CN101797640A - Sinter-hardening powder and their sintered compacts - Google Patents
Sinter-hardening powder and their sintered compacts Download PDFInfo
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- CN101797640A CN101797640A CN200910143016A CN200910143016A CN101797640A CN 101797640 A CN101797640 A CN 101797640A CN 200910143016 A CN200910143016 A CN 200910143016A CN 200910143016 A CN200910143016 A CN 200910143016A CN 101797640 A CN101797640 A CN 101797640A
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Abstract
The invention relates to a sinter-hardening raw powder and a sintered compact thereof. The sinter-hardening raw powder can yield a press-and-sinter compact with high hardness. The raw powder for sintering includes Fe as its primary component and also includes 0.3-0.8 wt % C, 5.0-12.0 wt % Ni, 1.0-5.0 wt % Cr, and 0.1-2.0 wt % Mo, wherein the mean particle size of the raw powder for sintering is between 50 and 100 mum. The sintered-tempered compact has high hardness without performing the quenching process.
Description
Technical field
The present invention relates to a kind of sinter-hardening powder, particularly relate to a kind of sinter-hardened material powder and sintered body thereof that is used for producing at sintered part(s) the constituent of high rigidity by powder metallurgical technique.
Background technology
In order to obtain high rigidity, most of sintered part(s)s need heat treatment (for example quenching (quenching)) so that form martensite (martensite).Yet, carry out to quench simultaneously, may owing to when part from volumetric expansion or the thermal stress that owing to the quick cooling of Quenching Treatment cause of austenite (austenite) when being transformed into martensite take place for example to be out of shape, some problems such as size is inconsistent or break.In addition, part is carried out heat treatment and caused extra cost.Therefore, in compacting sintering technology, add iron powder to by high hardenability (hardenability) alloying element with carbon and for example molybdenum, nickel, manganese and chromium, form sinter-hardening powder, extrude green compact (green compact) again, and will sintered part(s) be cooled to finished product with cooldown rate fast behind the green sintering with the hardness that is higher than HRC30.The example of the alloy that produces by the method is from the Ancorsteel 737SH (Fe-0.42Mn-1.40Ni-1.25Mo-0.5C) of He Genasi (Hoeganaes) company and Ancorsteel 4300 (Fe-1Cr-1Ni-0.8Mo-0.6Si-0.1Mn-0.5C) powder and from the ATOMET 4701 (Fe-0.45Mn-0.90Ni-1.00Mo-0.45Cr-0.5C) of Quebac Metal Porder Co., Ltd. (Quebec Metal Powders limited).Yet required minimum cooldown rate is generally 30 ℃/minute, so that produce martensite.The 5th, 682, disclose the example of sinter-hardening powder in No. 588 United States Patent (USP)s, it relates to by the copper (Cu) of the nickel (Ni) of 1 to 3 percentage by weight, 1 to 2 percentage by weight and powdered graphite are added to and having by the nickel (Ni) of 3 to 5 percentage by weights, the molybdenum (Mo) of 0.4 to 0.7 percentage by weight and the mixture of powders that all the other pre-alloyed powders of forming for iron (Fe) produce.The powder of being advocated is suppressed, sintering between 1130-1230 ℃, and cool off to obtain sinter-hardened effect with 5-20 ℃/minute speed subsequently.This can improve technology by the minimum cooldown rate that reduces by 30 described in the technology as mentioned previously ℃/minute.Yet, the intensity of these sinter-hardening powders and other character, especially ductility and toughness, still unsatisfactory.
(the Metal Powder Industries Federation of MPIF, MPIF) the some material standards that are used for sinter-hardened alloy have also been stated, example is the FLNC-4408 (Ni of 1.0-3.0 percentage by weight, 0.65-0.95 the Mo of percentage by weight, 1.0-3.0 the Cu of percentage by weight, 0.05-0.3 the Mn of percentage by weight, 0.6-0.9 the C of percentage by weight, and remainder is Fe) and the FLC2-4808 (Ni of 1.2-1.6 percentage by weight, 1.1-1.4 the Mo of percentage by weight, 1.0-3.0 the Cu of percentage by weight, 0.3-0.5 the Mn of percentage by weight, 0.6-0.9 the C of percentage by weight, and remainder is Fe) the low-alloy steel powder.After sintering and tempering, sinter-hardened FLC2-4808 steel can reach 7.2g/cm
3The hardness of the hot strength of 1070MPa and HRC40 under the density, but ductility is less than 1.0%.Another standard of prealloy steel that can be sinter-hardened is FL-5305 (Fe-3Cr-0.5Mo-0.5C), and it can reach 7.3g/cm
3Density under the hot strength of 1100MPa and the hardness of HRC 33, but ductility is less than 1.0%.Although these alloys are sinter-hardened types, engineering properties is unsatisfactory, and required cooldown rate is still very fast, is at least 30 ℃/minute.Therefore, extra high cooldown rate system must be installed in sintering furnace.In addition, although this cooldown rate is slower than the quench rates of oil or water, these high cooldown rates still enough fast and cause for example distortion, size is inconsistent and problem such as quenching crackle.Therefore, still be starved of a kind of new sinter-hardened alloy, it can produce high rigidity, high strength and good ductility, and allows the use of low cooldown rate.
