CN101827675B - Method for obtaining forged carburized powder metal part - Google Patents
Method for obtaining forged carburized powder metal part Download PDFInfo
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- CN101827675B CN101827675B CN200780101184.9A CN200780101184A CN101827675B CN 101827675 B CN101827675 B CN 101827675B CN 200780101184 A CN200780101184 A CN 200780101184A CN 101827675 B CN101827675 B CN 101827675B
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- prefabricated blank
- carburizing
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- gear
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- 238000000034 method Methods 0.000 title claims abstract description 74
- 239000002184 metal Substances 0.000 title claims abstract description 35
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 35
- 239000000843 powder Substances 0.000 title claims abstract description 22
- 238000005255 carburizing Methods 0.000 claims abstract description 110
- 238000005242 forging Methods 0.000 claims abstract description 66
- 238000005245 sintering Methods 0.000 claims abstract description 25
- 238000001816 cooling Methods 0.000 claims abstract description 16
- 238000010000 carbonizing Methods 0.000 claims description 27
- 230000008569 process Effects 0.000 claims description 18
- 238000007596 consolidation process Methods 0.000 claims description 14
- 238000013459 approach Methods 0.000 claims description 12
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 11
- 229910052698 phosphorus Inorganic materials 0.000 claims description 11
- 239000011574 phosphorus Substances 0.000 claims description 11
- 239000012255 powdered metal Substances 0.000 claims description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 10
- 229910052799 carbon Inorganic materials 0.000 claims description 9
- 239000000428 dust Substances 0.000 claims description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 5
- 239000000956 alloy Substances 0.000 claims description 2
- 229910045601 alloy Inorganic materials 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 239000007787 solid Substances 0.000 claims description 2
- 230000006641 stabilisation Effects 0.000 claims description 2
- 238000011105 stabilization Methods 0.000 claims description 2
- 238000004140 cleaning Methods 0.000 claims 1
- 230000002045 lasting effect Effects 0.000 claims 1
- 238000003892 spreading Methods 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 description 16
- 230000007246 mechanism Effects 0.000 description 11
- 238000012545 processing Methods 0.000 description 10
- 239000000047 product Substances 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 230000008901 benefit Effects 0.000 description 4
- 238000010791 quenching Methods 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 230000000171 quenching effect Effects 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000000314 lubricant Substances 0.000 description 2
- 240000001439 Opuntia Species 0.000 description 1
- 238000012356 Product development Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000010953 base metal Substances 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 210000000481 breast Anatomy 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- -1 closely knit Substances 0.000 description 1
- 238000004320 controlled atmosphere Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
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- 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
- B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
- B22F5/08—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of toothed articles, e.g. gear wheels; of cam discs
-
- 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
- B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
- B22F2998/10—Processes characterised by the sequence of their steps
-
- 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
- B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
- F16H55/02—Toothed members; Worms
- F16H55/06—Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Gears, Cams (AREA)
- Forging (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Powder Metallurgy (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
A method for obtaining a selectively non-carburized powder metal part. The steps include compacting, sintering, removing, forging and cooling. A metal powder is compacted to form a preform having at least one first surface in which a forged part is required to have a case depth and at least one second surface in which a carburized portion is required to be removed prior to forging. The preform is then sintered and carburized. After carburizing the at least one second surface of the preform is removed and subsequently forged and cooled. The forged part has at least one second surface having improved post forging properties and at least one first surface having improved performance features. A part made from the present method is also provided.
Description
Technical field
The present invention relates to a kind of powder metal component of forging, more particularly, relate to a kind of powder metal component and manufacture method thereof of non-carburizing selectively.
Background technology
More and more need to reduce the manufacturing process of producing cost, time and step in parts.Conventionally, the final relevant benefit of manufacturing process is inevitable first relevant with customer requirement with improving, thereby by product development be modified into and there is good size, machinery and/or Performance Characteristics.For example, typical differential mechanism side gear may have any or all performance requirement in following performance requirement, such as: the keyway region that requires dimensional accuracy, high shear strength and Bu Shi resistance; Require hub face and the thrust face of dimensional accuracy, surface smoothness and case-carbonizing compatibility; Require the gear geometry of dimensional accuracy, surface smoothness and best profile; And may require impact resistance, wearability, anti-strip and different surface and tooth intensity and the core intensity of core metallurgical performance.Advantageously or in other words, different incompatibility manufacturing process, casting, the forging of steel or the forging of powdered-metal, can obtain different performance requirements for identical parts.
