US20030215349A1 - Production method of high density iron based forged part - Google Patents

Production method of high density iron based forged part Download PDF

Info

Publication number
US20030215349A1
US20030215349A1 US10/374,720 US37472003A US2003215349A1 US 20030215349 A1 US20030215349 A1 US 20030215349A1 US 37472003 A US37472003 A US 37472003A US 2003215349 A1 US2003215349 A1 US 2003215349A1
Authority
US
United States
Prior art keywords
iron based
powder
sintering
forging
less
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/374,720
Other languages
English (en)
Inventor
Naomichi Nakamura
Shigeru Unami
Satoshi Uenosono
Masashi Fujinaga
Takashi Yoshimura
Mitsumasa Iijima
Shin Koizumi
Hiroyuki Amma
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Unisia Automotive Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Unisia Automotive Ltd filed Critical Hitachi Unisia Automotive Ltd
Assigned to HITACHI UNISIA AUTOMOTIVE, LTD. reassignment HITACHI UNISIA AUTOMOTIVE, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: UNAMI, SHIGERU, NAKAMURA, NAOMICHI, UENOSONO, SATOSHI, FUJINAGA, MASASHI, AMMA, HIROYUKI, IIJIMA, MITSUMASA, KOIZUMI, SHIN, YOSHIMURA, TAKASHI
Publication of US20030215349A1 publication Critical patent/US20030215349A1/en
Assigned to HITACHI, LTD. reassignment HITACHI, LTD. MERGER (SEE DOCUMENT FOR DETAILS). Assignors: HITACHI UNISIA AUTOMOTIVE, LTD.
Abandoned legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/17—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by forging
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10—Sintering only
    • B22F3/1003—Use of special medium during sintering, e.g. sintering aid
    • B22F3/1007—Atmosphere
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B22F2003/248—Thermal after-treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
    • B22F2998/10—Processes characterised by the sequence of their steps