Exist some to have and similar compacting sintering of composition of the present invention and metal injection moulding alloy at present.There is not unsuitable ductility loss in order to obtain improved hot strength, Marshall people such as (Marshall) discloses a kind of metal powder mixture in No. 1009425 BP, can make the sintered steel object by it, its composition comprises Ni, the Mn of 0.1 to 2 percentage by weight, the Mo of 0.1-5 percentage by weight, the C of 0.1-1 percentage by weight of 1-4.9 percentage by weight, and remaining is that iron adds common impurity.It further discloses, and nearly the iron of 5 percentage by weights can be by one or more other element replacements, and described element can influence the hot strength and the ductility of sintered part(s) sharply.The kind of described element and the upper limit comprise the aluminium (Al) of 1 percentage by weight, 0.3 the boron of percentage by weight (B), the chromium of 5 percentage by weights (Cr), the copper of 5 percentage by weights (Cu), the magnesium of 1 percentage by weight (Mg), niobium of 4 percentage by weights (Nb) and/or tantalum (Ta), 0.3 the phosphorus of percentage by weight (P), the silicon of 1 percentage by weight (Si), the titanium of 2 percentage by weights (Ti), the tungsten of 4 percentage by weights (W), 0.3 the vanadium of percentage by weight (V), 0.6 the zirconium of percentage by weight (Zr), 0.6 the lead (Pb) of selenium of percentage by weight (Se) and 0.5 percentage by weight.In order to obtain the complete advantage of this composition, No. 1009425 BP also stated and should use mixed-powder to replace pre-alloyed powder because can obtain showing, better engineering properties.
The 7th, describe in 163, No. 569 United States Patent (USP)s with the present invention in another alloy like the powdery type that discloses, it proposes a kind of pre-alloyed powder that is used for sintering, owing to use pre-alloyed powder, its can produce have high density, accurate dimension and the even sintered body of character.Particle mean size is below 8 microns or 8 microns.Described powder can be directly with the material powder that acts on metal injection moulding technology.Also can pass through spray-drying (spray drying) with the flowing property of its granulating, and suppress, remove binding agent and sintering subsequently with the improvement attritive powder.Yet pre-alloyed powder has many shortcomings, and for example pre-alloyed powder uses when drawing method, and the hardening effect that alloying element produced can cause bad compressibility and to the heavy wear of mould.In addition, because each element in the pre-alloyed powder homogenizes, agglutinating property reduces, and sintered density is relatively poor.
Owing to use these shortcomings of pre-alloyed powder, it is to make with high compressibility powder that great majority need the compacting sintering part of high green density, the present invention adopts element powders or softer ferroalloy powder as basic powder, for example Fe, Fe-Mo, Fe-Cr or Fe-Cr-Mo powder, it contains few carbon and nickel, because its compressibility of the ferroalloy powder of carbon containing and nickel is poor, the content of general carbon and nickel is lower than 0.1 percent by weight.
The above-mentioned background technology emphasizes to manufacture that the powder metallurgy product with high rigidity needs the basic powder of careful selection, powder size, the type (that is, element powders or ferroalloy powder) of the powder used as alloy and the good design combination of high hardenability alloying element kind and addition etc.Even being familiar with the technology of powder metallurgical technique and the people of practice also is not easy design or selects this combination.This be why exist few its hardness of sinter-hardened alloy and intensity can with the present invention in the hardness that the obtains reason suitable with intensity.The character that obtains among the present invention Quenching Treatment behind the sintering.Only need be in tempering after the sintering.
Summary of the invention
In view of the aforementioned technical background, the objective of the invention is to, overcome the defective that existing sinter-hardening powder and sintered body thereof exist, and a kind of new sinter-hardened material powder and sintered body thereof be provided, technical problem to be solved is to need not to quench by the sintered body that described sinter-hardened raw material powder mixture can be after sintering obtains to have high rigidity immediately, only need tempering after the sintering, thus be suitable for practicality more.
The object of the invention to solve the technical problems realizes by the following technical solutions.For achieving the above object, comprise iron (Fe) as its main constituent and also comprise the carbon (C) of 0.3 to 0.8 percentage by weight, the nickel (Ni) of 5.0 to 12.0 percentage by weights, the chromium (Cr) of 1.0 to 5.0 percentage by weights, the molybdenum (Mo) and the common impurity of 0.1 to 2.0 percentage by weight according to sinter-hardened material powder of the present invention, the particle mean size of the wherein said material powder that is used for sintering is between 50 μ m and 100 μ m, and this sinter-hardened powder is to be basic powder with iron powder or the prealloy powder that contains low-carbon (LC), low nickel.
