CN1947896B - Method of manufacturing the anti-wear sintered member - Google Patents

Abstract

Making a wear resistant member by compacting a powder mixture containing a matrix forming powder and a hard phase forming powder, the matrix forming powder containing 90 mass % or more of particles having a maximum diameter of 46 microns, and the hard phase forming powder being 40 to 70 mass % with respect to the powder mixture.

Description

The manufacturing approach of wearability sintered component

Technical field

The present invention relates to be suitable for the manufacturing approach of the wearability sintered component of various sliding components, relate to the manufacturing approach that is used in the wearability sintered component of high surface pressure power lower slider especially.Under such situation, towards various uses proposed to have disperseed Co-Mo-Si-Cr be hard mutually or high-speed steel be the wearability sintered component (spy open flat 08-109450 communique, spy are opened flat 02-270943 communique, the spy opens flat 01-068447 communique) of hard phase.In addition, proposed various improvement dispersion the wearability sintered component of hard phase (spy open 2002-356704 communique, spy are opened the 2003-119542 communique, the spy opens the 2005-154798 communique).

The sintered component of powder metallurgic method, in alloy substrate, disperseing desirable hard is easy mutually, is applicable to the various sliding components of the internal combustion engine of automobile etc. with sliding component and bearing etc., be accompanied by the high performance of the machine that is assembled with sliding component in recent years, environment for use is harsh day by day, and is corresponding for it, requires sintered slide member that higher wearability is arranged.In addition, different according to suitable position, require to have at high temperature wearability, oxidative resistance or the like, along with its scope of application enlarges, hope to improve the wearability under various environment.

Under such situation, towards various uses proposed to have disperseed Co-Mo-Si-Cr be hard mutually or high-speed steel be the wearability sintered component (spy open flat 08-109450 communique, spy are opened flat 02-270943 communique, the spy opens flat 01-068447 communique) of hard phase.In addition, proposed various improvement dispersion the wearability sintered component of hard phase (spy open 2002-356704 communique, spy are opened the 2003-119542 communique, the spy opens the 2005-154798 communique).

Particularly automobile engine is because high performance makes condition of work become harsh more in recent years, and the valve seat that on engine, uses need tolerate than existing harsh environment for use condition.For example, in the LPG engine that is equipped on the taxi, the sliding contact surface of valve and valve seat uses under drying regime morely, therefore with petrolic valve seat ratio, quick abrasion.In addition, be attached with under the environment of greasy filth the high doped fuel engine resembling, the occasion high to the surface pressure of valve seat, perhaps resemble the Diesel engine for HTHP contract than occasion because greasy filth makes that wearing and tearing are promoted.The occasion of under such rigorous environment, using requires wearability good, also requires not take place the high strength of fatigued phenomenon simultaneously.

On the other hand, also can the automatic regulating valve position and the also positive practicability of valve system of the emergency adjustment device of valve driving timing even possess the prooving of valve seat., by not talkative being resolved of engine life problem that the prooving of valve seat causes, hope that the valve seat of exploitation excellent in abrasion resistance is used material.In addition; In recent years; Not only be that the exploitation that target is also paid attention to economy and cheap automobile also obtains paying attention to day by day with the high performance; Therefore use sintered alloy as valve seat from now on, requirement be do not need the additional mechanism providing additional operation of above-mentioned lash adjusting device and so on, have high temperature abrasion resistance, a high-intensity sintered alloy.

Valve seat as such is used sintered alloy, discloses that in the spot shape matrix of Fe-Co system and Fe-Cr system, to have disperseed Co-Mo-Si be the technology (the public clear 59-037343 communique of spy) of hard particles and is that to have disperseed Co-Mo-Si in the matrix be the technology (special fair 05-055593 communique) of hard particles at Fe-Co.In addition, disclose that to have disperseed Co-Mo-Si in the matrix that in Fe-Co system, has added Ni be the technology (special fair 07-098985 communique) of hard particles and to have disperseed Co-Mo-Si be the Fe base alloy (spy opens flat 02-163351 communique) of hard particles.

Summary of the invention

Opening flat 08-109450 communique, spy above-mentioned spy opens flat 02-270943 communique, spy and opens flat 01-068447 communique, spy and open 2002-356704 communique, spy and open 2003-119542 communique, spy to open the hard that proposes in the 2005-154798 communique be respectively the hard phase that demonstrates excellent characteristic mutually; But known clearly that instead wearability and intensity reduce when adding hard phase forming element in a large number in order further to improve wearability.Therefore, result from the reason that the wearability of a large amount of interpolations of hard phase forming element reduces, then make full use of hard effectively and can increase substantially wearability mutually if can eliminate.Therefore, the objective of the invention is to, provide and do not damage wearability and intensity etc., and in matrix, more volume disperse the manufacturing approach of hard phase.

In addition; It is that Mo amount in the hard particles is the alloys below the 40 quality % that special public clear 59-037343 communique, special fair 05-055593 communique, special fair 07-098985 communique, spy open alloy that flat 02-163351 communique put down in writing, but the sintered alloy that contains this hard particles has high high temperature abrasion resistance, high strength., in recent years, hope to obtain having further high temperature abrasion resistance, high-intensity sintered alloy.Particularly in recent years in the CNG engine of practicability, the engines such as heavy duty diesel engine that high-output power is used, be accompanied by Metal Contact, higher to the load of seat material, hope that therefore exploitation also brings into play the material of high wearability under the environment of that kind.

Therefore, the objective of the invention is to, provide particularly in high load engine environment such as CNG engine and heavy duty diesel engine, the sintering valve seat and the manufacturing approach thereof of the high temperature abrasion resistance that performance is excellent.

The manufacturing approach of wearability sintered component of the present invention; It is characterized in that; Be to carry out the press-powder moulding with the material powder that hard forms powder mutually, and carry out the manufacturing approach of the wearability sintered component of sintering, in this manufacturing approach containing matrix formation powder; 90 quality % of matrix formation powder are above to be the powder of maximum particle diameter 46 μ m, and the addition that hard forms powder mutually is 40-70 quality %.

Because it is hard that hard forms powder mutually, therefore in material powder, contain in a large number sometimes, the compressibility of infringement material powder, the density of press-powder body reduces.Even the low-density press-powder body that sintering is such, density can not improve yet, and can only obtain the result of low-density sintered body, and intensity and wearability reduce.In addition; Even the briquetting pressure when increasing the press-powder moulding, improve the density of press-powder body by the strong hand; Because it is high that hard hard forms the coefficient of elasticity of powder mutually, so when from mould, extracting after the moulding, be compressed and hard that strain forms also elastic recovery of powder mutually.Its result, the powder that when moulding, forms closed state each other is destroyed, even sintering does not carry out powder fusion (neck length one-tenth) each other yet, intensity and wearability reduce.

Know that on the other hand when using micropowder as material powder, the whole surface area of powder becomes big; Corresponding with it, powder contact area each other increases, and therefore carries out sintering and can realize densified; But know that also the use of micropowder can damage the fillibility and the compressibility of material powder.Therefore, as the method that improves the press-powder volume density, do not use the method for micropowder.

The inventor etc. are conceived to the compressibility difference but through sintering and densified micropowder has been expected it is formed the situation that powder is mixed together use mutually with hard.Its result finds, through adding the micropowder more than the ormal weight, forms powder mutually even add hard in a large number, and through densified, wearability and intensity also increase substantially.The present invention is based on such knowledge opinion and accomplishes; It is characterized in that; Carrying out the press-powder moulding to containing matrix formation powder with the material powder that hard forms powder mutually; And carry out in the manufacturing approach of wearability sintered component of sintering, it is the powder of maximum particle diameter 46 μ m that matrix forms 90 quality % of powder above, hard forms the ratio that powder accounts for mutually in material powder be 40-70 quality %.In the present invention; Because the matrix that uses a large amount of hard to form powder and micropowder mutually forms powder, so compressibility is poor, but passes through micropowder; The whole surface area of powder increases, and the constrictive reduction of densified effects compensate behind the sintering that brings thus is more than sufficient.Therefore, can access the sintered body of sufficient sintered density, therefore can give full play to the characteristic that hard forms powder mutually, improve wearability and intensity.

It is the powder of 46 μ m that material powder uses maximum particle diameter, and this can obtain through adopting 325 purpose sieve grate classifications.At this moment; The occasion of the powder that aspect ratio (major diameter/minor axis) is big; Minor axis is the powder below the 46 μ m even major diameter surpasses 46 μ m, and through the comb hole of this sieve grate, such powder that has passed through 325 purpose sieve grates is equivalent to " maximum particle diameter 46 μ m " of the present invention sometimes.In order to obtain above-mentioned effect of the present invention, particle diameter is that the powder below the 46 μ m must contain more than the 90 quality % in matrix formation powder.

Densified effect during sintering can fully realize through matrix being formed powder densification, therefore especially need hard form powder mutually and also uses micro mist, and hard can use the granularity all the time used to constitute mutually.But, can obtain densification further owing to form mutually when containing micropowder in the powder at hard morely, therefore preferred.

