Heat-resistant component for chemical processing apparatus and method for producing same

Abstract

A heat-resistant component for a chemical processing apparatus is formed from a ferritic Cr-steel that contains Cr in an amount of from 13% by weight to 30% by mass. The ferritic Cr-steel has a creep rate of 1×10 −5 1 h or less at 700° C. under stress of 100 MPa, and an oxidation weight gain of 10 mg/cm 2 or less after being maintained in a 650° C. water vapor for 1,000 h. The heat-resistant component for a chemical processing apparatus is produced by hot working the ferritic Cr-steel in a temperature range of 850 to 1,200° C., forming the ferritic Cr-steel into a component shape, subjecting the steel to an annealing treatment in a temperature range of 1,000 to 1,250° C., and cooling the steel to 400° C. or less at a cooling rate of 100° C./min or higher.

1 - 7 . (canceled) 
     
     
         8 . A heat-resistant component for a chemical processing apparatus that performs a high-temperature chemical treatment for a feedstock at 650° C. or higher,
 characterized in that the heat-resistant component is formed from a ferritic Cr-steel of a chemical composition that includes, in % by mass, 
 Cr: 13 to 30%, 
 Ni: 1×10 −1  to 2.5%, 
 C: 1×10 −3  to 1×10 −1 %, and 
 N: 1×10 −3  to 1×10 −1 %, and that the ferritic Cr-steel additionally includes one or more of the following additional components in % by mass, 
 Mo: 5×10 −1  to 5%, 
 W: 5×10 −1  to 1×10%, 
 V: 5×10 −2  to 4×10 −1 %, 
 Nb: 1×10 −2  to 1×10 −1 %, 
 Co: 1×10 −1  to 1×10%, and 
 B: 2×10 −3  to 4×10 −3 %, 
 wherein the ferritic Cr-steel allows for inclusion of unavoidable impurities, includes Fe as the remaining part, and forms a ferrite phase, and 
 wherein the ferritic Cr-steel has a creep rate of 1×10 −5 /h or less at 700° C. under stress of 100 MPa, and an oxidation weight gain of 10 mg/cm 2  or less after being maintained in a 650° C. water vapor for 1,000 h. 
 
     
     
         9 . The heat-resistant component for a chemical processing apparatus according to  claim 8 , wherein Ni is added in an amount that satisfies the relationship Ni>10(C+N), where Ni, C, and N each represent the amount of each component added (in % by mass), when C is added in 1×10 −2 % by mass or more and/or Ni is added in 1×10 −2 % by mass or more. 
     
     
         10 . The heat-resistant component for a chemical processing apparatus according to  claim 8 , wherein the ferrite phase is 70 volume % or more. 
     
     
         11 . The heat-resistant component for a chemical processing apparatus according to  claim 8 ,
 wherein at least one of carbide and nitride, and an intermetallic compound are precipitated in crystal grains.   
     
     
         12 . The heat-resistant component for a chemical processing apparatus according to  claim 11 , wherein Mo and W are added in amounts that satisfy the relationship Mo+0.5W 3.0% by mass, where Mo and W each represent the amount of each component added (in % by mass). 
     
     
         13 . A process for producing a heat-resistant component for a chemical processing apparatus,
 the process comprising hot working the ferritic Cr-steel of the chemical composition of  claim 8  in a temperature range of 850 to 1,200° C., forming the ferritic Cr-steel into a component shape, subjecting the steel to an annealing treatment in a temperature range of 1,000 to 1,250° C., and cooling the steel to 400° C. or less at a cooling rate of 100° C/min or higher.