CN1029512C - Powder mixture for powder metallurgy and binder therefor - Google Patents
Powder mixture for powder metallurgy and binder therefor Download PDFInfo
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- CN1029512C CN1029512C CN 92113441 CN92113441A CN1029512C CN 1029512 C CN1029512 C CN 1029512C CN 92113441 CN92113441 CN 92113441 CN 92113441 A CN92113441 A CN 92113441A CN 1029512 C CN1029512 C CN 1029512C
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Abstract
A powder mixture for powder metallurgy comprising a starting powder for powder metallurgy containing a metal powder, a powder of physical property improving ingredients and a lubricant and, blended therewith as a binder, a synthetic styrenic rubber copolymer comprising: 5 to 75 parts by weight of styrene and 95 to 25 parts by weight of butadiene and/or isoprene, as the monomer ingredient or a hydrogenation product thereof. The binder can suppress the segregation of the physical property improver and the lubricant, as well as dusting upon handling the powder.
Description
The present invention relates to a kind of powder mixture that is used for powder metallurgy.Particularly, described powder mixture comprises the material powder and the adhesive of powder used in metallurgy.Material powder is a matrix component with metal dust (as iron powder or comminuted steel shot), and is mixed with powder (as alloying element, graphite etc.) and the lubricant powder that improves the physical property component; Adhesive is then for having the copolymer of specific components ratio.
In using metal dust such as iron powder or the powder metallurgy of comminuted steel shot as primary raw material, for the physical property (for example strength character or processing characteristics) of improving sintered article, often and alloy element such as copper, nickel, chromium and molybdenum, improve the powder of component of physical property such as graphite, p and s, and lubricant powder such as zinc stearate mix mutually.
Also disclose a kind of alloy steel powder for powder metallurgy among the Japanese kokai publication sho 61-253301, its composition is mainly iron, contains C, Mn and O in addition, and at least a in the element such as Cr, Ni, Si, Cu, Mo, also can contain S when needing.But it is low that it mainly provides oxygen content, the powder used in metallurgy powdered steel and the method for making thereof that have excellent moldability.
In general, the component and the lubricant powder of physical properties such as improvement powder size, proportion are changed significantly.For example, at the parent metal powder is that a kind of iron powder or comminuted steel shot (a kind of iron-comminuted steel shot of general name hereinafter) and the component of improving the powder physical property are under the situation of graphite, phosphorus etc., because each proportion difference, the difference of proportion often cause worsening forming segregation after the mixing in the process of compacting the performance and the uniformity of sintered article.In addition, if the lubricant powder that is used to prolong die life produces segregation, often cause when from mould, taking out goods that then discharging pressure increases, and cause the powder property fluctuation.
As the method that prevents above-mentioned segregation, proposed as open clear 56-136901 and the described deposition process of the clear 63-103001 of Te Kai Japanese Patent Application Publication specification spy, for example by using a kind of organic binder bond to make graphite powder to iron/comminuted steel shot or suchlike powder deposition method.
But because the organic binder bond described in above-mentioned document is hydrophilic, they reduce flowability or cause that powder gets rusty with regard to the problem that absorbs moisture is unavoidably arranged when storing, and this will reduce the quality of sintered metal product.In addition, the effect of iron powder/comminuted steel shot ripple bonding strength between this because the organic binder bond tool improves a lot, and do not improve iron powder/comminuted steel shot and improve powder physical property component powders and lubricant powder between bonding strength, therefore the segregation effect that prevents for class powder such as graphite is not enough, and must a large amount of binding agent of fusion in order to reach better effect.Therefore, because bonding (reunion) between each iron powder/comminuted steel shot is significant, after mixing and drying, pulverising step is absolutely necessary again.
In view of the foregoing finished the present invention, an object of the present invention is to provide a kind of powder mixture that is used for powder metallurgy, it does not have the problem reuniting of parent metal powder such as between sex change and mobile reduction or each parent metal powder.Can prevent not satisfied dispersion, can prevent to improve the component powders of physical property or the segregation of lubricant powder, and can suppress the dirt powder man-hour adding.
