KR100238953B1 - Process for the preparation of functionally gradient material tin on carbon steel - Google Patents

Abstract

The present invention relates to a method for producing a TiN / carbon steel gradient functional material comprising applying TiN powder or a ceramic powder containing a TiN component to a surface of a carbon steel material and scanning the accelerated electron beam after pressing. Among other things, it is possible to work continuously and to simplify the manufacturing process. In addition, there is an advantage that can prevent the pores and cracks generated during the production by the addition of a solvent.

Description

PROCESS FOR THE PREPARATION OF FUNCTIONALLY GRADIENT MATERIAL TIN ON CARBON STEEL}

The present invention relates to a method for producing TiN / carbon steel functionally gradient materials using an accelerated electron beam.

Conventional known methods for producing functional materials include chemical vapor deposition, physical vapor deposition, plasma spray coating, diffusion bonding, laser welding, and the like.

These methods have disadvantages of difficulty in working in the air, complicated manufacturing processes, high time and cost, and difficulty in continuous manufacturing. In addition, since the material is exposed to the air for a long time, it is difficult to expect the improvement of material properties due to the decrease of the interfacial bonding force due to the formation of the oxide layer.

Accordingly, an object of the present invention is to produce a TiN / carbon steel gradient functional material capable of working in the air, can be continuous operation, improve the material properties of the gradient functional layer and can prevent pores or cracks generated during manufacturing To provide.

1 is a graph showing the content change of the Ti element component with the depth from the surface of the TiN / carbon steel gradient functional material prepared according to an embodiment of the present invention.

2 is a graph showing the change in hardness with depth from the surface of the TiN / carbon steel gradient functional material prepared according to an embodiment of the present invention.

In order to achieve the above object, the present invention provides a method for producing a TiN / carbon steel gradient functional material comprising applying a TiN powder or a ceramic powder containing a TiN component to a surface of a carbon steel material and scanning the accelerated electron beam after pressing. .

Hereinafter, the present invention will be described in detail.

The base material of the inclined functional material used in the present invention is ordinary carbon steel, and preferably carbon steel containing 0.1-0.4% by weight of carbon and trace amounts of alloying elements. TiN powder or ceramic powder containing a TiN component is applied to the surface of the carbon steel material. Considering the material properties as the warp functional material, a TiN powder or a ceramic powder containing a TiN component having high hardness and excellent heat resistance, abrasion resistance, and corrosion resistance is used. In addition, a solvent (flux) can be mixed and used, in which the solvent acts to suppress the formation of an oxide layer and the generation of pores and quench cracks, preferably Na ₂ B ₄ O ₇ -10H ₂ O. The surface curing effect varies according to the mixing ratio of the TiN powder and the solvent.As the content ratio of the TiN powder increases, the curing effect may be increased, but porosity, quenching cracks, partial dissolution of the TiN powder, and heterogeneous mixing occur. When is increased, the thickness of the inclined functional layer increases, but the maximum hardness value decreases. Therefore, it can be seen that the mixing ratio of TiN / solvent greatly affects the curing effect, the thickness of the inclined functional layer, and the occurrence of manufacturing defects, and it is preferable that the solvent is 50% or less with respect to the mixture.

To simplify the manufacturing process, it is preferable to use a dry mixing method when mixing TiN / solvent, and to apply uniform pressure on carbon steel under pressure to maintain uniform density [Korean Journal of Metals, Vol.31 (1993), p. 921, etc. See literature.

As described above, TiN or TiN / solvent is coated on the carbon steel material, and then an accelerated electron beam is used. The use of high voltage accelerators makes it possible to work in the atmosphere and to manufacture continuously. When the high-output focusing energy obtained by accelerating the electron beam is directly transmitted to the material, this energy is instantly converted into thermal energy, which can be used as a powerful heat source. Therefore, when the accelerated electron beam having a high energy is projected onto the TiN powder coated carbon steel, the TiN powder and a portion of the surface of the carbon steel are melted and alloyed in a short time. At this time, it is preferable to scan the accelerated electron beam in the range of 1.0 to 2.5 MeV at a speed of 1-40 cm ² / sec, particularly preferably a speed of 3 cm ² / sec.