People know that when in powder metallurgic method, using micropowder, the flowability of material powder and fillibility reduce, and as its countermeasure, adopt the method that the micropowder granulation is become size to a certain degree, in the present invention, can be suitable for such comminution granulation.

Here; Hard forms powder mutually; Be not only above-mentioned spy and open flat 08-109450 communique, spy and open flat 02-270943 communique, spy and open flat 01-068447 communique, spy and open 2002-356704 communique, spy and open 2003-119542 communique, spy and open that disclosed hard forms powder mutually in the 2005-154798 communique etc., also preferably become the hard powder mutually of the tissue more than at least a kind that in alloy phase, is dispersed with in silicide, carbide, boride, nitride and the intermetallic compound through sintering.In addition, among these hard form powder mutually, especially preferably by quality ratio, has the powder of forming that Mo:20-60%, Cr:3-12%, Si:1-12%, surplus are made up of Co and unavoidable impurities.Form the hard phase that powder forms mutually by this hard; Become in having corrosion resistance and stable on heating Co alloy phase and be dispersed with the metal structure of separating out particle that is the main body with the molybdenum silicide that wearability and lubricity are provided, high as wearability sintered component effect.

Matrix forms powder, can use for example above-mentioned spy to open flat 08-109450 communique, spy and open flat 02-270943 communique, spy and open flat 01-068447 communique, spy and open 2002-356704 communique, spy and open 2003-119542 communique, spy and open the matrix that always always uses of 2005-154798 communique etc. and form powder.In addition, in material powder,, can add the for example powdered graphite of 0.1-1.2 quality % for reinforced iron-base matrix and formation carbide.In addition, also can add manganese sulfide, magnesium silicate be mineral etc. improve machinability improve the machinability powder.

In the sliding component of internal combustion engine, the member that has corrosion resistance also will pay attention to simultaneously in order to be used for such purposes, when forming powder use powder of stainless steel as matrix, can be guaranteed not only that wearability has also further improved corrosion proof wearability sintered component.Powder of stainless steel can use powder of stainless steel arbitrarily.For example, can use ferrite-group stainless steel Cr, high to the corrosion resistance of oxidizing acid that contains 11-32 quality %, can use the C that further contains 0.15-1.2 quality % therein raising the martensitic stainless steel of intensity and wearability.In addition, also can use the Cr that contains 11-32 quality % and 3.5-22 quality % Ni, improved corrosion proof austenite stainless steel to non-oxidizing acid.

Further, through in above-mentioned stainless steel, containing the Mo of 0.3-7 quality %, when improving creep resistant, acid resistance, corrosion resistance, pitting corrosion resistance, can also improve quick machinability.In addition, through containing the Cu of 1-4 quality %, when improving acid resistance, corrosion resistance, pitting corrosion resistance, can also give precipitation-hardening property.In addition, through containing the Al of 0.1-5 quality %,, can also give precipitation-hardening property improving weldability and stable on heating while.In addition, through containing the N below the 0.3 quality %, in scalable crystal grain,, therefore can reduce the amount of the Ni of high price because N is the substitute element of Ni.In addition, because Mn also is the substitute element of Ni, therefore, can contain the Mn of 5.5-10 quality % in order to reduce the Ni amount.Through containing the Si of 0.15-5 quality %, can improve oxidative resistance, hear resistance and anti-sulfuric acid property, through containing the Nb below the 0.45 quality %, can improve anti-grain boundary corrosion property.In addition,, weldability can be improved,, machinability can be improved through containing the P below the 0.2 quality %, the S below the 0.15 quality % through containing the Se below the 0.15 quality %.

Then, sintering valve seat of the present invention sees to possess 3 kinds of schemes from the state of metal structure.Below these sintering valve seats and manufacturing approach thereof are described.

The sintering valve seat of [1] the 1st scheme

The sintering valve seat of the 1st scheme can be described as basic comprising of the present invention; It is characterized in that; Present following tissue, promptly form Co by Mo:20-60 quality %, Cr:3-12 quality %, Si:1-5 quality %, surplus forms, in Co base alloy phase, separates out molybdenum silicide with unavoidable impurities hard mutually, the tissue that in matrix, disperses with 40-70 quality %; Simultaneously, matrix does not contain pearlite, sorbite and bainite.Express to Fig. 4 (a), Fig. 4 (b) pattern the metal structure of the sintering valve seat of the 1st scheme.Below to the metal structure of valve seat of the present invention, contain explanations one by one such as element.

< content of hard phase >

The hard phase; As above-mentioned; Composition by Mo:20-60 quality %, Cr:3-12 quality %, Si:1-5 quality %, and the Co and the unavoidable impurities of surplus form; Be presented on the tissue of mainly separating out molybdenum silicide in the Co base alloy phase, in sintering valve seat of the present invention, such hard 40-70 quality % that in the iron-based body, is scattered here and there.

Fig. 7 be pattern the figure of the metal structure of the valve seat that is made up of existing wearability sintered alloy is shown.According to this figure, in existing valve seat, the hard of in alloy phase, the separating out molybdenum silicide 5-40 quality % that in matrix, is scattered here and there the clump shape.According to such metal structure; Therefore the amount of hard phase is few, directly contacts with counter-element and under the high surface pressure force environment that slides, body portion becomes basic point at the body portion of hard beyond mutually; Plastic flowing, adhesion take place, and hard can not be restrained this pressure mutually and wear and tear.

On the other hand, in the present invention, the dispersion amount of hard phase is 40-70 quality %, with existing hard mutually dispersion amount compare; Therefore be scattered here and there in large quantities, even under the high surface pressure power, the body portion of hard beyond mutually also is difficult to directly contact with counter-element; In addition, even come in contact, body portion produces plastic flowing; Because the effect of a large amount of hard phases has prevented its distortion, becomes the structure that is difficult for taking place wearing and tearing.Moreover preferred hard surpasses 40 quality % mutually and disperses.

Hard phase among the present invention, when the Mo amount reached about 45 quality %, the molybdenum silicide of separating out demonstrated the form of in Co base alloy substrate, separating out with grain shape the clump shape shown in Fig. 4 (a).On the other hand, when the Mo silicide is about 48 quality % when above, shown in Fig. 4 (b), the molybdenum silicide of separating out demonstrates the form that becomes one blockly and separate out.In the application invention, resemble above-mentioned ground and disperse the hard phases in a large number in matrix, improve wearabilities, so the form of the molybdenum silicide of separating out can be above-mentioned form arbitrarily.

Sintering valve seat of the present invention owing in the matrix of sintering valve seat, disperseed to reach the hard phase of 40-70 quality % in large quantities, therefore demonstrates extremely good wearability.Because hard forms powder mutually and reduces compressibility, thus the ratio of hard phase after a little while the density ratio uprise.The ratio of hard phase is during less than 40 quality %, and the density ratio uprises, and reaches more than 90%, and is if therefore only be conceived to the density ratio, then favourable concerning wearability., in the present invention,, demonstrate the effect of the constrictive reduction of compensation significant raising wearability more than sufficient through disperseing the hard phase more than the 40 quality %.On the other hand, when surpassing 70 quality %, the influence that the compressibility of material powder reduces is big, and formed body density reduces.Its result, sintered body (valve seat) density reduces, and matrix strength reduces, and instead wearability reduces simultaneously.

Above-mentioned hard phase; Through to forming in the powder at the matrix that always is applicable to the sintering valve seat always; Add, mix by Mo:20-60 quality %, Cr:3-12 quality %, Si:1-5 quality %, and the Co of surplus carry out the press-powder moulding with the material powder that the hard of forming that unavoidable impurities is formed forms powder mutually, and sintering and forming.

The basis of the numerical definiteness that the one-tenth of hard phase is grouped into is following.

Mo:20-60 quality %

Mo mainly combines with Si, forms the molybdenum silicide of wearability, lubricity excellence, helps to improve the wearability of sintered alloy.In addition, a part also combines Co to separate out with the form of compound silicide.In addition, a part is diffused in the iron-based body, helps the fixing of hard phase, helps quenching degree raising, hear resistance raising, the corrosion resistance of iron-based body to improve, formed by carbide the raising of the wearability of bringing etc. simultaneously.Mo content is less than the occasion of 20 quality %, and the quantitative change of the molybdenum silicide of separating out is few, and the raising of wearability is insufficient.

On the other hand, Mo content is 20 quality % when above, has separated out the molybdenum silicide of q.s, and the effect that improves wearability becomes remarkable.In addition, the amount of separating out of molybdenum silicide increases with hard Mo content mutually pro rata, but when Mo amount reaches about 45 quality %, and the molybdenum silicide of separating out separates out with grain shape in the alloy substrate of hard phase that (Fig. 4 a) with being clump shape.When Mo amount than this amount also for a long time, the result who separates out the particle increase who separates out separates out particle and is bonded to each other the clump shape, when the Mo silicide is about 48% when above, molybdenum silicide is and becomes one blockly and separate out (Fig. 4 b).But when Mo content surpassed 60 quality %, the hardness that hard forms powder mutually uprised, the compressibility during the infringement moulding, even the manufacturing approach of stating after adopting, the density of valve seat is than also less than 90%, and the result that matrix strength reduces, instead wearability reduces.In addition, formed hard becomes fragile mutually, and therefore owing to impact, a part comes off, and through the effect of grounds travel, instead wearability reduces.Therefore, Mo content is defined as 20-60 quality %.

