CN102225469B - Ceramic grid-enhanced metal wear-resistant composite and preparation method thereof - Google Patents
Ceramic grid-enhanced metal wear-resistant composite and preparation method thereof Download PDFInfo
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- CN102225469B CN102225469B CN 201110150166 CN201110150166A CN102225469B CN 102225469 B CN102225469 B CN 102225469B CN 201110150166 CN201110150166 CN 201110150166 CN 201110150166 A CN201110150166 A CN 201110150166A CN 102225469 B CN102225469 B CN 102225469B
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Abstract
The invention discloses a ceramic grid-enhanced metal wear-resistant composite and a preparation method thereof, wherein the ceramic grid-enhanced metal wear-resistant composite consists of a metal-base wear-resistant part body, a groove is arranged on the surface of the metal-base wear-resistant part body and internally provided with a ceramic grid, a clearance is reserved between the ceramic grid and the metal-base wear-resistant part body, and self-fluxing alloy powder sintering body in metallurgy combination with the metal-base wear-resistant part body is arranged in the clearance and the meshes of the ceramic grid. In the invention, under the vacuum sintering state, the ceramic grid can not produce defects such as cracking, breaking and the like; the self-fluxing alloy and the wear-resistant part matrix are in metallurgy combination, so that the combination with the ceramic grid is firm; the process is simple, and the prepared materials can achieve the needed hardness without thermal treatment; and the difficultly in combining the ceramic with the metal matrix can be solved, and the defects brought by s pouring process can be avoided.
Description
Technical field
The present invention relates to a kind of ceramic grid and strengthen abrasion-resistant metal composite and preparation method.Belong to the metal-base composites preparation field, be specially adapted to power plant, steel mill or cement plant Roller of Coal Grinder and mill etc.
Background technology
Wearing and tearing are a kind of fundamental types that parts lost efficacy, and are prevalent in many industrial departments such as metallurgy, mine, electric power, machinery, national defence, military project, Aero-Space, and this has caused the significant wastage of material and the huge consumption of the energy.According to incompletely statistics, the present domestic annual metal wear resistant material that consumes is up to more than 5,000,000 tons, wherein because causing the steel ball consumption of ball mill, wearing and tearing reach 1,000,000 tons every year, ball mill and various lining board of crusher consume nearly 400,000 tons, nearly 700,000 tons of roll consumption, various engineering excavation machines and loading machine bucket tooth, Wearproof transfer piping made, grinder hammerhead, creeper tread and grinding roller, lining board for grinding discs etc. consumptions surpass 600,000 tons, and 200,000 tons of railway switch and wheels, various mould steel consume nearly 1,500,000 tons.
Above data improve the abrasion resistance properties of plant equipment and parts as can be known, can greatly reduce energy resource consumption, enhance productivity.As everyone knows, pottery has high abrasion resistance properties, and metal has good processing toughness.These performances are difficult in same material harmonious, and in order to solve this contradiction, using composite is to select preferably.
The ceramic base metallic composite can get up high rigidity, high wear resistance performance and the good toughness combination of metallic matrix of pottery, is a kind of widely used composite.
Common wear resistance castings is strengthened mainly to be divided into and is added particle and become particle strengthening with in-situ endogenic.Adding ceramics particle strengthened method is divided into mechanical mixing method and adds that ceramic particle, Infiltration Casting method add ceramic particle, centre spinning adds ceramic particle etc.
Yet adding the ceramic particle casting has the three aspects: drawback: the pollution of first particle and basal body interface and the generation of attachment make matrix and strengthen the diamond retention reduction; It two is restrictions that the ratio that strengthens particle is subject to initial powder, and most particle sizes are all greater than 1 μ m, and grain shape is wedge angle matrix is isolated effect; It three is that thermodynamic stability is poor, strengthens particle and at high temperature easily decomposes.Although original position generates the ceramic particle method and is improved at foundry goods and ceramic wetability, have that the foundry goods wearing layer is thin, the influence factor of chemical reaction is many, wild phase only is the defectives such as cermet, also be not easy to the preparation of larger wear resistance castings.
