阅读说明：本技术 一种三维预制体结构wc颗粒增强铁基复合材料的制备方法 (Preparation method of WC particle reinforced iron-based composite material with three-dimensional prefabricated body structure ) 是由 张飞 李祖来 伍星 �山泉 蒋业华 苟浩杰 廖泽鑫 于 2021-08-23 设计创作，主要内容包括：本发明公开一种三维预制体结构WC颗粒增强铁基复合材料的制备方法,属于复合材料制备方法技术领域。将WC颗粒、Ni粉、高碳铬铁粉按一定比例球磨混合均匀,将软体胶类加到具有不同孔状结构的塑料模具中凝固,形成中间凸起而周围凹槽的模具,将混合均匀的粉末填充到凹槽中制成带孔洞的预制体坯料,利用胶模较高的弹塑性将预制体取出放在加热炉中加热,使预制体中粘结剂固化成形,再将预制体放置到砂型型腔中固定,将金属铁液浇注到型腔中,使金属液流入到预制体孔洞中,溶解孔洞周围的预制体结构,形成均匀的WC铁基复合材料。本发明提出的制备方法工艺简单,可操作性强,生产周期较短,具有较均匀的复合材料组织,可显著提高WC铁基复合材料的硬度和耐磨性。(The invention discloses a preparation method of a WC particle reinforced iron-based composite material with a three-dimensional prefabricated body structure, and belongs to the technical field of preparation methods of composite materials. Ball-milling WC particles, Ni powder and high-carbon ferrochrome powder according to a certain proportion, uniformly mixing, adding soft glue into plastic molds with different porous structures for solidification to form molds with convex middle parts and peripheral grooves, filling the uniformly mixed powder into the grooves to prepare prefabricated body blanks with holes, taking out the prefabricated bodies by utilizing the higher elasticity and plasticity of the glue molds, placing the prefabricated bodies in a heating furnace for heating, solidifying and forming binders in the prefabricated bodies, placing the prefabricated bodies in a sand mold cavity for fixation, pouring molten metal iron into the cavity, allowing the molten metal to flow into the holes of the prefabricated bodies, dissolving the structures of the prefabricated bodies around the holes, and forming the uniform iron-based WC composite material. The preparation method provided by the invention has the advantages of simple process, strong operability, short production period and uniform composite material structure, and can obviously improve the hardness and the wear resistance of the WC iron-based composite material.)

1. A preparation method of a WC particle reinforced iron-based composite material with a three-dimensional prefabricated body structure is characterized by comprising the following steps of: preparing a porous three-dimensional preform structure in advance, and then dissolving and diffusing the preform by using a metal iron liquid to form a composite material, wherein the three-dimensional preform comprises, by weight, 40-60% of WC particles, 30-40% of Ni powder and 10-20% of high-carbon ferrochrome powder, and the particle size of the WC particles is 80-180 mu m; the particle size of the Ni powder is 250-350 meshes, and the particle size of the high-carbon ferrochrome powder is 200-300 meshes.

2. The method of preparing a three-dimensional preform structure WC particle-reinforced iron-based composite material according to claim 1, characterized in that: the metal iron liquid is high-chromium cast iron liquid.

3. The method for preparing a three-dimensional preform structure WC particle-reinforced iron-based composite material according to claim 1 or 2, comprising in particular the steps of:

(1) weighing WC particles, Ni powder and high-carbon ferrochromium powder serving as three-dimensional preform raw materials according to weight percentage, adding a bonding curing agent, and then adding the mixture into a ball milling tank for vacuum ball milling to obtain mixed powder;

(2) adding the soft glue into plastic molds with different sizes and different hole-shaped structures, solidifying the soft glue to form a mold with a plurality of bulges in the middle and grooves at the periphery, and adding the mixed powder after ball milling into the mold to be filled and compacted;

(3) placing a die containing prefabricated body structure powder in a heating furnace for stepped heating, curing a bonding curing agent when the bonding curing agent is heated to enable the prefabricated body raw material powder to be well combined, and then taking out the prefabricated body to obtain three-dimensional prefabricated body structures with different sizes and specifications;

(4) and (3) placing the three-dimensional preform structure in a sand mold cavity for fixing, pouring molten metal into the cavity, making the molten metal flow into holes of the preform structure, and permeating into the preform, so that the preform around the holes is dissolved and dispersed, thereby forming the uniform WC iron-based composite material.