Molybdenum silicide to separate out form can be the form separated out with grain shape with being clump shape be any form in the form that becomes one blockly and separate out.But; Under the form that the former molybdenum silicide is separated out with being clump shape; Under the environment that Metal Contact takes place, the alloy phase that plays the molybdenum silicide hard phase in addition of hard particles function partly becomes basic point, has the tendency that plastic flowing, adhesion takes place, be prone to take place wearing and tearing.On the other hand, be under the form that becomes one blockly and separate out, can suppress plastic flowing and the generation of adhesion of the alloy phase part of hard phase through the pin effect, can improve wearability at the latter's molybdenum silicide.Therefore, the preferred latter's molybdenum silicide is the form that becomes one blockly and separate out.

Cr:3-12 quality %

Cr helps the reinforcement of the Co matrix of hard phase.In addition, in the iron-based body, spread, hard is fixed in the iron-based body, solid solution is simultaneously strengthened matrix in the iron-based body, helps to improve wearability thus.In addition, Cr is diffused in the iron-based body, helps the fixing of hard phase, help simultaneously to improve the iron-based body quenching degree, by forms corrosion resistance raising that the passivation tunicle brings, by forming wearability raising that carbide brings etc.In addition; After in the sintering valve seat of the 2nd scheme stated; Through form Cr that diffuses to the powder in the iron-based body and the S combination of supplying with through sulfide powder mutually from hard, the chromium sulfide that forms the lubricity excellence on every side in the hard phase helps wearability to improve.When Cr contained quantity not sufficient 3 quality %, these effects were little.On the contrary, when Cr content surpasses 12 quality %, because Cr is the element that is prone to oxidation, so powder surface formation oxide film thereon, in the carrying out that hinders sintering, because oxide film thereon makes and therefore constrictive reduction takes place the powder hardening.For this reason, even the manufacturing approach of stating after adopting, the density of valve seat compares also less than 90%, the result that matrix strength reduces, and instead wearability reduces.According to the above, Cr content is defined as 3-12 quality %.

Si:1-5 quality %

Si main with the Mo reaction, form the molybdenum silicide of wearability, lubricity excellence, help to improve the wearability of sintered alloy.Si content can not obtain enough molybdenum silicides less than the occasion of 1 quality %, so the raising effect of wearability is insufficient.On the other hand, when Si content was superfluous, the Si that is not diffused in the matrix with the Mo reaction increased.The diffusion of Si to a certain degree in matrix, hard in matrix fixing aspect and aspect through making the sclerosis of iron-based body improve wearability be effective., the diffusion of superfluous Si makes the iron-based body really up to the mark, and becomes fragile, and in the wearability that reduces the iron-based body, also increases the aggressiveness of counter-element thus.Therefore not preferred.,, then can make the Mo amount suitably here, avoid increasing the hardness of powder if reduction is not measured with the Si that Mo reacts.Therefore, with not being diffused into the upper limit that 5 quality % that the Si in the matrix begins to increase are defined as Si content with Mo reaction.According to the above, Si content is defined as 1-5 quality %.

Co: surplus

Co helps the hear resistance of hard phase and corrosion resistance to improve as the alloy substrate of hard phase.In addition, in the iron-based body, spread, hard is fixed in the iron-based body, help to improve the hear resistance of iron-based body simultaneously.

(content of matrix)

Sintering valve seat of the present invention when carrying out the metal structure observation, for example with the occasion of corrosion such as nital, is presented on the metal structure that is dispersed with above-mentioned hard phase in whole the matrix for white.This whole metal structure for white is to form in mutually contained various Elements Diffusion to the iron-based body of above-mentioned hard, owing to contain the hard phase in a large number, therefore on whole of metal structure, reflected its effect.That is, the matrix that this is white, through solid solution each alloying element from the hard phase, characteristics such as wearability, corrosion resistance and hear resistance obtain improvement.But when from the various elemental diffusion of hard phase when insufficient, and residual, above-mentioned effect becomes insufficient to this part as pearlite, sorbite or bainite.For this reason, as the matrix of sintering valve seat of the present invention, must not contain these and lack wearability, corrosion resistance, stable on heating tissue, i.e. pearlite, sorbite and bainite.Specifically, matrix is the line and staff control more than a kind or 2 kinds in ferrite (high alloy ferrite), retained austenite and the martensite, is more preferably a kind or 2 kinds line and staff control in retained austenite and the martensite.

As stated; The matrix of sintering valve seat of the present invention is owing to from the various elemental diffusion of the hard phase of a large amount of dispersions, improve as the necessary various characteristics of valve seat; But form as it, recommend to use the composition that contains the following alloying element more than a kind or 2 kinds.

Mo:0.2-5 quality %

Mo is the element with following action: improve the quenching degree of matrix, thereby improve the effect of intensity, wearability; Improve the temper softening drag of matrix, the effect that the wearability when preventing to use repeatedly reduces; Improve elevated temperature strength, creep strength, improve the effect of intensity, wearability; Make the austenite sclerosis, the effect that improves intensity, wearability; Form carbide, improve the effect of wearability; Through with the Cr solid solution, improve corrosion proof effect; Or the like.When the Mo quantity not sufficient of giving matrix 0.2 quality %, above-mentioned effect is insufficient.In addition, Mo is the slow element of diffusion velocity, compares with giving with the form of simple substance powder; Preferably give with the form of alloy powder, but this occasion, when the Mo amount surpasses 5 quality %; The hardness of alloy powder increases, and the compressibility of material powder is further impaired.

Cr:0.05-4 quality %

Cr is the element with following action: improve the quenching degree of matrix, thereby improve the effect of intensity, wearability; Form passivating film, improve corrosion proof effect; Form carbide, improve the effect of wearability; Make the austenite sclerosis, the effect that improves intensity, wearability; Or the like.When giving the Cr quantity not sufficient 0.05 quality % of matrix, above-mentioned effect is insufficient.In addition, because Cr is the element that is prone to oxidation, therefore when giving with the form of simple substance powder, because the effect of firm oxide, element does not spread.For this reason, preferred Cr gives with the form of alloy powder.But when the Cr amount surpassed 4 quality %, the hardness of material powder increased, and the compressibility of material powder is further impaired.

V:0.05-0.6 quality %

V is the element with following action: make the austenite sclerosis, the effect that improves intensity, wearability; Form carbide, improve the effect of wearability; Improve the temper softening drag of matrix, the effect that the wearability when preventing to use repeatedly reduces; Prevent AUSTENITE GRAIN COARSENING, improve the effect of intensity, wearability; Or the like.When giving the V quantity not sufficient 0.05 quality % of matrix, above-mentioned effect becomes insufficient.In addition, V is the slow element of diffusion velocity, compares with giving with the form of simple substance powder; Preferably give with the form of alloy powder, but this occasion, when the V amount surpasses 0.6 quality %; The hardness of alloy powder increases, and the compressibility of material powder is further impaired.

Ni:0.1-10 quality %

Ni is the element with following action: improve the quenching degree of matrix, thereby improve the effect of intensity, wearability; Form austenite, matrix is given the effect of toughness; The corrosion proof effect that improves matrix with Cr; Or the like.When giving the Ni quantity not sufficient 0.1 quality % of matrix, above-mentioned effect becomes insufficient, when the Ni amount surpasses 10 quality %; Though it is excellent aspect corrosion resistance, toughness; It is superfluous that but the austenite that wearability is low becomes, and instead wearability reduces, simultaneously in the occasion of giving with the form of alloy powder; The hardness of alloy powder increases, and the compressibility of material powder is further impaired.Moreover, because Ni is the diffusion velocity element faster in the iron-based body, therefore both can give with the form of simple substance powder, can give with the form of alloy powder again.

Cu:0.5-5 quality %

Cu has the quenching degree that improves matrix, improves the element of the effect of intensity, wearability.When the Cu quantity not sufficient of giving matrix 0.5 quality %, above-mentioned effect becomes insufficient, and when the Cu amount surpassed 5 quality %, soft free copper disperseed in matrix in a large number, the infringement wearability.Moreover, because Cu is the fast element of diffusion velocity in the iron-based body, therefore both can give with the form of simple substance powder, can give with the form of alloy powder again.

Co:5.5-7.5 quality %

Co has matrix is given hear resistance, prevented intensity, wearability reduces effect, solid solution in austenite, when using repeatedly, keeps the element of the effect etc. of matrix hardness.When the Co quantity not sufficient of giving matrix 5.5 quality %, above-mentioned effect becomes insufficient.In addition, Co is the slower element of diffusion velocity, compares with giving with the form of simple substance powder; Preferably give with the form of alloy powder, but this occasion, when the Co amount surpasses 7.5 quality %; The hardness of alloy powder increases, and the compressibility of material powder is further impaired.