Referring to Fig. 1, in order to meet some performance requirements in these performance requirements, gear 10, by powdered-metal 14 is forged to form, then carries out case-carbonizing to this gear and approaches constant active surface carburizing depth 16 to realize.The broken section of Fig. 1 there is shown the constant active surface carburizing depth 16 for each gear teeth 12.The parameter being controlled in order to realize the constant carburizing of approaching of complete closely knit parts is conventionally known, and these parameters are particular stiffness, the case-carbonizing degree of depth and carbon gradient.Yet, approach the constant case-carbonizing degree of depth and might not in the product after forging, realize wanted machinery or machined character.Advantageously, in final products, realize the balance of the better control of these performance requirements, not affected by manufacturing process, thereby save time, processing or cost.
A kind of manufacturing process performance requirement, that be commonly referred to as " sintering carburizing " that is used for improving powder metal component is disclosed in name and is called in the United States Patent (USP) 3,992,763 of " Method of Making Powdered Metal Parts ".This technique has been pointed out, in sintering or afterwards and before forging, carries out carburizing, to improve the case-carbonizing degree of depth at the critical wall place of final forging product, thereby without the subsequent heat treatment technique that is used for realizing case-carbonizing hardness.Name is called the United States Patent (USP) 4 of " Method of Making a Through-Hardened Scale-Free ForgedPowdered Metal Article Without Heat Treatment After Forging ", 002,471 have disclosed a kind of mode of manufacturing the forging iron powder Base Metal article of high Rc hardness, and it is without carry out further machined, surface treatment or heat treatment after quenching.
Also have, name is called the United States Patent (USP) 4 of " Method of Making Selectively Carburized Forged PowderMetal Parts ", 165,243 have disclosed a kind of technique that needs additional step, comprise: before sintering, to parts, add mask, and remove this mask after carburizing and before forging, thereby on parts, obtain the surface of selected carburizing.
Yet, following technique is not pointed out or implied to above-mentioned patent: before forging, can remove carburized surface to realize specific material requirements in final forging product, improved dimensional accuracy, performance characteristic are provided simultaneously or on parts, manufacture with improvement carburized surface and non-carburized surface.And above-mentioned patent is not pointed out or implies by removing technique to provide tactic and uncomplicated control.
Therefore, need a kind of before forging the manufacturing process of the carburized surface of removing component, in final forged part, leaving selected carburized surface and non-carburized surface thus.And, need a kind of technique, this technique forge and quench before the carburizing part of removing component strategically, in the non-carburizing part of parts, can carry out operating after improved forging thus, thereby can in the useful forged carburized part of holding member, realize the tighter character such as tolerance, improved keyway grade or improved shear strength.Also need a kind of parts with improved dimensional accuracy or performance characteristic.
Summary of the invention
According to above-mentioned needs, a kind of gear and manufacture method are provided, for removed a part of carburized surface before forging, thereby leave selected carburized surface, there is improved performance characteristic, and selected non-carburized surface for improvement of forging after character to improve tolerance and grade.
Specifically, provide a kind of for obtaining the method for non-carburized powder metal part selectively.The method comprises consolidation, sintering, removal, forging and cooling.Metal dust is carried out to consolidation to form prefabricated blank, this prefabricated blank has at least one first surface part and at least one second surface part, in first surface part, forged part need to have case-carbonizing hardness depth, and in second surface part, need to before forging, remove carburizing part.Then prefabricated blank is carried out to sintering and carburizing.After carburizing, remove at least one second surface part of prefabricated blank, forge subsequently with cooling.Forged part has at least one second surface that has improved shear strength character and at least one has the first surface of case hardness character.