Above-mentioned purpose of the present invention can be reached by a kind of powder mixture that is used for powder metallurgy, this powder mixture comprises the material powder that is used for powder metallurgy, described material powder contains metal dust, improves the powder and the lubricant powder of the component of physical property, the powder of described improvement physical property component is selected from one or more inorganic powders in copper, nickel, chromium, molybdenum, graphite, manganese sulfide, the p and s
It is characterized in that the powder mixture of described powder used in metallurgy also comprises adhesive,
Described adhesive is with the butadiene of the styrene of 5-75 weight portion and 95-25 weight portion and/or isoprene synthesizing styrene rubbery copolymer or its hydrogenated products as monomer component,
Described adhesive is with the solid constituent timing, and it is 0.1-0.3 weight % with respect to the use level of the described material powder of 100 weight portions, and the weight average molecular weight of described binding agent is 10,000-1000,000.
Above-mentioned copolymer or its hydrogenated products itself have industrial value as a kind of binding agent that is used for metallurgical powder stock.
In order to overcome the above-mentioned problems in the prior art, the present invention has carried out various researchs, and the result confirms, can address the above problem fully by using aforesaid special copolymer.In other words, can prevent to improve the segregation of the component of powder physical property and lubricant powder effectively and do not cause and for example sex change, reunion or the mobile problem that reduces of parent metal powder also can suppress the dirt powder that powder mixture adds man-hour.
By reading the description about the preferred specific embodiments of the present invention of accompanying drawing, these and other purposes of the present invention and superior feature are conspicuous, wherein
Fig. 1 is the flow chart of explanation test method; And
Fig. 2 is the cross-sectional view that is used to measure graphite dispersion rate device.
Now with the definite reason of process of the test explanation as monomer component in the copolymer of binding agent, in the test shown in Fig. 1 (flow chart), prepare a kind of net powder (" ATOMEL 300M " as the parent metal powder, product trade name by the manufacturing of Kobe system steel company, granularity: less than 180 μ m) and graphite powder (" 1651J ", product trade name by the preparation of South Westen company, particle mean size: 2 microns), use the compound of back a kind of powder of the preceding a kind of powder contain 99 parts by weight and 1 parts by weight.
With vaned batch mixer with the high-speed stirred powder stock in, splash into or spray into a kind of organic binder bond that will describe from below, and about 5 minutes of strong agitation, change into to relax and stir, be dried a predetermined period of time then, to remove solvent.Extract the dry powder of crossing of part then as the sample of measuring the graphite dispersion rate.With 0.75%(weight) the zinc stearate powder be added in the powder that keeps dry as lubricant, and stir them and be used to measure mobile sample with preparation.Under situation about making with lubricator, also can graphite powder and lubricant be attached on the parent metal powder simultaneously by means of a kind of binding agent.
In order to measure the graphite dispersion rate, use funnel type glass tube 2(internal diameter a: 16mm, high: 106mm) with a micropore (nuclipore) filter (12 μ m order), this glass tube 2 is connected with millipore filter as shown in Figure 2, with the sample powder P(25g that obtains as mentioned above) put into wherein, and make nitrogen flow through 20 minutes from the below with 0.8 liter/minute flow, so that measure the graphite dispersion rate according to following formula.
Graphite dispersion rate (%)=(1-nitrogen passes through carbon amount before by carbon amount/nitrogen afterwards) * 100
In addition, measure flowability according to JIS-Z-2502.
As an embodiment, using styrene and butadiene to constitute as monomer component under the situation of binding agent, the graphite dispersion rate and the mobile influence of check combined polymerization comparison powder mixture the results are shown in table 1.
Table 1
Bonding graphite flowability in the adhesive powder raw material
Copolymer is formed the mixed volume dispersion rate (S/50g) in (weight) weight average molecular weight toluene solution
Styrene butadiene agglomerant concentration (%) solids content (%) (%) (adds Z
n-S
t)
100-Yue 100,000 5 0.2 5.4 26.8
80 20 ″ 5 0.2 3.8 26.9
70 30 ″ 5 0.2 2.7 27.0
60 40 ″ 5 0.2 1.2 27.2
40 60 ″ 5 0.2 0 28.5
30 70 ″ 5 0.2 0 29.0
20 80 ″ 5 0.2 0 31.4
10 90 ″ 5 0.2 0 34.2
5 95 " 5 0.2 0 is poor
-100 " 5 0.2 0 is poor
Zn-St: zinc stearate (lubricant)
As seeing,,, reduce the flowability of powder mixture and cause the problem of press-powder mouldability though can suppress the graphite dispersion rate if cinnamic combined polymerization is than less than 5 parts (being benchmark with weight here and hereinafter) by table 1.On the other hand, if cinnamic combined polymerization then can not fully reduce the graphite dispersion rate, and can not fully reach the effect of binding agent than surpassing 75 parts.Therefore, for satisfying graphite dispersion rate and flowability simultaneously, styrene must be defined within 5-75 part/95-25 part scope with the combined polymerization ratio of butadiene.For above-mentioned trend, using isoprene as the monomer component of planning with styrene copolymerisation, use butadiene and isoprene together or use under their situation of hydrogenated products, also can reach identical effect basically.