The matrix that contains above-mentioned alloying element can obtain through the powdered steel of using for example following (A)-(E).Be following or the like powdered steel: be the powdered steel that Fe and unavoidable impurities are formed (A) by Mo:1.5-5 quality % and surplus; (B) be the powdered steel that Fe and unavoidable impurities are formed by Cr:2-4 quality %, Mo:0.2-0.4 quality %, V:0.2-0.4 quality % and surplus; (C) be the powdered steel that Fe and unavoidable impurities are formed by Co:5.5-7.5 quality %, Mo:0.5-3 quality %, Ni:0.1-3 quality % and surplus; (D) be the powdered steel that Fe and unavoidable impurities are formed by Mo:0.4-4 quality %, Ni:0.6-5 quality %, Cu:0.5-5 quality %, Cr:0.05-2 quality %, V:0.05-0.6 quality % and surplus; Be the part diffusion powdered steel that Fe and unavoidable impurities are formed (E) by Ni:1-10 quality %, Cu:1-3 quality %, Mo:0.4-1.0 quality % and surplus.These powdered steel are powdered steel of in existing sintering valve seat, using, and market is on sale, can obtain at an easy rate.These powdered steel can only be used a kind, in reaching the scope of above-mentioned composition, can mix multiple the use.And then, also can mix and use with nickel by powder, copper powders may.

< manufacturing approach of sintering valve seat >

Sintering valve seat of the present invention; It is characterized in that; In matrix, disperse above-mentioned hard to reach 40-70 quality % mutually in large quantities, simultaneously, in matrix, do not have pearlite, bainite and sorbite; The position that such hear resistance and corrosion resistance are low is each alloying element from the hard inadequate part of diffusion of iron-based body in opposite directions, takes place to the occasion that surpasses diffusion length greatly forming the distance of powder surface to the powder center from matrix.Therefore; If use from surface that matrix forms powder the powder of the distance at powder center less than the diffusion length of each alloying element; Use micropowder if promptly form powder as matrix; Then in iron-based body integral body, become evenly from the diffusion of the alloying element of hard phase, bring the effect of these alloying elements equably can for matrix integral body.For this reason, in the manufacturing approach of sintering valve seat of the present invention, the maximum particle diameter that the matrix of use forms powder is defined as 74 μ m.In addition, form powder, contain the occasion that maximum particle diameter surpasses the powder of 74 μ m, in matrix, be prone to the inadequate position of corrosion resistance, hear resistance of residual pearlite, bainite, sorbite and so on as matrix.

In addition; Sintering valve seat of the present invention is the valve seat that has disperseed a large amount of hard phases; When only increasing hard for the amount that is increased in the hard phase of disperseing in the matrix and form the addition of powder in the matrix material powder mutually, can not obtain having the sintering valve seat of good density ratio.That is since hard to form powder mutually hard, therefore when in material powder, containing in a large number sometimes, the compressibility of infringement material powder, the density of press-powder body reduces.Even the low-density press-powder body that sintering is such, density can not improve, and can only obtain the result of low-density sintered body, and intensity and wearability reduce.In addition, when force improving the density of press-powder body, even the briquetting pressure when increasing the press-powder moulding; Because it is high that hard hard forms the coefficient of elasticity of powder mutually, thus after the moulding when mould is pulled out, be compressed and hard that strain takes place forms the powder elastic recovery mutually; The powder that when moulding, forms closed state each other is destroyed; Even sintering does not carry out the fusion (neck length one-tenth) between powder yet, intensity and wearability reduce.On the other hand; Resemble when forming powder and use micropowder as matrix above-mentioned; It is big that the surface area of powder becomes, and powder this moment contact area each other increases, and therefore carries out sintering and can realize densified; Even contain the material powder that hard forms powder mutually in large quantities, also obtain as this effect of the necessary density of sintering valve seat.

The addition that forms powder at hard mutually is the occasion of 40-70 quality %; Use the powder below the maximum particle diameter 74 μ m if form powder, then resemble and to obtain not residual pearlite, bainite and sorbitic tissue in matrix above-mentioned, can obtain as the necessary density of sintering valve seat simultaneously as matrix; Matrix forms the thin powder of powder; Distance from the surface to the center is more little, and surface area becomes big simultaneously, and densified being prone to during sintering carries out.Therefore, use that to have maximum particle diameter be that the powder that powder accounts for more than 90%, maximum particle diameter is 74 μ m of 46 μ m is more effective as the micropowder that the granularity of surplus constitutes.

When hard forms powder also when the micro mist mutually, the compressibility of material powder further reduces, so hard forms powder mutually, and need to use maximum particle diameter be the big powder of particle diameter to a certain degree of 150 μ m.Preferably, form the powder that powder uses the powder that contains the maximum particle diameter 74 μ m more than the 40 quality % mutually as hard, like this, form powder with respect to above-mentioned matrix, can guarantee that hard forms the size of powder mutually, constrictive reduction is very little.

Powdered graphite is diffused into matrix and forms in the powder when sintering, the reinforced iron matrix, and simultaneously, its part is separated out with the carbide form, helps to improve matrix and hard wearability mutually.During such powdered graphite addition less than 0.8 quality %, its effect is insufficient.On the other hand, when surpassing 2.0 quality %, the amount of the carbide of separating out is excessive, and matrix strength reduces, and instead wearability reduces, and simultaneously, matching side is aggressive to become big.Therefore, the addition of powdered graphite is defined as 0.8-2.0 quality %.

What obtained by above knowledge opinion is the manufacturing approach of sintering valve seat of the present invention; This manufacturing approach is characterised in that; In maximum particle diameter is in the matrix formation powder of 74 μ m; Add to mix maximum particle diameter is 150 μ m, form by Mo:20-60 quality %, Cr:3-12 quality %, Si:1-5 quality %, and the Co of surplus form powder 40-70 quality % and powdered graphite 0.8-2.0 quality % mutually with the hard that unavoidable impurities is formed; The material powder press-powder that obtains thus is shaped to after the desired shape, carries out sintering.

Maximum particle diameter is the powder of 74 μ m, is the powder that has passed through 200 purpose sieve grates, and maximum particle diameter is the powder of 46 μ m, is the powder that has passed through 300 purpose sieve grates, and maximum particle diameter is the powder of 150 μ m, is the powder that has passed through 90 purpose sieve grates.Therefore, come classification, can obtain the powder that desirable above-mentioned granularity constitutes through adopting these sieve grates.

In addition, matrix forms powder, can use the mixed-powder more than a kind or 2 kinds in the powdered steel that has above-mentioned (A)-(E) that always use now.In addition, in order to strengthen matrix, also can in the scope of above-mentioned composition, use nickel by powder, copper powders may.

The sintering valve seat of [2] the 2nd schemes

The sintering valve seat of the 2nd scheme is characterized in that, in the metal structure of the sintering valve seat of above-mentioned the 1st scheme, around the hard phase, separates out the chromium sulfide that is scattered here and there.The metal structure of the sintering valve seat of Fig. 5 (a), expression the 2nd invention of Fig. 5 (b) pattern ground; Through the excellent chromium sulfide of lubricity separate out be scattered in the hard phase around; Deal with smoothly and be applied to the load that hard is gone up mutually; Prevent hard phase self plastic flowing, its result, wearability can further improve.Moreover; Fig. 5 (a) is the figure of the form separated out at the molybdenum silicide that hard is separated out in mutually with being clump shape; Fig. 5 (b) is the figure that is the form that becomes one blockly and separate out at the molybdenum silicide that hard is separated out in mutually; Around the hard phase, separate out the chromium sulfide of dispersion, in all case all have the effect of improving lubricity.

Disperse such chromium sulfide in order around the hard phase, to separate out; In material powder, the amount that reaches 0.04-5 quality % with the S in material powder amount is added at least a kind the sulfide powder that comprises among (F) molybdenum bisuphide powder, (G) tungsten disulfide powder, (H) iron sulfide powder, (I) copper sulfide powder and is got final product.Thus, sulfide powder (F)-(I) decomposes the S that produces when sintering, is diffused into the Cr reaction the iron-based body with form powder mutually from hard, separates out chromium sulfide mutually on every side at hard.

The metal sulfide imperfect stability; Part metal sulfide is prone to decompose when sintering; Molybdenum bisuphide, tungsten sulfide, iron sulfide, and copper sulfide be prone under given conditions decompose, this is recorded in the list of references (chemical voluminous dictionary 9 minimos upright altogether publish Showa Corporation's distribution on March 15th, 39).In addition, in the sintering process of reality, through moisture contained in the atmosphere, oxygen, hydrogen be adsorbed in the moisture on iron powder surface and the disengaging of oxygen; Sometimes satisfy decomposition condition and decompose; In addition, the sulfide and the activated metal surface reaction that at high temperature becomes, catalyst action is played in the activated metal surface that perhaps at high temperature becomes; Promote the decomposition of sulfide, this can fully take into account.On the other hand, manganese sulfide and chromic sulfide are also judged the awkward metal sulfide that decomposes according to above-mentioned list of references.In addition, the formation ability of sulfide is relevant with electronegativity, and S has and is prone to combine with the low element of electronegativity, the tendency of formation sulfide, and here, the electronegativity of each element sorts as follows:

Mn(1.5)＜Cr(1.6)＜Fe，Ni，Co，Mo(1.8)＜Cu(1.9)

Because therefore the easiest combination of Mn optionally separates out manganese sulfide.This sequence is also consistent with the record of above-mentioned list of references.Therefore, in the manufacturing approach of sintering valve seat of the present invention, as the S supply source, use comprises at least a kind sulfide powder among (F) molybdenum bisuphide powder, (G) tungsten disulfide powder, (H) iron sulfide powder, (I) copper sulfide powder.