A kind of parts of being made by method of the present invention are also provided.These parts comprise non-carburizing part, in non-carburizing part, can realize and forge rear operation with less processing cost or time, and the while is because non-carburized material part provides improved tolerance or size Control compared with soft matter.These parts also comprise carburizing part, carburizing partly has the beneficial property such as improved wearability, bearing capacity, impact resistance or bending fatigue strength, and these beneficial properties forge manufacturing process by the processing sintering carburizing that approaches clean shape and finally obtain.
Accompanying drawing explanation
In order more completely to understand the present invention, now with reference to being shown specifically in the accompanying drawings and at each inventive aspect described below.
Fig. 1 shows the partial sectional view of case-carbonizing gear.
Fig. 2 shows according to an embodiment of the invention, uses partial sectional view favourable, that have the differential mechanism side gear of variable surface carburizing depth profile.
Fig. 3 shows the microstructure of the active surface carburizing depth below of the gear shown in Fig. 2.
Fig. 4 shows the microstructure in the active surface carburizing depth of the gear shown in Fig. 2.
The stereogram of the prefabricated blank after product of the present invention after Fig. 5 shows and to forge representational, sintering required, aspect of the present invention.
The partial sectional view of the representative prefabricated blank that Fig. 6 A shows Fig. 5 after carburizing.
Fig. 6 B shows the partial sectional view of the carburizing part of removing from the prefabricated blank of Fig. 6 A by the removal technique before forging.
The stereogram of the differential mechanism side gear that Fig. 7 shows according to an embodiment of the invention, made by the prefabricated blank of Fig. 6 B.
Fig. 8 shows according to an embodiment of the invention, be used for obtaining the schematic diagram of the technique of variable surface carburizing depth powder metal gear.
Fig. 9 shows according to schematic diagram of the present invention, process example that be used for obtaining forged carburized powder metal part.
The specific embodiment
In all figure, identical Reference numeral is used for indicating parts identical in each figure.Therefore, can be suitably simultaneously with reference to each figure.In some cases, for the sake of clarity, the same parts in different figure may have different Reference numerals.
Fig. 2 shows according to an embodiment of the invention, has the partial sectional view of the differential mechanism side gear 50 of variable surface carburizing depth profile 58.Fig. 7 shows according to the stereogram of differential mechanism side gear 50 of the present invention, that made by the prefabricated blank 184 of Fig. 6 B.Forward to acquisition selectively aspect the present invention of the powder metal component of non-carburizing before, first by discussing in one aspect of the invention, use gear 50 favourable, that there is variable surface carburizing depth profile 58.
Differential mechanism side gear 50 comprises a plurality of teeth 52 and is formed on the variable surface carburizing depth profile 58 in the carburizing part of gear 50.Each tooth in a plurality of teeth 52 has first surface 54 and tooth core or root 56.Differential mechanism side gear 50 has pivot center 60, and wherein, tooth 52 is along radially extending with the same general direction of rotary gear axis line, but tilts with respect to this pivot center.Differential mechanism side gear 50 also comprises and the axially aligned axial zone keyway of pivot center 60 inside 62.With keyway inside 62, be formed in the non-carburizing part of gear 50, this non-carburizing part can partly be come to obtain selectively by removed the carburizing of prefabricated blank before forging, just as discussed herein.
Variable surface carburizing depth profile 58 is formed in a plurality of teeth 52.Variable surface carburizing depth profile 58 advantageously provides a kind of gear, and this gear has good tooth wearability and in tooth root portion 56, has good impact resistance on first surface 54.Variable surface carburizing depth profile 58 refers to the active surface carburizing depth profile of realizing after forging by carried out carbon diffusion before forging gear.Here having discussed can be by the final variable surface carburizing depth profile 58 of realizing of Forging Technology.
Although described this technique for differential mechanism side gear 50, should be able to predict, variable surface carburizing depth profile 58 can be realized and unrestricted on other parts or gear, and these gears comprise bevel gear, differential gear or pinion.
Differential mechanism side gear 50 can be by low-alloy, closely knit, iron-based powder metal material forms entirely.Yet, should be able to predict, gear can be made by various dissimilar forging powdered-metal steel.
