Hard phase forming alloy powder, wear resistant sintered alloy, and production method for wear resistant sintered alloy

Abstract

A hard phase forming alloy powder, for forming a hard phase dispersed in a sintered alloy, consists of, by mass %, 15 to 35% of Mo, 1 to 10% of Si, 10 to 40% of Cr, and the balance of Co and inevitable impurities. A production method, for a wear resistant sintered alloy, includes preparing a matrix forming powder, the hard phase forming alloy powder, and a graphite powder. The production method further includes mixing 15 to 45% of the hard phase forming alloy powder and 0.5 to 1.5% of the graphite powder with the matrix forming powder into a raw powder. The production method further includes compacting the raw powder into a green compact having a predetermined shape and includes sintering the green compact. A wear resistant sintered alloy exhibits a metallic structure in which 15 to 45% of a hard phase is dispersed in a matrix. The hard phase consists of, by mass %, 15 to 35% of Mo, 1 to 10% of Si, 10 to 40% of Cr, and the balance of Co and inevitable impurities.

1 . A hard phase forming alloy powder for forming a hard phase dispersed in a sintered alloy, the hard phase forming alloy powder consisting of, by mass %, 15 to 35% of Mo, 1 to 10% of Si, 10 to 40% of Cr, and the balance of Co and inevitable impurities. 
   
   
       2 . The hard phase forming alloy powder according to  claim 1 , wherein the amount of Cr is 20 to 40%. 
   
   
       3 . The hard phase forming alloy powder according to  claim 1 , wherein not more than 80 mass % of Co is substituted by Fe. 
   
   
       4 . The hard phase forming alloy powder according to  claim 1 , wherein not more than 5 mass % of Mn is added to the composition. 
   
   
       5 . A production method for a wear resistant sintered alloy, comprising:
 preparing a matrix forming powder, the hard phase forming alloy powder recited in  claim 1 , and a graphite powder;   mixing 15 to 45% of the hard phase forming alloy powder and 0.5 to 1.5% of the graphite powder with the matrix forming powder into a raw powder;   compacting the raw powder into a green compact having a predetermined shape; and   sintering the green compact.   
   
   
       6 . The production method for the wear resistant sintered alloy according to  claim 5 , wherein the matrix forming powder is a mixed powder consisting of 1 to 5 mass % of a nickel powder and the balance of an iron powder. 
   
   
       7 . The production method for the wear resistant sintered alloy according to  claim 6 , wherein the iron powder is an ore-reduced iron powder including 0.3 to 1.5 mass % of metallic oxides. 
   
   
       8 . The production method for the wear resistant sintered alloy according to  claim 5 , wherein the matrix forming powder is an iron alloy powder consisting of 1 to 5 mass % of Cr and the balance of Fe and inevitable impurities. 
   
   
       9 . The production method for the wear resistant sintered alloy according to  claim 8 , wherein the iron alloy powder further includes at least one of Mo, V, and Nb at not more than 2.4 mass %. 
   
   
       10 . The production method for the wear resistant sintered alloy according to  claim 5 , the matrix forming powder is a mixed powder consisting of an iron alloy powder and not more than 5 mass % of a nickel powder with respect to the raw powder, and the iron alloy powder consists of 1 to 5 mass % of Cr and the balance of Fe and inevitable impurities. 
   
   
       11 . The production method for the wear resistant sintered alloy according to  claim 5 , wherein the matrix forming powder is an iron alloy powder consisting of, by mass %, 3 to 8% of Co, 1 to 2% of Ni, 1 to 2% of Mo, and the balance of Fe and inevitable impurities. 
   
   
       12 . The production method for the wear resistant sintered alloy according to  claim 5 , wherein the matrix forming powder is a mixed powder consisting of an iron alloy powder and not more than 5 mass % of a nickel powder with respect to the raw powder, and the iron alloy powder consists of, by mass %, 3 to 8% of Co, 1 to 2% of Ni, 1 to 2% of Mo, and the balance of Fe and inevitable impurities. 
   
   
       13 . The production method for the wear resistant sintered alloy according to  claim 5 , wherein the matrix forming powder is an iron alloy powder consisting of, by mass %, 1 to 3% of Ni, 0.5 to 2% of Mo, 0.1 to 1% of Cr, 0.1 to 0.5% of Mn, and the balance of Fe and inevitable impurities. 
   
   
       14 . The production method for the wear resistant sintered alloy according to  claim 5 , wherein the matrix forming powder is a mixed powder consisting of an iron alloy powder and not more than 5 mass % of at least one of a nickel powder and a copper powder with respect to the raw powder, and the iron alloy powder consists of, by mass %, 1 to 3% of Ni, 0.5 to 2% of Mo, 0.1 to 1% of Cr, 0.1 to 0.5% of Mn, and the balance of Fe and inevitable impurities. 
   
   
       15 . The production method for the wear resistant sintered alloy according to  claim 5 , wherein the matrix forming powder is an iron alloy powder consisting of 1 to 7 mass % of Mo and the balance of Fe and inevitable impurities. 
   
   
       16 . The production method for the wear resistant sintered alloy according to  claim 5 , wherein the matrix forming powder is a mixed powder consisting of an iron alloy powder and not more than 5 mass % of a nickel powder with respect to the raw powder, and the iron alloy powder consists of 1 to 7 mass % of Mo and the balance of Fe and inevitable impurities. 
   