In order to use the sulfide powder of above-mentioned that kind, around the hard phase, separate out the chromium sulfide grain that disperses q.s, the addition of sulfide powder divides by S, needs more than the 0.04 quality %.On the other hand, the interpolation of the sulfide powder of surplus causes decomposing the residual pore amount in back and increases, and causes that thus the intensity of valve seat reduces, and results from this, will cause wearability and reduce, and therefore, its upper limit need be controlled at the amount of counting 5 quality % by the S branch.In addition, because sulfide powder decomposes when sintering, disappears, therefore when using thick sulfide powder, exist the position of sulfide powder behind sintering, to become thick pore and residual, the particle diameter of the sulfide powder that therefore uses is to be advisable below the 43 μ m.

The sintering valve seat of [3] the 3rd schemes

The sintering valve seat of the 3rd scheme is in the matrix of the sintering valve seat of the 2nd scheme, has further disperseed the sintering valve seat of separating out the lubricated phase of chromium sulfide grain of 5-20 quality % with being clump shape.The metal structure of the sintering valve seat of Fig. 6 (a), expression the 3rd invention of Fig. 6 (b) pattern ground; Through the excellent chromium sulfide of lubricity be scattered in the hard phase around; Point-like ground disperses this to separate out the lubricated phase of this chromium sulfide with in matrix, being clump shape simultaneously; The lubricity of matrix improves, and wearability is enhanced.Moreover; Fig. 6 (a) is the figure of the form separated out at the molybdenum silicide that hard is separated out in mutually with being clump shape; Fig. 6 (b) is the figure that is the form that becomes one blockly and separate out at the molybdenum silicide that hard is separated out in mutually; Separate out the lubricated phase that chromium sulfide is arranged with in matrix, being clump shape, in all case all have the effect of improving lubricity.

When the cut valve seat, sulfide is evenly dispersed in the occasion in the matrix, and cutter head collides sulfide equably; Therefore; When cutting resistance reduced, because the chip fracture effect, the removal of cutting powder became easy; Can prevent the savings of heat on cutter head, the effect that the machinability of tool temperature reduction etc. improves uprises.On the other hand, because sulfide grain self is little, therefore lubricity, the raising wearability in order to improve matrix needs a large amount of sulfide, but when in matrix, disperseing a large amount of sulfide, can cause that matrix strength reduces.

For this reason, in the present invention,, realize the raising of matrix wearability through an amount of chromium sulfide that does not cause the degree that matrix strength reduces through being clump shape ground, the point-like ground excellent chromium sulfide of dispersion lubricity in matrix.During such lubricated dispersion amount less than 5 quality % in matrix, it is insufficient to improve the effect that the wearability brought improves by the lubricity of matrix.On the other hand, when chromium sulfide disperseed above 20 quality %, the intensity reduction of matrix became remarkable.Therefore, the dispersion of chromium sulfide in matrix need be 5-20 quality %.

Separate out the lubricated phase that above-mentioned chromium sulfide grain is arranged with being clump shape, can form through the chrome-bearing steel powder that in material powder, adds the Cr that contains 4-25 quality %.That is, in sintering process, above-mentioned sulfide powder decomposes the S that produces, and combines with Cr in the chrome-bearing steel powder, and chromium sulfide is separated out in the part of original chrome-bearing steel powder, becomes thus in matrix, to be clump tissue of shape ground dispersion.Therefore, the composition of the composition of lubricated phase and original chrome-bearing steel powder is unanimous on the whole, is the lubricated phase of the Cr that contains 4-25 quality %.In addition, separate out the alloy substrate of the part that chromium sulfide is arranged, for Fe-Cr is an alloy substrate with being clump shape.

When being somebody's turn to do the Cr quantity not sufficient 4 quality % in lubricating mutually, separating out of chromium sulfide becomes insufficient, can not help wearability to improve.On the other hand, when the Cr amount surpassed 25 quality %, the hardening of chrome-bearing steel powder in the constrictive while of infringement, produce the σ phase and embrittlement, so the upper limit need be defined as 25 quality %.

The chrome-bearing steel powder of the Cr of the lubricated alike above-mentioned that kind 4-25 of containing quality capable of using % forms, and this chrome-bearing steel powder can be selected a kind among following (L)-(Q) particularly at least.That is the chrome-bearing steel powder of, (L) forming by the Fe and the unavoidable impurities of Cr:4-25 quality % and surplus; (M) by the Fe of Cr:4-25 quality %, Ni:3.5-22 quality % and surplus and the chrome-bearing steel powder that unavoidable impurities is formed; (N) by Cr:4-25 quality %, Ni:3.5-22 quality %, be selected from Mo:0.3-7 quality %, Cu:1-4 quality %, Al:0.1-5 quality %, below the N:0.3 quality %, Mn:5.5-10 quality %, Si:0.15-5 quality %, below the Nb:0.45 quality %, below the P:0.2 quality %, below the S:0.15 quality % and among below the Se:0.15 quality % more than at least a kind, and the Fe of surplus and the chrome-bearing steel powder that unavoidable impurities is formed; (O) by Cr:4-25 quality %, Ni:3.5-22 quality %, be selected from Mo:0.3-7 quality %, Cu:1-4 quality %, Al:0.1-5 quality %, below the N:0.3 quality %, Mn:5.5-10 quality %, Si:0.15-5 quality %, below the Nb:0.45 quality %, below the P:0.2 quality %, below the S:0.15 quality % and among below the Se:0.15 quality % more than at least a kind, and the Fe of surplus and the chrome-bearing steel powder that unavoidable impurities is formed; (P) by Cr:7.5-25 quality %, Mo:0.3-3.0 quality %, C:0.25-2.4 quality %, and V:0.2-2.2 quality % and more than a kind or 2 kinds of W:1.0-5.0 quality %, the Fe of surplus and the chrome-bearing steel powder that unavoidable impurities is formed; (Q) by the Fe of Cr:4-6 quality %, Mo:4-8 quality %, V:0.5-3 quality %, W:4-8 quality %, C:0.6-1.2 quality % and surplus and the chrome-bearing steel powder that unavoidable impurities is formed.

Above-mentioned (L) is the Fe-Cr alloy, and this alloy that Cr surpasses 12 quality % is that people know as the ferrite-group stainless steel powder.In addition, resembling above-mentioned (N) the ferrite-group stainless steel powder that improves characteristic with other elements also can use.Above-mentioned (M) is the Fe-Ni-Cr alloy, and this alloy that Cr surpasses 12 quality % is that people know as the austenite stainless steel powder.In addition, resembling above-mentioned (O) the austenite stainless steel powder that improves characteristic with other elements also can use.Above-mentioned (P) is that people know as the mould comminuted steel shot, and originally, the Cr that contains separates out as chromium carbide, but resembles the present invention the occasion with the S coexistence, and the major part of the Cr that separates out is separated out as chromium sulfide.Moreover, obtain partly residual chromium carbide, perhaps molybdenum carbide, vanadium carbide, tungsten carbide, and their double carbide separate out and mutually lubricated with the coexistence of chromium sulfide.Above-mentioned (Q) is that people know as the high-speed tool comminuted steel shot; Same with above-mentioned (P); Obtain separating out beyond the chromium sulfide partly residual chromium carbide except coexisting with S; Perhaps molybdenum carbide, vanadium carbide, tungsten carbide, and their double carbide separate out and mutually lubricated with the coexistence of chromium sulfide.

In the sintering valve seat of the 3rd scheme of the present invention, above-mentioned lubricated mutually in carbide can all separate out with chromium sulfide.Specifically; Use the occasion of above-mentioned (P) and chrome-bearing steel powder (Q); Become the tissue that carbide is separated out with chromium sulfide in lubricating mutually, but in this occasion, through carbide precipitate in lubricating mutually; Prevent the plastic flowing of the alloy substrate part of lubricated phase, can improve wearability more.Relatively chrome-bearing steel powder (P) with (Q), (P) side obtains the lubricated phase that carbide is separated out fewly, (Q) side obtain carbide separate out more than lubricated phase, can be according to the suitable selection of desirable characteristic.

The sintering valve seat of above-mentioned 1-the 3rd scheme, the method that can and use the interpolation of always carrying out to improve the material of machinability is made.For example, can use in the pore of above-mentioned wearability sintered component or powder grain border disperse silicic acid magnesium is at least a kind method among mineral, boron nitride, manganese sulfide, calcirm-fluoride, bismuth, chromic sulfide, the lead.

