KR100628998B1 - Metal of drip feed carburization method - Google Patents

Abstract

The present invention relates to a deep feed carburizing method of a metal, and more particularly, a metal in which an appropriate amount of acetone or paraffin oil, which is an organic solvent, is thermally decomposed into a methanol base in a carburizing furnace, to generate and penetrate into a carburizing gas in a furnace. The present invention relates to a carburizing method of a drip feed, wherein a preheating step of inserting a metal material in the carburizing furnace and preheating the temperature at 900 ° C. for 30 minutes, maintaining the atmosphere temperature in the furnace after the preheating step at 920 ° C., and methanol 10 The furnace temperature is increased to 850 ° C. through a carburizing and diffusion step of mixing and spraying by weight% and 90% by weight of acetone and diffusing the gas generated by pyrolysis for 3 hours and simultaneously for 2 hours. Hardening of the metal material by a hardening step of heat treatment while maintaining for a minute and quenching into cooling oil at 65 ° C., and cooling while maintaining for 20 minutes through the hardening step. Is characterized in that the HRc 58 ~ 61, the effect can be solved by replacing the acetone or paraffin oil to solve the environmental problems, the decomposition of acetone in the methanol base in the furnace and penetrated into the carburizing gas, the hardness of the carburized layer is HRC 58 ~ 61 Carburization hardness can be obtained, and the microstructure of the carburized layer is also an ideal structure and has a very good effect.

Red stock carburizing method, acetone, hardness, paraffin oil

Description

Metal of Drip Feed Carburization method

1 is a heat treatment cycle graph by the red stock carburizing method of a metal according to the present invention,

2 to 13 are photographs of metal structures generated in Examples 1 to 12.

The present invention relates to a deep feed carburizing method of a metal, and more particularly, a metal in which an appropriate amount of acetone or paraffin oil, which is an organic solvent, is thermally decomposed into a methanol base in a carburizing furnace, to generate and penetrate into a carburizing gas in a furnace. It relates to the carburizing method of drip feed.

In general, there are three types of metal carburizing heat treatment methods: solid carburizing, liquid carburizing, and gas carburizing. Solid carburizing is a method of carburizing by mixing carbonate, which is a catalyst with activated carbon, and complicated work method, low productivity, and difficult atmosphere management. Because of this, liquid carburization is not used except in special cases, and liquid carburizing is used as a method of dissolving sodium cyanide (NaCN) salt or because it is not only harmful to the human body as a poison, but also pollutes the environment. have.

On the other hand, gas carburization is a heat treatment method in which propane is modified by using an atmosphere gas. In this heat treatment method, since the airtightness of the furnace is important, it is possible only in a furnace called All Case. However, this furnace has the disadvantage of being expensive and having a large size of heat-treated product, which is difficult to process and expensive to operate.

  Therefore, in order to solve the shortcomings of the metal carburization heat treatment method, a drip feed heat treatment was also developed. As a method, the red wine is currently used by mixing benzene with methanol base.

However, benzene is forbidden to be used as a carcinogen, and in particular, benzene-based carburizing atmosphere is hydrocarbon-based with high octane number, so it absorbs a large amount of heat in the furnace, so the inside temperature of the furnace becomes uneven and sooting in heat treatment quality. Due to such problems, it is difficult to obtain a uniform heat treatment structure, a problem that is likely to occur poor tissue such as over-precipitation.

In addition, there is also a problem in that the over-precipitation occurs locally due to excessive supply of carbon.

Therefore, the present invention is to solve the above-mentioned problems as the benzene currently in use is difficult to use due to environmental problems, the decomposition of the appropriate amount of acetone, which is an organic solvent in the methanol base in the furnace to penetrate into the carburizing gas Its purpose is to expect quality improvement of carburized heat treated products through drip feed carburizing method.

 Meanwhile, in the present invention, DMF, urea, etc., including acetone, may be used as an alternative subject to be applied.

The present invention for achieving the above object is in the carburizing furnace in a deep feed carburizing method of acetone to a methanol base in the furnace to maintain the atmospheric temperature of the furnace at 920 ℃ pyrolysis to produce a carburizing gas to penetrate The preheating step of inserting the metal material in the carburizing furnace to preheat the temperature at 900 ° C. for 30 minutes, followed by the preheating step was carried out by mixing and spraying 10% by weight of methanol and 90% by weight of acetone. Carburizing and diffusion step of carburizing and diffusion for 2 hours at the same time, heat treatment while maintaining the furnace temperature at 850 ℃ for 30 minutes through the carburization and diffusion step, quenching step to quench the cooling oil at 65 ℃, 20 through the quenching step It characterized in that the red cast carburizing method of the metal, characterized in that the hardness of the metal material is HRc 58 ~ 61 by the cooling step of cooling while maintaining for a minute. do.