The present invention compared with prior art has tangible advantage and beneficial effect.By technique scheme, sinter-hardened material powder of the present invention and sintered body thereof have following advantage and beneficial effect at least: sinter-hardened material powder of the present invention is can be in sintering furnace sinter-hardened and need not to use quick cooling with normal stove cooldown rate, and the sintered body of acquisition is without any need for Quenching Treatment.Only need lonneal just can obtain optimum engineering properties.Because the elimination of for example crackle that takes place during quick cooling or quenching and the defective of distortion can also obtain higher production yield.
In sum, sinter-hardened material powder of the present invention can produce the compacting sintering base substrate with high rigidity.The described material powder that is used for sintering comprises Fe as its key component, and the C, the Ni of 5.0 to 12.0 percentage by weights, the Cr of 1.0 to 5.0 percentage by weights and the Mo of 0.1 to 2.0 percentage by weight that also comprise 0.3 to 0.8 percentage by weight, the particle mean size of the wherein said material powder that is used for sintering is between 50 μ m and 100 μ m.The base substrate of described sintering and tempering has high rigidity under the situation without any Quenching Treatment.
Above-mentioned explanation only is the general introduction of technical solution of the present invention, for can clearer understanding technological means of the present invention, and can be implemented according to the content of specification, and for above-mentioned and other purposes, feature and advantage of the present invention can be become apparent, below especially exemplified by preferred embodiment, and conjunction with figs., be described in detail as follows.
Description of drawings
Fig. 1 illustrates when Cr content increases, and by using metal injection moulding technology and use the hardness of the sintered body that fine carbonyl iron powder makes at first to increase, reaches maximum when about 0.7 percentage by weight, and the figure that reduces subsequently.
Fig. 2 illustrates when Cr content increases, and by using compacting sintering technology and use the hardness of the sintered body that the crude iron powder makes at first to increase, reaches maximum when about 3 percentage by weights, and the figure that reduces subsequently.
The specific embodiment
Reach technological means and the effect that predetermined goal of the invention is taked for further setting forth the present invention, below in conjunction with accompanying drawing and preferred embodiment, to sinter-hardened material powder and its specific embodiment of sintered body, structure, feature and the effect thereof that foundation the present invention proposes, describe in detail as after.
Relevant aforementioned and other technology contents, characteristics and effect of the present invention can be known to present in the detailed description of graphic preferred embodiment is consulted in following cooperation.By the explanation of the specific embodiment, when can being to reach technological means that predetermined purpose takes and effect to obtain one more deeply and concrete understanding to the present invention, yet appended graphic only provide with reference to the usefulness of explanation, be not to be used for the present invention is limited.
In order to make sinter-hardened base substrate economically, must have high indurative element with the amount and the ratio interpolation of optimum with high strength and high rigidity.Carbon, manganese, silicon, chromium, molybdenum and nickel are most popular elements in casting, the wrought alloy steel.Yet these elements are not to be suitable for sintered part(s) all, unless take some preventive measures.For instance, residual oxygen in chromium quite reactive and easy and the sintering atmosphere or steam reaction and formation chromium oxide.Manganese is even has more reactive element, and easy and sintering atmosphere are reacted and the formation manganese oxide.Therefore and manganese and chromium have very high steam pressure, and when sintering pressed compact in a vacuum, the manganese that keeps in the sintered part(s) and the amount of chromium can significantly reduce usually, unless argon gas is backfilling into certain level during sintering in a vacuum.
Silicon is another high response element, and during sintering comparable Cr and the easier formation oxide of Mn.Although there are these problems, these alloying elements still can provide good induration, and condition is to add these elements with the form of ferroalloy powder, to reduce its activity, and use the good sintering atmosphere (for example, having low dew point) of control, make to prevent that oxide from forming.One of method of using among the present invention is to use ferroalloy powder (for example Fe-Cr, Fe-Mn, Fe-Si) and derivative (for example, Fe-Cr-Mo and Fe-Cr-Mo-Mn) thereof.These ferroalloy powdeies can be used as basic powder or as the alloy powder that adds base iron powder, decide on its compressibility.These highly active Cr, Si and Mn element alloying in alloy powder and is used the pure element powder to compare its activity significantly to reduce.Therefore, these active elements can be in the normal sintering stove solid solution and can not form oxide in ferrous substrate, and provide required hardenability.In addition, sintering atmosphere should have high reducing power, for example has high hydrogen content and low water vapour content.When using vacuum drying oven, the necessary enough height of level of vacuum are in case the formation of oxidation thing.Simultaneously, should add the inert gas (for example argon gas) of some backfills, have the loss of the element (for example Cr and Mn) of high steam pressure with minimizing.