4. The method of preparing a three-dimensional preform structure WC particle-reinforced iron-based composite material according to claim 3, characterized in that: the added WC particles are spherical or irregular, the bonding curing agent is water glass, and the addition amount of the bonding curing agent is 5-8% of the mass of the mixed powder.

5. The method of preparing a three-dimensional preform structure WC particle-reinforced iron-based composite material according to claim 3, characterized in that: and (4) forming holes in the three-dimensional preform obtained in the step (3) into a circular shape, wherein the diameter of each hole is 5-15 mm, and the thickness of the preform around each hole is 5-15 mm.

6. The method for preparing the WC particle-reinforced iron-based composite material with the three-dimensional preform structure according to any one of claims 3 to 5, wherein the method comprises the following steps: the conditions of the stepwise heating were: heating to 50-100 ℃ and preserving heat for 5-10 min, and then heating to 100-200 ℃ and preserving heat for 3-5 min.

7. The method of preparing a three-dimensional preform structure WC particle-reinforced iron-based composite material according to claim 6, characterized in that: the bottom pouring type gravity casting is adopted when the metal iron liquid is cast, and the casting temperature is 1450-1550 ℃.

Technical Field

The invention relates to a preparation method of a WC particle reinforced iron-based composite material with a three-dimensional prefabricated body structure, belonging to the technical field of ceramic particle reinforced metal-based composite materials.

Background

The traditional high-chromium cast iron is a common single-metal wear-resistant material at present, the high-chromium cast iron has insufficient wear resistance under working conditions of certain abrasive wear and the like, and the wear resistance is reduced along with the increase of the use environment temperature, and the like, and the ceramic particle reinforced steel-iron-based composite material has high hardness and high modulus of ceramic reinforced particles and good toughness and formability of iron base, wherein the WC particle reinforced iron-based composite material has high wear resistance, is easy to prepare and low in cost, so that extensive research is caused. Researchers at home and abroad carry out series research on WC reinforced iron-based composite materials, and patent CN 108103387A provides a nano WC particle reinforced high-chromium iron-based powder metallurgy material, which adopts 40h ball milling of WC particles, adds a plurality of alloy elements such as Cu, Mo, Ni, Cr, graphite and the like, and sinters the mixture in a hot pressing furnace to obtain the iron-based composite material with the nano WC particles, but the addition of a large amount of alloy elements increases the production cost, the ball milling process time is longer, and the production period is increased. In addition, the integral composite material has a certain composite effect on small and medium-sized wear-resistant parts, integral composite on large wear-resistant parts is difficult to realize, an infiltration layer of molten metal and a prefabricated body structure is small, and even the defects of shrinkage porosity and shrinkage cavity and the like are generated, so that the wear resistance of the composite material is reduced.

Disclosure of Invention

In order to overcome the defect of the ceramic particle reinforced iron base, the invention provides a preparation method of a WC particle reinforced iron base composite material with a three-dimensional prefabricated body structure, which comprises the following steps: preparing a porous three-dimensional preform structure in advance, and then dissolving and diffusing the preform by using a metal iron liquid to form a composite material, wherein the three-dimensional preform comprises, by weight, 40-60% of WC particles, 30-40% of Ni powder and 10-20% of high-carbon ferrochrome powder, and the particle size of the WC particles is 80-180 mu m; the particle size of the Ni powder is 250-350 meshes, and the particle size of the high-carbon ferrochrome powder is 200-300 meshes; the metal iron liquid is high-chromium cast iron liquid.