Table 2 illustrates a kind of characteristic of terpolymer, it is 57: 85 that this copolymer contains proportional: the butyl acrylate-methylmethacrylate 5(weight ratio)-acrylic acid, (comparative example: weight average molecular weight about 50000) and according to binding agent of the present invention (styrene of copolymer and the ratio of butadiene are 35: 65, weight average molecular weight: 100000) compare as general example to select other organic binder bonds.
As mentioned above, test method is identical.As by seeing in the table, binding agent of the present invention is compared with other organic binder bonds, and graphite dispersion rate and mobile both are good.
Table 2
Graphite dispersion rate flowability in the powder stock in the binding agent kind toluene solution
Agglomerant concentration binding agent combined amount (%) (S/50g)
(%) (solids content: %)
S-B
Copolymer 10 0.2 2.7 26.8
(embodiment)
A-MMA
Copolymer 10 0.2 20.4 27.8
(comparative example)
S-B copolymer=SB
A-MMA copolymer=acrylic acid-methylmethacrylate copolymer
It is as mentioned above that a kind of preferred copolymer of the binding agent that uses is in the present invention formed.When using this binding agent, binding agent must evenly flow through whole powder system in blend step, and when just in time covering the surface of parent metal powder equably, must be effectively and component and the lubricant of improving the powder physical property.For this purpose, should be taken into account that the concentration of binding agent and the amount that is added in the initial powder are important equally.In view of the foregoing, using the ratio of styrene and butadiene is 35: 65 copolymer (weight average molecular weight about 100,000), and carries out the test to the influence of graphite dispersion rate of agglomerant concentration in the toluene solution and addition.In this test, also study the influence comparing productivity ratio drying time and produce (agglomerant concentration in the toluene solution be 5% and powder stock in the binding agent combined amount be that 0.1%(is as solids content) situation under, time ratio is being drying time 1 be benchmark calculating).The results are shown in table 3.
Table 3
Binding agent addition (%) graphite dispersion rate dried powder raw material
Bonding in (%) time ratio in the powder stock in the toluene solution
The binding agent mixture solution of binding agent mix
Concentration (%) resultant (solid resultant (%)
：%）
2.5 0.03 8.5 0.4 1.2
0.05 7.1 1.0 2.0
0.10 3.2 2.1 4.0
5 0.05 6.5 0.4 1.0
0.10 1.0 1.0 2.0
0.15 0 1.8 3.0
0.20 1.1 2.4 4.0
10 0.10 2.9 0.5 1.0
0.15 0.7 0.8 1.5
0.20 0 1.1 2.0
0.25 0 1.4 2.5
15 0.15 1.7 0.5 1.0
0.30 0 1.1 2.0
As seeing, when adding binding agent (bipolymer), not only must consider the solution concentration and the addition in the powder stock (as solid) of binding agent, and must consider the binder solution addition in the powder stock by table 3.If the binder solution quantity not sufficient then can not evenly flow through whole iron powder surface, and cause insufficient bonding, this just is difficult to fully suppress segregation and graphite disperses.On the other hand, if addition is excessive, then segregation originally takes place and causes inhomogeneous mixing in binder solution in mixed system, and this just local hypodynamic part that bonds that forms makes it be difficult to achieve the goal.
Therefore, when adding binding agent, preferably be controlled at 1.0-3.0%(by initial powder in the addition of solution form) in the scope.If as the absolute magnitude deficiency of the binding agent of solid, then dry back cohesive force is not enough.On the other hand, if absolute magnitude is excessive, then powder mixture is partly reunited, and needs to pulverize again, therefore, wishes it is 0.1-0.3% as the addition of solid, and 0.1-0.2% preferably.
In addition, though generally can not stipulate preferred solution concentration, because it changes with the molecular weight (degree of polymerization) of terpolymer, and solution viscosity depends on the molecular weight of terpolymer, and normally used concentration is 5-15%, and 5-10% preferably.