The Ti content of the inclined functional layer of the inclined functional material prepared as described above is preferably 1-25%.

The present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited only to the following examples.

Example

Chemical composition prepared the carbon steel as follows.

element C Si Mn Cu Ni Cr Mo P S Fe Content (% by weight) 0.280 0.193 0.670 0.366 0.151 0.195 0.011 0.023 0.023 Remainder

TiN powder was mixed with Na ₂ B ₄ O ₇ -10H ₂ O powder, which was a solvent, and four kinds of TiN / solvent mixtures were prepared by changing solvent ratios in the mixture to 0, 15, 30, and 50%. The TiN / solvent mixture was uniformly applied to the surface of the carbon steel sheet with a thickness of about 1 mm, pressurized, and the TiN / carbon steel gradient functional material was prepared by projecting a high energy electron beam. For convenience, specimens using mixtures having solvent ratios of 0, 15, 30, and 50% were referred to as Samples A, B, C, and D, respectively. The electron beam accelerator used at this time was the high voltage electron accelerator of the Bucharer Institute of Nuclear Physics, the energy range of the electron accelerator was 1.0-2.5 MeV, the maximum power was 80 kW, the maximum electron beam current was 60 mA, and the maximum electron beam diameter was 1.27 cm. . The electron beam projection conditions are determined by process variables such as beam power, beam travel speed, and material variables such as specific heat and thermal conductivity. The beam energy used in this study is 1.4 MeV, input power 5-10 kW, beam travel speed 3 cm ² / sec.

After cutting the surface portion of the specimen projected by the electron beam in parallel with the projection direction, the change of chemical composition and microhardness was investigated according to the distance from the surface of the specimen. The chemical composition was investigated by changing the chemical composition and microhardness according to the distance from the surface of the specimen using an energy dispersive analyzer mounted on the scanning electron microscope. The chemical composition was quantitatively measured according to the distance from the surface of the specimen using an energy dispersing analyzer mounted on the scanning electron microscope. The results are shown in FIG. As can be seen in FIG. 1, the component of the Ti element decreases downwards under the projection layer. In addition, the change of the microhardness before and after the projection was measured with a Vickers microhardness, which is shown in FIG. 2. As can be seen in Figure 2 according to the present invention it can be seen that the thickness of the inclined functional layer increases according to the amount of solvent added, the hardness change of the inclined functional layer can be seen to change almost linearly.

As can be seen from FIG. 1 and FIG. 2, the TiN powder and a portion of the carbon steel are melted and mixed to reduce the Ti component according to the depth from the surface. As shown in FIG. 2, the hardness of the surface hardness layer is 2 compared to the original matrix. It is possible to produce warp functional material which increases by -3 times and gradually decreases the hardness value with distance from the surface.

Unlike the general manufacturing method, manufacturing the inclined functional material by the accelerated electron beam projection is a simple process, which enables continuous operation in the air, and thus, manufacturing cost is expected to be reduced, thereby widening the use range of the inclined functional material.

Claims (5)

A method of manufacturing a TiN / carbon steel gradient functional material, comprising applying TiN powder or a ceramic powder containing a TiN component to a surface of a carbon steel material under atmospheric conditions, and then pressurizing and then scanning an accelerated electron beam to the coated surface. The method of claim 1, The TiN powder or the ceramic powder containing the TiN component is made of a mixture with a solvent and applied, wherein the solvent is mixed to 50% or less with respect to the mixture. The method according to claim 1 or 2, Wherein said carbon steel material comprises 0.1-0.4 weight percent carbon. The method of claim 2, And dry mixing the solvent with the TiN powder or the ceramic powder containing the TiN component to form a mixture. The method according to claim 1 or 2, Ti content of the inclined functional layer of the inclined functional material is 1-25%.

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