CN108220755A - A kind of method for preparing zirconium oxide-zirconium carbide particle enhancing gray cast iron - Google Patents

Abstract

The invention belongs to the field of cast iron materials, in particular to a method for preparing gray cast iron reinforced with zirconia-zirconium carbide particles. The mixed powder of activated carbon, graphite, zirconia powder, petroleum coke (or coal coke), and zirconium powder is blown into the gray cast iron melt through the mixed gas of carbon dioxide, methane, argon and oxygen, and the reinforced particles are formed through the reaction. The invention solves the problems of poor wettability between the added particles and the matrix alloy, easy interface reaction and poor structure stability because the reinforcing particles are produced by reaction in the gray cast iron melt. Particle-reinforced gray cast iron materials can take advantage of the gray cast iron matrix and reinforcing phase at the same time, and significantly improve the strength, elastic modulus, hardness and wear resistance of gray cast iron. At the same time, due to its low cost, high strength and high rigidity, particle reinforced gray cast iron materials have broad application prospects in modern industrial production fields such as advanced manufacturing.

Description

A method for preparing zirconia-zirconium carbide particle reinforced gray cast iron

technical field

The invention relates to the field of cast iron materials, in particular to a method for preparing gray cast iron reinforced with zirconia-zirconium carbide particles.

Background technique

Iron-carbon alloys with a carbon content greater than 2.11% are called cast iron. Most or all of the carbon in gray cast iron is in the form of free-state flake graphitization, and its fracture is gray. It has certain mechanical properties and good machining performance. , widely used in industrial production. In order to improve the mechanical properties of gray cast iron, the industry usually adopts inoculation treatment to obtain fine pearlite matrix and fine and uniformly distributed flake graphite structure in order to improve the mechanical properties of gray cast iron. The obtained inoculated cast iron can surpass the existing mechanical properties of gray cast iron The basis is obtained high-strength cast iron. In recent years, with the development of high-end mechanical and electrical products, the requirements for the mechanical properties of cast iron need to be further improved. Particle-reinforced gray cast iron materials can take advantage of the gray cast iron matrix and reinforcing phase at the same time, and significantly improve the strength, elastic modulus, and Hardness and wear resistance. At the same time, due to its low cost, high strength and high rigidity, particle reinforced gray cast iron materials have broad application prospects in modern industrial production fields such as advanced manufacturing.

For gray cast iron materials, under the premise of high strength and high rigidity; at the same time, gray cast iron is required to maintain good shock absorption performance, certain toughness, high hardness and wear resistance, which is widely used in industrial production for gray cast iron materials. Application matters. However, the stiffness, strength, hardness and wear resistance of gray cast iron materials need to be further improved, so as to achieve higher strength and wear resistance, and further expand the application field of gray cast iron.

Based on the above purpose, a method of adding non-toxic and non-polluting zirconia-zirconium carbide particles to the gray cast iron is adopted to enhance the strength, good toughness and hardness of the gray cast iron material. The chemical composition and weight percentage of the gray cast iron base material of the present invention are: C: 2.6-3.0, Mn: 0.8-1.3, Ni: 1-1.5, Cr: 0.2-0.4, P: 0.01-0.05, S: 0.03-0.15, ZrO: 0.2-0.8, Sn: 0.01-0.1. At present, in the patent application numbers 201210329569.3 and 201210404904.1 of the existing gray cast iron in my country, it is proposed that the inoculation treatment or the addition of rare earth and other elements in the casting process can improve the toughness, hardness and wear resistance of the gray cast iron material, but it must be achieved Higher strength and wear resistance require further research. The invention proposes a preparation method of a zirconia-zirconium carbide particle-reinforced gray cast iron material with stable processing technology, low production cost, no pollution discharge, and organization and production under conventional smelting conditions. Compared with traditional gray cast iron materials, the strength, Toughness, hardness and wear resistance are greatly improved. Therefore, in the present invention, the purpose of enhancing the mechanical properties of the gray cast iron material is achieved by adding zirconia-zirconium carbide particles.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and provide a preparation of a zirconia-zirconium carbide particle-reinforced gray cast iron material that has stable processing technology, low production cost, no pollution discharge, and can be organized and produced under conventional smelting conditions. Compared with the traditional gray cast iron material, the strength, toughness, hardness and wear resistance are greatly improved.