Definitions

  • the present invention relates to improvements in a method of producing or manufacturing an iron based forged part that is suitable for mechanical parts, and more particularly to the method by which reduction of a forging load is achieved improving the density and dimensional precision of the forged part.
  • Powder metallurgy technology allows producing or manufacturing a complicatedly shaped part in a near-net shape and with high dimensional precision, resulting in a large reduction in cutting cost.
  • iron based powder metallurgical products iron based powder products or iron based sintered products
  • further higher mechanical strength is in demand in order to realize smaller size and lighter weight.
  • the iron-based sintered parts are generally producing or manufactured according to the following processes. That is, iron-based metal powder is mixed with alloying powder such as graphite powder, copper powder and a lubricant such as zinc stearate, lithium stearate, thereby an iron based powder mixture is prepared. At the next step, the iron based powder mixture is filled in a metallic die followed by compacting, thereby preparing a compacted body. Then, the compacted body is sintered to produce a sintered body. The thus obtained sintered body is, as needs arise, subjected to sizing or cutting to form a product.
  • the sintered body is further subjected to carburizing heat treatment or bright heat treatment.
  • the density of the formed body obtained according to such a process is at most in the range of substantially 6.6 to 7.1 Mg/m 3 . Accordingly, the density of a sintered body obtained from the formed body is to this extent.
  • the iron based powder product iron based sintered part
  • it is effective to make the formed body higher in the density and therefrom to obtain a denser sintered part (sintered body).
  • the denser the sintered part (sintered body) is, the less pores are in the part, resulting in an improvement in the mechanical properties such as tensile strength, impact resistance value, and fatigue strength.
  • a sintering-cold forging method in which, for instance, a powder metallurgical method and a cold forging method are combined has been proposed in JP-A-1-123005,in which a product having the density substantially close to a true one can be obtained.
  • the sintering-cold forging method is a forming and processing method in which a pre-form (preliminarily formed body) that is obtained by sintering metal powder is subjected to the cold forging followed by re-sintering, and thereby obtaining a final product having a higher density structure.
  • JP-A-1-123005 is a sintering cold forging method in which a sintered pre-form (for cold forging) with a liquid lubricant coated on a surface thereof is tentatively compacted in a die followed by applying a negative pressure on the preform to suck and remove the liquid lubricant further followed by a main compacting in the die and still further followed by re-sintering.
  • the liquid lubricant that is coated and infiltrates the inside of the pre-form before the tentative compacting is sucked before the main compacting, and accordingly fine pores inside thereof are crushed flatly and eliminated at the main compacting, resulting in a denser final product.
  • the density of an end sintered-product obtained according to the method is at most about 7.5 Mg/m 3 , there is a limit in the mechanical strength thereof.
  • the producing processes includes mixing iron powder and iron alloy powder with graphite powder and a lubricant; forming a powder mixture into a preliminarily formed product followed by tentatively sintering; subsequently applying cold forging that gives at least 50% plastic working followed by sintering, annealing, and rolling; and thereby obtaining a final product (sintered member).
  • JP-A-11-117002 discloses a metallic powder forming material.
  • the metallic powder forming material is obtained by tentatively sintering a preliminarily formed body that is obtained by compacting metallic powder in which metal powder containing iron as a main component and mixed with 0.3% or more by weight of graphite and that has a density of 7.3 Mg/M 3 or more, preferably at a temperature in the range of 700 to 1000° C.
  • the metallic powder forming material has a structure in which in graphite remains in grain boundaries of metal powder.
  • a method of producing a sintered body includes a step of tentatively sintering, at a certain temperature, a preliminarily formed body that is obtained by compacting metallic powder in which metal powder containing iron as a main component and 0.3% or more by weight of graphite are mixed and has a density of 7.3 Mg/m 3 or more, thereby obtaining a metallic powder forming material having a structure in which the graphite remains in grain boundaries of metal powder; a step of re-compressing in which the metallic powder forming material obtained according to the tentative sintering is re-compacted; and a step of re-sintering in which a re-compacted body obtained according to the re-compressing is re-sintered.
  • an alloy steel powder re-sintered processed body is disclosed.
  • the alloy steel powder re-sintered body is manufactured by tentatively sintering, at a certain temperature, a preliminarily formed body that is obtained by compacting metallic powder in which alloy steel powder and 0.1% or more by weight of graphite are mixed and has a density of 7.3 Mg/m 3 or more, thereby forming a metallic powder forming material having a structure in which the graphite remains in grain boundaries of metal powder; re-compression forming the metallic powder forming material thereby forming an alloy steel powder plasticity-processed body having a densified structure that contains substantially no voids; and re-sintering the alloy steel powder plasticity-processed body at a certain temperature, thereby obtaining the alloy steel powder re-sintered processed body that has a structure to which graphite diffuses out and a structure where graphite remains at a certain ratio in accordance with
  • JP-A-2000-303106 and JP-A-2000-355726 a higher density and higher strength sintered body can be obtained.
  • JP-A-2000-303106 and JP-A-2000-355726 when the density of the material before the re-compression forming is less than 7.3 Mg/m 3 , depending on the re-compression forming method, there is a problem in that a high density and high dimensional precision part is difficult to be obtained.
  • Another object of the present invention is to provide an improved producing method of a high density iron based forged part, which makes it possible to produce a high density and high precision iron based forged part at a lower forging load.