The sinter-hardening powder that discloses among the present invention comprises C, the Ni of 5.0-12.0 percentage by weight, the Cr of 1.0-5.0 percentage by weight, the Mo of 0.1-2.0 percentage by weight of 0.3-0.8 percentage by weight, and the particle mean size of material powder that wherein is used for sintering is between 50 μ m and 100 μ m.Described powder can further contain at least a element among the following P of following Si of 2 percentage by weights or 2 percentage by weights following Cu, 1 percentage by weight or 1 percentage by weight following Mn, 1 percentage by weight or 1 percentage by weight and 1 percentage by weight or 1 percentage by weight, and wherein nearly the iron content of 3 percentage by weights can be by the one or more replacements in these elements.Even the sinter-hardening powder that discloses among the present invention is through also hardening to blank sintering HRC30 or the hardness more than the HRC30 with the slow speed cooling that is lower than 30 ℃/min behind the sintering.
Ni can produce high hardenability and also can give element with high tenacity and percentage elongation to sintered body.And, comparing with other alloying element of great majority of for example Cu, Mo, Cr, Mn and Si, Ni is a very effective additive aspect the sintered density of improving the steel billet body and toughness.Therefore, it is favourable adding Ni in sinter-hardening powder.In the present invention, preferred Ni content is between 5 percentage by weights and 12.0 percentage by weights, because sinter-hardened characteristic is not obvious when Ni content is lower than 5 percentage by weights, or when Ni content is higher than 12 percentage by weights, because after sintering, will keep too much austenite, so sinter-hardened effect weakens.On the other hand, when Ni content during greater than 12 percentage by weights, the benefit of acquisition is limited, and the cost of sintered part(s) increases.Produce bad compressibility owing to contain the pre-alloyed powder of Ni, therefore preferably add most of Ni (if not all) to basic powder with element Ni form of powder.
The distribution of Ni in the sintered steel is because its slow diffusion rate in iron and inhomogeneous usually.Another reason is that carbon has fast diffusion rate in iron, but and therefore quick penetration enter the core of iron powder.When Ni when the iron powder core spreads because carbon has increased the chemical potential of Ni, just carbon can repel Ni.Therefore, in Fe matrix, be difficult to the Ni that homogenizes, and therefore, its sinter-hardened benefit reduces.So its intensity of zone and the hardness of the high ni content that forms are lower, and when becoming part and using in heavily stressed fragile down position.Yet the present invention finds that the repulsive interaction between Ni and the C alleviates when Cr exists, and the distribution of Ni becomes more evenly, and this has used X ray to draw and prove.Distribute and the elimination in the zone of soft high ni content the total hardness increase of sintered body by Ni uniformly.
The chromium content that uses among the present invention is between 1 percentage by weight and 5 percentage by weights.Cr is during less than 1 percentage by weight, and the hardenability effect is unimportant.When Cr content surpasses 5 percentage by weights, martensitic amount will reduce.Cr can be included in the basic powder, for example Fe-Cr pre-alloyed powder and derivative thereof (for example Fe-Cr-Mo powder).Cr also can the Fe-Cr powder and the form of derivative add base iron powder to.As mentioned above, this will reduce the active of Cr and guarantee that it does not form chromium oxide during sintering, therefore can keep to help Ni to be solidly soluted into validity in the ferrous substrate.Yet the amount of required Cr depends on the granularity and the employed Ni content of iron powder.
Table 1 and Fig. 1 show, by using fine carbonyl iron powder to add other element powder or alloy powder as basic powder and according to the composition of Fe-8Ni-0.8Mo-xCr-0.5C (x changes to 3 percentage by weights from 0), and use metal injection moulding technology, the hardness of the sample of sinter-hardened and tempering at first increases along with the increase of Cr, when about 0.7 percentage by weight, reach maximum, and increase along with the amount of Cr subsequently and reduce.The amount of Cr that this means 3 percentage by weights is too big for the homogenizing of Ni, because hardness is lower than HRC30.Yet when using the crude iron powder as basic powder, the difficulty that becomes homogenizes.Therefore, the homogenize amount of the required Cr of Ni increases.By using thick water-atomized iron powder end (particle mean size) and add other element powder or alloy powder, and use the effect of provable this meal of compacting sintering technology according to the composition of Fe-4Ni-0.5Mo-0.5C with 75 μ m.The hardness that table 1 and Fig. 2 show base substrate at first increases with the increase of work Cr, reaches maximum when the Cr of about 3 percentage by weights, and increases along with the amount of Cr subsequently and reduce.These examples show, for Ni homogenize and optimum Cr content that hardness is required increases and increases along with the granularity of iron powder.Reason is, under the situation of thicker base iron powder, and the good homogenieity that needs long time or higher temperature obtain these elements.Except the granularity effect, optimum Cr content further depends on the amount of Ni in the sintered body.These examples prove, are to obtain high rigidity, and the compositing range of required alloying element has only a narrow range, (in for example above-mentioned example at iron particle size of selecting among the present invention and Ni amount).