Forward Fig. 2 to, the first surface 54 of each tooth of differential mechanism side gear 50 comprises crest top land 64, pitch line face 66, root circle edged surface 68 and root diameter face or tooth root table top 70.Variable surface carburizing depth profile 58 is represented by following active surface carburizing depth substantially: crest top land 64 is 2.4mm; Pitch line face 66 is 1.9mm; Root circle edged surface 68 is 0.4mm; And tooth root table top 70 is 0.8mm.This is to be realized by carbon diffusion and follow-up forging for prefabricated blank.Although do not point out in this embodiment concrete quantity, but should be able to recognize, variable surface carburizing depth profile can have any non-constant active surface carburizing depth profile on specific areal cross-section, and the specific distribution type shown in being not limited to here.
Variable surface carburizing depth profile 58 also can recently be represented by the case-carbonizing degree of depth.By the case-carbonizing degree of depth to measuring, compare to provide active surface carburizing depth ratio, active surface carburizing depth ratio such as crest top land 64 with root circle edged surface 68, the active surface carburizing depth ratio of pitch line face 66 and root circle edged surface 68, or the active surface carburizing depth ratio of tooth root table top 70 and root circle edged surface 68.For example, crest top land 64 is 6: 1 with the variable surface carburizing depth ratio of root circle edged surface 68, pitch line face 66 is 19: 4 with the variable surface carburizing depth ratio of root circle edged surface 68, and tooth root table top 70 is 2: 1 with the variable surface carburizing depth ratio of root circle edged surface 68.Approach in the effective range of the constant case-carbonizing degree of depth 16 that the case-carbonizing depth ratio of 1: 1 is considered to be in the gear 10 shown in Fig. 1.
Advantageously, on whole variable surface carburizing depth profile 58, bosom and the case-carbonizing depth ratio between the most shallow place of active surface carburizing hardness can be 6: 1, realize thus the better engineering properties such as tooth wearability and impact resistance.
The tooth root 56 of gear 50 can comprise middle tooth portion 74, root 76 and core 78, and the hardness of middle tooth portion 74 is about 43HRC, and the hardness of root 76 is about 31HRC, and the hardness of core 78 is about 32HRC.Although these hardness numerical value only represent, have the gear that improves engineering properties, the core hardness ratio obtaining between middle tooth portion 74 and root or core 76,78 approaches 4: 3.Higher core hardness has good tooth impact resistance, is the gear of ductility than representative.The such gear of gear has the core hardness ratio that approaches 1: 1 as shown in Figure 1, so ductility is poor.
Fig. 3 shows the microstructure of the active surface carburizing depth below of gear shown in Fig. 2, and Fig. 4 shows the microstructure in the active surface carburizing depth of gear shown in Fig. 2.Depth boundary is that effective phosphorus content of material becomes and approaches constant and can effectively represent part by variable surface carburizing depth profile 58.
Forward the method for manufacturing with the powder metal gear of variable surface carburizing depth to, Fig. 8 shows a kind of technique.This technique starts from blend step 20, then carries out some possible steps: filling 22, consolidation 24, sintering 26, carburizing 28, preheating 30, variable forging 32 and cooling 34.After forging, operation 36 also can be used to further strengthen gear.For the sake of brevity, because some processing steps in these processing steps are well-known for the technical staff who forges powdered-metal field, so some aspects of technique of the present invention are below only discussed.In this, material selection, Temperature Treatment and consolidation pressure are only briefly discussed.
Blend step 20 approaches uniform mixture and is ready to various metal dusts by material being mixed into realize, and comprises any required adhesive or lubricant, thereby is ready to be filled into consolidation model in filling step 22 process.Consolidation step 24 comprises metal dust consolidation become to prefabricated blank, and this prefabricated blank has and spreads all over the uniformly initial phosphorus content of approaching of its.By binding agent or the lubricant that metal dust is also necessary with graphitic composition, mix to form prefabricated blank, can realize this initial phosphorus content.This prefabricated blank comprises at least one cross section, and wherein, as discussed herein, final forged part obtains variable surface carburizing depth profile.