  • the present inventors in order to overcome the above problems, have intensively studied sintering conditions and forming conditions, intending to obtain a high density iron based forged part.
  • it has been found effective to preliminarily forming or compacting a powder mixture followed by sintering at a temperature that allows added graphite to diffuse into a matrix and in a low nitrogen atmosphere, or furthermore followed by applying cold closed die forging or cold enclosed die forging after applying annealing.
  • the density after the preliminary forming is low, a forged part that has a high density and is remarkably improved in the dimensional precision can be obtained.
  • the forming (forging) after the sintering can be performed under a low forming (forging) load.
  • a method of producing a high density iron based forged part comprises the following steps in the sequence set forth: (a) preparing iron based powder mixture containing iron based metal powder and graphite powder; (b) preliminarily compacting the iron based powder mixture to form a preliminary compact; (c) sintering the preliminary compact in a non-oxidizing atmosphere whose nitrogen partial pressure is 30 kPa or less, at a temperature of 950° C. or more and of 1300° C. or less to form a forming material; and (d) forging the forming material by closed die forging or enclosed die forging to produce a high density forged part.
  • FIG. 1 is a block diagram showing a typical example of a method of producing a high density iron based forged part, according to the present invention.
  • a method of producing or manufacturing a high density iron based (ferrous) forged part comprises the following steps in the sequence set forth: (a) preparing iron based powder mixture containing iron based metal powder and graphite powder; (b) preliminarily compacting the iron based powder mixture to form a preliminary compact; (c) sintering the preliminary compact in a non-oxidizing atmosphere whose nitrogen partial pressure is 30 kPa or less, at a temperature of 950° C. or more and of 1300° C. or less to form a forming material; and (d) forging the forming material by closed die forging or enclosed die forging to produce a high density forged part.
  • iron based metal powder and graphite powder, and optionally powder for alloy are used as raw material powder for the high density iron based formed part.
  • the iron based metal powder to be used can be appropriately selected according to the usage, and, though not restricted to a particular one. From a view point of compressibility, in the present invention, an iron based metal powder that has a composition that contains, by mass %, carbon of 0.05% or less, oxygen of 0.3% or less, nitrogen of 0.010% or less and a balance of iron and inevitable impurities can be preferably used as the iron based metal powder.
  • an oxygen content in the iron based metal powder is preferable to be as low as possible from a view point of compactibility.
  • oxygen is an inevitably included impurity
  • 0.02% by mass that can be inexpensively and industrially put into practice is preferably set as a lower limit.
  • a preferable oxygen content is 0.03 to 0.2% by mass.
  • a nitrogen content in the iron based metal powder is preferable to be as low as possible from a view point of decreasing the forging load.
  • the nitrogen content is preferably set at 0.010% by mass or less.
  • a particle diameter of the iron based metal powder that is used in the invention is preferable to be, in terms of an average particle diameter, in the range of 30 to 120 ⁇ m that can be industrially manufactured at low cost.
  • the average particle diameter is a value of a mid-point (d 50 ) of a so-called weight cumulative particle size distribution.
  • one kind or two or more selected from Mn, Mo, Cr, Ni, Cu and V can be contained, and furthermore one kind or two or more selected from Mn: 1.2% by mass or less, Mo: 2.3% by mass or less, Cr: 3.0% by mass or less, Ni: 5.0% by mass or less, Cu: 2.0% by mass or less and V: 1.4% by mass or less can be preferably contained in the iron based metal powder.
  • Mn, Mo, Cr, Ni, Cu and V are 1.0% by mass or less for Mn, 2.0% by mass or less for Mo, 3.0% by mass or less for Cr, 5.0% by mass or less for Ni, 2.0% by mass or less for Cu and 1.0% by mass or less for V.
  • All of Mn, Mo, Cr, Ni, Cu and V can increase the mechanical strength or the hardenability of the sintered body, so that, as needs arise, these can be selected and contained.
  • These alloying elements may be previously alloyed with the iron based metal powder, or may be partially diffused and adhered to (or partially allowed with) the iron based metal powder thereby forming a partial alloy, or may be mixed with metal powder (alloying powder) for alloy.
  • the partially alloyed one being most excellent in the compactibility when compared under the same alloy amount, is preferable.
  • Mn, Mo, Cr, Ni, Cu, and V exceed 1.2% by mass, 2.3% by mass, 3.0% by mass, 5.0% by mass, 2.0% by mass and 1.4% by mass, respectively, the hardness of forming material (or material to be formed) becomes higher, resulting in an increase of the forming load at the forging.
  • the graphite powder that is used as the raw material powder, with an intention to secure a certain mechanical strength of a forged part or to increase the hardenability at the heat treatment is preferably contained in an iron based powder mixture (including the iron based metal powder and the graphite powder) by 0.03 to 0.5% by mass with respect to a total amount of the iron based metal powder and the graphite powder.
  • an iron based powder mixture including the iron based metal powder and the graphite powder
  • a strength improvement effect of a sintered body is insufficient
  • the content of the graphite powder exceeds 0.5% by mass, a compression load at the forging becomes excessive.
  • the content of the graphite powder in the iron based powder mixture is preferable to be in the range of 0.03 to 0.5% by mass with respect to the total amount of the iron based metal powder and the graphite powder.
  • a lubricant such as a metal soap such as zinc stearate, lithium stearate, and calcium stearate, a higher fatty acid amide such as stearic acid amide, oleic acid amide, and ethylene bis-stearamide, a higher fatty acid such as stearic acid and oleic acid, spindle oil, turbine oil and wax can be added to be contained.
  • a content of the lubricant is preferable to be in the range of 0.1 to 0.6 parts by weight with respect to 100 parts by weight of the total of the iron based metal powder and the graphite powder.
  • the iron based powder mixture that is mixed at the above ratio is preferably followed by subjecting to preliminary (compression) forming or compacting.