Chinese invention patent (CN 101585081A) adopts binding agent and specific mould to prepare ceramic performs, then pour into a mould, simple to operate, can produce in batches, but because metal is different with ceramic thermal coefficient of expansion, and pottery is prone to crackle, particularly oxide ceramics crackle, Fragmentation Phenomena are more obvious in the casting process, in addition, the combination between metal and the pottery is mechanical bond and can not realize metallurgical binding.Chinese invention patent (201010235198.3) adopts metal dust to mix with ceramic particle together with mould to carry out sintering in the vacuum drying oven sintering furnace; metal powder is bonded together the formation precast body with ceramic particle; precast body is put into the end face of casting mold die cavity; and then precast body poured into a mould, form particulate reinforced composite.This technique has solved the difficult problem of oxide ceramics infiltration, and ceramic particle be combined well with molten metal, but technique still complexity, particle and metal combination still are mechanical bond in essence.
Yet self-melting alloy refers to that fusing point is lower, voluntarily deoxidation in the melting process, slag making, can " wetting " substrate surface and present a class alloy of metallurgical binding.Behind the alloy graining, in solid solution, can form the dispersion-strengtherning phase of high rigidity, the intensity of alloy and hardness are improved.
At present, most self-melting alloy all add an amount of boron, element silicon and make in iron-based, Ni-based, cobalt-base alloys.Low-alloyed fusing point can fall in boron, silicon, and can cause between the solid phase of alloy and the liquid phase wider temperature range being arranged, boron, element silicon all can with common matrix material, such as nickel, cobalt, iron etc., at high temperature generate low-melting eutectic, make the alloy melting point decrease, the fusing point of Ni-based, cobalt-based, iron-base self-fluxing alloy is respectively about 800 ℃, 800 ℃, 1000 ℃.In addition, boron, element silicon can be put forward heavy alloyed hardness.
Summary of the invention
The object of the present invention is to provide good ceramic grid enhancing abrasion-resistant metal composite and the preparation method of anti-wear performance who is metallurgical binding and high strength interlock between simple, the ceramic grid of a kind of technique and the metallic matrix by self-melting alloy.
Technical solution of the present invention is:
A kind of ceramic grid strengthens the abrasion-resistant metal composite, it is characterized in that: comprise Metal Substrate wearing piece body, at Metal Substrate wearing piece body surface groove is set, ceramic grid is set in the groove, gapped between pottery grid and the Metal Substrate wearing piece body, the self-fluxing alloyed powder sintered body with Metal Substrate wearing piece body metallurgical binding is set in the mesh of described gap and ceramic grid.
Described Metal Substrate wearing piece material is potassium steel, steel alloy, high carbon ferro-chrome or nickel chromium triangle low-alloy cast iron; Described ceramic network graticule mesh hole is column, shape of threads, taper or rhombus; Described self-fluxing alloyed powder is Ni-based, iron-based or cobalt-based self-melting alloy; Described ceramic grid is cermet, oxide ceramics, nitride ceramics, carbide ceramics.
A kind of ceramic grid strengthens abrasion-resistant metal composite manufacture method, it is characterized in that: comprise the following steps: successively
(1) take the Metal Substrate wearing piece as body, at body surface groove is set;
The ceramic grid that (2) will sinter is put into the wearing piece groove, gapped between pottery grid and the body, it is suitable for the mixed self-fluxing alloyed powder of absolute ethyl alcohol to fill up in the gap, the addition of absolute ethyl alcohol is 1%～4% of self-fluxing alloyed powder quality, also fill full self-fluxing alloyed powder in the grid hole, and then wearing piece integral body is positioned over 80 ℃～100 ℃ lower dryings;
(3) dried wearing piece integral body is put into vacuum drying oven, be that 1000 ℃～1150 ℃, vacuum are sintering under the 0.1Pa in temperature, self-fluxing alloyed powder generation melting also produces firmly metallurgical binding with the wearing piece matrix, and ceramic grid is wrapped in the wearing piece groove securely by self-melting alloy;
(4) after the cooling, from vacuum drying oven, take out, get product.
The pottery grid is cermet, oxide ceramics, nitride ceramics or carbide ceramics, and mesh can be cylindricality, taper, thread-shaped or rhombus.
Product surface hardness of the present invention is HRC65～75.
Advantage of the present invention:
(1) under the vacuum-sintering state, ceramic grid can not crack, the defective such as cracked;
(2) bottom surface of self-melting alloy and wearing piece matrix, side, surface produce metallurgical binding, and form the metallic object grid and ceramic grid interlock firm;
(3) simple, the preparation material of technique just need not heat-treated and can be reached required hardness;
(4) solve pottery and metallic matrix in conjunction with the difficult problem of difficulty, avoided under the molten iron high temperature that pouring technology brings causing from the different of the thermal coefficient of expansion of pottery ceramic cracked defective;
(5) the wear-resisting workpiece surface is made of ceramic grid and self-melting alloy, makes wearing piece have higher wearability.
