Ferrous seal sliding parts and producing method thereof

Abstract

A ferrous seal sliding part excellent in heat crack resistance, seizure resistance and abrasion resistance is provided. The ferrous seal sliding part has a seal sliding surface, wherein the seal sliding surface has a quench hardened layer having a structure in which a martensite parent phase forms a solid solution with carbon of 0.15 to 0.6 wt % and contains cementite dispersed therein in a content of 3 to 50% by volume.

1 - 13 . (canceled)  
     
     
         14 . A producing method for a ferrous seal sliding part comprising; 
 a preparing step for preparing a steel product containing carbon of 0.5 to 1.8 wt % and further one or more alloy element selected from the group consisting of Cr of 0.3 to 3 wt %, V of 0.1 to 0.5 wt %, Mo of 0.3 to 2 wt % and W of 0.5 to 2 wt %; and    a quenching step for heating said steel product at a heating rate such that temperature rises from Al transformation temperature to a quenching temperature in the range of 850 to 1100° C. within 10 seconds and then rapidly cooling.    
     
     
         15 . A producing method for a ferrous seal sliding part comprising; 
 a preparing step for preparing a cast iron selected from the group consisting of a gray cast iron, a nodular graphite cast iron, a vermicular graphite cast iron and a pearlite malleable cast iron, in which graphite is dispersed in a parent phase having a pearlite structure containing carbon of 2 to 4.5 wt % and further one or more alloy element selected from the group consisting of Cr of 0.5 to 4 wt %, V of 0.1 to 0.5 wt %, Mo of 0.3 to 2 wt % and W of 0.5 to 2 wt %; and    a quenching step for heating said cast iron at a heating rate such that temperature rises from Al transformation temperature to a quenching temperature in the range of 850 to 1100° C. within 10 seconds and then rapidly cooling.    
     
     
         16 . A producing method for a ferrous seal sliding part comprising; 
 a preparing step for preparing a white cast iron containing carbon of 2 to 4.5 wt % and further one or more alloy element selected from the group consisting of Cr of 0.5 to 4 wt %, V of 0.1 to 0.5 wt %, Mo of 0.3 to 2 wt % and W of 0.5 to 2 wt %, or a cast iron in which cementite of said white cast iron is partially graphitized; and    a quenching step for heating said cast iron at a heating rate such that temperature rises from Al transformation temperature to a quenching temperature in the range of 850 to 1100° C. within 10 seconds and then rapidly cooling.    
     
     
         17 . A producing method for a ferrous seal sliding part according to any one of  claims 14  to  16  further comprising; 
 a heat treatment step for concentrating one or more alloy element selected from the group consisting of Cr, V, Mo and W in cementite in said ferrous seal sliding part.    
     
     
         18 . A producing method for a ferrous seal sliding part according to any one of  claims 14  to  16  further comprising; 
 a heat treatment step for dispersing a pearlite structure region comprising platy cementite and ferrite in an area ratio of 20% or more in a steel before quenching.    
     
     
         19 . A producing method for a ferrous seal sliding part according to any one of  claims 14  to  16 , 
 wherein said preparing step for preparing said steel product or said cast iron is a step for preparing a steel product or a cast iron containing either any one of Si of 0.5 to 3.5 wt % or Al of 0.25 to 2 wt %, or both Si and Al in a total amount of 0.5 to 3.5 wt %.    
     
     
         20 . A producing method for a ferrous seal sliding part according to any one of  claims 14  to  16 , 
 wherein said preparing step for preparing said steel product or said cast iron is a step for preparing a steel product or a cast iron containing Mn and Ni in a total amount of 2 to 7 wt %.    
     
     
         21 . A producing method for a ferrous seal sliding part according to any one of claims  15  and  16 , 
 wherein said cast iron contains Cu of 5 to 15 wt % whereby Cu alloy phase is dispersed in 3 to 10% by volume.    
     
     
         22 . A producing method for a ferrous seal sliding part according to any one of  claims 14  to  16 , 
 wherein said heating rate is 150° C./sec or more.    
     
     
         23 . A producing method for a ferrous seal sliding part according to any one of  claims 14  to  16 , 
 wherein a pre-heating step for preheating said steel product or said cast iron at 300° C. to Al transformation temperature after said preparing step and before said quenching step.