  • preliminary compacting normally well known compacting technology such as a die lubrication method, a multi-stage forming method with a divided die, a CNC press method, a hydrostatic press method, a press forming method disclosed in JP-A-11-117002, a hot forming method, or combinations thereof can be applicable.
  • the press forming method disclosed in, for instance, JP-A-11-117002 without heating raw material powder and a die, a compacted body (or compact) having a higher density can be easily manufactured.
  • a density of a preliminarily formed or compacted body is preferably set at less than 7.3 Mg/m 3 .
  • the density of the preliminarily compacted body is set at less than 7.3 Mg/m 3 , there is an effect in that restrictions on the conditions of the raw material powder such as the iron based powder being used and so on and on the conditions of the preliminary forming or compacting can be largely alleviated.
  • the density of the preliminarily compacted body is less than 7.3 Mg/m 3 , a forged part having a higher density can be obtained.
  • the density of the preliminarily compacted body may be 7.3 Mg/m 3 or more.
  • the preliminarily compacted body is sintered and supplied as the forming material.
  • the sintering is performed in a non-oxidizing atmosphere whose nitrogen partial pressure is 30 kPa or less at a temperature of 950° C. or more and of 1300° C. or less.
  • the sintering temperature is less than 950° C.
  • the diffusion of graphite into the matrix becomes insufficient. Accordingly, residual graphite, in a recrystallization process, diffuses into the matrix, and thereby disappears and leaves pores, resulting in likelihood of causing strength lowering.
  • the sintering temperature exceeds 1300° C., an improvement effect of formability saturates, and by contrast, the manufacturing cost remarkably increases, resulting in being economically disadvantageous.
  • the sintering temperature is restricted to 950° C. or more and 1300° C. or less.
  • the sintering is carried out in a vacuum, in an Ar gas, or in an atmosphere that is a non-oxidizing one such as a hydrogen gas and whose nitrogen partial pressure is 30 kPa or less.
  • As a preferable atmosphere there is a hydrogen-nitrogen gas mixture whose hydrogen concentration is, for instance, 70% by volume or more.
  • the nitrogen partial pressure exceeds 30 kPa, the nitrogen content in the forming material exceeds 0.010% by mass, resulting in incapability of expecting the above effects.
  • the sintering time though appropriately determined depending on an object and conditions, is normally preferably set in the range of 600 to 7200 S.
  • the preliminarily compacted body may be subjected to annealing at a temperature preferably lower than the sintering temperature to prepare a forming material.
  • the forming material can be appreciably improved in the compression properties (cold forgeability).
  • the annealing after the sintering is preferably carried out at a temperature in the range of 400 to 800° C.
  • the nitrogen reduction effect becomes smaller.
  • an atmosphere during the annealing- similarly to the atmosphere during the sintering, is preferable to be a non-oxidizing one.
  • the nitrogen partial pressure in the annealing atmosphere is preferable to be 95 kPa or less. The nitrogen partial pressure in the atmosphere during the annealing and that in the atmosphere during the sintering are not necessarily required to be the same.
  • the sintering period of time is preferably set in the range of 600 to 7200 s.
  • the annealing period of time is less than 600 s, the nitrogen reduction effect is slight, and when the annealing period of time exceeds 7200 s, in addition to saturation of the effect, the productivity becomes lower.
  • the more preferable period of time is 1200 to 3600 s.
  • the sintering and the subsequent annealing without taking out the material from a sintering furnace in which the sintering is carried out, are continuously performed.
  • the annealing is subsequently applied as it is.
  • the annealing is applied at a temperature in the range of 400 to 800° C.
  • the temperature is not necessarily held evenly at a definite temperature and may be gradually lowered, for instance, from 800 to 400° C.
  • the cooling speed may be lowered so as to take 600 to 7200 s, preferably 3600 to 7200 s, more excessively than a time (about 2400 s) that is necessary to pass the above temperature region at a normal cooling speed.
  • the forming material is cold forged, and thereby a forged part is prepared.
  • the forging is a closed die forging or an enclosed die forging.
  • the “closed die forging” in the invention means the forging in which an almost all surface of the forming material is restrained by a surface of a die so that the material may not be forced out through a clearance of the die, the forging is carried out.
  • the “enclosed die forging” in the invention means the forging in which after the material is confined into the die, the material is pressed by means of a punch or the like, and thereby the material is allowed to fill a space in the die.
  • die lubrication can be preferably applied.
  • the die lubrication can be preferably applied according to an ordinary method in which either a lubricant is coated before the forging or a solid lubricant is used at the forging.
  • the die is one that has a closed structure or an enclosed structure, and one in which a certain amount of clearance can be set with respect to the forming material is preferably used.
  • the clearance is set, since a certain amount of plastic flow can be induced in the forming material at the forging, the density can be further improved.
  • the obtained forged part is subjected to a final processing as it is to form a product, or, as needs arise, to re-sintering and/or heating process to form a product.
  • the heating process can be selected from a carburizing process, a hardening process, a tempering process or the like.
  • a carburizing process in an atmosphere whose carbon potential is about 0.6 to 1%, the forged part, after being heated at a temperature in the range of about 800 to 900° C., is preferably subjected to oil hardening.