Further, the preparation method of the WC particle reinforced iron-based composite material with the three-dimensional preform structure specifically comprises the following steps:

(1) weighing WC particles, Ni powder and high-carbon ferrochromium powder serving as three-dimensional preform raw materials according to weight percentage, adding a bonding curing agent, and then adding the mixture into a ball milling tank for vacuum ball milling to obtain mixed powder;

(2) soft rubber (such as fluororubber and silicon rubber) with certain resilience plastic deformation capability, heat resistance and high temperature resistance is added into plastic molds with different sizes and different porous structures, a mold with a plurality of bulges in the middle and grooves around is formed after the soft rubber is solidified, and the mixed powder after ball milling is added into the mold and is filled and compacted;

(3) placing a die containing prefabricated body structure powder in a heating furnace for stepped heating, curing a bonding curing agent when the bonding curing agent is heated to enable the prefabricated body raw material powder to be well combined, and then taking out the prefabricated body to obtain three-dimensional prefabricated body structures with different sizes and specifications;

(4) and (3) placing the three-dimensional preform structure in a sand mold cavity for fixing, pouring molten metal into the cavity, making the molten metal flow into holes of the preform structure, and permeating into the preform, so that the preform around the holes is dissolved and dispersed, thereby forming the uniform WC iron-based composite material.

Preferably, the WC particles added in the step (1) are spherical or irregular, the bonding curing agent is water glass, and the addition amount of the bonding curing agent is 5-8% of the mass of the mixed powder.

Preferably, the shape of the holes in the three-dimensional preform obtained in step (3) of the present invention is circular, the diameter of the holes is 5-15 mm, and the thickness of the preform around the holes is 5-15 mm. According to practical needs, the shape of the holes in the method of the present invention can also be square, polygonal or irregular.

Preferably, the conditions of the stepwise heating of the present invention are: heating to 50-100 ℃ and preserving heat for 5-10 min, and then heating to 100-200 ℃ and preserving heat for 3-5 min.

Preferably, bottom pouring type gravity casting is adopted during the casting of the molten metal iron, and the casting temperature is 1450-1550 ℃.

All percentages in the present invention are mass percentages unless otherwise specified.

The principle of the invention is as follows: the WC/Fe-based surface layer composite material is taken as a research system, and alloy powder is added into a plastic die to form a three-dimensional preform structure with holes of different shapes and a certain wall thickness, so that preforms of different thicknesses and different structures can be obtained as required. Selecting WC particles which are high in hardness and modulus and completely wet with iron base, adding Ni which is insoluble in water and has plasticity and high temperature resistance, and simultaneously adding a small amount of high-carbon ferrochrome powder for promoting the particles to be dissolved in the compounding process, so that the composite material is convenient to apply to a wear-resistant composite material which runs in a heat-resistant wear-resistant service environment. The three-dimensional preform structure is heated in a heating furnace in a stepped mode, the binder is heated and solidified to enable the alloy powder of the preform to be well combined, then the preform is compounded with high-chromium cast iron with good toughness, the metal liquid infiltration capacity and the preform dissolution dissipation are utilized in the process, the metal liquid and WC ceramic particles in the preform are made to fully react, along with the reaction, a hard phase is separated out, an even surface layer integral composite material is formed, and the preparation of the high-thickness composite material is achieved. In addition, the element distribution and the tissue form in the composite material can be regulated and controlled by designing process parameters such as different hole diameters, hole wall thicknesses and the like, so that the thickness, the tissue uniformity and the performance of the composite layer are synchronously improved.

The invention has the beneficial effects that:

(1) designing a preform structure according to actual requirements to obtain a mold with a preliminary shape, filling a soft rubber material with certain resilience plastic deformation capacity, heat resistance and high temperature resistance into the mold to obtain a mold with a protrusion in the middle and a certain gap width around the protrusion, adding uniformly mixed preform powder into the mold, fully spreading and compacting, and realizing preforms with different structural characteristics and specifications.