Table 1 displaying Fe granularity and Ni content are to the influence of the optimum Cr content of Fe-8Ni-0.8Mo-0.5C and Fe-4Ni-0.5Mo-0.5C.
Table 1
When design casting or wrought alloy bulk or pre-alloyed powder, the optimum content of alloying element will be than low in the mixed-powder, because realized homogenizing of various alloying elements between melting stage.Casting and another reason than low-alloy content of wrought alloy be, raw material must be enough soft so that can carry out plastic deformation (for example, extrude, forge) and other secondary operation (for example, machining) to satisfy the size standard of part.Obtain optimum engineering properties with quenching and temper more subsequently.By contrast, powder metallurgical technique is clean forming technology (net shaping).Therefore, the part after sintering has obtained that size should be arranged, this moment if only through sinter-hardened and further Quenching Treatment will be an individual advantage.This has eliminated the defective that forms usually during quenching.The elimination of quenching technical also makes sinter-hardened material more economical and more competitive.Therefore, the optimum that designs at the sinter-hardening powder that is used for the compacting sintering product among the present invention is formed and is careful design, and is different from AISI and MPIF standard alloy steel.The narrow compositing range that discloses among the present invention is producing new and is being effective aspect the result unexpectedly.
Molybdenum is another effective alloying element, and the amount of using among the present invention is between 0.1 percentage by weight and 2 percentage by weights.When Mo content surpasses 2 percentage by weights, because the martensitic quantity not sufficient that produces in the sintered part(s), hardness will reduce.And molybdenum also is expensive element.Under the situation of adding too much Mo, it is too high that the cost of sintered products will become, and therefore feasible comparing with those homologues of making by other manufacturing process do not have competitiveness.The interpolation of Mo can be added molybdenum with elements Mo powder, iron molybdenum powder or the form that contains the complicated iron molybdenum pre-alloyed powder of other alloying element.
Manganese has very high hardenability, and only needs a small amount of.The amount of the Mn that uses among the present invention is less than 1.0 percentage by weights.When the amount of Mn surpassed 1.0 percentage by weights, ferrous substrate was reinforced and compressibility significantly reduces.In order to reduce its activity and to prevent to form oxide during the sintering, the present invention adds manganese with the ferrimanganic form of powder, and described ferrimanganic powder can further contain other alloying element, and manganese also can the prealloy form be included in the basic powder.
Silicon also has high hardenability, and only needs on a small quantity, and the amount of using among the present invention is less than 1 percentage by weight.When Si content surpassed 1 percentage by weight, sintered body became crisp and was not suitable for constitutional detail.In order to reduce the active of Si and to prevent that oxide from forming, the interpolation of Si can be added silicon with the form of iron Si powder, and described iron Si powder can further contain other alloying element silicon and also can the prealloy form be included in the basic powder.
Most economical and effective hardening element is a carbon.For example in most of powdered metal parts, can supply carbon, also can supply carbon from carbon black powders from powdered graphite.
The interpolation of the above alloying element can the element powders form or is added with the alloy powder form.When adding with the alloy powder form, this alloy powder can contain two or more elements, and can iron be that prealloy (ferrous prealloyed) powder or foundry alloy (master alloy) form of powder are added base iron powder to.
In order to obtain high rigidity, the selection of basic powder is crucial.For instance, the Electralloy powder of elemental iron powder or tool high-compressibility (for example Fe-Mo, Fe-Cr or Fe-Cr-Mo powder) is preferred, and these powder can obtain high green density and therefore obtain high sintered density base substrate.By contrast, the pre-alloyed powder that contains carbon and/or nickel is difficult to be pressed into high density.Granularity also is crucial.Attritive powder can be provided for the high drive of sintering owing to big surface area.Yet flowing property is bad and apparent density is lower, easily cause compacting during mould fill uneven problem.By contrast, these problems are not obvious for corase meal.In addition, the compacting sintering part needs accurate dimensions usually after sintering.This means size change during sintering, should keep minimum and therefore attritive powder be not preferred.The granularity of the basic powder that uses among the present invention is between 50 μ m and 100 μ m.
The selected combination of the constituent by basic powder and alloying element the invention provides a kind of sinter-hardening powder, and its generation has the sinter-hardened base substrate of high rigidity and need not to quench.