  • the forged part in order to inhibit a surface of the sintered body from being oxidized at high temperatures and from being decarbonized, it is preferable that in a protective atmosphere such as an inert atmosphere such as an Ar gas or a nitrogen atmosphere containing hydrogen, the forged part is heated at a temperature in the range of about 800 to 950° C. followed by the oil hardening. Still furthermore, also in vacuum carburizing hardening and in high frequency hardening, the forged part, after being heated at a temperature in the above range, can be preferably hardened. These heat treatments can improve the mechanical strength of a product. Still furthermore, after the hardening is applied, as needs arise, the tempering process may be applied. A tempering temperature is preferably set at a temperature in a normally known tempering temperature range of 130 to 250° C. Before or after the heat treatment, in order to adjust a dimension and shape, machining may be applied to the forged part.
  • a protective atmosphere such as an inert atmosphere such as an Ar gas or a nitrogen atmosphere
  • a certain amount of MoO 3 powder was compounded with atomized pure iron powder (“KIP301A” produced by Kawasaki Steel Corporation) followed by blending by using a V-type blender for 15 min, so that a powder mixture is formed.
  • KIP301A atomized pure iron powder
  • V-type blender for 15 min, so that a powder mixture is formed.
  • the MoO 3 powder was reduced and Mo was allowed diffusing to and sticking on a surface of an iron particle, and accordingly partially alloyed iron based metal powder A was formed.
  • an amount of Mo was 1.0% by mass, in which 1.0% by mass of Mo was partially alloyed.
  • the iron based metal powder A contained 0.15% by mass of Mn as an alloy component which had been previously alloyed.
  • iron based metal powder B in which 1.0% by mass of Mo and 0.13% by mass of Mn had been previously alloyed was produced, in which 1.0% by mass of Mo was previously alloyed.
  • Both iron based metal powders A and B contained 0.01% by mass of C, 0.15% by mass or less of O, and 0.01% by mass or less of N. Average particle diameters (d 50 ) of the iron based metal powders A and B were in the range of 70 to 80 ⁇ m.
  • Each of the two kinds of iron based metal powders A and B was blended with graphite powder and a lubricant by using a V-type blender, so that an iron based powder mixture was prepared.
  • a lubricant zinc stearate was used.
  • the kinds of the iron based metal powders and contents of the graphite are shown in Table 1.
  • the iron based power mixture was filled in a die and, with a forming pressure adjusted by means of a hydraulic compacting machine, was preliminarily formed or compacted, so that a tablet-like preliminarily compacted body having 30 mm diameter and 13 mm height was formed.
  • the density of the preliminarily compacted body is in the range of 6.88 to 7.12 Mg/m 3 as shown in Table 1.
  • the obtained preliminarily compacted body was sintered under the sintering conditions shown in Table 1, so that a forming material was prepared.
  • the sintering conditions in Table 1 includes kinds of atmospheres in which the sintering was made, nitrogen partial pressure in the atmospheres, temperatures at which sintering was made, and times for which the sintering was made.
  • the sintering was continuously followed by the annealing under annealing conditions shown in Table 1.
  • the annealing conditions in Table 1 includes kinds of atmospheres in which the annealing was made, nitrogen partial pressure in the atmospheres, temperatures at which annealing was made, and times for which the annealing was made.
  • the obtained forming material was put in a die having a closed structure and subjected to the cold closed die forging, so that a disc-like forged part having a dimension of 30 mm diameter and 13 mm thickness was produced as a product.
  • the forging load at the closed die forging was measured.
  • the forgings at the forgings loads of 748 MPa and 1177 MPa were conducted for each sample (each forming material) as shown in Table 2.
  • the density and the hardness of the obtained forged part were measured according to Archimedes method and by use of a Rockwell hardness gauge (B-scale), respectively, as shown in Table 2.
  • the forged part (product) was observed, and thereby a ratio of an area through which an outer peripheral surface of the product comes into contact with the die to an area of the outer peripheral surface of the die was obtained, so that the transfer properties are evaluated as shown in Table 2.
  • a value of the ratio is 95% or more, the transfer properties are evaluated as A; 90% or more and less than 95%, B; 80% or more and less than 90%, C; and less than 80%, D. It can be said that the larger the value is, the more excellent the dimensional precision is.
  • the presence of the contact between the outer peripheral surface of the product and the die is judged according to the presence of luster of the outer periphery surface of the product. When the product comes into contact with the die, the luster can be observed on the outer peripheral surface of the product.
  • Examples (Sample Nos. 1, 2, 5 and 6) are higher in the density (that is, can be forged under a lower load) and excellent in the transfer properties (excellent in the dimensional precision) as compared with Comparative examples (Sample Nos. 3, 4, 7 and 8) in which the sintering was made under-a higher nitrogen partial pressure, when formed under the same forging load. Furthermore, Examples (Sample Nos. 5 and 6) in which the annealing was applied after the sintering are higher in the density and excellent in the transfer properties as compared with Examples (Sample Nos. 1 and 2) in which no annealing was made, when formed under the same forging load. Furthermore, Examples (Sample Nos.
  • Example 13 in which the annealing was made at a temperature in the range of 400 to 800° C. are higher in the density and excellent in the transfer properties, as compared with Example (Sample No. 12) in which the annealing was made at 300° C. and Examples (Sample Nos. 15 and 16) in which the annealing was made at 900° C., when formed under the same forging load.
  • Examples (Sample Nos. 1 and 5) in which the partially alloyed iron based metal powder A is used are higher in the density and excellent in the transfer properties, as compared with Examples (Sample Nos. 10 and 11) in which the preliminarily alloyed iron based metal powder B was used, when formed under the same forging load.
  • a higher density iron based forged part can be produced or manufactured at a low forging load and additionally with higher dimensional precision. Accordingly, significant industrial benefits can be attained by the production method fo the present invention.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Powder Metallurgy (AREA)
  • Forging (AREA)
US10/374,720 2002-02-28 2003-02-27 Production method of high density iron based forged part Abandoned US20030215349A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2002054244A JP3741654B2 (ja) 2002-02-28 2002-02-28 高密度鉄基鍛造部品の製造方法
JP2002-054244 2002-02-28

