Ni-BASED SUPERALLOY WITH EXCELLENT OXIDIZATION RESISTANCE AND CREEP PROPERTY AND METHOD OF MANUFACTURING THE SAME

Abstract

The present disclosure relates to a Ni-based superalloy with excellent oxidation resistance and creep properties, which is suitable for parts of energy plants and chemical plants under a corrosive oxidative/reductive atmosphere, which stainless steel cannot withstand, through adjustment of alloy components and control of process conditions and a method of manufacturing the same. The Ni-based superalloy includes: chromium (Cr): 20˜26 wt %, tungsten (W): 13˜17 wt %, molybdenum (Mo): 1˜5 wt %, manganese (Mn): 0.1˜1.0 wt %, silicon (Si): 0.1˜0.6 wt %, aluminum (Al): 0.1˜1.0 wt %, lanthanum (La): 0.01˜0.06 wt %, carbon (C): 0.01˜0.20 wt %, and the balance of nickel (Ni) and unavoidable impurities.

What is claimed is: 
     
         1 . A Ni-based superalloy with excellent oxidation resistance and creep properties, comprising: chromium (Cr): 20˜26 wt %, tungsten (W): 13˜17 wt %, molybdenum (Mo): 1˜5 wt %, manganese (Mn): 0.1˜1.0 wt %, silicon (Si): 0.1˜0.6 wt %, aluminum (Al): 0.1˜1.0 wt %, lanthanum (La): 0.01˜0.06 wt %, carbon (C): 0.01˜0.20 wt %, and the balance of nickel (Ni) and unavoidable impurities. 
     
     
         2 . The Ni-based superalloy according to  claim 1 , further comprising: 0.001˜0.015 wt % of boron (B). 
     
     
         3 . The Ni-based superalloy according to  claim 1 , having a yield strength (YS) of 195˜300 MPa, a tensile strength (TS) of 420˜580 MPa, and an elongation (El) of 35˜55%, under temperature conditions of 700° C. 
     
     
         4 . The Ni-based superalloy according to  claim 1 , having a yield strength (YS) of 160˜200 MPa, a tensile strength (TS) of 235˜300 MPa, and an elongation (El) of 48˜59%, under high temperature conditions of 900° C. 
     
     
         5 . A method of manufacturing a Ni-based superalloy with excellent oxidation resistance and creep properties, comprising:
 (a) preparing an alloy by mixing and dissolving raw materials comprising chromium (Cr): 20˜26 wt %, tungsten (W): 13˜17 wt %, molybdenum (Mo): 1˜5 wt %, manganese (Mn): 0.1˜1.0 wt %, silicon (Si): 0.1˜0.6 wt %, aluminum (Al): 0.1˜1.0 wt %, lanthanum (La): 0.01˜0.06 wt %, carbon (C): 0.01˜0.20 wt %, and the balance of nickel (Ni) and unavoidable impurities;   (b) hot rolling the alloy;   (c) annealing the hot rolled alloy; and   (d) cooling the annealed alloy.   
     
     
         6 . The method according to  claim 5 , wherein the alloy further comprises 0.001˜0.015 wt % of boron (B). 
     
     
         7 . The method according to  claim 5 , wherein hot rolling is performed at a reduction rate of 40˜80% and at 1100˜1250° C. 
     
     
         8 . The method according to  claim 5 , wherein annealing the hot rolled alloy comprises:
 (c-1) solution annealing the hot rolled alloy at 1200˜1280° C.; and   (c-2) aging the solution annealed alloy at 700˜850° C.   
     
     
         9 . The method according to  claim 5 , further comprising:
 additionally annealing the cooled alloy at 950˜1100° C. for 0.5˜4 hours after cooling the annealed alloy.