US2022243308A1PendingUtilityA1

Spheroidal graphite cast iron, cast article and automobile structure part made thereof, and method for producing spheroidal graphite cast iron article

Assignee: HITACHI METALS LTDPriority: Mar 24, 2016Filed: Apr 22, 2022Published: Aug 4, 2022
Est. expiryMar 24, 2036(~9.7 yrs left)· nominal 20-yr term from priority
Inventors:Lin Wang
C22C 37/10C22C 37/04C21C 1/10C22C 33/10
80
PatentIndex Score
0
Cited by
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References
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Claims

Abstract

A spheroidal graphite cast iron meeting N(5-)≥250, N5-20)/N(5-)≥0.6, and N(30-)/N(5-)≤0.2, wherein N(5-) represents the number (/mm2) of graphite particles having equivalent-circle diameters of 5 μm or more, N(5-20) represents the number (/mm2) of graphite particles having equivalent-circle diameters of 5 μm or more and less than 20 μm, and N(30-) represents the number (/mm2) of graphite particles having equivalent-circle diameters of 30 μm or more, among graphite particles observed in an arbitrary cross section of at least 1 mm2.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
         1 . A cast article formed by a spheroidal graphite cast iron, wherein graphite particles observed in an arbitrary cross section of at least 1 mm 2  meet 
       
         
           
             
               
                 
                   N 
                   
                     ( 
                     
                       5 
                       - 
                     
                     ) 
                   
                 
                 ≥ 
                 
                   3 
                   ⁢ 
                   0 
                   ⁢ 
                   0 
                 
               
               , 
               
                 
 
               
               ⁢ 
               
                 
                   
                     N 
                     
                       ( 
                       
                         5 
                         - 
                         20 
                       
                       ) 
                     
                   
                   / 
                   
                     N 
                     
                       ( 
                       
                         5 
                         - 
                       
                       ) 
                     
                   
                 
                 ≥ 
                 0.6 
               
               , 
               and 
             
           
         
         
           
             
               
                 
                   
                     N 
                     
                       ( 
                       
                         30 
                         - 
                       
                       ) 
                     
                   
                   / 
                   
                     N 
                     
                       ( 
                       
                         5 
                         - 
                       
                       ) 
                     
                   
                 
                 ≤ 
                 
                   0 
                   . 
                   2 
                 
               
               , 
             
           
         
         wherein N (5-)  represents the number (/mm 2 ) of graphite particles having equivalent-circle diameters of 5 μm or more, N (5-20)  represents the number (/mm 2 ) of graphite particles having equivalent-circle diameters of 5 μm or more and less than 20 μm, and N (30-)  represents the number (/mm 2 ) of graphite particles having equivalent-circle diameters of 30 μm or more, 
         wherein the cast article has a thickness of 40 mm or more in as-cast casting. 
       
     
     
         2 . The cast article according to  claim 1 , wherein said graphite particles meet N (2-5) ≥100, wherein N (2-5)  represents the number (/mm 2 ) of graphite particles having equivalent-circle diameters of 2 μm or more and less than 5 μm. 
     
     
         3 . The cast article according to  claim 1 , wherein said graphite particles meet 
       
         
           
             
               
                 
                   N 
                   
                     ( 
                     
                       5 
                       - 
                       20 
                     
                     ) 
                   
                 
                 / 
                 
                   N 
                   
                     ( 
                     
                       5 
                       - 
                     
                     ) 
                   
                 
               
               ≥ 
               
                 
                   0 
                   . 
                   6 
                 
                 ⁢ 
                 5. 
               
             
           
         
       
     
     
         4 . The cast article according to  claim 1 , wherein said graphite particles meet D max ≥50.4 μm, wherein D max  represents the maximum equivalent-circle diameter of graphite particles. 
     
     
         5 . The cast article according to  claim 1 , wherein said graphite particles meet −0.15≤[N (5-10) -N (15-20) ]/N (5-10) ≤0.25, wherein N (5-10)  represents the number (/mm 2 ) of graphite particles having equivalent-circle diameters of 5 μm or more and less than 10 μm, and N (15-20)  represents the number (/mm 2 ) of graphite particles having equivalent-circle diameters of 15 μm or more and less than 20 μm. 
     
     
         6 . The cast article according to  claim 1 , wherein said cast article is a structure part for automobiles. 
     
     
         7 . A method for producing a cast article of spheroidal graphite cast iron of  claim 1 , comprising
 pressing a surface of a melt poured into a gas-permeable casting mold by a gas at pressure of 1-100 kPa, before said melt starts eutectic solidification; and   solidifying said melt while supplying said gas into said casting mold.   
     
     
         8 . The method for producing a cast article according to  claim 7 , wherein said pressure is 10-50 kPa. 
     
     
         9 . The method for producing a cast article according to  claim 7 , wherein said method meets 
       
         
           
             
               
                 0 
                 ≤ 
                 
                   d 
                   ⁢ 
                   
                     
                       t 
                       
                         p 
                         ⁢ 
                         E 
                       
                     
                     / 
                     d 
                   
                   ⁢ 
                   
                     t 
                     E 
                   
                 
                 ≤ 
                 1 
               
               , 
             
           
         
         wherein dt E  represents a time period from the start of eutectic solidification of said melt to the completion of the eutectic solidification, and dt pE  represents a time period from the start of eutectic solidification of said melt to the completion of said pressing.

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