The technical scheme of the patent of the present invention is: the present invention is a preparation method of gray cast iron material reinforced with zirconia-zirconium carbide particles, and the precursor of zirconia-zirconium carbide particles is mixed by a mixed gas of carbon dioxide, methane, argon and oxygen The powder is blown into the gray cast iron melt, and a self-propagating combustion synthesis reaction occurs during the blowing process. Ultrafine zirconia-zirconium carbide reinforcement particles are generated through the reaction, and silver powder and copper powder are combined with tungsten carbide-silicon carbide particles to enhance the resistance The hot gray cast iron melt is added and smelted at a ratio of 1:99 by mass, and then mechanically mixed and stirred, modified, refined, and poured to obtain an ingot through high-pressure torsion and severe plastic deformation to obtain zirconia-zirconia carbide with antibacterial properties Particle-reinforced heat-resistant high-strength gray cast iron material.

In the above preparation method, the zirconia powder is added with absolute ethanol and stirred evenly, treated by ultrasonic vibration for 5 minutes to 10 minutes, then adding nano-sized activated carbon powder, continued ultrasonic vibration treatment for 10 minutes to 50 minutes, and then transferred to the crucible , and then calcined in a vacuum furnace at a high temperature of 1550-1800°C and held for 3 hours, cooled with the furnace and then ground; finally, ultrafine zirconia powder and zirconium carbide mixed powder particles with an average particle size of 40 nanometers to 100 nanometers were obtained.

ZrO ₂ +3C=(electric furnace) ZrC+2CO↑

The volume ratio of each component in each mixed gas in the above preparation method is methane (8-45): argon (8-35): oxygen (8-35): carbon dioxide (8-70); the pressure of the mixed gas is 0.05-0.3MPa, gas flow rate 0.02-0.15m ³ /min. Carbon dioxide is used to provide C element, and carbon dioxide and oxygen are used to provide O element. Argon is used as a diluent to adjust the reaction rate and particle growth rate.

The preparation method of the gray cast iron material reinforced by zirconia-zirconium carbide particles, the temperature of the gray cast iron melt is 700-800°C. The reaction time to generate reinforced particles is 10-60 minutes, and the higher the particle content requirement, the longer the reaction time to generate reinforced particles.

(1) The reaction-enhancing phase is ZrC and _ZrO2 particles synthesized in the melt state, and the following reactions mainly occur in the melt state:

CO ₂ +Zr=ZrO ₂ +2[C]

CO ₂ +Zr=ZrC+2[O]

ZrO ₂ +3[C]=ZrC+2CO↑

O ₂ +Zr=ZrO ₂

C+Zr=ZrC

CH ₄ +Zr=ZrC+2H ₂

Moreover, the reaction of the two products also has decomposition and further reaction between each other, which is a balanced process of mutual promotion and decomposition, so as to achieve the final balanced reaction speed. The size of the reinforcing particles is 0.1-1 μm. By adjusting the reaction time, reaction temperature, and the composition of the mixed gas, the composition (ratio of ZrC and ZrO ₂ ), particle size, quantity and distribution of the reinforced particles generated by the reaction can be controlled, so as to meet the use requirements of different parts. Activated carbon and graphite are used to provide carbon elements, and zirconia powder is used to provide zirconium carbide and zirconium elements.

The mixed preparation method of the precursor of zirconia-zirconium carbide particles: Stir the nano-sized zirconia powder, absolute ethanol and nano-sized activated carbon powder evenly, and then transfer them to the crucible after ultrasonic vibration treatment for 5 minutes to 50 minutes. Then it is calcined at 1550-1800°C in a vacuum furnace and held for 3 hours, cooled with the furnace and then ground; finally, ultrafine zirconia powder and zirconium carbide precursor powder with an average particle size of 40 nm-100 nm are obtained. The addition amount of precursor powder of superfine zirconia powder and zirconium carbide particles is 5% of alloy melt weight;

The chemical composition and weight percentage of the alloy used in the matrix of the present invention are: C: 2.6-3.0, Mn: 0.8-1.3, Ni: 1-1.5, Cr: 0.2-0.4, P: 0.01-0.05, S: 0.03-0.15, Cu: 0.2-0.8, Sn: 0.01-0.1. It can be smelted and provided through the above-mentioned components requiring alloy smelting. The gray cast iron base material is smelted in a resistance heating crucible furnace, and the silver powder and copper powder added to the hot gray cast iron melt are particles with an average particle size of 40 nanometers to 100 nanometers obtained by mechanical ball milling for 24 hours; In smelting, zirconia-zirconium carbide particles reinforce the heat-resistant gray cast iron material and then add silver powder and copper powder. The ratio of silver powder and copper powder is 50:50. The mass content of the zirconium particle-reinforced heat-resistant gray cast iron material is 1%, and the melt of the silver powder and copper powder and the zirconia-zirconium carbide particle-reinforced heat-resistant gray cast iron material is added and smelted in a ratio of 1:99 by mass percentage, After mechanical mixing and stirring, modification treatment, refining and pouring, the ingot of gray cast iron material reinforced with zirconia-zirconium carbide particles is obtained. The obtained ingot is deformed by high-pressure torsion at 400-500°C. The high-pressure torsion processing parameters are: the speed of the indenter is 600rpm, and the downforce is 1.2GPa. The test shows that the obtained zirconia-zirconium carbide particle-reinforced heat-resistant gray cast iron has high strength. toughness. The result is a gray cast iron material with greatly improved strength, toughness and hardness.

The zirconia-zirconium carbide particle-reinforced gray cast iron material does not require special equipment (no vacuum melting furnace, high temperature and high pressure equipment), and can be produced in a conventional gray iron foundry, and the smelted cast iron melt is directly poured into the pre-prepared In the casting mold, dentures are made after cooling. The invention has low investment, quick effect, and can quickly recover the investment cost.

Compared with the existing gray cast iron technology, the preparation method of zirconia-zirconium carbide particle reinforced gray cast iron material has the following advantages:

(1) The wear resistance, strength and durability are significantly improved, and the difference in mechanical properties of the samples poured at intervals of 2 hours is less than 6%, which will be conducive to the stable production of large batches and small-sized materials. The reinforcement particles are small in size, evenly distributed, high in structure stability, free from pollution on the surface, and well combined with the gray cast iron matrix. The room temperature mechanical properties and wear resistance of the material are significantly improved, especially suitable for applications such as materials and key aerospace components.

(2) The structure of cast iron has good stability and will not decompose toxic gases or dissolved substances, which is good for the health of customers. Because the reinforcing particles of the present invention are generated by the reaction in the melt of gray cast iron, it solves the problem of the relationship between the added particles and the cast iron matrix. Poor wettability, prone to interfacial reactions, and poor tissue stability. Due to the small size of the generated particles, the floating/sinking speed caused by the difference in specific gravity is small, it is not easy to segregate, and the production process has high stability.

(2) Obtained zirconia-zirconium carbide particles reinforced copper and silver metal combination in heat-resistant gray cast iron material has broad-spectrum antibacterial properties, which increases the application range of the material.

Description of drawings

The following is a detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings and examples.

Fig. 1 obtains the optical microstructure photograph of the sample of zirconia-zirconium carbide particle reinforced gray cast iron material;

Fig. 2 obtains the true stress-strain curve of the sample of gray cast iron material reinforced with zirconia-zirconium carbide particles.

From the optical photo of gray cast iron reinforced with zirconia-zirconium carbide particles shown in Figure 1, it can be seen that ZrC particles are uniformly distributed and in the sample, and that uniform ZrC particles are contained in the matrix of gray cast iron, which can greatly improve the mechanical properties of gray cast iron. performance. From the tensile true stress-strain curve of the gray cast iron sample reinforced with zirconia-zirconium carbide particles shown in Figure 2, it can be seen that the strength is 180.6% higher than that of the traditional sample.

Detailed ways

The best embodiment of the present invention is given below: according to the chemical composition range, the heat-resistant gray cast iron of the present invention is melted in a resistance heating crucible furnace. The chemical composition and weight percentage of the gray cast iron base material of the present invention are: C: 2.6-3.0, Mn: 0.8-1.3, Ni: 1-1.5, Cr: 0.2-0.4, P: 0.01-0.05, S: 0.03-0.15, Cu: 0.2-0.8, Sn: 0.01-0.1. The molten metal is heated to 1520°C, and the alloy is smelted through the above-mentioned composition requirements for smelting and providing. The gray cast iron matrix material is smelted in a resistance heating crucible furnace, and the precursor mixed powder of zirconia-zirconium carbide particles is blown into the gray cast iron melt through a mixed gas of carbon dioxide, methane, argon and oxygen. During the blowing process A self-propagating combustion synthesis reaction is produced in the medium, and ultrafine zirconia-zirconium carbide reinforced particles are generated through the reaction, which are blown into the cast iron melt, the gas pressure is 0.1Mpa, the gas flow rate is 0.05 m ³ /Min, the time is 10 minutes, and the amount of mixed powder added is 5% of the weight of the cast iron melt, add silver powder and copper powder to the zirconia-zirconium carbide particle reinforced heat-resistant gray cast iron material melt in smelting, and the addition ratio of silver powder and copper powder is 50:50, silver The mass content of powder and copper powder in the tungsten carbide-silicon carbide particle reinforced heat-resistant gray cast iron material is 1%, and the melt of silver powder and copper powder and tungsten carbide-silicon carbide particle reinforced heat-resistant gray cast iron material is Addition smelting at a ratio of 1:99, the silver powder and copper powder added to the gray cast iron melt are particles with an average particle size of 40 nanometers to 100 nanometers obtained by mechanical ball milling for 24 hours; then undergo modification and refining treatment, pouring the mold, heat preservation, and pouring and casting at 20 minutes and 80 minutes respectively. After mechanical mixing, metamorphic treatment, refining, and pouring, the ingot of heat-resistant gray cast iron material reinforced with tungsten carbide-silicon carbide particles was obtained, and the cast iron material was obtained. The ingot is deformed by high-pressure torsion at 400-500°C. The processing parameters of high-pressure torsion are: the speed of the indenter is 600rpm, and the downforce is 1.2GPa. T6 treatment is then carried out, and performance testing is carried out. The experimental results show that the tensile strength of the gray cast iron material reinforced by zirconia-zirconium carbide particles is 452.5Mpa, the Brinell hardness is 292, the corrosion performance: the weight loss ratio is 0.01761%, and the cost is 2.8 yuan/Kg. For example, after 80 minutes of heat preservation, the tensile strength at room temperature is 432.7 Mpa, the Brinell hardness is 281, the corrosion performance: the weight loss ratio is 0.01783%, and the cost is 2.8 yuan/Kg. Thus it can be seen that although the price of the zirconia-zirconium carbide particle reinforced gray cast iron material of the present invention is slightly higher than that of traditional gray cast iron, the tensile strength of the material of the present invention, wear resistance, especially hardness and structural stability are all significantly improved, and The production process has good stability and is convenient for mass production.

Claims (6)

1. in a kind of method for preparing zirconium oxide-zirconium carbide particle enhancing gray cast iron, it is characterized in that by carbon dioxide, methane, The precursor mixed-powder of zirconium oxide-zirconium carbide particle is blown into gray cast iron melt by the mixed gas of argon gas and oxygen, is being blown Self-propagating combustion synthetic reaction is generated during entering, generating superfine zirconia-zirconium carbide by reaction enhances particle, by silver powder End and copper powders and the heat-resisting gray cast iron melt of tungsten carbide-SiC particles reinforced are 1 by mass percentage:99 ratio is added Add melting, using mechanization mixing, Metamorphism treatment, refining, cast, obtain ingot casting and become by the violent plasticity of high pressure torsion Shape obtains the zirconium oxide with anti-microbial property-zirconium carbide particle enhancing heat-resistant high-strength gray cast iron material；

（a）The chemical composition and weight percent of gray cast iron basis material be for：C：2.6-3.0, Mn：0.8-1.3, Ni：1- 1.5, Cr：0.2-0.4, P：0.01-0.05, S：0.03-0.15, Cu：0.2-0.8, Sn：0.01-0.1；

（b）The volume proportion of each component is methane in mixed gas（8-45）：Argon gas（8-35）：Oxygen（8-35）：Carbon dioxide （8-70）；The pressure of mixed gas is 0.05-0.3MPa, gas flow 0.02-0.15m³/min；

（c）The precursor mixing preparation method of zirconium oxide-zirconium carbide particle：By the Zirconium oxide powder of nano-scale, absolute ethyl alcohol Stirred evenly with the active carbon powder of nano-scale, by sonic oscillation handle -50 minutes 5 minutes after, after be transferred in crucible, Then in a vacuum furnace under 1550-1800 DEG C of high-temperature calcination and keep the temperature 3 hours, furnace cooling then grind;It finally obtains average Superfine zirconia powder and the zirconium carbide precursor powder that granularity is 40 nanometers -100 nanometers；

（d）The precursor powder addition of superfine zirconia powder and zirconium carbide particle is the 5% of alloy melt weight；

（e）The silver powder and copper powders added into hot gray cast iron melt are put down by what mechanization ball-milling method obtained for 24 hours The particle that equal graininess is 40 nanometers -100 nanometers.

2. a kind of method for preparing zirconium oxide-zirconium carbide particle enhancing gray cast iron according to claim 1, it is characterized in that grey Cast iron matrix material melt contains the C element that weight percent is 2.6-3.0, Mn elements that weight percent is 0.8-1.3, again Measure the Mn elements that percentage is 1-1.5,1480-1560 DEG C of the temperature of gray cast iron melt.

3. according to a kind of method for preparing zirconium oxide-zirconium carbide particle enhancing gray cast iron of claim 1, it is characterized in that：Reaction life Time into enhancing particle is 15-60 minutes, and the time of the higher reaction generation enhancing particle of granule content requirement is longer.

4. a kind of method for preparing zirconium oxide-zirconium carbide particle enhancing gray cast iron according to claim 1, it is characterized in that： Into melting, zirconium oxide-zirconium carbide particle enhances in heat-resisting gray cast iron material melt adds silver powder and copper powders again, wherein silver The adding proportion of powder and copper powders is is 50：50, silver powder and copper powders enhance heat-resisting ash in zirconium oxide-zirconium carbide particle Mass content in cast iron materials is 1%, and silver powder and copper powders are enhanced heat-resisting gray cast iron material with zirconium oxide-zirconium carbide particle It is 1 by mass percentage to expect melt:99 ratio is added melting, by mechanization mixing, Metamorphism treatment, refining, Cast obtains zirconium oxide-zirconium carbide particle enhancing gray cast iron material ingot casting.

5. a kind of method for preparing zirconium oxide-zirconium carbide particle enhancing gray cast iron according to claim 1, it is characterized in that： It obtains ingot casting to deform by high pressure torsion at 400-500 DEG C, high pressure torsion machined parameters are：The rotating speed of pressure head for 600rpm, under Pressure is 1.2GPa, and test shows that obtained zirconium oxide-zirconium carbide particle enhances heat-resisting gray cast iron and has high-strength tenacity.

6. a kind of method for preparing zirconium oxide-zirconium carbide particle enhancing gray cast iron according to claim 1, it is characterized in that： Obtaining copper and silver metal in zirconium oxide-heat-resisting gray cast iron material of zirconium carbide particle enhancing and combining has broad-spectrum antiseptic attribute, increase The application range of the material.