Sintering step 26 and carburization step 28 can complete simultaneously, or carburization step can carry out completing after sintering to prefabricated blank.Sintering prefabricated blank can combine metal dust.To the carburizing of prefabricated blank, substantially can increase initial phosphorus content, thereby develop the carbon gradient from prefabricated blank surface to core.By controlled carbon atmosphere being provided and prefabricated blank being remained in this controlled atmosphere and continues a predetermined amount of time, just can form carbon gradient.Must in prefabricated blank, obtain the case-carbonizing degree of depth of substantial constant, thereby improve the metal critical flow in forging process, to realize the variable surface carburizing depth of being wanted in the parts after forging.Certainly, concentration gradient, part geometry and car-burization condition have determined the uniformity of carburization process.The ideal zone of the necessary case-carbonizing degree of depth critical metal flow in prefabricated blank geometry, forging process in prefabricated blank decides.In order to realize the variable surface carburizing depth profile in the said gear 50 being recorded by proposed ratio, to prefabricated blank, to carry out the case-carbonizing degree of depth of carburizing be tooth depth 1/4, but also can meet by making that prefabricated blank is carried out to 7/8 of 1/20 or tooth depth that the case-carbonizing degree of depth of carburizing is tooth depth.Should be able to predict, the too little case-carbonizing degree of depth in prefabricated blank can cause non-carburized zone.Can also predict, the too large case-carbonizing degree of depth in prefabricated blank can cause approaching constant case-carbonizing depth profile type.Fig. 6 A shows that the representative prefabricated blank 84 of Fig. 5 is after carburization process, the partial sectional view of carburizing prefabricated blank 85.Prefabricated blank 85 has the case-carbonizing degree of depth 86 that realize, substantial constant after prefabricated blank is carried out to sintering and carburizing.
Thereby variable forging step 32 is included in the prefabricated blank acquisition parts substantially closely knit, clean shape that forge carburizing under a forging temperature and a forging pressure.
Due to the symmetric property of forging mold and the symmetric property of carburizing prefabricated blank, for the variable surface carburizing depth profile of gear, cause each tooth to have and approach symmetrical profile.Yet should be able to recognize, also can use different carburizing schemes and forge step to obtain a plurality of variable surface carburizing depth profiles.
By adopting forging module to improve changeably the critical flow of carburized metal part, just can realize variable surface carburizing depth profile in Forging Technology process.In fact, by in the constant case-carbonizing depth-size strategy ground press-in die part of carburized powder metal prefabricated blank, wherein, in forging process, the some parts of prefabricated blank is stretched and attenuate, and the other parts of prefabricated blank are thickeied and deepened by the powdered-metal of carburizing.Again, before forging, the case-carbonizing degree of depth in carburized powder metal prefabricated blank is too shallow or too deeply can in final products, not produce variable case-carbonizing depth profile type.
Cooling step 34 allows forged part to obtain specific metallurgical performance, thereby causes gear to have wanted variable surface carburizing depth profile.Forged part can be undertaken cooling by oil quenching, shrend, air quenching or other method that is suitable for powdered-metal Forging Technology.
Comprise before cooling and make forged part stop the stop step of one period of time of staying, can be by making the temperature stabilization of component materials improve character.
Before forging, for prefabricated blank, be preheating to the institute that the available preheating step of a pre-forging temperature can improve in Forging Technology process and want metal flow.
After alternative forging, operate 36 and can comprise according to final specification requirement product is carried out to turning, scraping, surface grinding, quarter keyway and reaming, be ready to thus washing, packing or shipment.
Due to suitable selection and the combination to powdered-metal, consolidation mould, process time, processing temperature, tonnage, forging mold and cooling means, can obtain a kind of profile, that approach clean shape, complete closely knit product of variable surface carburizing depth that has, can make thus the machine operations (if some words) needing minimize, thereby be conducive to save cost and improve performance.
Forward the method for manufacture forged carburized powder metal part of the present invention to, Fig. 9 shows a kind of embodiment of technique.This technique starts from blend step 120, then carries out following steps; Filling 122, consolidation 124, sintering 126, carburizing 128, remove 130, forge 132 and again end at cooling 134.After forging, operation 136 also can be used to further strengthen gear.In technique shown in Fig. 8, with this method of Fig. 9 mutually compatible above-mentioned compatible processing step also can be used to further improve powder metal component.For the sake of brevity, because some processing steps in these processing steps are well-known for the technical staff who forges powdered-metal field, so only some aspects of technique of the present invention have below mainly been discussed.