(2) The mould containing the powder is sequentially heated to a certain temperature and insulated by a stepped heating and curing method, so that the binder in the powder is solidified and formed, and the prefabricated body is taken out by utilizing the excellent deformability of the soft rubber, thereby being beneficial to demoulding of the three-dimensional prefabricated body structure and improving the bonding strength of the three-dimensional prefabricated body structure.

(3) The prefabricated body structure and the high-chromium cast iron matrix are compounded through a casting infiltration method, molten metal and the prefabricated body with the three-dimensional prefabricated body structure fully react to be dissolved and dispersed, the thickness of a formed composite layer is increased, the composite structure is uniform, and the compactness is good.

(4) The WC ceramic particle configuration composite material obtained by the invention can dissolve a prefabricated body into molten iron in a large area, precipitate high-hardness carbide, can be applied to large ceramic particle reinforced iron-based wear-resistant parts, and obtains high hardness and wear resistance.

Drawings

FIG. 1 is a schematic diagram of the principle of the WC iron-based composite forming process of the invention.

Detailed Description

The process of the present invention is further illustrated by the following examples, but the scope of the invention is not limited to the contents of the examples.

Example 1

In the preparation method of the three-dimensional preform structure WC particle-reinforced iron-based composite material according to this embodiment, the composite forming process is shown in fig. 1, and specifically includes the following steps:

(1) respectively weighing 40% of irregular WC particles, 40% of Ni powder and 20% of high-carbon ferrochromium powder, wherein the particle size of the irregular WC particles is 80 microns, the particle size of the Ni powder is 250 meshes, and the particle size of the high-carbon ferrochromium powder is 200 meshes, then adding water glass, putting the mixture into a ball milling tank, and carrying out vacuum ball milling to obtain preform powder, wherein the adding mass of the water glass is 5% of the mass of the preform powder.

(2) Adding the fluororubber into a plastic mould with a pore structure with the diameter of 5mm, solidifying to form a mould with a circular bulge with the middle of 5mm and a groove at the periphery, and adding the prefabricated powder into the mould to be filled and compacted.

(3) And (3) placing the die containing the prefabricated body structure powder in a heating furnace, heating to 100 ℃ in a step-by-step manner, preserving heat for 10min, heating to 200 ℃ and preserving heat for 5min, and taking out the prefabricated body from the die to obtain the three-dimensional prefabricated body structure with the hole diameter of 5 mm.

(4) Placing the prefabricated body in a sand mold cavity for fixing, pouring high-chromium cast iron liquid into the cavity at the pouring temperature of 1550 ℃, and adopting bottom pouring type gravity casting to enable the molten metal to flow into holes of the prefabricated body structure, so that the prefabricated body around the holes is dissolved and dispersed, and thus the uniform WC iron-based composite material is formed.

The WC iron-based composite material prepared by the embodiment is proved to be a composite material prepared by the method to be dissolved to form an obvious composite layer area compared with high-chromium cast iron without any preform through microhardness and three-body abrasive wear experiments,

the thickness is about 180 μm, the microhardness is increased from 452HV of the matrix to 816HV of the composite layer, and the wear resistance is improved by 23%.

Example 2

The preparation method of the three-dimensional preform structure WC particle reinforced iron-based composite material specifically comprises the following steps:

(1) respectively weighing 50% of irregular WC particles, 35% of Ni powder and 15% of high-carbon ferrochromium powder, wherein the particle size of the irregular WC particles is 130 micrometers, the particle size of the Ni powder is 300 meshes, and the particle size of the high-carbon ferrochromium powder is 250 meshes, then adding water glass, putting the mixture into a ball milling tank, and carrying out vacuum ball milling to obtain preform powder, wherein the adding mass of the water glass is 6% of the mass of the preform powder.