According to the present invention, the preferred molecular weight of synthesizing styrene rubbery copolymer is 10,000-1000, and 000, preferably 30,000-500,000(is according to the even molecular weight meter of weight average).If molecular weight is too little, then often cause playing cmpletely effect as binding agent, and opposite, if molecular weight is excessive, then cause inhomogeneous mixing, and the effect that prevents segregation can not fully be provided.
In addition, table 4 illustrates and uses styrene-butadiene (35: 65) copolymer (weight average molecular weight: about 100000) make binding agent according to the method described above, when changing binder solution concentration and binding agent addition, measure the result of graphite dispersion rate and conglobation property (residual rates on 250 microns sieves), and when sneaking into 0.75% zinc stearate powder, measure mobile and constrictive result (sample size: diameter 11.3mm * high 10mm, forming pressure: 5t/cm).In this table, for the not example of adding additives is shown more simultaneously.
Table 4
Binding agent graphite agglomeration compressibility
The bond powders raw material dispersion rate (mesh of binding agent binding agent in powder stock
+ 250Mobile (5ton/cm
2)
Toluene solution agent combined amount (solid contain in bonding μ m) (5)
In concentration amounts: %) agent solution mixes (%)
(%) resultant (%)
5 0.10 2.0 3.2 0 28.9 6.92
6 0.12 2.0 1.5 0 28.5 6.92
6 0.24 4.0 0 0.02 26.4 6.89
Copolymer 8 0.12 1.5 2.1 0 28.2 6.92
8 0.16 2.0 0 0 27.6 6.91
8 0.20 2.5 0 0.01 27.1 6.90
10 0.15 1.5 0 0 27.9 6.91
10 0.20 2.0 0 0.01 27.5 6.90
Do not add---68 0 34.7 6.91
As being seen by table 4, when not adding binding agent, the graphite dispersion rate is very big, and can significantly suppress the graphite dispersion rate by adding an amount of binding agent of the present invention.In addition, described in iron powder mixing graphite powder and lubricant as the test specimen of an embodiment, but in order to improve, the present invention also can be used for adding the situation of other alloy elements, manganese sulfide, phosphorus, sulphur etc. in iron powder or comminuted steel shot.
In addition, table 5 illustrates the same procedure of using in a kind of powder mixture, the employing table 1 and measures graphite dispersion rate and mobile result, described powder mixture comprises comminuted steel shot (ATOME " 300M ", product trade name by the manufacturing of Koeb system steel company, granularity is less than 180 microns) the 0.8%(weight of mixing as the parent metal powder, therewith) graphite powder (native graphite, 3 microns of particle mean sizes), 2.0%(weight) copper powder (atomized copper powder: 30 microns of particle mean sizes) and 0.75%(weight) stearic acid zinc powder.In powder stock, add styrene-butadiene (with 35: 65 weight ratios) copolymer (weight average molecular weight: about 100 as binding agent, 000) and mix, the concentration of binding agent in toluene solution be 10% and by 0.2%(weight) add as solids content.
Table 5
Powder material compound: the 2%Cu-0.8%-0.75% zinc stearate-all the other: Fe
Adhesive powder raw material graphite flowability
Copolymer is formed the dispersion (S/50g) that mixes in the weight average toluene solution
Bonding binding agent rate in (weight %) molecular weight adds
Agent concentration (solids content (%) Zn-St
Styrene butadiene: %)
35 65 about 100,000 10 0.2 0 25.8
As seeing by the result, according to the present invention, can prevent very light in weight and the easily segregation of the component of the improvement powder physical property of segregation (graphite or similarly material) and lubricant powder or dispersion and do not reduce the flowability (formability) that is used for powder metallurgy effectively.
As according to described above the present invention, component by using synthesizing styrene rubbery copolymer as binding agent to prevent to improve the powder physical property and lubricant powder are at the parent metal powder, the for example segregation in iron/comminuted steel shot, or adding the dirt powder in man-hour, described copolymer is by the styrene of predetermined ratio and butadiene and/or isoprene copolymer closes or their hydrogenated products prepares.As the metal dust as matrix, that can mention also has for example the most general iron/comminuted steel shot, and metal dust, for example copper powder, bronze powder, titanium valve, aluminium powder, nickel powder and cobalt powder or their alloyed powder.
In addition, be mixed into component in the metal dust, the various physical properties that also are used to improve sintered metal product that can mention, for example various components of intensity, wearability and machinability as improving physical property.For example, can be used as the example of the inorganic powder that is used to improve iron/powdered steel metallurgical product physical property as the inorganic powder of copper, nickel, chromium, molybdenum, graphite, MnS, p and s and so on.Because the combined amount of inorganic powder changes with its kind, therefore, generally can not stipulate, but combined amount is pressed and the ratio of powder stock total amount 0.1-3%(weight normally).