For the technique of correct understanding Fig. 9, temporarily should note the prefabricated blank 184 of Fig. 6 B.Fig. 6 B shows the partial sectional view that carrys out the carburizing part 188 of removal from the prefabricated blank 85 of Fig. 6 A by the removal technique before forging.The partial sectional view of the representative prefabricated blank 84 that Fig. 6 A shows Fig. 5 after carburizing.Prefabricated blank 184 comprises at least one first surface 185, the case-carbonizing degree of depth 186, at least one second surface 187 and carburizing part 188.Select selectively the carburizing part 188 that will remove from prefabricated blank before forging.By removed selectively this carburizing part before forging, cause final parts to there is the good machined ability for secondary operation, for example, in relatively soft non-carburized material, obtain higher keyway grade or tighter reaming tolerance.From the final strategy obtaining sintering carburizing and Forging Technology process, in improved carburizing part, can further obtain additional benefit.
Get back to the technique of Fig. 9, the powder metal component of non-carburizing need to become metal dust consolidation the consolidation step of prefabricated blank selectively.
When prefabricated blank being carried out to sintering and carburizing simultaneously in order to obtain prefabricated blank 187, after step or first sintering, the step successively of carburizing can realize with above-mentioned sintering process and carburization process.
As well known in the art, for the typical sintering temperature of powder of stainless steel be approximately 2000 degrees Fahrenheits to 2100 degrees Fahrenheits, and the initial phosphorus content of prefabricated blank can be less than 0.22% by weight.By carburizing, at least the first phosphorus content in first surface can be 0.22% to 0.37% by weight.
On at least one second surface of prefabricated blank, remove the step of carburizing part implemented before forging.Remove at least one carburizing part and advantageously cause forged part at least one first surface, to there is carburizing part with its useful case-carbonizing hardness, provide simultaneously at least one wherein material not by the second surface of hardened case.Remove the carburizing part 188 that step allows strategically to remove the prefabricated blank of sintering second surface 187 before forging.Removing technique can complete with the known method such as punching press, machined or grinding.An advantage of removal carburizing part is: it has been avoided complicated and bother, be used for controlling adding mask and going mask operation of carbon distribution in sintering carburization process process.Being used for another advantage under soft state relatively, that remove carburizing part in sintering prefabricated blank is to extend life tools, obtain thus such as keyway grade, for the superior performance characteristic of article.And, conventionally carve keyway operation and be parts considered to be in after forging compared with completing under hard state, thereby can cause unnecessary tool wear and reduce keyway tolerance or performance.
Then complete and forge and cooling step, thereby the parts that obtain have shear strength character and have hardness properties at least one first surface at least one second surface.Forging and cooling step can complete by the known accepted method of technical staff of being familiar with powdered-metal forging field, are at the temperature of approximately 1600 degrees Fahrenheit to 1800 degrees Fahrenheits conventionally for powdered steel metal.Also wish to obtain a kind of complete closely knit parts substantially, by applying the forging pressure of common 50-70 Tons per Inch, can make these parts there is at least 99.6% of solid density.
If final parts are to forge to approach clean shape afterwards, should in consolidation step, by forming prefabricated blank suitable or oversized dimensions, consider the material of removing in removal step process.
Technique as given in Fig. 9 also can advantageously adopt the given variable forging step of the technique of Fig. 8.Specifically, can, after removing step, in the forging process of the carburizing part of at least one first surface of prefabricated blank, realize the variable surface carburizing depth profile in final parts.In this case, if parts are gears manufactured according to the present invention, these parts can have variable surface carburizing depth as shown in Figure 2, have simultaneously larger keyway grade and shear strength required compared with JUSTSOFT's internal diameter.
According to the made parts of the technique of the present invention of Fig. 9, can comprise any parts with required crust and pressure release surface.Specifically, the technique of the present invention of Fig. 9 is particularly advantageous in toothed gear.
Although proposed various processing steps, only want them to be limited in the scope or order as described in claims of the present invention.In addition, although contact some embodiment, invention has been described, will be understood that the present invention is not limited to these embodiment.Therefore, the present invention cover that all in the spirit and scope can be included in appended claims substitute, modification and equivalent structure.