Description of drawings
The invention will be further described below in conjunction with drawings and Examples.
Fig. 1 has the coal pulverizer lining board for grinding discs that ceramic grid strengthens.
Fig. 2 has the Roller of Coal Grinder surface liner plate that ceramic grid strengthens.
The specific embodiment
Embodiment 1: the coal pulverizer mill
(1) take the coal pulverizer lining board for grinding discs as body, at body surface groove is set;
The ceramic grid that (2) will sinter is put into the liner plate groove, gapped between pottery grid and the body, it is suitable for the mixed self-fluxing alloyed powder of absolute ethyl alcohol that in the gap and surface is filled up, the addition of absolute ethyl alcohol is 1%～4% of self-fluxing alloyed powder quality, it is full suitable for the mixed self-fluxing alloyed powder of absolute ethyl alcohol also to fill in the grid hole, and then wearing piece integral body is positioned over 80 ℃～100 ℃ lower dryings;
(3) dried liner plate integral body being put into the vacuum drying oven temperature is that 1000 ℃～1150 ℃, vacuum are sintering under the 0.1Pa, self-fluxing alloyed powder generation melting also produces firmly metallurgical binding with wearing piece bottom surface, side, surface, and ceramic grid is wrapped in the wearing piece groove securely by self-melting alloy.If ceramic grid is cermet, then self-melting alloy and its generation metallurgical binding; If ceramic grid is oxide ceramics, nitride ceramics, carbide ceramics, then grid hole can be designed to cylindricality, taper or thread-shaped, and this structure can make ceramic network lattice and self-melting alloy produce firmly interlocking;
(4) after the cooling, from vacuum drying oven, take out, liner plate is assembled in the mill surface, can obtain coal pulverizer mill surface and have the wearing composite material that ceramic grid strengthens body.
Embodiment 2: Roller of Coal Grinder
(1) take Roller of Coal Grinder surface liner plate as body, at body surface groove is set;
The ceramic grid that (2) will sinter is put into the liner plate groove, gapped between pottery grid and the body, it is suitable for the mixed self-fluxing alloyed powder of absolute ethyl alcohol to fill up in gap and the surface, the addition of absolute ethyl alcohol is 1%～4% of self-fluxing alloyed powder quality, it is full suitable for the mixed self-fluxing alloyed powder of absolute ethyl alcohol also to fill in the grid hole, and then wearing piece integral body is positioned over 80 ℃～100 ℃ lower dryings;
(3) dried liner plate integral body being put into the vacuum drying oven temperature is that 1000 ℃～1150 ℃, vacuum are sintering under the 0.1Pa, self-fluxing alloyed powder generation melting also produces firmly metallurgical binding with wearing piece bottom surface, side, surface, and ceramic grid is wrapped in the wearing piece groove securely by self-melting alloy.If ceramic grid is cermet, then self-melting alloy and its generation metallurgical binding; If ceramic grid is oxide ceramics, nitride ceramics, carbide ceramics, then grid hole can be designed to cylindricality, taper or thread-shaped, and this structure can make ceramic network lattice and self-melting alloy produce firmly interlocking;
(4) after the cooling, from vacuum drying oven, take out, liner plate is assembled in roller surface, can obtain the Roller of Coal Grinder surface and have the wearing composite material that ceramic grid strengthens body.
Claims (2)
1. a ceramic grid strengthens abrasion-resistant metal composite manufacture method, it is characterized in that: ceramic grid strengthens the abrasion-resistant metal composite and comprises Metal Substrate wearing piece body, at Metal Substrate wearing piece body surface groove is set, ceramic grid is set in the groove, gapped between pottery grid and the Metal Substrate wearing piece body, the self-fluxing alloyed powder sintered body with Metal Substrate wearing piece body metallurgical binding is set in the mesh of described gap and ceramic grid; The preparation method comprises the following steps: successively
(1) take the Metal Substrate wearing piece as body, at body surface groove is set;
The ceramic grid that (2) will sinter is put into the wearing piece groove, gapped between pottery grid and the body, it is suitable for the mixed self-fluxing alloyed powder of absolute ethyl alcohol that in the gap and surface is filled up, the addition of absolute ethyl alcohol is 1%～4% of self-fluxing alloyed powder quality, also fill full self-fluxing alloyed powder in the grid hole, and then ceramic grid metal composite wearing piece integral body is positioned over 80 ℃～100 ℃ lower dryings;
(3) dried ceramic grid metal composite wearing piece integral body is put into vacuum drying oven, be that 1000 ℃～1150 ℃, vacuum are sintering under the 0.1Pa in temperature, self-fluxing alloyed powder generation melting also produces firmly metallurgical binding with the wearing piece matrix, and ceramic grid is wrapped in the wearing piece groove securely by self-melting alloy;
(4) after the cooling, from vacuum drying oven, take out, get product.