Example 1
Follow the sample 1 listed in the table 2 and 2 composition, the iron powder that makes water fogging is mixed with fine element Ni, Mo, Cu and powdered graphite, 0.8% zinc stearate (as lubricant) and fine Fe-Cr or Fe-Si pre-alloyed powder.Mixture is suppressed, removed lubricant 15 minutes down at 550 ℃, and subsequently at 1200-1250 ℃ of following sintering.3,4 and No. 5 samples use Fe-3Cr-0.5Mo as basic powder, wherein are added with lubricant, element Ni, Cu powder, powdered graphite and fine Fe-Mn pre-alloyed powder.No. 6 samples are to prepare by hybrid lubricant, element Ni and powdered graphite and Fe-1.5Cr-0.2Mo pre-alloyed powder.For preparing sample 7,8 and No. 9, mix 50%Fe-3Cr-0.5Mo powder and 50%Fe-1.5Cr-0.2Mo powder, and subsequently as basic powder.Add the Ni and the powdered graphite of different amounts subsequently to basic powder.The particle mean size of basis powder is between 50 μ m and 100 μ m.All these samples in the table 2 are sintered to about 7.2g/cm
3Density.Use 6 ℃/minute and 30 ℃ of/minute two kinds of cooldown rates, its cooldown rate is to record between 600 ℃ and 300 ℃.After sintering, under 180 ℃ with sample tempering 2 hours.With 1 to No. 6 sample of 6 ℃/minute speed coolings and the whole hardness of cooling off with 30 ℃/minute speed that obtain greater than HRC30 of 7,8 and No. 9 samples.Another advantage with sinter-hardened base substrate of composition of the present invention is to obtain rational ductility.For instance, the percentage elongation of the sample in the table 2 is all greater than 1%.Contain No. 9 samples of 12% Ni even can produce about 3.0% percentage elongation.This ductility makes these sinter-hardened base substrates be suitable as constitutional detail.Relatively, most of current sinter-hardened samples only have the percentage elongation less than 1%.
Table 2 shows to have some sintering of the composition (percentage by weight) that discloses among the present invention and the hardness of tempering base substrate.
Table 2
| Catalogue number(Cat.No.) | ??C | ??Ni | ??Mo | ??Cr | Other | ??Fe | The basis powder | Hardness HRC |
| ??1* | ??0.50 | ??5.0 | ??0.5 | ??1.5 | ??0.5Cu | Remainder | ??Fe | ??31 |
| ??2* | ??0.50 | ??5.0 | ??0.5 | ??5.0 | ??0.5Si | Remainder | ??Fe | ??34 |
| ??3* | ??0.50 | ??5.0 | ??0.5 | ??3.0 | ??0.2Mn，0.5Cu | Remainder | ??Fe-3Cr-0.5Mo | ??39 |
| ??4* | ??0.38 | ??5.0 | ??0.5 | ??3.0 | ??0.2Mn | Remainder | ??Fe-3Cr-0.5Mo | ??37 |
| ??5* | ??0.59 | ??5.0 | ??0.5 | ??3.0 | ??- | Remainder | ??Fe-3Cr-0.5Mo | ??33 |
| ??6* | ??0.50 | ??5.0 | ??0.2 | ??1.5 | ??- | Remainder | ??Fe-1.5Cr-0.2Mo | ??31 |
| ??7** | ??0.40 | ??6.0 | ??0.3 | ??2.1 | ??- | Remainder | ??Fe-3Cr-0.5Mo+Fe-1.5Cr-0.2Mo | ??34 |
| ??8** | ??0.40 | ??8.0 | ??0.3 | ??2.1 | ??- | Remainder | ??Fe-3Cr-0.5Mo+Fe-1.5Cr-0.2Mo | ??39 |
| ??9** | ??0.30 | ??12.0 | ??0.3 | ??2.0 | ??- | Remainder | ??Fe-3Cr-0.5Mo+Fe-1.5Cr-0.2Mo | ??35 |
Note: * cools off under 6 ℃/minute
* cools off under 30 ℃/minute
Comparative Example
10, the Fe-3Cr-0.5Mo of 11 and No. 12 sample use mixing and Fe-1.5Cr-0.2Mo powder are as basic powder.Add the Ni and the powdered graphite of different amounts subsequently to basic powder.As shown in table 3, No. 10 samples only have 2% Ni and 0.26% C, compare No. 7 samples with No. 7 samples and have the similar composition of Cr and Mo but have 6% Ni and 0.4% C, so No. 10 samples have low frit hardness.The importance of Ni and C in the composition that this example indication discloses in the present invention.Though 11 and No. 12 samples show that also it contains many slightly Ni, owing to the low soft that causes of its carbon content.13 to No. 18 sample uses the Fe-Cr-Mo pre-alloyed powder as basic powder, and it mixes with powdered graphite.For 15 and No. 16 samples, add extra Ni.When being sintered to the density of 7.3g/cm3, the hardness of 13 to No. 16 samples is lower than HRC30 when cooling off with 6 ℃/minute slow speed.13 and No. 14 sample hardness is low to be because of not containing Ni, 15 and No. 16 sample hardness hang down be because of carbon content low.Do not contain Ni but No. 17 high sample Fe-1.5Cr-0.2Mo of carbon content, though cool off fast with 48 ℃ of/minute speed, still not sinter-hardened.Yet, do not contain Ni but also high No. 18 samples of carbon content because it contains the Cr and the Mo of higher amount, and just can obtain the hardness of HRC33 soon because of cooldown rate.As a comparison, though No. 9 samples in the table 2 its have C, Cr and the Mo of low amount, but because of containing 12%Ni, only need cool off the hardness that can obtain HRC35, the hardness height of No. 18 samples of this hardness ratio with slower 30 ℃/minute.Comprise the importance of Ni in these examples show sinter-hardening powders, as the example that contains in the table 2 of Ni of a large amount proves.Yet good sinter-hardened powder needs all alloying elements that good combination is arranged.For instance, 15 and No. 16 samples have high Ni content but have low C content.The hardness of these two samples still is lower than HRC30.The importance of the combination of this proof C and Ni.