Claims (16)
1. for obtaining a method for non-carburized powder metal part selectively, comprise following step successively:
Metal dust consolidation is become to prefabricated blank, described prefabricated blank has at least one first surface, described first surface defining surface carburizing depth hardness surface, and described prefabricated blank has at least one second surface, the carburizing part that described second surface restriction will be removed before forging;
Described prefabricated blank in turn or is side by side carried out to sintering and carburizing;
Remove the described carburizing part on described at least one second surface of described prefabricated blank;
Forge described prefabricated blank to obtain forged part; And
Cooling described forged part, thus described forged part has at least one second surface with character after improved forging and at least one has the first surface of case hardness character.
2. the method for claim 1, is characterized in that, described forged part quenches cooling by oil bath after forging and temperature stabilization.
3. the method for claim 1, is characterized in that, sintering temperature is in 2000 degrees Fahrenheit to 2100 degrees Fahrenheits.
4. the method for claim 1, is characterized in that, that described powdered-metal causes described prefabricated blank to have spreading all over is whole, uniformly initial phosphorus content substantially.
5. method as claimed in claim 4, it is characterized in that, comprise: by the controlled carbon atmosphere of sufficient endogas being provided and described prefabricated blank being remained on to a lasting predetermined amount of time in described controlled carbon atmosphere, so that described prefabricated blank is carried out to carburizing, the phosphorus content in described prefabricated blank is increased to substantially and be greater than described initial phosphorus content, the institute that described predetermined amount of time is enough to obtain at least one first surface of described forged part wants the case-carbonizing degree of depth.
6. method as claimed in claim 5, is characterized in that, the described initial phosphorus content of described prefabricated blank is less than 0.22% by weight, and is 0.22%-0.37% by weight with the final phosphorus content of described carburizing described at least one first surface partly.
7. the method for claim 1, is characterized in that, in 1600 degrees Fahrenheits, at the temperature of 1800 degrees Fahrenheits, is swaged to a density, and this density is solid density at least 99.6%, thereby obtains described forged part.
8. the method for claim 1, is characterized in that, the step of removing the described carburizing part on described at least one second surface of described prefabricated blank realizes by soft turning or reaming.
9. the method for claim 1, is characterized in that, makes the oversize material that will remove in removal process with compensation of described prefabricated blank, causes thus approaching after forging the parts of clean shape.
10. the method for claim 1, is characterized in that, final forged part is to approach clean shape.
11. the method for claim 1, is characterized in that, are also included in cooling cleaning afterwards.
12. the method for claim 1, is characterized in that, are also included in the cooling rigid turning of carrying out afterwards.
13. the method for claim 1, is characterized in that, described metal dust is low-alloy iron based metal powder.
14. the method for claim 1, it is characterized in that, forge described prefabricated blank so that described forged part has variable surface carburizing depth profile on described at least one first surface, described variable surface carburizing depth profile is by adopting forging mold group to realize to improve changeably the critical flow of described metallized carbon part when forging described forged part.
15. 1 kinds have the method for the gear of non-carburized powder metal part selectively for providing, comprise following step successively:
Metal dust consolidation is become to prefabricated blank, described prefabricated blank has at least one gear surface, described gear surface defining surface carburizing depth hardness surface, and described prefabricated blank has at least one keyway surface, the carburizing part that described keyway surface restriction will be removed before forging;
Described prefabricated blank in turn or is side by side carried out to sintering and carburizing;
Thereby described prefabricated blank is carried out to the lip-deep described carburizing part of described at least one keyway that described prefabricated blank is removed in turning or reaming;
Forge described prefabricated blank to obtain forged part; And
Cooling described forged part, wherein said forged part has at least one keyway surface with shear strength character and at least one has the gear surface of case hardness character.