These materials that improve machinability are at high temperature also stable, even add in the material powder with the form of powder, in sintering process, also do not decompose, and are dispersed in the pore or the powder grain border as the material that improves machinability, further improve machinability.In addition, and with the addition of the material powder that improves machinability of the occasion of the method for adding the material improve machinability, when adding, the intensity of infringement wearability sintered component cause wearability and reduce, so preferred upper limit is 2.0 quality % superfluously.

In addition; In sintering valve seat of the present invention; Can resembling that above-mentioned patent documentation 2 grades are put down in writing and with following technology: the arbitrary substance among employing lead or metal, copper or copper alloy, the acrylic resin; The pore that the method for employing dipping or solution infiltration is full of the wearability sintered component improves machinability thus.

That is, having lead or metal, copper or copper alloy, acrylic resin in the pore through making, is the continuous cutting that cutter head and the base material of sintering valve seat of instrument always contacts when cutting.Therefore, has following effect: reduce the impact of the instrument that gives, prevent the cutter head damage, improve machinability.In addition, because lead or metal, copper or copper alloy are soft, therefore attached to instrument sword face; The cutter head of protection instrument prevents the formation of built-up edge, improves the life-span of machinability and instrument; Simultaneously; In use, between the subtend face of valve seat and valve, play the kollag effect, the effect of the wearing and tearing that reduce both sides is arranged.In addition, the thermal conductivity of copper or copper alloy is high, and the heat that when cutting, cutter head is produced is dispersed into the outside, prevents cutter head portion accumulated heat, and the effect that alleviates the damage of cutter head portion is arranged.

According to the present invention, can access when containing a large amount of hard phases, have the wearability sintered component of sufficient sintered density, therefore can improve the wearability and the intensity of existing wearability sintered component more.In addition, use powder of stainless steel to form the wearability sintered component of powder as matrix, the corrosion resistance of matrix improves, and the occasion that all will pay attention in corrosion resistance and wearability is preferred.

In addition, according to the present invention, through in the matrix of sintering valve seat, disperseing the hard phase of 40-70 quality %,, also can bring into play further high wearability even under to the high severe environment of mistake of the load of the seat material that is accompanied by Metal Contact.Therefore, under high load engine environment such as CNG engine, heavy duty diesel engine, obtain the effect of the excellent high temperature abrasion resistance of performance.

Description of drawings

Fig. 1 is the curve map of ratio with the relation of density ratio and wear extent of the powder below the particle diameter 46 μ m in the expression embodiment of the invention.

Fig. 2 is that the hard in the expression embodiment of the invention forms the addition of powder and the curve map of the relation of density ratio and wear extent mutually.

Fig. 3 be the hard of expression in the embodiment of the invention form mutually in the powder Mo amount and density than and the curve map of the relation of wear extent.

Fig. 4 be pattern express the figure of metal structure of the sintering valve seat of the 1st scheme among the present invention.

Fig. 5 be pattern express the figure of metal structure of the sintering valve seat of the 2nd scheme among the present invention.

Fig. 6 be pattern express the figure of metal structure of the sintering valve seat of the 3rd scheme among the present invention.

Fig. 7 be pattern express the figure of the metal structure of existing sintering valve seat.

Fig. 8 is the curve map of relation of amount and the wear extent of the hard phase of expression in the embodiment of the invention.

Fig. 9 is the Mo amount of the hard of expression in the embodiment of the invention in mutually and the curve map of the embodiment of the relation of wear extent.

Figure 10 is the curve map that the matrix in the expression embodiment of the invention forms granularity formation with the relation of wear extent of powder.

Figure 11 is the curve map of relation of kind and the wear extent of the matrix of expression in the embodiment of the invention.

Figure 12 is the curve map of S amount and the relation of wear extent in the main assembly of expression in the embodiment of the invention.

Figure 13 is the curve map of relation of kind and the wear extent of the sulfide powder of expression in the embodiment of the invention.

Figure 14 is the curve map of the relation of the lubricated and wear extent in the expression embodiment of the invention.

Figure 15 is the curve map of the relation of expression lubricated in embodiment of the invention kind and wear extent of forming powder mutually.

Figure 16 is the metal structure photo of the present invention's example (the sintering valve seat of the 1st scheme), comparative example and existing example among the embodiment.

Figure 17 is the metal structure photo of the sintering valve seat of the 2nd scheme of the present invention.

Figure 18 is the metal structure photo of the sintering valve seat of the 3rd scheme of the present invention.

The specific embodiment

[embodiment 1]

Form powder as matrix; Preparation has the powder of stainless steel that is equivalent to JIS standard SUS316 that the granularity shown in the table 1 constitutes; Form powder mutually as hard, prepare to represent, the Co base alloy powder of forming by the Co and the unavoidable impurities of Mo:28%, Si:2.5%, Cr:8%, surplus with mass ratio; Form in the powder hard that adds, mixes 60 quality % at matrix and form powder mutually, obtained material powder.This material powder press-powder under briquetting pressure 1.2GPa is shaped to the circular plate shape of diameter 30mm, thickness 10mm, with the press-powder body that obtains like this in ammonia atmosphere with 1250 ℃ * 1Hr sintering, made the sample of specimen coding 01-05.For these samples, when measuring the density ratio, carry out the reciprocating sliding friction test, measured the wear extent after the test.Table 1 illustrates these results in the lump.

Reciprocating sliding friction test, be on one side with the side of the roller (pairing material) of diameter 15mm, thickness 22mm with the load of regulation by being pressed on the above-mentioned circular plate shape test film, on one side make the friction test that reciprocatingly slides.In this test,, use the surface of steel ingot that is equivalent to JIS standard SUS316 has been implemented the chromising processing (in surface-coated chromium as roll material; Form the siderochrome intermetallic compounds layer of hard, to improve the processing of wearability, sintering resistance and corrosion resistance etc.), under following experimental condition, carry out the reciprocating sliding friction test: load is 40N; The frequency that reciprocatingly slides is 20Hz; The amplitude that reciprocatingly slides is 1.5mm, and test period is 20min, and test temperature is a room temperature.Its result is remembered in the lump in table 1, simultaneously shown in Fig. 1.

Table 1

Judged and can be known that the ratio of having used micropowder is the specimen coding 05 that the matrix of 30 quality % forms powder by Fig. 1, the addition that forms powder owing to hard mutually is many; Be 60 quality %, so the reduction of the density of press-powder body, because this density reduces; Even sintered density is lower than also, be 83%.Therefore, matrix strength reduces, and wear extent is also many.On the other hand, the ratio that forms the micropowder below the 46 μ m in the powder along with matrix increases, and has promoted densifiedly through sintering, and the density of sample is than increase point-blank, and wear extent reduces simultaneously.Can know that in addition when the ratio of the micropowder below matrix forms 46 μ m in the powder reached 90%, the density ratio was 90%, wear extent sharply reduces.

[embodiment 2]

Form powder as matrix; The ratio of the powder below the 46 μ m that preparation is used with the specimen coding of embodiment 1 02 is 95% the powder of stainless steel that is equivalent to JIS standard SUS316; Form powder mutually as hard; The Co base alloy powder that preparation is used in embodiment 1 obtains material powder with the mixed shown in the table 2.Use this material powder, under the condition identical, carry out the press-powder moulding, and sintering, made the sample of specimen coding 06-10 with embodiment 1.For these samples, carry out the test identical with embodiment 1, result of the test is shown among table 2 and Fig. 2 with the result of the test of the specimen coding 02 of embodiment 1.

Table 2

Distinguished that by Fig. 2 hard forms the specimen coding 06 of powder addition less than 40 quality % mutually, although density is than high, the dispersion amount of hard phase is few, and the quantitative change of therefore wearing and tearing is big.On the other hand, forming the powder addition mutually at hard is the occasion more than the 40 quality %, and wear extent diminishes, and wearability improves.But, along with forming the powder addition mutually, hard increases, demonstrate density than the tendency that reduces; Hard forms the specimen coding 10 of the addition of powder above 70 quality % mutually; The reduction of density ratio is remarkable, and the intensity of matrix and wearability reduce as a result, and wear extent increases.Confirm that according to the above hard forms the powder addition mutually and when the scope of 40-70 quality %, has the effect that improves wearability.

[embodiment 3]

Form powder as matrix; The ratio of the powder below the 46 μ m that preparation is used with the specimen coding of embodiment 1 02 is 95% the powder of stainless steel that is equivalent to JIS standard SUS316; Form powder mutually as hard; Prepare the Co base alloy powder of the composition shown in the table 3, form in the powder hard that adds, mixes 60 quality % at matrix and form powder mutually, obtain material powder.Use these material powders, under the condition identical, carry out the press-powder moulding, and sintering, made the sample of specimen coding 11-16 with embodiment 1.For these samples, carry out the test identical with embodiment 1, result of the test is shown among table 3 and Fig. 3 with the evaluation result of the specimen coding 02 of embodiment 1.