Table 3 is showed the hardness of the Comparative Example of some sintering and tempering.
Table 3
| Catalogue number(Cat.No.) | ??C | ??Ni | ??Mo | ??Cr | The basis powder | Hardness, HRC |
| ??10** | ??0.26 | ??2.0 | ??0.3 | ??2.2 | ??Fe-3Cr-0.5Mo+Fe-1.5Cr-0.2Mo | ＜20(HRB87) |
| ??11** | ??0.13 | ??8.0 | ??0.3 | ??2.1 | ??Fe-3Cr-0.5Mo+Fe-1.5Cr-0.2Mo | 27 |
| ??12** | ??0.26 | ??4.0 | ??0.3 | ??2.2 | ??Fe-3Cr-0.5Mo+Fe-1.5Cr-0.2Mo | 27 |
| ??13*FL-5208 | ??0.7 | ??- | ??0.2 | ??1.5 | ??Fe-1.5Cr-0.2Mo | ＜20(HRB80) |
| ??14*FL-5305 | ??0.5 | ??- | ??0.5 | ??3.0 | ??Fe-3Cr-0.5Mo | ＜20(HRB89) |
| ??15* | ??0.28 | ??5.0 | ??0.5 | ??3.0 | ??Fe-3Cr-0.5Mo | HRC22 |
| ??16* | ??0.28 | ??8.0 | ??0.5 | ??3.0 | ??Fe-3Cr-0.5Mo | HRC24 |
| ??17**FL-5208 | ??0.7 | ??- | ??0.2 | ??1.5 | ??Fe-1.5Cr-0.2Mo | ＜20(HRB98) |
| ??18**FL-5305 | ??0.5 | ??- | ??0.5 | ??3.0 | ??Fe-3Cr-0.5Mo | 33 |
* cooling under 6 ℃/minute
* cools off under 48 ℃/minute
More than describe and reach a conclusion, sinter-hardened constituent of the present invention can obtain hardness greater than HRC30 easily for the sintered body that carries out the stove cooling with about 6-30 ℃/minute speed.When cooling off with very fast cooldown rate, hardness further increases.By contrast, current sinter-hardened alloy need use minimum 30 ℃/minute cooldown rate to realize HRC30 and the above hardness of HRC30.Because low cooldown rate is acceptable for constituent of the present invention, so sintered body has the advantage of size Control preferably, less defects and lower cost aspect.
Because the combination of the careful selection of the alloying element of basic powder and optimal amount and type the invention solves problem mentioned above.Described mixture of powders uses elemental iron powder (for example atomizing or reduced iron powder) or ferroalloy powder (having high compressibility) as basic powder.Particle mean size is between 50 μ m and 100 μ m.Alloying element is made up of C, the Ni of 5.0-12.0 percentage by weight, the Cr of 1.0-5.0 percentage by weight, the Mo of 0.1-2.0 percentage by weight of 0.3-0.8 percentage by weight.More than form at least a other less important intensified element that can further contain the amount below 5.0 percentage by weights or 5.0 percentage by weights.The group that the optional free Cu of intensified element, Mn, Si and P form.In addition, the invention provides and can need not to use quick cooling with the sinter-hardened sintered body of normal stove cooldown rate below 30 ℃/minute in sintering furnace, other sinter-hardening powder needs described quick cooling.Sintered body provided by the invention is without any need for Quenching Treatment.Only need lonneal to obtain optimum engineering properties.Because the elimination of for example crackle that takes place during quick cooling or quenching and the defective of distortion also can obtain higher production yield.
The above, it only is preferred embodiment of the present invention, be not that the present invention is done any pro forma restriction, though the present invention discloses as above with preferred embodiment, yet be not in order to limit the present invention, any those skilled in the art, in not breaking away from the technical solution of the present invention scope, when the technology contents that can utilize above-mentioned announcement is made a little change or is modified to the equivalent embodiment of equivalent variations, in every case be not break away from the technical solution of the present invention content, according to technical spirit of the present invention to any simple modification that above embodiment did, equivalent variations and modification all still belong in the scope of technical solution of the present invention.
