Iron-based sintered powder metal body, manufacturing method thereof and manufacturing method of iron-based sintered component with high strength and high density

An iron-based sintered powder metal body the density of which is about 7.3 Mg/m3 or more,

• which consists of,
• at least about 0.10 mass % and at most about 0.50 mass % of carbon,
• at most about 0.3 mass % of oxygen, and
• at most about 0.010 mass % of nitrogen,
• at least one element selected from the group consisting of,
• at most about 1.2 mass % of manganese,
• at most about 2.3 mass % of molybdenum,
• at most about 3.0 mass % of chromium,
• at most about 5.0 mass % of nickel,
• at most about 2.0 mass % of copper, and
• at most about 1.4 mass % of vanadium, and
• the remainder being iron and inevitable impurities, and
• which comprises at most about 0.02 mass % of free carbon.

A method of producing an iron-based sintered powder metal body comprising the step of:

• mixing at least,
• an iron-based powder consisting of,
• at most about 0.05 mass % of carbon,
• at most about 0.3 mass % of oxygen,
• at most about 0.010 mass % of nitrogen, and
• remainder being iron and inevitable impurities, and
• graphite powder of at least about 0.03 mass % and at most about 0.5 mass % based on the total weight of the iron-based powder and the graphite powder, and optionally,
• lubricant of at least about 0.1 weight parts and at most about 0.6 weight parts based on 100 weight parts of total weight of the iron-based powder and the graphite powder,
• resulting in iron-based powder mixture,
• compacting said iron-based powder mixture into a preform the density of which is about 7.3 Mg/m3 or more, and preliminarily sintering said perform in a nonoxydizing atmosphere in which partial pressure of nitrogen is about 30 kPa or less and at a temperature more than about 1000° C. and at most about 1300° C.

A method of producing an iron-based sintered powder metal body comprising the step of:

• mixing at least,
• an iron-based powder consisting of,
• at most about 0.05 mass % of carbon,
• at most about 0.3 mass % of oxygen,
• at most about 0.010 mass % of nitrogen, and
• remainder being iron and inevitable impurities, and
• graphite powder of at least about 0.03 mass % and at most about 0.5 mass % based on the total weight of the iron-based powder and the graphite powder, and optionally,
• lubricant of at least about 0.1 weight parts and at most about 0.6 weight parts based on 100 weight parts of total weight of the iron-based powder and the graphite powder,
• resulting in iron-based powder mixture, compacting said iron-based powder mixture into a preform the density of which is about 7.3 Mg/m3 or more, preliminary sintering said preform at a temperature more than about 1000° C. and at most about 1300° C., and annealing the preliminarily sintered preform.

A method of producing an iron-based sintered component comprising the step of:

• mixing at least,
• an iron-based powder consisting of,
• at most about 0.05 mass % of carbon,
• at most about 0.3 mass % of oxygen,
• at most about 0.010 mass % of nitrogen, and
• remainder being iron and inevitable impurities, and
• graphite powder of at least about 0.03 mass % and at most about 0.5 mass % based on the total weight of the iron-based powder and the graphite powder, and optionally, lubricant of at least about 0.1 weight parts and at most about 0.6 weight parts based on 100 weight parts of total weight of the iron-based powder and the graphite powder,
• resulting in iron-based powder mixture, compacting said iron-based powder mixture into a preform the density of which is about 7.3 Mg/m3 or more, preliminarily sintering said preform in a nonoxydizing atmosphere in which partial pressure of nitrogen is about 30 kPa or less and at a temperature more than about 1000° C. and at most about 1300° C., resulting in sintered powder metal body, re-compacting said sintered powder metal body, resulting in a re-compacted component, and re-sintering and/or subjecting to a heat treatment said re-compacted component.

A method of producing an iron-based sintered component comprising the step of:

• mixing at least,
• an iron-based powder consisting of,
• at most about 0.05 mass % of carbon,
• at most about 0.3 mass % of oxygen,
• at most about 0.010 mass % of nitrogen, and
• remainder being iron and inevitable impurities, and
• graphite powder of at least about 0.03 mass % and at most about 0.5 mass % based on the total weight of the iron-based powder and the graphite powder, and optionally, lubricant of at least about 0.1 weight parts and at most about 0.6 weight parts based on 100 weight parts of total weight of the iron-based powder and the graphite powder,
• resulting in iron-based powder mixture, compacting said iron-based powder mixture into a preform the density of which is about 7.3 Mg/m3 or more, preliminarily sintering said preform at a temperature more than about 1000° C. and at most about 1300° C., annealing preliminarily sintered preform, resulting in a sintered powder metal body
• re-compacting said sintered powder metal body, resulting in a re-compacted component, and
• re-sintering and/or subjecting to a heat treatment said re-compacted component.