Table 3

Distinguished by Fig. 3, be used as the specimen coding 11 of the M0 quantity not sufficient 20 quality % in the Co base alloy powder of hard phase, because the amount of separating out of molybdenum silicide lacks, the quantitative change of therefore wearing and tearing is big.On the other hand, the Mo amount in the Co base alloy powder is the above samples of 20 quality %, and along with the Mo amount increases, the amount of separating out of molybdenum silicide increases, and demonstrates the tendency that wear extent reduces.But the density ratio is along with the amount of the Mo in the Co base alloy powder increases the tendency that demonstrates reduction, and the Mo amount surpasses the specimen coding 16 of 60 quality %, and the density ratio is less than 90%, and wear extent sharply increases.Confirm that according to the above using the Co-Mo-Si-Cr series alloy powder to form the occasion of powder mutually as hard, the Mo amount is preferably 20-60 quality %.

[embodiment 4]

Form powder as matrix; The ratio of the powder below the 46 μ m that preparation is used with the specimen coding of embodiment 1 03 is 90% the powder of stainless steel that is equivalent to JIS standard SUS316; And the hard of the composition shown in the preparation table 4 forms powder mutually; Form in the powder hard that adds, mixes 60 quality % at matrix and form powder mutually, obtain material powder.Use these material powders, under the condition identical, carry out the press-powder moulding, and sintering, made the sample of specimen coding 17-23 with embodiment 1.For these samples, carry out the test identical with embodiment 1, result of the test is shown in Table 4 with the result of the test of the specimen coding 03 of embodiment 1.

Table 4

Judge confirmation by table 4; Even hard forms the occasion that the addition of powder reaches 60 quality % mutually; If using the ratio of the powder below the 46 μ m as matrix formation powder is the powder more than 90%; Even then the change matrix forms the kind that powder and hard form powder mutually, also can obtain excellent abrasive, and confirm effect of the present invention.

[embodiment 5]

Preparation has the composition shown in the table 5 and forms powder with the matrix formation powder that granularity constitutes mutually with hard; Mix with the match ratio shown in the table 1; The material powder that obtains thus press-powder under briquetting pressure 800MPa is shaped to after the annular shape of external diameter 30mm, internal diameter 20mm, height 10mm; The press-powder body that obtains is carried out sintering with 1200 ℃ * 1 hour in decomposing ammonia atmosphere, made the sample of specimen coding 01-19.For these samples, carried out pressure ring intensity and simple and easy wear test, result of the test is shown in table 6.Hard forms powder mutually, and to have used maximum particle diameter be 150 μ m's.In addition, specimen coding 19 is to use the powder of the granularity formation of always always using to be used as the existing example that matrix forms powder.

Simple and easy wear test at high temperature applies under the state that impacts and slide and carries out.Specifically, above-mentioned ring test sheet is processed into the valve seat shape that inner peripheral portion has 45 ° of conical surfaces, sintered alloy is pressed into is entrenched on the aluminum alloy housing.Secondly; To partly have of the rotation of the pairing material (valve) of the disc-shape of 45 ° of conical surfaces with the outer peripheral edges portion that SUH-36 base material is made through electric motor driven eccentric cam; Make it to do the lower piston motion, the conical surface of sintered alloy and pairing material collides each other repeatedly thus.That is, the action of valve, the opening operation that repeats to lift off a seat through the eccentric cam that rotates through motor driven and through the effect of valve spring to the action of the multiple seat of valve seat, move thereby go up lower piston.In this test, heat pairing material with burner, to carry out the temperature setting and make that sintered alloy is 350 ℃, it is 2800 times/minute that simple and easy wear test is impacted number of times, the repetition time is 10 hours.Measure the wear extent of the valve seat after testing like this and the wear extent of valve, estimate.

Table 5

※ part diffusion-alloyed powder

Table 6

The influence of the amount of the hard phase of in matrix, disperseing (hard forms the addition of powder mutually)

The sample of specimen coding 01-06 through comparison sheet 5 and table 6 has been investigated the amount (hard forms the addition of powder mutually) of the hard phase of in matrix, disperseing and the relation of wear extent.Its result is shown in Fig. 8.Numbering among Fig. 8 is a specimen coding.Distinguish by Fig. 8, the sample (specimen coding 01) of the quantity not sufficient 40 quality % of the hard phase of in matrix, disperseing, wearability is insufficient, and prooving of valve seat quantitative change is big.On the other hand, when the amount of hard phase is 40 quality % (specimen coding 02), wearability improves, and prooving of valve seat quantitative change is little.In addition, when the amount of hard phase increased, the wearability of valve seat improved, and prooving of valve seat amount reduces, but the valve wear extent slowly increases.In addition, through increasing the amount of hard phase, the compressibility of material powder reduces, its result, and matrix strength (pressure ring intensity) reduces.Therefore, the amount of hard phase is the sample (specimen coding 05) of 70 quality %, the result that the valve seat matrix strength reduces, and the wear extent of valve seat increases on the contrary.But the amount of hard phase is the sample (specimen coding 05) of 70 quality %, and adding up to wear extent is permissible scope., the amount of hard phase surpasses the sample (specimen coding 06) of 70 quality %, and the influence that is reduced the valve seat wearability reduction that causes by matrix strength (pressure ring intensity) is big, and prooving of valve seat amount significantly increases.In addition, because the wearing and tearing powder of valve seat plays abrasive grains, so the valve wear extent also increases the surge of total wear extent.By above confirmation, the hard that in matrix, disperses has the effect that improves wearability when the scope of 40-70 quality %.

The influence of the Mo amount (hard mutually form in powder Mo amount) of hard in mutually

Through comparison sheet 5 and the specimen coding 03 of table 6, the sample of 07-11, the Mo amount (hard mutually form Mo amount in powder) of hard in mutually and the relation of wear extent have been investigated.Its result is shown in Fig. 9.Distinguish by Fig. 9, the sample (specimen coding 07) of the Mo quantity not sufficient 20 quality %s of hard in mutually, because the amount of the molybdenum silicide of separating out in mutually at hard is few, so wearability is low, prooving of valve seat quantitative change is big.On the other hand, the amount of the Mo silicide of hard in mutually is the sample (specimen coding 08) of 20 quality %, and separating out has enough molybdenum silicides, and prooving of valve seat amount is suppressed lowly.In addition, along with the Mo amount of hard in mutually increases, the amount of the molybdenum silicide of separating out increases, and prooving of valve seat amount reduces, but because the molybdenum silicide of hard increases, slowly increases when the Mo amount of hard in mutually surpasses 30 quality % as the wear extent of the valve of pairing material.In addition, matrix strength (pressure ring intensity) is along with the Mo amount of hard in mutually increases and reduce, and particularly the Mo amount sample (specimen coding 11) that surpasses 60 quality % reduces significantly.Because the amount of the Mo in the influence that this matrix strength reduces, hard mutually surpasses the sample (specimen coding 11) of 60 quality %, the reduction of its wearability is remarkable, and prooving of valve seat amount significantly increases.In addition, the wearing and tearing powder of valve seat plays abrasive grains, and the valve wear extent also increases as a result, adds up to wear extent to increase sharply.By above confirmation, the Mo amount of hard in mutually has the effect that improves wearability when the scope of 20-60 quality %.

Matrix forms the influence of the granularity formation of powder

Specimen coding 03 through comparison sheet 5 and table 6,12-14 and 19 sample have been investigated granularity that matrix forms powder and have been constituted the relation with wear extent.Its result is shown in Figure 10.Distinguished by Figure 10, form powder as matrix and do not contain the specimen coding 03,12 of the powder that surpasses 74 μ m and 13 sample that can realize the densified of matrix through sintering, matrix strength improves, wearability also improves.On the other hand, form the specimen coding 14 that powder contains the powder that surpasses 74 μ m as matrix, the matrix that brings through sintering densified insufficient, the intensity of matrix can not improve, and wearability is also insufficient.In addition, the major part that matrix forms powder has the specimen coding 19 (existing example) above the granularity formation of 74 μ m, and its tendency is more remarkable, and intensity of matrix (pressure ring intensity) and wearability be step-down all.By above confirmation, be the powder below the 74 μ m if form powder use maximum particle diameter as matrix, also can obtain all excellent sintering valve seat of matrix strength and wearability even then contain the occasion of hard phase in a large number.

Moreover; Relatively used the matrix below the 74 μ m to form the specimen coding 03,12 of powder and 13 sample; Along with the ratio of the powder below the 46 μ m becomes many, pressure ring intensity improves, and the ratio of the powder below the 46 μ m is that the sample of 90% specimen coding 03 demonstrates the highest pressure ring intensity.Having confirmed especially preferably to have following granularity thus constitutes: maximum particle diameter is that the powder below the 46 μ m accounts for more than 90%, and maximum particle diameter is that the powder below the 74 μ m is a surplus.

Here, for the sample (the present invention's example) of specimen coding 03, the sample (comparative example) of specimen coding 14 and the sample (existing example) of specimen coding 19, with the corrosion of 5% nital, when confirming metal structure, the metal structure photo is shown among Figure 16.The sample that confirms specimen coding 03 shown in figure 16 (the present invention's example) can't see pearlite, sorbite and bainite etc., the white phase that just forms through the Elements Diffusion from the hard phase in matrix.Confirmed the sample (comparative example) of specimen coding 14 on the other hand, the position of residual sorbite, bainite structure has been arranged in the body portion that adopts big powder to form.Therefore, the sample of specimen coding 14 can think that matrix strength and wearability reduce.In addition, the sample of specimen coding 19 (existing example), the major part of matrix is sorbite, bainite structure, and when sintering, can not realize densifiedly, the pore quantitative change is many.Because these situation, can think that the matrix strength and the wearability of sample of specimen coding 19 is low.

