Sintered alloy, method for production thereof and valve sheet

Abstract

To provide a sintered alloy capable of showing wear resistance and a process for producing the same as well as a valve seat of good wear resistance. A sintered alloy comprising 4-30% by weight Mo, 0.2-3% by weight C, 1-30% by weight Ni, 0.5-10% by weight Mn, 2-40% by weight Co, and the balance of inevitable impurities and Fe when the entirety is taken as 100% by weight. Aprocess for producing a sintered alloy in which a green compact of a raw mixture powder including hard particles is sintered, thereby producing said sintered alloy. A valve seat comprising said sintered alloy.

1 - 4 . (Canceled)  
     
     
         5 . The process for producing a sintered alloy set forth in  claim 12 , wherein said mixture powder comprises an Ni powder mixed in a proportion of 10% by weight or less when the entire mixture powder is taken as 100% by weight.  
     
     
         6 - 9 . (Canceled)  
     
     
         10 . A sintered alloy made by sintering a mixture powder composed of hard particles, a carbon powder, a Co powder, an Ni powder, and an Fe powder or a low alloy steel powder; 
 the hard particles comprising: 20-60% by weight Mo; 3% by weight or less C; 5-40 by weight Ni; 1-20% by weight Mn; 5-40% by weight Co; and the balance of inevitable impurities and Fe when the entire hard particles are taken as 100% by weight;    the mixture powder comprising: the hard particles in an amount of from 10 to 60% by weight; the carbon powder in an amount of from 0.2 to 2% by weight; the Co powder in an amount of 20% by weight or less; the Ni powder in an amount of 10% by weight or less; and the balance being the Fe powder or the low alloy steel powder when the entire mixture powder is taken as 100% by weight;    the sintered alloy comprising:    4-30% by weight Mo;    0.2-3% by weight C;    1-30% by weight Ni;    0.5-10% by weight Mn;    2-40% by weight Co; and    the balance of inevitable impurities and Fe when the entirety is taken as 100% by weight.    
     
     
         11 . The sintered alloy set forth in  claim 10 , wherein the hard particles further comprise at least one member selected from the group consisting of 10% by weight or less Cr and 4% by weight or less Si when the entirety is taken as 100% by weight; and 
 the sintered alloy further comprises at least one member selected from the group consisting of 5% by weight or less Cr and 2% by weight or less Si when the entirety is taken as 100% by weight.    
     
     
         12 . A process for producing a sintered alloy, comprising the steps of: 
 preparing a mixture powder composed of hard particles comprising: 20-60% by weight Mo; 3% by weight or less C; 5-40% by weight Ni; 1-20% by weight Mn; 5-40% by weight Co; and the balance of inevitable impurities and Fe when the entire hard particles are taken as 100% by weight, a carbon powder, a Co powder, and an Fe powder or a low alloy steel powder, the mixture powder comprising: the hard particles in an amount of from 10 to 60% by weight; the carbon powder in an amount of from 0.2 to 2% by weight; the Co powder in an amount of 20% by weight or less; and the balance being the Fe powder or the low alloy steel powder when the entire mixture powder is taken as 100% by weight;    molding the mixture powder, thereby forming a green compact; and    sintering the green compact, thereby making a sintered alloy.    
     
     
         13 . The process for producing a sintered alloy set forth in  claim 12 , wherein said hard particles further comprise at least one member selected from the group consisting of Cr in a proportion of 10% by weight or less and Si in a proportion of 4% by weight or less when the entire hard particles are taken as 100% by weight.  
     
     
         14 . A valve seat made by sintering a mixture powder composed of hard particles, a carbon powder, a Co powder, an Ni powder, and an Fe powder or a low alloy steel powder; 
 the hard particles comprising: 20-60% by weight Mo; 3% by weight or less C; 5-40% by weight Ni; 1-20% by weight Mn; 5-40% by weight Co; and the balance of inevitable impurities and Fe when the entire hard particles are taken as 100% be weight;    the mixture powder comprising: the hard particles in an amount of from 10 to 60% by weight; the carbon powder in an amount of from 0.2 to 2% by weight; the Co powder in an amount of 20% by weight or less; the Ni powder in an amount of 10% be weight or less; and the balance being the Fe powder or the low alloy steel powder when the entire mixture powder is taken as 100% by weight;    the valve seat comprising:    4-30% by weight Mo;    0.2-3% by weight C;    1-30% be weight Ni;    0.5-10% be weight Mn;    2-40% by weight Co; and    the balance of inevitable impurities and Fe when the entirety is taken as 100% by weight.    
     
     
         15 . The valve seat set forth in  claim 14 , wherein the hard particles further comprise at least one member selected from the group consisting of 10% by weight or less Cr and 4% by weight or less Si when the entirety is taken as 100% by weight; and 
 the valve seat further comprises at least one member selected from the group consisting of 5% by weight or less Cr and 2% by weight or less Si when the entirety is taken as 100% by weight.    
     
     
         16 . A sintered alloy made by sintering a mixture powder composed of hard particles, a carbon powder, a Co powder, and an Fe powder or a low alloy steel powder; 
 the hard particles comprising: 20-60% by weight Mo; 3% by weight or less C; 5-40% by weight Ni; 1-20% by weight Mn; 5-40% by weight Co; and the balance of inevitable impurities and Fe when the entire hard particles are taken as 100% by weight;    the mixture powder comprising: the hard particles in an amount of from 10 to 60% by weight; the carbon powder in an amount of from 02. to 2% by weight; the Co powder in an amount of 20% by weight or less; and the balance being the Fe powder or the low alloy steel powder when the entire mixture powder is taken as 100% by weight;    the sintered alloy comprising:    4-30% by weight Mo;    0.2-3% by weight C;    1-30% by weight Ni;    0.5-10% by weight Mn;    2-40% by weight Co; and    the balance of inevitable impurities and Fe when the entirety is taken as 100% by weight.    
     
     
         17 . A valve seat made by sintering a mixture powder composed of hard particles, a carbon powder, a Co powder, and an Fe powder or a low alloy steel powder; 
 the hard particles comprising: 20-60% by weight Mo; 3% by weight or less C; 5-40% by weight Ni; 1-20% by weight Mn; 5-40% by weight Co; and the balance of inevitable impurities and Fe when the entire hard particles are taken as 100% by weight;    the mixture powder comprising: the hard particles in an amount of from 10 to 60% by weight; the carbon powder in an amount of from 0.2 to 2% by weight, the Co powder in an amount of 20% by weight or less; and the balance being the Fe powder or the low alloy steel powder when the entire mixture powder is taken as 100% by weight;    the valve seat comprising:    4-30% by weight Mo;    0.2-3% by weight C;    1-30% by weight Ni;    0.5-10% by weight Mn;    2-40% by weight Co; and    the balance of inevitable impurities and Fe when the entirety is taken as 100% by weight.