2. ceramic grid according to claim 1 strengthens abrasion-resistant metal composite manufacture method, and it is characterized in that: described Metal Substrate wearing piece material is steel alloy, high carbon ferro-chrome or nickel chromium triangle low-alloy cast iron; Described ceramic network graticule mesh hole is cylindric, shape of threads, taper or diamond shaped; Described self-fluxing alloyed powder is Ni-based, iron-based or cobalt-based self-melting alloy; Described ceramic grid is cermet, oxide ceramics, nitride ceramics, carbide ceramics.
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| CN102225469B true CN102225469B (en) | 2013-01-09 |
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| CN102581271A (en) * | 2012-03-30 | 2012-07-18 | 吉林大学 | Powder metallurgy material mixing method |
| WO2014019588A1 (en) * | 2012-07-31 | 2014-02-06 | Flsmidth A/S | Method for producing a wear-resistant component |
| CN103131969B (en) * | 2013-03-07 | 2015-01-28 | 南通高欣金属陶瓷复合材料有限公司 | Ceramic grid enhanced metal matrix composite perform and preparation method thereof |
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| CN104588664B (en) * | 2015-01-30 | 2016-11-09 | 上海工程技术大学 | A kind of Metal Packaging ceramic matrix composite and preparation method thereof and application |
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| CN107740095A (en) * | 2017-10-19 | 2018-02-27 | 西安科技大学 | Metal composite wearing plate |
| CN108941561B (en) * | 2018-08-07 | 2020-04-10 | 吉林大学 | Coupling bionic part resistant to high-temperature erosion and abrasion |
| CN110744064B (en) * | 2019-11-20 | 2021-12-03 | 中国人民解放军军事科学院国防科技创新研究院 | Metal ceramic composite lattice armor with three-dimensional constraint structure and preparation method and application thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3916388B2 (en) * | 2000-09-14 | 2007-05-16 | 三島光産株式会社 | Manufacturing method of continuous casting mold |
| CN101214540A (en) * | 2008-01-07 | 2008-07-09 | 吉林大学 | Method for preparing TiC/TiB2 biphase ceramic granule partial reinforced manganese steel composite material |
| CN101239382A (en) * | 2008-03-12 | 2008-08-13 | 成都利君科技有限责任公司 | Abrasion-proof composite roller, board and manufacturing method thereof |
| CN101792906A (en) * | 2010-04-12 | 2010-08-04 | 吉林大学 | Bionic coupling method for processing machinery parts by local laser melting and consolidation |
| CN101844208A (en) * | 2010-04-01 | 2010-09-29 | 钱兵 | Production process of high-chromium alloy ceramic particle composite grids |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0689380B2 (en) * | 1988-12-07 | 1994-11-09 | 東芝機械株式会社 | Corrosion-resistant wear-resistant member and manufacturing method thereof |
-
2011
- 2011-06-07 CN CN 201110150166 patent/CN102225469B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3916388B2 (en) * | 2000-09-14 | 2007-05-16 | 三島光産株式会社 | Manufacturing method of continuous casting mold |
| CN101214540A (en) * | 2008-01-07 | 2008-07-09 | 吉林大学 | Method for preparing TiC/TiB2 biphase ceramic granule partial reinforced manganese steel composite material |
| CN101239382A (en) * | 2008-03-12 | 2008-08-13 | 成都利君科技有限责任公司 | Abrasion-proof composite roller, board and manufacturing method thereof |
| CN101844208A (en) * | 2010-04-01 | 2010-09-29 | 钱兵 | Production process of high-chromium alloy ceramic particle composite grids |
| CN101792906A (en) * | 2010-04-12 | 2010-08-04 | 吉林大学 | Bionic coupling method for processing machinery parts by local laser melting and consolidation |
Non-Patent Citations (2)
| Title |
|---|
| JP平2-156005A 1990.06.15 |
| JP特许第3916388号B2 2007.05.16 |
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