Publications (1)

Publication Number Publication Date
US20030215349A1 true US20030215349A1 (en) 2003-11-20

Family

ID=27800029

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/374,720 Abandoned US20030215349A1 (en) 2002-02-28 2003-02-27 Production method of high density iron based forged part

Country Status (5)

Country Link
US (1) US20030215349A1 (zh)
JP (1) JP3741654B2 (zh)
KR (1) KR20030071540A (zh)
CN (1) CN1442257A (zh)
DE (1) DE10308274B4 (zh)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030226128A1 (en) * 2002-05-31 2003-12-04 Kenji Arai Basic cell of gate array semiconductor device, gate array semiconductor device, and layout method for gate array semiconductor device
US20060099104A1 (en) * 2004-11-05 2006-05-11 H. L. Blachford Ltd./Ltee. Lubricants for powdered metals and powdered metal compositions containing said lubricants
US20060130553A1 (en) * 2004-12-17 2006-06-22 Dan Roth-Fagaraseanu Method for the manufacture of highly loadable components by precision forging
EP1839780A2 (en) * 2006-03-29 2007-10-03 Hitachi Powdered Metals Co., Ltd. Sintered gear with an area of high density and production method therefor
US20070231181A1 (en) * 2006-04-03 2007-10-04 Seiko Epson Corporation Method of manufacturing sintered body
US20100116240A1 (en) * 2007-04-04 2010-05-13 Gkn Sinter Metals, Llc. Multi-piece thin walled powder metal cylinder liners
US20110000457A1 (en) * 2008-01-04 2011-01-06 Donaldson Ian W Prealloyed copper powder forged connecting rod
US10213832B2 (en) 2012-03-28 2019-02-26 Hitachi Chemical Company, Ltd. Sintered member, pinion gear for starters, and production method therefor
EP2889388B1 (en) * 2012-08-23 2019-04-03 NTN Corporation Method of manufacturing a machine part
US10536048B2 (en) 2013-03-25 2020-01-14 Ntn Corporation Method for manufacturing sintered bearing, sintered bearing, and vibration motor equipped with same

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4640134B2 (ja) * 2004-11-25 2011-03-02 Ｊｆｅスチール株式会社 高強度高密度鉄基焼結体の製造方法
CN100427244C (zh) * 2005-07-08 2008-10-22 台湾真珠乐器股份有限公司 乐器、乐器组件的制备
CN101537495B (zh) * 2008-03-19 2010-12-01 宝山钢铁股份有限公司 还原金属粒子高速微锻成形工艺
JP5369290B2 (ja) * 2008-06-20 2013-12-18 株式会社栗本鐵工所 長尺合金ビレットの製造方法
JP6087042B2 (ja) * 2010-09-30 2017-03-01 日立化成株式会社 焼結部材の製造方法
CN103060055A (zh) * 2013-01-22 2013-04-24 曾锐 一种不锈钢专用粉末冶金润滑剂及其制备方法
JP6412315B2 (ja) * 2013-03-25 2018-10-24 Ntn株式会社 振動モータ
JP6412314B2 (ja) * 2013-04-09 2018-10-24 Ntn株式会社 焼結軸受の製造方法
CN104162670A (zh) * 2014-08-26 2014-11-26 无锡柯马机械有限公司 一种粉末冶金工艺
CN104162663A (zh) * 2014-08-26 2014-11-26 无锡柯马机械有限公司 一种粉末冶金工艺中粉末预处理的方法
CN105234341A (zh) * 2015-10-22 2016-01-13 安徽蓝博旺机械集团合诚机械有限公司 一种叉车转向节的粉末锻造方法
CN105312585A (zh) * 2015-10-22 2016-02-10 安徽蓝博旺机械集团精密液压件有限责任公司 一种叉车变速箱齿轮的粉末锻造方法

