Casting and method for manufacturing casting

Abstract

The present invention provides a Ni—B—Si three-element-based cast material containing a eutectic part of a solid phase mainly composed of Ni and B and a solid phase mainly composed of Ni and Si, wherein when a straight line is drawn in a surface or a cross section of the eutectic part, the average number of interfaces formed between the solid phase mainly composed of Ni and B and the solid phase mainly composed of Ni and Si on the straight line is at least 2.0 /μm. The present invention also provides a cast material comprising: hard phase particles mainly composed of a boride; and a binder phase containing an alloy containing Ni, Si, and B, wherein the average particle size of the hard phase particles is 3 μm or less, the average aspect ratio is 2.0 or less, the contact ratio is 35% or less, and an intensity ratio IA/IB is 1/10 or less, where IA is the intensity of a peak derived from Ni31Si12 observed at a diffraction angle 2θ within the range of 46.8° to 47.8°, and IB is the intensity of a peak derived from Ni3Si observed at a diffraction angle 2θ within the range of from 44.0° to 45.0°, the intensities being determined by X-ray diffraction measurement using CuKα radiation.

1 . A Ni—B—Si three-element-based cast material containing a eutectic part comprising a solid phase mainly composed of Ni and B and a solid phase mainly composed of Ni and Si,
 wherein when a straight line is drawn in a surface or a cross section of the eutectic part, the average number of interfaces formed between the solid phase mainly composed of Ni and B and the solid phase mainly composed of Ni and Si on the straight line is 2.0 /μm or more. 
 
     
     
         2 . The cast material according to  claim 1 ,
 wherein when two perpendicular straight lines are drawn in the surface or the cross section of the eutectic part, the average of the number of interfaces on one of the two straight lines and the number of interfaces on the other straight line is 2.0 /μm or more.   
     
     
         3 . A method for manufacturing the cast material according to  claim 1 , comprising steps of:
 melting a raw material for forming the cast material, thereby providing a raw material melt; and   cooling the raw material melt,   wherein the step of cooling the raw material melt comprises continuously cooling the raw material melt at a cooling rate of 100° C./min or more over the temperature range of a cooling start temperature to 400° C.   
     
     
         4 . The method for manufacturing the cast material according to  claim 3 ,
 wherein the raw material melt is cooled by pouring the raw material melt into a mold having a temperature of room temperature to 1100° C.   
     
     
         5 . A cast material comprising:
 hard phase particles mainly composed of a boride; and   a binder phase containing an alloy containing Ni, Si, and B,   wherein the average particle size of the hard phase particles is 3 μm or less, the average aspect ratio of the hard phase particles is 2.0 or less, the contact ratio between the hard phase particles is 35% or less,   the binder phase contains Ni3Si and Ni3B, and   the cast material has an intensity ratio I A /I B  of 1/10 or less, where I A  is the intensity of a peak derived from Ni31 Si12 observed at a diffraction angle 2θ within the range of 46.8° to 47.8°, and I B  is the intensity of a peak derived from Ni3Si observed at a diffraction angle 2θ within the range of from 44.0° to 45.0°, the intensities being determined by X-ray diffraction measurement using CuKα radiation.   
     
     
         6 . The cast material according to  claim 5 ,
 wherein the intensity ratio I A /I B  is 1/100 or less.   
     
     
         7 . The cast material according to  claim 5 ,
 wherein the hard phase particles comprises at least one of multiple borides represented by Mo2NiB2 and Mo2(Ni,Cr)B2.   
     
     
         8 . The cast material according to  claim 5 ,
 wherein the content of B in the cast material is 1 to 6% by weight.   
     
     
         9 . A method for manufacturing a cast material comprising hard phase particles mainly composed of a boride and a binder phase containing an alloy containing Ni, Si, and B, the method comprising:
 melting mixed raw materials for forming the cast material, thereby providing a melt mixture;   continuously cooling the melt mixture at a cooling rate of 100° C./min or more over the temperature range of the cooling start temperature to 400° C., thereby providing a sintered body; and   subjecting the sintered body to a heat treatment at a temperature of 700° C. to 950° C.   
     
     
         10 . The method for manufacturing a cast material according to  claim 9 ,
 wherein the raw material melt is cooled by pouring the raw material melt into a mold having a temperature of room temperature to 1100° C.