(2) Adding the fluororubber into a plastic mould with a 10 mm-diameter porous structure, solidifying to form a mould with a 10 mm-middle circular bulge and a groove at the periphery, and adding the prefabricated powder into the mould to be filled and compacted.

(3) And (3) placing the die containing the powder with the preform structure in a heating furnace, heating the die to 75 ℃ in a step-by-step manner, preserving heat for 7.5min, heating the die to 150 ℃ and preserving heat for 4min, and taking out the preform from the die to obtain the three-dimensional preform structure with the hole diameter of 10 mm.

(4) Placing the prefabricated body in a sand mold cavity for fixing, pouring high-chromium cast iron liquid into the cavity at the pouring temperature of 1500 ℃, adopting bottom pouring type gravity casting to enable the molten metal to flow into holes of the prefabricated body structure, and enabling the prefabricated body around the holes to be dissolved and dispersed, thereby forming the uniform WC iron-based composite material.

The WC iron-based composite material prepared in the embodiment is subjected to microhardness and three-body abrasive wear tests, and compared with high-chromium cast iron without any preform and the embodiment 1, the composite layer formed by dissolving the preform after the composite through the method is thicker than the embodiment 1, the thickness is 420 mu m, the microhardness is increased from the base 452HV to 848HV of the composite layer, and the wear resistance is improved by 28%.

Example 3

The preparation method of the three-dimensional preform structure WC particle reinforced iron-based composite material specifically comprises the following steps:

(1) respectively weighing 60% of irregular WC particles, 30% of Ni powder and 10% of high-carbon ferrochromium powder, wherein the particle size of the irregular WC particles is 180 mu m, the particle size of the Ni powder is 350 meshes, and the particle size of the high-carbon ferrochromium powder is 300 meshes, then adding water glass, putting the mixture into a ball milling tank, and carrying out vacuum ball milling to obtain preform powder, wherein the adding mass of the water glass is 8% of the mass of the preform powder.

(2) Adding silicon rubber into a plastic mould with a 15 mm-diameter hole-shaped structure, solidifying to form a mould with a 15 mm-middle circular bulge and a groove at the periphery, and adding the prefabricated powder into the mould to be filled and compacted.

(3) And (3) placing the die containing the prefabricated body structure powder in a heating furnace, heating to 50 ℃ in a step-by-step manner, preserving heat for 5min, heating to 100 ℃ and preserving heat for 3min, and taking out the prefabricated body from the die to obtain the three-dimensional prefabricated body structure with the hole diameter of 15 mm.

(4) Placing the prefabricated body in a sand mold cavity for fixing, pouring high-chromium cast iron liquid into the cavity at the pouring temperature of 1450 ℃, and adopting bottom pouring type gravity casting to enable the molten metal to flow into holes of the prefabricated body structure, so that the prefabricated body around the holes is dissolved and dispersed, and the uniform WC iron-based composite material is formed.

The microhardness and three-body abrasive wear test of the WC iron-based composite material prepared in the embodiment shows that compared with high-chromium cast iron without any preform and the embodiment 1, the composite material prepared by the method has the most obvious preform collapse, the thickness of the composite layer is the largest and reaches 665 mu m, the microhardness is increased from the base 452HV to the 862HV of the composite layer, and the wear resistance is improved by 36%.

Example 4

The result of the results of the preparation method of the iron-based composite material reinforced by the three-dimensional preform structure WC particles is that spherical WC particles are adopted, and the rest steps are the same as those in example 3, and the results show that the WC iron-based composite material prepared in this example is that the effect of the composite layer is only second to that in example 3 after being compounded by the method, and reaches 620 μm, compared with high-chromium cast iron without any preform and example 3, the microhardness is increased from the base 452HV to 854HV of the composite layer, and the wear resistance is improved by 32%.