For the component of improving the powder physical property, preferentially select for use particle mean size be generally less than 50 microns, preferably less than 30 microns fine powder so that powder can spread rapidly or can be in sintering process in parent metal the alloying by solid phase or liquid phase diffusion.Especially, using under the situation of graphite powder owing to use coarse granule often to cause in goods, forming pore, therefore require to use less than 10 microns, preferably less than 5 microns fine powder.
In addition, for when the powder core is suppressed by reduce between mould and the powder mixture or powder mixture in friction between each powder particle improve pressure density, and, sneak into lubricant powder in order to improve die life.For instance, use metallic soap such as zinc stearate, amide waxe such as ethylene bisamides or their combination product, and described addition by and the normally about 0.1-3%(weight of the ratio of powder stock total amount), be 0.3-1%(weight more generally).
For lubricant powder, the resistance that thick slightly granularity can reduce stampings when taking out from mould, but this can reduce as the compressibility of whole powder stock and even Combination.Therefore, preferentially use particle mean size less than about 50 microns, and preferably less than 30 microns powder.
So just constituted the present invention, and by using special copolymer as binding agent the uniformly dispersed and dirt mealiness of improving powder physical property component and lubricant powder to be improved, and do not produce the undesirable influence of parent metal powder, and can improve flowability and formability with mixture form, for powder metallurgy provides good powder mixture.
Claims (5)
1, a kind of powder mixture that is used for powder metallurgy, it comprises the material powder that is used for powder metallurgy, described material powder contains metal dust, improves the powder and the lubricant powder of the component of physical property, the powder of described improvement physical property component is selected from one or more inorganic powders in copper, nickel, chromium, molybdenum, graphite, manganese sulfide, the p and s
It is characterized in that the powder mixture of described powder used in metallurgy also comprises adhesive,
Described adhesive is with the butadiene of the styrene of 5-75 weight portion and 95-25 weight portion and/or isoprene synthesizing styrene rubbery copolymer or its hydrogenated products as monomer component,
Described adhesive is with the solid constituent timing, and it is 0.1-0.3 weight % with respect to the use level of the described material powder of 100 weight portions, and the weight average molecular weight of described binding agent is 10,000-1000,000.
2, the powder mixture that is used for powder metallurgy according to claim 1, the average grain diameter of wherein improving the physical property component powders is less than 50 microns.
3, the powder mixture that is used for powder metallurgy according to claim 1, the combined amount of wherein improving the physical property component powders accounts for 0.1-3 weight % in the material powder total amount.
4, the powder mixture that is used for powder metallurgy according to claim 1, wherein the particle mean size of lubricant is less than 50 microns.
5, according to claim 1 or the 4 described powder mixtures that are used for powder metallurgy, wherein the use level of the relative 100 weight portion material powders of lubricant is a 0.1-3%(weight).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP83400/92 | 1992-03-04 | ||
| JP4083400A JP2898461B2 (en) | 1991-04-22 | 1992-03-04 | Mixed powder and binder for powder metallurgy |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1075904A CN1075904A (en) | 1993-09-08 |
| CN1029512C true CN1029512C (en) | 1995-08-16 |
Family
ID=13801384
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 92113441 Expired - Lifetime CN1029512C (en) | 1992-03-04 | 1992-11-23 | Powder mixture for powder metallurgy and binder therefor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1029512C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE9401922D0 (en) * | 1994-06-02 | 1994-06-02 | Hoeganaes Ab | Lubricant for metal powder compositions, metal powder composition containing th lubricant, method for making sintered products using the lubricant, and the use of same |
| CN1108351C (en) * | 2000-08-24 | 2003-05-14 | 曹阳 | Forming agent for producing hard alloy |
| CN100369700C (en) * | 2005-12-22 | 2008-02-20 | 株洲钻石切削刀具股份有限公司 | Plasticizer for carbide alloy production |
| JP6655994B2 (en) * | 2016-01-13 | 2020-03-04 | 株式会社神戸製鋼所 | Mixed powder for powder metallurgy |
-
1992
- 1992-11-23 CN CN 92113441 patent/CN1029512C/en not_active Expired - Lifetime
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|---|---|
| CN1075904A (en) | 1993-09-08 |
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