The influence of the kind of matrix (matrix forms the kind of powder)

Through the specimen coding 03 of comparison sheet 5 and table 6, the sample of 15-18, the kind (matrix forms the kind of powder) of matrix and the relation of wear extent have been investigated.Its result is shown in Figure 11.Distinguish that by Figure 11 the addition that hard forms powder mutually contains 50 quality % in large quantities, and forming powder as matrix, to use maximum particle diameter be the occasion of the powder below the 74 μ m,, all demonstrate excellent abrasive no matter the kind that matrix forms powder how.But, therein, when using the Fe-5Mo powdered steel to form powder,, be minimum, for preferably although add up to the wear extent difference small as matrix.

[embodiment 6]

Having prepared matrix that the sample with the specimen coding 03 of embodiment 5 uses forms powder (amount of the powder below the 46 μ m is 90%; Surpass 46 μ m but be that the amount of the powder below the 74 μ m is 10% Fe-5Mo powder) form powder (maximum particle diameter is the Co-50Mo-3Si-9Cr alloy powder of 150 μ m) mutually with hard; Prepare molybdenum bisuphide powder, tungsten disulfide powder, iron sulfide powder, copper sulfide powder, manganese sulfide powder simultaneously; Mix with the match ratio shown in the table 7; With material powder that obtains like this and embodiment 5 press-powder moulding likewise, and sintering, made the sample of specimen coding 20-29.For these samples, carried out pressure ring intensity and simple and easy wear test, result of the test is shown in Table 8 with the result of the test of the specimen coding 03 of embodiment 1.

Table 7

Table 8

The additive effect of sulfide powder (effect of the Cr sulfide phase of around the hard phase, separating out)

Through specimen coding 03, the 20-25 of comparison sheet 7 and table 8, investigated the relation of sulfide powder addition and wear extent.Its result is shown in Figure 12.Being distinguished by Figure 12, in the sintering valve seat (specimen coding 03) of the 1st scheme, is the sulfide powder below the 5.0 quality % through the S amount of adding in the main assembly, further improves wearability.Especially, when the S amount is the scope of 0.8 quality % (specimen coding 22)-2 quality % (specimen coding 23) in the main assembly, improve the particular significant effect of wearability.But pressure ring intensity increases and reduces along with the sulfide powder addition, and when particularly the amount of the S in the main assembly was added (specimen coding 25) above 5.0 quality %, the influence that matrix strength reduces was big, and instead wearability reduces.

For the sample of specimen coding 22, with the corrosion of 5% nital, when confirming metal structure, the metal structure photo is shown among Figure 17.Can know the tissue of the grey that around the hard phase, is scattered here and there by Figure 17.This part is carried out EPMA separately analyze, the result has confirmed that Cr and S are coexisting, and infers this grey thus and is organized as chromium sulfide.Moreover, as the S supply source, fail to detect with the molybdenum bisuphide that powder morphology adds, therefore can think and decompose fully.Therefore, this chromium sulfide (grey) can think that S that molybdenum bisuphide decompose to produce combines with Cr in the matrix and the material of in matrix, separating out.

The influence of the kind of sulfide powder

Specimen coding 03,22,26-29 through comparison sheet 7 and table 8 have investigated the kind of sulfide powder and the relation of wear extent.Its result is shown in Figure 13.Distinguish that by Figure 13 through adding sulfide powder, no matter its kind how, pressure ring intensity reduces.It on the other hand; Use molybdenum bisuphide powder, tungsten disulfide powder, iron sulfide powder, and the occasion of copper sulfide powder as sulfide powder; Wear extent is littler than the sample that does not add sulfide powder (specimen coding 03); But in the occasion of using the manganese sulfide powder as sulfide powder, instead wear extent increases.This can think because molybdenum bisuphide, tungsten disulfide, iron sulfide and copper sulfide decompose when sintering, generate chromium sulfide, so wearability improves, but because manganese sulfide does not decompose, therefore because the influence that matrix strength reduces, wearability reduces on the contrary.

[embodiment 7]

The matrix of having prepared in the sample of the specimen coding 03 of embodiment 5, to use forms powder, and (amount of the powder below the 46 μ m is 90%; Surpass 46 μ m but be that the amount of the powder below the 74 μ m is 10% Fe-5Mo powder) form powder (maximum particle diameter is the Co-50Mo-3Si-9Cr alloy powder of 150 μ m) mutually with hard and as the molybdenum bisuphide powder of sulfide powder; Simultaneously as the lubricated powder that forms mutually; Prepare the chrome-bearing steel powder of the composition shown in the table 5, mix with the match ratio shown in the table 9, material powder that obtains like this and embodiment 1 press-powder moulding likewise; And sintering, made the sample of specimen coding 30-36.For these samples, carried out pressure ring intensity and simple and easy wear test, result of the test is shown in Table 10 with the result of the specimen coding 22 of the result of the sample of the specimen coding 03 of embodiment 5 and embodiment 6.

Table 9

Table 10

Lubricated effect of disperseing mutually (the lubricated additive effect that forms powder mutually)

Through specimen coding 22, the 30-33 of comparison sheet 9 and table 10, the amount (the lubricated addition that forms powder mutually) of lubricated phase and the relation of wear extent have been investigated.Its result is shown in Figure 14.Distinguish that by Figure 14 further disperse lubricated phase in the matrix through making, wearability further improves.Particularly the dispersion amount of lubricated phase is when the scope of 5 quality % (specimen coding 30)-10 quality % (specimen coding 31), and wearability improves significantly.But pressure ring intensity reduces when the dispersion amount of lubricated phase surpasses 10 quality %, and when particularly the dispersion amount of lubricated phase surpassed the interpolation (specimen coding 33) of 20 quality %, the influence that matrix strength reduces was big, and wearability reduces on the contrary.

For the sample of specimen coding 31, with the corrosion of 5% nital, when confirming metal structure, the metal structure photo is shown among Figure 18.Can know that by Figure 18 the tissue that is dispersed with grizzled particle is scattered in the matrix with hard with being clump shape mutually dividually.This part is carried out EPMA separately analyze, the result has confirmed that Cr and S are coexisting, and that infers this grey thus is organized as chromium sulfide.Can think that the phase through being dispersed with this chromium sulfide (lubricated phase) is scattered in the matrix with being clump shape, resemble above-mentioned wearability improve.

The lubricated influence that forms the kind of powder mutually

Through specimen coding 22,31, the 34-36 of comparison sheet 9 and table 10, the kind (the lubricated kind that forms powder mutually) of lubricated phase and the relation of wear extent have been investigated.Its result is shown in Figure 15.Can be known by Figure 15, be that alloy constitutes lubricated phase if adopt Fe-Cr, and then wearability improves than the occasion of the sample (specimen coding 22) that does not add lubricated phase.Confirmed thus can form lubricated phase, and can improve wearability through in material powder, adding various Fe-Cr series alloy powders.

Claims (2)

1. the manufacturing approach of a wearability sintered component is characterized in that, be to add in the powder and mix hard to form powder mutually and the material powder that obtains carries out the press-powder moulding, and carry out the manufacturing approach of the wearability sintered component of sintering forming at matrix,

In this manufacturing approach; It is the powder that has passed through 90 purpose sieve grates during with 90 purpose sieve grate classifications that above-mentioned hard forms powder mutually; By quality ratio; Have by what the Co of Mo:20-60%, Cr:3-12%, Si:1-12 quality %, surplus and unavoidable impurities were formed and form, and above-mentioned hard forms the hard phase that powder becomes the tissue that in the Co alloy phase, is dispersed with molybdenum silicide mutually

Above-mentioned matrix form powder be the ferrite-group stainless steel that contains the Cr of 11-32 quality %, the Cr that contains 11-32 quality % and 0.15-1.2 quality % C martensitic stainless steel and contain any powder of stainless steel of austenite stainless steel of Ni of Cr and the 3.5-22 quality % of 11-32 quality %; It more than its 90 quality % the powder that has passed through 300 purpose sieve grates during with 300 purpose sieve grate classifications; It is 50-70 quality % that above-mentioned hard forms powder shared ratio in the above-mentioned raw materials powder mutually

Wherein, said wearability sintered component is the wearability sintered component of in stainless steel base, having disperseed to become the hard phase of the tissue that in the Co alloy phase, is dispersed with molybdenum silicide.

2. the manufacturing approach of wearability sintered component according to claim 1; It is characterized in that; Above-mentioned powder of stainless steel; By quality ratio, further contain: below the Mo:0.3-7%, Cu:1-4%, Al:0.1-5%, N:0.3%, Mn:5.5-10%, Si:0.15-5%, below the Nb:0.45%, below the P:0.2%, below the S:0.15% and among below the Se:0.15% more than at least a kind.

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