Precipitation hardened Co-Ni based heat-resistant alloy and production method therefor

Abstract

A precipitation hardened Co—Ni based heat-resistant alloy is composed of, all by weight, not more than 0.05% of C; not more than 0.5% of Si; not more than 1.0% of Mn; 25 to 45% of Ni; 13 to 22% of Cr; 10 to 18% of Mo or 10 to 18% of Mo+½W; 0.1 to 5.0% of Nb; 0.1 to 5.0% of Fe; and further at least one kind of 0.007 to 0.10% of REM; 0.001 to 0.010% of B; 0.0007 to 0.010% of Mg and 0.001 to 0.20% of Zr; the balance of substantially Co and inevitable impurities, and Co 3 Mo or Co 7 Mo 6 is precipitated in boundaries between a fine twin structure and a parent phase.

What is claimed is:  
     
         1 . A precipitation hardened Co—Ni based heat-resistant alloy comprising by weight: 
 not more than 0.05% of C; not more than 0.5% of Si; not more than 1.0% of Mn; 25 to 45% of Ni; 13 to 22% of Cr; 10 to 18% of Mo or 10 to 18% of Mo+½W; 0.1 to 5.0% of Nb; 0.1 to 5.0% of Fe;  
 at least one kind of 0.007 to 0.10% of REM; 0.001 to 0.010% of B; 0.0007 to 0.010% of Mg and 0.001 to 0.20% of Zr;  
 the balance of Co and inevitable impurities;  
 a fine twin structure;  
 a parent phase; and  
 Co 3 Mo or Co 7 Mo 6  precipitated at boundaries of the fine twin structure and the parent phase.  
 
     
     
         2 . A precipitation hardened Co—Ni based heat-resistant alloy comprising by weight: 
 not more than 0.05% of C; not more than 0.5% of Si; not more than 1.0% of Mn; 25 to 45% of Ni; 13 to 22% of Cr; 10 to 18% of Mo or 10 to 18% of Mo+½W; 0.1 to 5.0% of Nb; 0.1 to 5.0% of Fe; 0.1 to 3.0% of Ti;  
 at least one kind of 0.007 to 0.10% of REM; 0.001 to 0.010% of B; 0.0007 to 0.010% of Mg and 0.001 to 0.20% of Zr;  
 the balance of Co and inevitable impurities;  
 a fine twin structure;  
 a parent phase; and  
 Co 3 Mo or Co 7 Mo 6  precipitated at boundaries of the fine twin structure and the parent phase.  
 
     
     
         3 . A production method for precipitation hardened Co—Ni based heat-resistant alloy, the method comprising the steps of: 
 preparing an alloy comprising by weight:  
 not more than 0.05% of C; not more than 0.5% of Si; not more than 1.0% of Mn; 25 to 45% of Ni; 13 to 22% of Cr; 10 to 18% of Mo or 10 to 18% of Mo+½W; 0.1 to 5.0% of Nb; 0.1 to 5.0% of Fe;  
 at least one kind of 0.007 to 0.10% of REM; 0.001 to 0.010% of B; 0.0007 to 0.010% of Mg and 0.001 to 0.20% of Zr; and  
 the balance of Co and inevitable impurities;  
 subjecting the alloy to a solid solution heat treatment; and  
 subjecting the alloy to an aging heat treatment at 600 to 800° C. for 0.5 to 16 hours in a condition of applying stress, thereby forming a fine twin structure in a parent phase, and precipitating Co 3 Mo or Co 7 Mo 6  at a boundary of the fine twin structure and the parent phase.  
 
     
     
         4 . A production method for precipitation hardened Co—Ni based heat-resistant alloy, the method comprising the steps of: 
 preparing an alloy comprising by weight: 
 not more than 0.05% of C; not more than 0.5% of Si; not more than 1.0% of Mn; 25 to 45% of Ni; 13 to 22% of Cr; 10 to 18% of Mo or 10 to 18% of Mo+½W; 0.1 to 5.0% of Nb; 0.1 to 5.0% of Fe; 0.1 to 3.0% of Ti;  
 at least one kind of 0.007 to 0.10% of REM; 0.001 to 0.010% of B; 0.0007 to 0.010% of Mg and 0.001 to 0.20% of Zr; and  
 the balance of Co and inevitable impurities;  
 subjecting the alloy to a solid solution heat treatment; and  
 subjecting the alloy to an aging heat treatment at 600 to 800° C. for 0.5 to 16 hours in a condition of applying stress, thereby forming a fine twin structure in a parent phase, and precipitating Co 3 Mo or Co 7 Mo 6  at a boundary of the fine twin structure and the parent phase.  
 
