CN1868635A - Preparation method of local reinforced steel base composite material for synthosizing TiC particle in mould - Google Patents

Abstract

The invention relates to a method for preparing a steel-based composite material locally synthesized by TiC particles in a mold, and its purpose is to overcome the conventional use of pure Ti powder to prepare endogenous TiC particle-reinforced steel-based composite materials, which is expensive and reacts violently in the cavity , the disadvantage of being difficult to control. The specific process includes two stages: the preparation of the reaction prefabricated block and the high-temperature synthesis reaction in the mold: a) The preparation of the prefabricated block is to uniformly mix a certain amount and particle size of Al powder, C powder, and Ti-Fe powder, press and form, and vacuum Heating equipment, dehumidification and degassing, and passivation treatment at the same time; b) The high-temperature synthetic particle reinforcement phase in the mold is to place a prefabricated block that has undergone vacuum high-temperature dehumidification, degassing and passivation treatment on the part of the casting that needs to be strengthened, and then cast the high-temperature molten steel into In the casting mold, the high-temperature synthesis reaction of the prefabricated block in the mold is initiated to generate a particle-reinforced phase. This method successfully solves the problems encountered in the preparation of particle-reinforced composite materials by adding particle method and integral reinforcement method.

Description

Preparation method of locally reinforced steel-matrix composite material synthesized in mold by TiC particles

technical field

The present invention relates to a method for preparing a locally reinforced cast steel-based composite material with particles, in particular to a method for preparing a locally reinforced cast steel-based composite material with TiC particles by using Ti-Fe powder instead of pure Ti powder.

Background technique

TiC particle-reinforced steel-matrix composites have become a hot spot in the research of steel-matrix composites due to their excellent comprehensive properties such as high strength, high specific modulus, heat resistance, and fatigue resistance. At present, pure Ti powder is generally used to prepare endogenous TiC particle-reinforced steel matrix composites. Due to the high price of pure Ti powder, it is not conducive to industrialization and commercialization, and the reaction in the cavity is relatively violent and difficult to control. Therefore, The present invention proposes a preparation method of local TiC particle reinforced casting steel matrix composite material with simple process, low cost and easy popularization and use, that is, Ti-Fe powder is used instead of pure Ti powder to prepare TiC particles of the reinforcing phase, which improves the prepared TiC particles. While improving the performance of composite materials, the cost is greatly reduced.

Contents of the invention

The purpose of the present invention is to overcome the conventional use of pure Ti powder to prepare endogenous TiC particle-reinforced steel matrix composites, which is expensive, and reacts violently in the cavity and is difficult to control, and provides a simple process, low cost, and easy to popularize. A method for the preparation of locally reinforced steel matrix composites using in-mold synthesis of TiC particles.

According to the relevant alloy phase diagram, considering that the reaction and cooling process are carried out in a non-equilibrium state, the following reactions may occur in molten iron:

             

         

         

         

Through thermodynamic calculations, it can be seen that for the Fe-Ti-C-Al system, the thermodynamic stability of TiC is much greater than that of Fe ₂ Ti, TiAl ₃ , Fe ₃ C, Al ₄ C ₃ and other phases, and in most cases, in TiC can be formed in molten steel at 1600 °C. It provides a theoretical basis for the study of high-temperature synthesis of Fe-Ti-C-Al system to prepare TiC particles locally reinforced cast steel matrix composites.

The specific technical scheme of the present invention is: place the prefabricated block after vacuum degassing in the part of the casting that needs to be reinforced, pour the matrix molten steel, make the prefabricated block in the mold undergo a high-temperature synthesis reaction to generate a TiC particle reinforcement phase, and prepare the TiC particles locally reinforced steel matrix composites. The process includes two stages: the preparation of the reaction prefabricated block and the high-temperature synthesis reaction in the mold:

(1) Preparation of prefabricated blocks: Al powder (industrial aluminum powder), C powder, Ti-Fe powder (20%≤Ti content≤80%) of a certain amount and granularity are packed in ball mill, ball mill 4-10h, make uniform, then put the uniformly mixed raw materials into the mold, press them at room temperature, and then put the pressed prefabricated blocks into the vacuum heating device, 10 ^-6 ≤vacuum degree ≤10 ^-1 MPa, at 5-30 ℃/min heating rate to 300±100℃, dehumidification and degassing for 3±1.5 hours, and argon gas for pretreatment at the same time;

Wherein the atomic ratio of Ti and C is 0.8-1.2, 0≤Al content≤30%, the particle size of C powder is less than 100 μm, and the particle size of Al and Ti-Fe powder is less than 200 μm.