   
       17 . The production method for the wear resistant sintered alloy according to  claim 5 , wherein the raw powder further includes at least one kind of powder of machinability improving material at 0.3 to 2 mass %, and the powder of the machinability improving material is selected from the group consisting of a lead powder, a disulfide molybdenum powder, a manganese sulfide powder, a boron nitride powder, a calcium metasilicate mineral powder, and a calcium fluoride powder. 
   
   
       18 . The production method for the wear resistant sintered alloy according to  claim 5 , wherein the wear resistant sintered alloy obtained by sintering has pores, and the production method further comprising infiltrating or impregnating the pores with one selected from the group consisting of lead, lead alloy, copper, copper alloy, and acrylic resin. 
   
   
       19 . A wear resistant sintered alloy exhibiting a metallic structure in which 15 to 45% of a hard phase is dispersed in a matrix, the hard phase consisting of, by mass %, 15 to 35% of Mo, I to 10% of Si, 10 to 40% of Cr, and the balance of Co and inevitable impurities. 
   
   
       20 . The wear resistant sintered alloy according to  claim 19 , wherein not more than 80 mass % of Co is substituted by Fe in the composition of the hard phase. 
   
   
       21 . The wear resistant sintered alloy according to  claim 19 , wherein the hard phase further includes not more than 5 mass % of Mn. 
   
   
       22 . The wear resistant sintered alloy according to  claim 19 , wherein the wear resistant sintered alloy has an overall composition consisting of, by mass %, 1 to 5% of Ni, 2.25 to 33.3% of Co, 1.5 to 18% of Cr, 2.25 to 15.75% of Mo, 0.15 to 4.5% of Si, 0.5 to 1.5% of C, and the balance of Fe and inevitable impurities, and the matrix is made of an Fe—Ni—C alloy. 
   
   
       23 . The wear resistant sintered alloy according to  claim 22 , wherein the matrix of the Fe—Ni—C alloy includes at least one kind of an oxide of a metal at 0.15 to 1.25 mass % with respect to the overall composition, and the metal is selected from the group consisting of aluminum, silicon, magnesium, iron, titanium, and calcium. 
   
   
       24 . The wear resistant sintered alloy according to  claim 19 , wherein the wear resistant sintered alloy has an overall composition consisting of, by mass %, 2.34 to 20.73% of Cr, 2.25 to 15.75% of Mo, 0.15 to 4.5% of Si, 2.25 to 33.3% of Co, 0.5 to 1.5% of C, and the balance of Fe and inevitable impurities, and the matrix is made of an Fe—Cr—C alloy. 
   
   
       25 . The wear resistant sintered alloy according to  claim 24 , wherein the matrix of the Fe—Cr—C alloy further includes at least one of Mo, V, and Nb at not more than 2 mass % with respect to the overall composition. 
   
   
       26 . The wear resistant sintered alloy according to  claim 24 , wherein the matrix of the Fe—Cr—C alloy further includes Ni at not more than 5 mass % with respect to the overall composition. 
   
   
       27 . The wear resistant sintered alloy according to  claim 19 , wherein the wear resistant sintered alloy has an overall composition consisting of, by mass %, 1.5 to 18% of Cr, 0.54 to 1.69% of Ni, 3.09 to 16.84% of Mo, 0.15 to 4.5% of Si, 4.76 to 37.66% of Co, 0.5 to 1.5% of C, and the balance of Fe and inevitable impurities, and the matrix is made of an Fe—Co—C alloy. 
   
   
       28 . The wear resistant sintered alloy according to  claim 27 , wherein the matrix of the Fe—Co—C alloy further includes Ni at not more than 5 mass % with respect to the overall composition. 
   
   
       29 . The wear resistant sintered alloy according to  claim 19 , wherein the wear resistant sintered alloy has an overall composition consisting of, by mass %, 1.58 to 18.55% of Cr, 0.54 to 2.54% of Ni, 2.67 to 16.84% of Mo, 0.15 to 4.5% of Si, 2.25 to 33.30% of Co, 0.05 to 0.42% of Mn, 0.5 to 1.5% of C, and the balance of Fe and inevitable impurities, and the matrix is made of an Fe—Ni—Mo—C alloy. 
   
   
       30 . The wear resistant sintered alloy according to  claim 29 , wherein the matrix of the Fe—Ni—Mo—C alloy further includes at least one of Ni and Cu at not more than 5.0 mass % with respect to the overall composition. 
   
   
       31 . The wear resistant sintered alloy according to  claim 19 , wherein the wear resistant sintered alloy has an overall composition consisting of, by mass %, 1.5 to 18% of Cr, 3.09 to 19.57% of Mo, 0.15 to 4.5% of Si, 2.25 to 33.3% of Co, 0.5 to 1.5% of C, and the balance of Fe and inevitable impurities, and the matrix is made of an Fe—Mo—C alloy. 
   
   
       32 . The wear resistant sintered alloy according to  claim 31 , wherein the matrix of the Fe—Mo—C alloy further includes Ni at not more than 5.0 mass % with respect to the overall composition. 
   
   
       33 . The wear resistant sintered alloy according to  claim 19 , wherein the sintered alloy has pores and grain boundaries, at least one kind of powder of machinability improving material is dispersed in the pores and the grain boundaries at 0.3 to 2 mass %, and the machinability improving material is selected from the group consisting of lead, disulfide molybdenum, manganese sulfide, boron nitride, calcium metasilicate mineral, and calcium fluoride. 
   
   
       34 . The wear resistant sintered alloy according to  claim 19 , wherein the sintered alloy has pores filled with one kind selected from the group consisting of lead, lead alloy, copper, copper alloy, and acrylic resin.