Method For Manufacturing High-Density Iron-Based Compacted Body and High-Density Iron-Based Sintered Body

Abstract

An iron-based compact having a high density and also an iron-based sintered body having a high strength and a high density are manufactured with a high productivity by pre-compacting an iron-based mixed powder prepared by mixing an iron-based metal powder and a graphite powder; pre-sintering the resulting pre-compacted iron-based mixed powder at a temperature higher than 1000° C. but not higher than 1300° C. to produce a sintered iron-based powder preform containing C: 0.10 to 0.50 mass %, O: 0.3 mass % or less, and N: 0.010 mass % or less and having a density of 7.2 Mg/m 3 or more; and subjecting the sintered iron-based powder preform to high-velocity compaction at a compaction energy density of 1.8 MJ/m 2 or more (1.4 MJ/m 2 or more for a sintered pure-iron based powder preform).

1 - 11 . (canceled) 
     
     
         12 . A method for manufacturing a high-density iron-based compact comprising:
 mixing an iron-based metal powder, a graphite powder, and optionally a lubricant to produce an iron-based mixed powder;   pre-compacting the iron-based mixed powder;   pre-sintering the resulting pre-compacted iron-based mixed powder at a temperature higher than about 1000° C., but not higher than about 1300° C. to produce a sintered iron-based powder preform containing C: about 0.10 to about 0.50 mass %, O: about 0.3 mass % or less, and N: about 0.010 mass % or less and having a density of about 7.2 Mg/m 3  or more; and   subjecting the sintered iron-based powder preform to high-velocity compaction at least one.   
     
     
         13 . The method according to  claim 12 , wherein the high-velocity compaction is conducted at a compaction energy density of about 1.8 MJ/m 2  or more. 
     
     
         14 . The method according to  claim 12 , wherein the balance of the sintered iron-based powder preform is substantially Fe, and the high-velocity compaction is conducted at a compaction energy density of about 1.4 MJ/m 2  or more and about 2.2 MJ/m 2  or less. 
     
     
         15 . The method according to  claim 12 , wherein the sintered iron-based powder preform further contains an alloy component, and the high-velocity compaction is conducted at a compaction energy density of about 1.8 MJ/m 2  or more and about 3 MJ/m 2  or less. 
     
     
         16 . The method according to  claim 12 , wherein the sintered iron-based powder preform further includes an alloy component to have a composition containing at least one of Mn: about 1.2 mass % or less, Mo: about 2.3 mass % or less, Cr: about 3.0 mass % or less, Ni: about 5.0 mass % or less, Cu: about 2.0 mass % or less, and V: about 1.4 mass % or less. 
     
     
         17 . The method according to  claim 12 , wherein the sintered iron-based powder preform further includes an alloy component to have a composition containing at least one of Mn: about 1.2 mass % or less, Mo: about 2.3 mass % or less, Cr: about 1.0 mass % or less, Ni: about 5.0 mass % or less, Cu: about 2.0 mass % or less, and V: about 1.4 mass % or less. 
     
     
         18 . The method according to  claim 12 , wherein the sintered iron-based powder preform further includes an alloy component to have a composition containing at least one of Mn: about 1.2 mass % or less, Mo: about 2.3 mass % or less, and Ni: about 5.0 mass % or less and the balance being Fe and unavoidable impurities. 
     
     
         19 . The method according to  claim 12 , wherein the high-velocity compaction is performed at a ram velocity of about 2 m/s or more. 
     
     
         20 . The method according to  claim 12 , wherein the preliminary sintering is performed in a non-oxidative atmosphere having a nitrogen partial pressure of about 30 kPa or less. 
     
     
         21 . The method according to  claim 12 , wherein the preliminary sintering is performed in a non-oxidative atmosphere having a nitrogen partial pressure of about 95 kPa or less, and the resulting pre-sintered iron-based powder preform is annealed at a temperature of about 400° C. to about 800° C. to produce the sintered iron-based powder preform having a density of about 7.2 Mg/m 3  or more. 
     
     
         22 . A method for manufacturing a high-density iron-based sintered body comprising re-sintering and/or conducting heat treatment on the high-density iron-based compact produced by the method according to  claim 12 . 
     
     
         23 . The method according to  claim 13 , wherein the sintered iron-based powder preform further includes an alloy component to have a composition containing at least one of Mn: about 1.2 mass % or less, Mo: about 2.3 mass % or less, Cr: about 3.0 mass % or less, Ni: about 5.0 mass % or less, Cu: about 2.0 mass % or less, and V: about 1.4 mass % or less. 
     
     
         24 . The method according to  claim 15 , wherein the sintered iron-based powder preform further includes an alloy component to have a composition containing at least one of Mn: about 1.2 mass % or less, Mo: about 2.3 mass % or less, Cr: about 3.0 mass % or less, Ni: about 5.0 mass % or less, Cu: about 2.0 mass % or less, and V: about 1.4 mass % or less. 
     
     
         25 . The method according to  claim 13 , wherein the sintered iron-based powder preform further includes an alloy component to have a composition containing at least one of Mn: about 1.2 mass % or less, Mo: about 2.3 mass % or less, Cr: about 1.0 mass % or less, Ni: about 5.0 mass % or less, Cu: about 2.0 mass % or less, and V: about 1.4 mass % or less. 
     
     
         26 . The method according to  claim 15 , wherein the sintered iron-based powder preform further includes an alloy component to have a composition containing at least one of Mn: about 1.2 mass % or less, Mo: about 2.3 mass % or less, Cr: about 1.0 mass % or less, Ni: about 5.0 mass % or less, Cu: about 2.0 mass % or less, and V: about 1.4 mass % or less. 
     
     
         27 . The method according to  claim 13 , wherein the sintered iron-based powder preform further includes an alloy component to have a composition containing at least one of Mn: about 1.2 mass % or less, Mo: about 2.3 mass % or less, and Ni: about 5.0 mass % or less and the balance being Fe and unavoidable impurities. 
     
     
         28 . The method according to  claim 15 , wherein the sintered iron-based powder preform further includes an alloy component to have a composition containing at least one of Mn: about 1.2 mass % or less, Mo: about 2.3 mass % or less, and Ni: about 5.0 mass % or less and the balance being Fe and unavoidable impurities. 
     
     
         29 . A method for manufacturing a high-density iron-based sintered body comprising re-sintering and/or conducting heat treatment on the high-density iron-based compact produced by the method according to  claim 13 . 
     
     
         30 . A method for manufacturing a high-density iron-based sintered body comprising re-sintering and/or conducting heat treatment on the high-density iron-based compact produced by the method according to  claim 14 . 
     
     
         31 . A method for manufacturing a high-density iron-based sintered body comprising re-sintering and/or conducting heat treatment on the high-density iron-based compact produced by the method according to  claim 15 .