0    V up to 0.5    W up to 0.5    Cu up to 0.5    Co up to 6.5    Ti up to 0.5    Al up to 1.5    Nb up to 0.5    O up to 0.05    P up to 0.03    S up to 0.03.    
     
     
         11 . The material of  claim 7 , wherein the alloy comprises one or more accompanying elements in the following concentrations, in % by weight: 
 Mo less than 1.0    V up to 0.5    W up to 0.5    Cu up to 0.5    Co up to 6.5    Ti up to 0.5    Al up to 1.5    Nb up to 0.5    O up to 0.05    P up to 0.03    S up to 0.03.    
     
     
         12 . The material of  claim 5 , wherein the hardness of the material is higher than 250 HB.  
     
     
         13 . The material of  claim 6 , wherein the hardness of the material is at least 300 HB.  
     
     
         14 . The material of  claim 5 , wherein the nickel content of the alloy is higher by not more than 4.8% than the value obtained according to the equation of  claim 1 .  
     
     
         15 . The material of  claim 7 , wherein the hardness of the material is higher than 250 HB.  
     
     
         16 . The material of  claim 15 , wherein the hardness is at least 300 HB.  
     
     
         17 . The material of  claim 7 , wherein the nickel content of the alloy is higher by not more than 4.8% than the value obtained according to the equation of  claim 1 .  
     
     
         18 . The material of  claim 9 , wherein the hardness of the material is higher than 250 HB.  
     
     
         19 . The material of  claim 10 , wherein the hardness is at least 300 HB.  
     
     
         20 . The material of  claim 11 , wherein the nickel content of the alloy is higher by not more than 4.8% than the value obtained according to the equation of  claim 1 .  
     
     
         21 . The material of  claim 1 , wherein the alloy comprises elements in the following concentrations, in % by weight: 
 C 0.04 to 0.15    Si 1.22 to 2.36    Mn 1.00 to 3.95    Cr 23.9 to 26.5    Ni 17.9 to 25.45    N 0.018 to 0.20    Mo less than 1.0    V up to 0.5    W up to 0.5    Cu up to 0.5    Co up to 6.5    Ti up to 0.5    Al up to 1.5    Nb up to 0.5    O up to 0.05    P up to 0.03    S up to 0.03    and wherein the hardness of the material is at least 300 HB.    
     
     
         22 . A process for producing a material for parts and tools for use at a temperature of up to 750° C., which comprises providing an initial product from an alloy having a composition of, in % by weight, 
 Carbon (C) 0.01 to 0.25  
 Silicon (Si) 0.35 to 2.5  
 Manganese (Mn) 0.4 to 4.3  
 Chromium (Cr) 16.0 to 28.0  
 Nickel (Ni) 15.0 to 36.0  
 Nitrogen (N) 0.01 to 0.29  
 provided that the nickel content of the alloy is equal to or higher than the value formed by the chromium content plus 1.5 silicon minus 0.12 manganese minus 18 nitrogen minus 30 carbon minus the numerical value of 6:  
 Ni≧Cr+1.5×Si−0.12×Mn−18×N−30×C−6  
 with the balance iron (Fe) and accompanying elements and impurities; and subjecting the initial product to cold forming to produce a material having a hardness of at least 230 HB.  
 
     
     
         23 . The process of  claim 22 , wherein the initial product is formed by a process comprising hot forming and, subsequently at least one of subjecting to solution annealing and cooling down from the forming temperature.  
     
     
         24 . The process of  claim 23 , wherein the cooling down is by forced cooling.  
     
     
         25 . The process of  claim 22 , wherein the cold forming is carried out over the whole circumference and radially perpendicular to the longitudinal axis of the initial product.  
     
     
         26 . The process of  claim 22 , wherein the hardness of the material is higher than 250 HB.  
     
     
         27 . The process of  claim 26 , wherein the hardness is at least 300 HB.  
     
     
         28 . The process of  claim 22 , wherein the nickel content of the alloy is higher by not more than 4.8% than the value obtained according to the equation of  claim 22 .  
     
     
         29 . The process of  claim 22 , wherein the alloy comprises one or more elements in the following concentrations, in % by weight: 
 C 0.02 to 0.20    Si 0.50 to 2.48    Mn 0.62 to 4.05    Cr 20.1 to 27.6    Ni 16.1 to 27.3    N 0.014 to 0.23.    
     
     
         30 . The process of  claim 26 , wherein the alloy comprises one or more elements in the following concentrations, in % by weight: 
 C 0.04 to 0.15    Si 1.22 to 2.36    Mn 1.00 to 3.95    Cr 23.9 to 26.5    Ni 17.9 to 25.45    N 0.018 to 0.20.    
     
     
         31 . The process of  claim 27 , wherein the alloy comprises elements in the following concentrations, in % by weight: 
 C 0.04 to 0.15    Si 1.22 to 2.36    Mn 1.00 to 3.95    Cr 23.9 to 26.5    Ni 17.9 to 25.45    N 0.018 to 0.20.    
     
     
         32 . The process of  claim 30 , wherein one or more accompanying elements are present in the following concentrations, in % by weight: 
 Molybdenum (Mo) less than 1.0    Vanadium (V) up to 0.5    Tungsten (W) up to 0.5    Copper (Cu) up to 0.5    Cobalt (Co) up to 6.5    Titanium (Ti) up to 0.5    Aluminum (Al) up to 1.5    Niobium (Nb) up to 0.5    Oxygen (O) up to 0.05    Phosphorus (P) up to 0.03    Sulfur (S) up to 0.03.    
     
     
         33 . The process of  claim 22 , wherein the degree of cold forming is at least 6%.  
     
     
         34 . The process of  claim 25 , wherein the degree of cold forming is at least 12%.  
     
     
         35 . A hot working tool, comprising a cold formed material of an alloy having a composition of, in % by weight: 
 Carbon (C) up to 0.25    Silicon (Si) up to 2.5    Manganese (Mn) up to 4.3    Chromium (Cr) 16.0 to 28.0    Nickel (Ni) 15.0 to 36.0    Nitrogen (N) 0.01 to 0.29    provided that the nickel content of the alloy is equal to or higher than the value formed by the chromium content plus 1.5 silicon minus 0.12 manganese minus 18 nitrogen minus 30 carbon minus the numerical value of 6:    Ni≧Cr+1.5×Si−0.12×Mn−18×N−30×C−6    with the balance being iron (Fe) and accompanying elements and impurities.    
     
     
         36 . The hot working tool of  claim 35 , wherein the cold formed material has a hardness of at least 230 HB.  
     
     
         37 . The hot working tool of  claim 36 , wherein the material has t a hardness of higher than 250 HB.  
     
     
         38 . The hot working tool of  claim 36 , wherein the tool can be used at a working temperature of higher than 555° C.  
     
     
         39 . The hot working tool of  claim 35 , wherein the tool can be used at a working temperature of higher than 602° C.  
     
     
         40 . The hot working tool of  claim 37 , wherein the tool can be used at a working temperature of up to 750° C.  
     
     
         41 . A mold for machine pressed glass, wherein the mold is made, at least in part, from the material of  claim 1 .  
     
     
         42 . A tool in the glass industry, which comprises the material of  claim 1 .  
     
     
         43 . A process for the manufacture of a part or tool for use at elevated temperature, comprising providing the material of  claim 1  and making it into said part or tool.