 
     
     
         5 . A production method for precipitation hardened Co—Ni based heat-resistant alloy, the method comprising the steps of: 
 preparing an alloy comprising by weight: 
 not more than 0.05% of C; not more than 0.5% of Si; not more than 1.0% of Mn; 25 to 45% of Ni; 13 to 22% of Cr; 10 to 18% of Mo or 10 to 18% of Mo+½W; 0.1 to 5.0% of Nb; 0.1 to 5.0% of Fe;  
 at least one kind of 0.007 to 0.10% of REM; 0.001 to 0.010% of B; 0.0007 to 0.010% of Mg and 0.001 to 0.20% of Zr; and  
 the balance of Co and inevitable impurities;  
 subjecting the alloy to a solid solution heat treatment;  
 subjecting the alloy to a cold working or a warm working having a reduction ratio of not less than 40%; and  
 subjecting the alloy to an aging heat treatment at 600 to 800° C. for 0.5 to 16 hours in a condition of applying stress, thereby forming a fine twin structure in a parent phase, and precipitating Co 3 Mo or Co 7 Mo 6  at a boundary of the fine twin structure and the parent phase.  
 
 
     
     
         6 . A production method for precipitation hardened Co—Ni based heat-resistant alloy, the method comprising the steps of: 
 preparing an alloy comprising by weight: 
 not more than 0.05% of C; not more than 0.5% of Si; not more than 1.0% of Mn; 25 to 45% of Ni; 13 to 22% of Cr; 10 to 18% of Mo or 10 to 18% of Mo+½W; 0.1 to 5.0% of Nb; 0.1 to 5.0% of Fe; 0.1 to 3.0% of Ti.  
 at least one kind of 0.007 to 0.10% of REM; 0.001 to 0.010% of B; 0.0007 to 0.010% of Mg and 0.001 to 0.20% of Zr; and  
 the balance of Co and inevitable impurities;  
 subjecting the alloy to a solid solution heat treatment;  
 subjecting the alloy to a cold working or a warm working having a reduction ratio of not less than 40%; and  
 subjecting the alloy to an aging heat treatment at 600 to 800° C. for 0.5 to 16 hours in a condition of applying stress, thereby forming a fine twin structure in a parent phase, and precipitating Co 3 Mo or Co 7 Mo 6  at a boundary of the fine twin structure and the parent phase.  
 
 
     
     
         7 . A production method for precipitation hardened Co—Ni based heat-resistant alloy, the method comprising the steps of: 
 preparing an alloy comprising by weight: 
 not more than 0.05% of C; not more than 0.5% of Si; not more than 1.0% of Mn; 25 to 45% of Ni; 13 to 22% of Cr; 10 to 18% of Mo or 10 to 18% of Mo+½W; 0.1 to 5.0% of Nb; 0.1 to 5.0% of Fe;  
 at least one kind of 0.007 to 0.10% of REM; 0.001 to 0.010% of B; 0.0007 to 0.010% of Mg and 0.001 to 0.20% of Zr; and  
 the balance of Co and inevitable impurities;  
 subjecting the alloy to a solid solution heat treatment;  
 subjecting the alloy to a cold working or a warm working having a reduction ratio of not less than 40%; and  
 subjecting the alloy to an aging heat treatment at 800° C. to 950° C. for 0.5 to 16 hours, thereby forming a fine twin structure in a parent phase, and precipitating Co 3 Mo or Co 7 Mo 6  at a boundary of the fine twin structure and the parent phase.  
 
 
     
     
         8 . A production method for precipitation hardened Co—Ni based heat-resistant alloy, the method comprising the steps of: 
 preparing an alloy comprising: all by weight, not more than 0.05% of C; not more than 0.5% of Si; not more than 1.0% of Mn; 25 to 45% of Ni; 13 to 22% of Cr; 10 to 18% of Mo or 10 to 18% of Mo+½W; 0.1 to 5.0% of Nb; 0.1 to 5.0% of Fe; 0.1 to 3.0% of Ti;  
 at least one kind of 0.007 to 0.10% of REM; 0.001 to 0.010% of B; 0.0007 to 0.010% of Mg and 0.001 to 0.20% of Zr; and  
 the balance of Co and inevitable impurities;  
 subjecting the alloy to a solid solution heat treatment;  
 subjecting the alloy to a cold working or a warm working having a reduction ratio of not less than 40%; and  
 subjecting the alloy to an aging heat treatment at 800° C. to 950° C. for 0.5 to 16 hours, thereby forming a fine twin structure in a parent phase, and precipitating Co 3 Mo or Co 7 Mo 6  at a boundary of the fine twin structure and the parent phase.