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837930A (en) * 1972-01-17 1974-09-24 Int Nickel Co Method of producing iron-chromium-aluminum alloys with improved high temperature properties
US4069044A (en) * 1976-08-06 1978-01-17 Stanislaw Mocarski Method of producing a forged article from prealloyed-premixed water atomized ferrous alloy powder
US4393563A (en) * 1981-05-26 1983-07-19 Smith David T Cold forced sintered powder metal annular bearing ring blanks
US4954171A (en) * 1987-09-30 1990-09-04 Kawasaki Steel Corp. Composite alloy steel powder and sintered alloy steel
US4985309A (en) * 1987-08-01 1991-01-15 Kawasaki Steel Corporation Alloyed steel powder for powder metallurgy
US5516483A (en) * 1994-02-07 1996-05-14 Stackpole Limited Hi-density sintered alloy
US5754937A (en) * 1996-05-15 1998-05-19 Stackpole Limited Hi-density forming process
US5938814A (en) * 1997-02-25 1999-08-17 Kawasaki Steel Corporation Iron based powder mixture for powder metallurgy
US6159266A (en) * 1997-10-14 2000-12-12 Unisia Jecs Corporation Sintered powder metal bodies and process for producing the same
US6203753B1 (en) * 1996-05-13 2001-03-20 The Presmet Corporation Method for preparing high performance ferrous materials
US6514307B2 (en) * 2000-08-31 2003-02-04 Kawasaki Steel Corporation Iron-based sintered powder metal body, manufacturing method thereof and manufacturing method of iron-based sintered component with high strength and high density

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01123005A (ja) * 1987-11-09 1989-05-16 Mazda Motor Corp 焼結冷間鍛造方法
JP3869620B2 (ja) * 1999-04-16 2007-01-17 株式会社日立製作所 合金鋼粉成形素材と合金鋼粉加工体及び合金鋼粉成形素材の製造方法
JP3871825B2 (ja) * 1999-04-16 2007-01-24 株式会社日立製作所 金属質粉成形素材の再圧縮成形体及びその再圧縮成形体から得られる焼結体並びにそれらの製造方法

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837930A (en) * 1972-01-17 1974-09-24 Int Nickel Co Method of producing iron-chromium-aluminum alloys with improved high temperature properties
US4069044A (en) * 1976-08-06 1978-01-17 Stanislaw Mocarski Method of producing a forged article from prealloyed-premixed water atomized ferrous alloy powder
US4393563A (en) * 1981-05-26 1983-07-19 Smith David T Cold forced sintered powder metal annular bearing ring blanks
US4985309A (en) * 1987-08-01 1991-01-15 Kawasaki Steel Corporation Alloyed steel powder for powder metallurgy
US4954171A (en) * 1987-09-30 1990-09-04 Kawasaki Steel Corp. Composite alloy steel powder and sintered alloy steel
US5516483A (en) * 1994-02-07 1996-05-14 Stackpole Limited Hi-density sintered alloy
US6203753B1 (en) * 1996-05-13 2001-03-20 The Presmet Corporation Method for preparing high performance ferrous materials
US5754937A (en) * 1996-05-15 1998-05-19 Stackpole Limited Hi-density forming process
US5938814A (en) * 1997-02-25 1999-08-17 Kawasaki Steel Corporation Iron based powder mixture for powder metallurgy
US6159266A (en) * 1997-10-14 2000-12-12 Unisia Jecs Corporation Sintered powder metal bodies and process for producing the same
US6514307B2 (en) * 2000-08-31 2003-02-04 Kawasaki Steel Corporation Iron-based sintered powder metal body, manufacturing method thereof and manufacturing method of iron-based sintered component with high strength and high density
US6696014B2 (en) * 2000-08-31 2004-02-24 Jfe Steel Corporation Iron-based sintered powder metal body, manufacturing method thereof and manufacturing method of iron-based sintered component with high strength and high density