(2) In-mold high-temperature synthetic particle reinforcement phase: place a prefabricated block that has been dehumidified and pretreated at the part of the casting that needs to be reinforced, and pour high-temperature molten steel into the mold to trigger the reaction of the prefabricated block in the mold to generate particle reinforcement. Phase, prepared TiC particles locally reinforced cast steel matrix composites.

The present invention has the following advantages:

1) Using Ti-Fe powder instead of pure Ti powder makes the high-temperature synthesis reaction in the cavity relatively mild and easy to control;

2) The process is simple, the cost is low, easy to popularize and apply, and carry out large-scale commercial production;

3) Successfully solved the problem of poor impact toughness of the steel matrix composite material produced by the overall composite method;

4) It avoids the disadvantages of poor wettability, easy contamination, poor interfacial bonding, particle segregation, and easy distribution in grain boundaries caused by the addition of particles.

Description of drawings

Fig. 1(a) Al(10wt%)+C+Ti-Fe interface structure between the matrix and the reinforced area of the steel matrix composite material locally reinforced by particles;

Fig. 1(b) Al(30wt%)+C+Ti-Fe interface structure between the matrix and the reinforced area of the steel matrix composite material locally reinforced by particles;

Fig. 2(a) Al(10wt%)+C+Ti-Fe structure in the reinforced area of the steel matrix composite material locally reinforced by particles;

Fig. 2(b) Particle-reinforced steel-matrix composite reinforced area structure Al(30wt%)+C+Ti-Fe.

Detailed ways

Using the high-temperature reaction endogenous TiC particles prepared by the invention to locally reinforce the cast steel-based composite material greatly improves the mechanical properties and wear resistance of the composite material while not affecting the inherent advantages of the matrix steel, and has good application prospects and markets. potential. Using manganese steel, 45 ^# steel, and 35CrMnSi as substrates respectively, the microhardness (HV) and wear resistance of the TiC particles locally reinforced cast steel matrix composites prepared have been greatly improved. 4.34 times that of steel, 2.4 times that of 45 ^# steel matrix, and 2.3 times that of 35CrMnSi matrix. The specific data are shown in Table 1.

Table 1 Material Microhardness (HV) Relative wear resistance Ti:C Al content Manganese steel matrix matrix reinforcement zone 45 ^# steel matrix matrix reinforcement zone 35CrMnSi matrix matrix reinforcement zone 416112271813277051306 14.3412.412.3 0.81.01.1 30% 20% 5%

The present invention is a preparation process of TiC particle locally reinforced steel-based composite material that is easy to popularize and use. Ti-Fe powder is used to replace pure Ti powder, which greatly reduces production costs. The method of prefabricated blocks makes the formation of TiCp and the molding of castings one time The production efficiency is improved, the waste of energy is reduced, and the shortcomings of the particle-reinforced composite material prepared by the method of adding particles and the overall reinforcement method are successfully avoided.

Claims (1)

1. A method for preparing a locally reinforced steel matrix composite material synthesized by TiC particles in a mold, characterized in that the process includes two stages of reaction prefabricated block preparation and in-mold high-temperature synthesis reaction. a) Preparation of prefabricated blocks: put industrial Al powder, C powder, and Ti-Fe powder of a certain amount and particle size into a ball mill, wherein 20%≤Ti content≤80%, ball mill for 4-10h to make it uniform, and then put The uniformly mixed raw materials are put into the mold, pressed at room temperature, and then the pressed prefabricated block is placed in a vacuum heating device, 10 ^-6 ≤ vacuum degree ≤ 10 ^-1 MPa, heated at 5-30°C/min Heating at a rate of 300±100°C, dehumidification and degassing for 3±1.5 hours, and at the same time passing argon for passivation treatment; wherein the atomic ratio of Ti and C is 0.8-1.2, 0≤Al content≤30%, C powder particle size<100μm, Al, Ti-Fe powder particle size <200μm. b) In-mold high-temperature synthetic particle reinforcement phase: place prefabricated blocks that have undergone vacuum high-temperature dehumidification, degassing, and pretreatment on the part of the casting that needs to be reinforced, and then pour high-temperature molten steel into the mold to initiate the high-temperature synthesis reaction of the prefabricated blocks in the mold. The particle-reinforced phase is generated, and the TiC particle locally reinforced cast steel matrix composite is prepared.

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