Claims (7)
1. sinter-hardened material powder, it is characterized in that it comprises the main constituent of iron conduct and further comprises the carbon of 0.3 to 0.8 percentage by weight, the nickel of 5.0 to 12.0 percentage by weights, the chromium of 1.0 to 5.0 percentage by weights and the molybdenum of 0.1 to 2.0 percentage by weight, the particle mean size of described material powder that wherein is used for sintering is between 50 μ m and 100 μ m, and this sinter-hardened powder is to be basic powder with iron powder or the prealloy powder that contains low-carbon (LC), low nickel.
2. sinter-hardened material powder according to claim 1 is characterized in that it further contains at least a element in the following phosphorus of following silicon of 2 percentage by weights or 2 percentage by weights following copper, 1 percentage by weight or 1 percentage by weight following manganese, 1 percentage by weight or 1 percentage by weight and 1 percentage by weight or 1 percentage by weight.
3. sinter-hardened material powder according to claim 2 is characterized in that it contains the manganese of the copper of 0.5 to 1.5 percentage by weight, 0.1 to 0.8 percentage by weight and the silicon of 0.1 to 0.8 percentage by weight.
4. sinter-hardened material powder according to claim 1 is characterized in that it contains the chromium of the nickel of the carbon of 0.4 to 0.7 percentage by weight, 6.0 to 10.0 percentage by weights, 1.5 to 4 percentage by weights, the molybdenum of 0.2 to 1.5 percentage by weight.
5. sinter-hardened material powder according to claim 1 is characterized in that wherein said low-carbon (LC), its carbon of prealloy powder of low nickel and the content of nickel of containing is lower than 0.1 percent by weight.
6. sinter-hardened material powder according to claim 1 is characterized in that wherein said nickel, chromium, molybdenum powder are element powders or ferroalloy powder or described both mixture.
7. a sintered body is characterized in that the composition that it comprises sinter-hardened material powder according to claim 1.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US12/366,627 US20090142220A1 (en) | 2004-06-10 | 2009-02-05 | Sinter-hardening powder and their sintered compacts |
| US12/366,627 | 2009-02-05 |
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| CN101797640A true CN101797640A (en) | 2010-08-11 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103567447A (en) * | 2012-07-31 | 2014-02-12 | 台耀科技股份有限公司 | Method for preparing powder metallurgy workpiece and workpiece thereof |
| CN105834413A (en) * | 2015-01-29 | 2016-08-10 | 精工爱普生株式会社 | Metal powder for powder metallurgy, compound, granulated powder, and sintered body |
| CN109202067A (en) * | 2017-11-10 | 2019-01-15 | 宁波市鄞州业鑫汽车零部件有限公司 | It is a kind of that the sinter-hardened process of powder metallurgy product is realized using normal sintering furnace |
| CN111902556A (en) * | 2018-03-26 | 2020-11-06 | 杰富意钢铁株式会社 | Alloy steel powder for powder metallurgy and iron-based mixed powder for powder metallurgy |
| CN114286872A (en) * | 2019-10-03 | 2022-04-05 | 住友电工烧结合金株式会社 | Sintered component and method for producing sintered component |
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2009
- 2009-05-22 CN CN200910143016A patent/CN101797640A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103567447A (en) * | 2012-07-31 | 2014-02-12 | 台耀科技股份有限公司 | Method for preparing powder metallurgy workpiece and workpiece thereof |
| CN105834413A (en) * | 2015-01-29 | 2016-08-10 | 精工爱普生株式会社 | Metal powder for powder metallurgy, compound, granulated powder, and sintered body |
| CN109202067A (en) * | 2017-11-10 | 2019-01-15 | 宁波市鄞州业鑫汽车零部件有限公司 | It is a kind of that the sinter-hardened process of powder metallurgy product is realized using normal sintering furnace |
| CN111902556A (en) * | 2018-03-26 | 2020-11-06 | 杰富意钢铁株式会社 | Alloy steel powder for powder metallurgy and iron-based mixed powder for powder metallurgy |
| CN111902556B (en) * | 2018-03-26 | 2021-11-19 | 杰富意钢铁株式会社 | Alloy steel powder for powder metallurgy and iron-based mixed powder for powder metallurgy |
| US11236411B2 (en) | 2018-03-26 | 2022-02-01 | Jfe Steel Corporation | Alloyed steel powder for powder metallurgy and iron-based mixed powder for powder metallurgy |
| CN114286872A (en) * | 2019-10-03 | 2022-04-05 | 住友电工烧结合金株式会社 | Sintered component and method for producing sintered component |
| CN114286872B (en) * | 2019-10-03 | 2022-07-08 | 住友电工烧结合金株式会社 | Sintered component and method for producing sintered component |
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