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030226128A1 (en) * 2002-05-31 2003-12-04 Kenji Arai Basic cell of gate array semiconductor device, gate array semiconductor device, and layout method for gate array semiconductor device
US7329302B2 (en) * 2004-11-05 2008-02-12 H. L. Blachford Ltd./Ltee Lubricants for powdered metals and powdered metal compositions containing said lubricants
US20060099104A1 (en) * 2004-11-05 2006-05-11 H. L. Blachford Ltd./Ltee. Lubricants for powdered metals and powdered metal compositions containing said lubricants
US20060130553A1 (en) * 2004-12-17 2006-06-22 Dan Roth-Fagaraseanu Method for the manufacture of highly loadable components by precision forging
US7571528B2 (en) 2004-12-17 2009-08-11 Rolls-Royce Deutschland Ltd & Co Kg Method for the manufacture of highly loadable components by precision forging
US7905018B2 (en) 2006-03-29 2011-03-15 Hitachi Powdered Metals Co., Ltd. Production method for sintered gear
US20070283778A1 (en) * 2006-03-29 2007-12-13 Hitachi Powdered Metals Co., Ltd. Sintered gear and production method therefor
EP1839780A3 (en) * 2006-03-29 2007-12-12 Hitachi Powdered Metals Co., Ltd. Sintered gear with an area of high density and production method therefor
EP2052800A1 (en) * 2006-03-29 2009-04-29 Hitachi Powdered Metals Co., Ltd. Production method of a sintered gear with an area of high density
EP1839780A2 (en) * 2006-03-29 2007-10-03 Hitachi Powdered Metals Co., Ltd. Sintered gear with an area of high density and production method therefor
US20070231181A1 (en) * 2006-04-03 2007-10-04 Seiko Epson Corporation Method of manufacturing sintered body
US20100116240A1 (en) * 2007-04-04 2010-05-13 Gkn Sinter Metals, Llc. Multi-piece thin walled powder metal cylinder liners
US20110000457A1 (en) * 2008-01-04 2011-01-06 Donaldson Ian W Prealloyed copper powder forged connecting rod
US8935852B2 (en) 2008-01-04 2015-01-20 Gkn Sinter Metals, Llc Prealloyed copper powder forged connecting rod
US10213832B2 (en) 2012-03-28 2019-02-26 Hitachi Chemical Company, Ltd. Sintered member, pinion gear for starters, and production method therefor
EP2889388B1 (en) * 2012-08-23 2019-04-03 NTN Corporation Method of manufacturing a machine part
US10536048B2 (en) 2013-03-25 2020-01-14 Ntn Corporation Method for manufacturing sintered bearing, sintered bearing, and vibration motor equipped with same
EP2980964B1 (en) * 2013-03-25 2020-08-19 NTN Corporation Method for manufacturing sintered bearing

Also Published As

Publication number Publication date
DE10308274A1 (de) 2003-12-11
DE10308274B4 (de) 2007-03-01
KR20030071540A (ko) 2003-09-03
JP2003253372A (ja) 2003-09-10
JP3741654B2 (ja) 2006-02-01
CN1442257A (zh) 2003-09-17

Similar Documents

Publication Publication Date Title
US20030215349A1 (en) Production method of high density iron based forged part
US6696014B2 (en) Iron-based sintered powder metal body, manufacturing method thereof and manufacturing method of iron-based sintered component with high strength and high density
EP1755810B1 (en) Iron-based gear wheels produced by a process comprising uniaxially compacting, sintering and surface densifying
CA2355559C (en) Alloyed steel powder for powder metallurgy
US6193927B1 (en) High density forming process with ferro alloy and prealloy
JP5671526B2 (ja) 高強度低合金焼結鋼
US20080202651A1 (en) Method For Manufacturing High-Density Iron-Based Compacted Body and High-Density Iron-Based Sintered Body
EP1097770B1 (en) Powder metallurgy process
JPH10324944A (ja) 粉末冶金用鉄基混合粉
JP4923801B2 (ja) 高密度鉄基成形体および高強度高密度鉄基焼結体の製造方法
US6143240A (en) High density forming process with powder blends
JP4640134B2 (ja) 高強度高密度鉄基焼結体の製造方法
JP3729764B2 (ja) 鉄基粉末成形用素材、その製造方法および高強度高密度鉄基焼結体の製造方法
JP6743720B2 (ja) 粉末冶金用鉄基混合粉末およびその製造方法ならびに引張強さと耐衝撃性に優れた焼結体
JPH1150103A (ja) 粉末冶金用鉄粉の製造方法
JP4615191B2 (ja) 鉄基焼結体の製造方法
US6652618B1 (en) Iron based mixed power high strength sintered parts
JPH10280083A (ja) 粉末冶金用鉄基混合粉
WO2023157386A1 (ja) 粉末冶金用鉄基混合粉および鉄基焼結体

Legal Events

Date Code Title Description
AS Assignment

Owner name: HITACHI UNISIA AUTOMOTIVE, LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:NAKAMURA, NAOMICHI;UNAMI, SHIGERU;UENOSONO, SATOSHI;AND OTHERS;REEL/FRAME:014191/0167;SIGNING DATES FROM 20030411 TO 20030422

AS Assignment

Owner name: HITACHI, LTD., JAPAN

Free format text: MERGER;ASSIGNOR:HITACHI UNISIA AUTOMOTIVE, LTD.;REEL/FRAME:016245/0106

Effective date: 20041001

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION