Iron-based mixed powder for powder metallurgy and iron-based sintered compact
AssigneeKawasaki Steel Corporation
InventorsSatoshi Uenosono, Junichi Ohta, Akio Sonobe
Life of this patent
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Abstract
In order to improve machinability of a sintered compact, a phosphate compound of an alkali earth metal (calcium phosphate compound or the like) is mixed with an iron-based powder, or an alkali earth metal fluoride (calcium fluoride, or the like) is further mixed with the iron-based powder. Alternatively, the alkali earth metal fluoride, together with a graphite powder, is preferably fixed to recesses of the iron-based powder.
Claims27
An iron-based mixed powder for powder metallurgy comprising an iron-based powder, an alloying powder, a machinability improving powder containing a phosphate compound of an alkali earth metal, and a lubricant.
An iron-based sintered compact comprising calcium phosphate compound.
An iron-based sintered compact comprising calcium phosphate compounds at a total content of about 0.01 to about 0.39% by mass in terms of Ca.
An iron-based sintered compact comprising about 0.02 to about 0.39% by mass of Ca, and above about 0.040 to about 0.64% by mass of P.
An iron-based mixed powder for powder metallurgy comprising an iron-based powder, an alloying powder containing graphite powder, a machinability improving powder, a binder, and a lubricant, wherein the machinability improving powder contains an alkali earth metal fluoride powder, and the graphite powder and the alkali earth metal fluoride powder are fixed to surfaces of the iron-based powder with the binder.
A method for producing an iron-based mixed powder for powder metallurgy comprising:
- mixing together an iron-based powder, an alloying powder containing graphite powder, a machinability improving powder containing alkali earth metal fluoride powder and at least one binder;
- heating the resultant mixture to a temperature sufficient to melt at least one of the binders, with the proviso that the resultant mixture is heated to a temperature of about 10-100° C. higher than the melting point of the at least one binder when one binder is contained within the resultant mixture and heating to a temperature of the lowest melting temperature plus about 10° C. to the highest melting point when more than one binder is contained in the resultant mixture, while mixing to form a primary mixture;
- fixing the graphite powder and machinability improving powder to surfaces of the iron-based powder by cooling the primary mixture;
- and
- adding lubricant to the cooled primary mixture while mixing at a temperature of less than the lowest melting point of the lubricant.
A method for producing an iron-based mixed powder for powder metallurgy comprising:
- mixing an alloying powder, a machinability improving powder containing alkali earth metal fluoride powder and an iron-based powder;
- spraying liquid binder onto the resulting mixture while mixing;
- adding a binder to the resulting mixture and mixing to form a primary mixture;
- heating the primary mixture to about 110-150° while secondarily mixing the primary mixture to melt the binder;
- cooling the resulting secondary mixed powder to strongly fix the graphite powder and the machinability improving powder to surfaces of the iron-based powder;
- and
- adding a lubricant to the secondary mixed powder and performing tertiary mixing to provide a free lubricant present in a free state which is substantially not bonded to the iron-based powder.
Dependencies are inferred from the claim text.