16. methods as claimed in claim 15, is characterized in that, forge described prefabricated blank so that described forged part has variable surface carburizing depth profile on described at least one gear surface.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/US2007/076174 WO2009025660A1 (en) | 2007-08-17 | 2007-08-17 | Method for obtaining forged carburized powder metal part |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101827675A CN101827675A (en) | 2010-09-08 |
| CN101827675B true CN101827675B (en) | 2014-11-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200780101184.9A Active CN101827675B (en) | 2007-08-17 | 2007-08-17 | Method for obtaining forged carburized powder metal part |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP2010537048A (en) |
| CN (1) | CN101827675B (en) |
| DE (1) | DE112007003626T5 (en) |
| WO (1) | WO2009025660A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8517884B2 (en) * | 2006-03-24 | 2013-08-27 | Gkn Sinter Metals, Llc | Powder forged differential gear |
| AT509456B1 (en) * | 2010-08-31 | 2011-09-15 | Miba Sinter Austria Gmbh | SINTERED GEAR |
| DE102011075366A1 (en) * | 2011-05-05 | 2012-11-08 | Robert Bosch Gmbh | Method for producing hard metal workpiece, involves plastically deforming hard metal workpiece after sintering operation |
| CN109366107A (en) * | 2018-11-28 | 2019-02-22 | 合肥常青机械股份有限公司 | A kind of hollow and thin-walled part Forming Quality control method |
| US20220213584A1 (en) * | 2019-04-12 | 2022-07-07 | Gkn Sinter Metals, Llc | Variable Diffusion Carburizing Method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1170149B (en) * | 1959-02-11 | 1964-05-14 | Heinz Schmalz Dr Ing | Process for the powder-metallurgical production of roller bearing races from sintered steel |
| US3992763A (en) * | 1974-09-13 | 1976-11-23 | Federal-Mogul Corporation | Method of making powdered metal parts |
| US4165243A (en) * | 1978-05-31 | 1979-08-21 | Federal-Mogul Corporation | Method of making selectively carburized forged powder metal parts |
| GB2035197B (en) * | 1978-11-02 | 1982-09-15 | Toyo Boseki | Process for the prodoction of semipermeable hollow fibre membranes |
| WO2003095128A1 (en) * | 2002-05-08 | 2003-11-20 | Ass Ag | Crown gear |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4002471A (en) | 1973-09-24 | 1977-01-11 | Federal-Mogul Corporation | Method of making a through-hardened scale-free forged powdered metal article without heat treatment after forging |
| US4070920A (en) * | 1976-12-09 | 1978-01-31 | The Horsburgh And Scott Company | Composite gear having carburized teeth and method of making same |
| JPS6082656A (en) * | 1983-10-12 | 1985-05-10 | Toyota Motor Corp | Manufacture of vibration proof gear |
| JPH05295406A (en) * | 1992-04-20 | 1993-11-09 | Kawasaki Steel Corp | Production of ferrous sintered and cast material |
| US7641850B2 (en) * | 2003-03-18 | 2010-01-05 | The Penn State Research Foundation | Method and apparatus for strengthening of powder metal gears by ausforming |
-
2007
- 2007-08-17 CN CN200780101184.9A patent/CN101827675B/en active Active
- 2007-08-17 DE DE112007003626T patent/DE112007003626T5/en active Pending
- 2007-08-17 JP JP2010521825A patent/JP2010537048A/en active Pending
- 2007-08-17 WO PCT/US2007/076174 patent/WO2009025660A1/en active Application Filing
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1170149B (en) * | 1959-02-11 | 1964-05-14 | Heinz Schmalz Dr Ing | Process for the powder-metallurgical production of roller bearing races from sintered steel |
| US3992763A (en) * | 1974-09-13 | 1976-11-23 | Federal-Mogul Corporation | Method of making powdered metal parts |
| US4165243A (en) * | 1978-05-31 | 1979-08-21 | Federal-Mogul Corporation | Method of making selectively carburized forged powder metal parts |
| GB2035197B (en) * | 1978-11-02 | 1982-09-15 | Toyo Boseki | Process for the prodoction of semipermeable hollow fibre membranes |
| WO2003095128A1 (en) * | 2002-05-08 | 2003-11-20 | Ass Ag | Crown gear |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2009025660A1 (en) | 2009-02-26 |
| CN101827675A (en) | 2010-09-08 |
| JP2010537048A (en) | 2010-12-02 |
| DE112007003626T5 (en) | 2010-06-24 |
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