In the present invention, in the carburizing furnace, acetone is maintained at an atmosphere temperature of 920 ° C. in a furnace and pyrolyzed to generate and penetrate the carburizing gas, thereby inserting a metal material in the carburizing furnace. Preheating step of preheating the temperature to 900 ℃ for 30 minutes, after the preheating step is injected into 100% by weight of acetone by carburizing and diffusion step of diffusing the gas generated by pyrolysis for 2 hours at the same time for 3 hours, The hardness of the metal material is HRc by heat treatment while maintaining the furnace temperature at 850 ° C. for 30 minutes through carburizing and diffusion, and quenching with cooling oil at 65 ° C., and cooling while keeping it for 20 minutes through the hardening step. It is characterized in that the red stock carburizing method of the metal, characterized in that 58 to 61.

In addition, the present invention is a method of carburizing the drip feed of metal to pyrolyze paraffin oil in a furnace in a carburizing furnace in a furnace to generate and infiltrate the carburizing gas,

Preheating step of preheating the temperature to 900 ℃ 30 minutes by inserting a metal material in the carburizing furnace,

Carburizing, which maintains the atmospheric temperature of the furnace after the preheating step at 920 ° C., mixes and sprays 10% by weight of methanol and 90% by weight of paraffin oil to diffuse gas produced by pyrolysis for 3 hours and at the same time for 2 hours. Diffusion Stage,

A hardening step of maintaining the temperature in the furnace at 850 ° C. for 30 minutes through the carburizing and diffusion step and quenching it in cooling oil at 65 ° C.,

It is characterized in that the red cast carburizing method of the metal that the hardness of the metal material is HRc 58 ~ 61 by the cooling step of cooling while maintaining for 20 minutes through the quenching step.

In addition, the present invention is a method of carburizing the drip feed of metal in which the paraffin oil is pyrolyzed in a furnace in a carburizing furnace to generate and penetrate the carburizing gas.

Preheating step of preheating the temperature to 900 ℃ 30 minutes by inserting a metal material in the carburizing furnace,

Carburizing and diffusion step of maintaining the atmosphere temperature in the furnace after the preheating step to 920 ℃, infused with 100% by weight of paraffin oil for 3 hours while carburizing the gas produced by pyrolysis for 2 hours,

A hardening step of maintaining the temperature in the furnace at 850 ° C. for 30 minutes through the carburizing and diffusion step and quenching it in cooling oil at 65 ° C.,

It is characterized in that the red cast carburizing method of the metal that the hardness of the metal material is HRC 58 ~ 61 by the cooling step of cooling while maintaining for 20 minutes through the quenching step.

 Hereinafter, the red stock carburizing method of the metal according to the present invention will be described in detail.

1 is a heat treatment cycle graph by the red stock carburizing method of the metal according to the present invention, Figures 2 to 13 is a photograph of the metal structure generated in Examples 1 to 12.

First, the test equipment used in the practice of the present invention is a carburizing heat treatment furnace, a red cast pit type heating furnace, a pit type tempering furnace as a tempering equipment, an oil cooling tank for oil quenching work, and a red caster for pouring red liquid. This was used.

On the other hand, the metal material used in the present invention was used S20C and SCM421.

In the S20C composition ratio (%), 0.18 to 0.23 C, 0.15 to 0.35 Si, 0.30 to 0.60 Mn, 0.030 or less P, and 0.035 or less S, and the SCM421 composition ratio is 0.17 to 0.23 C, 0.15 to 0.35 Si, 0.70. It was composed of 1.00 Mn, 0.030 or less P, 0.035 or less S, 0.90 to 1.20 Cr, and 0.15 to 0.30 Mo.

In order to achieve the above object, the present invention was carried out through the atmosphere composition and heat treatment cycle conditions of the following examples in the method of drip carburizing a metal to generate and penetrate the carburizing gas in the carburizing furnace.

First Embodiment

In the first embodiment, the test conditions are as follows.

 As can be seen in Figure 1, the preheating step of preheating the temperature to 900 ℃ 30 minutes by inserting the metal material in the carburizing furnace, the atmosphere temperature in the furnace after the preheating step is maintained at 920 ℃, methanol 88% by weight + acetone Injected at 12% by weight, the gas produced by pyrolysis was heat treated while carburizing and diffusing for 3 hours and diffusing for 2 hours, and maintaining the temperature in the furnace at 850 ° C for 30 minutes through carburizing and diffusing. The red cast carburizing method of metal was performed by the hardening step which hardens into the cooling oil of degreeC, and the cooling step which cools, maintaining for 20 minutes through the said hardening step.

 As shown in FIG. 2, the desired carburization hardness was HRC58-60, but the carburization hardness obtained in the same experiment was less than HRC 30-35. For this reason, it was judged that the amount of CO that affects carbon potential is insufficient. Therefore, the composition ratio of acetone, a carburizing agent, should be increased.

Second Embodiment

In the second embodiment, the test conditions are as follows.

As can be seen in Figure 1, the preheating step of preheating the temperature to 900 ℃ 30 minutes by inserting the metal material in the carburizing furnace, the atmosphere temperature in the furnace after the preheating step is maintained at 920 ℃, methanol 82% by weight + acetone 18% by weight of the pyrolysis gas was carburized and diffused for 3 hours, followed by carburization and diffusion for 2 hours, and the heat treatment was carried out while maintaining the temperature in the furnace at 850 ° C. for 30 minutes through 65. The red cast carburizing method of metal was performed by the hardening step which hardens into the cooling oil of degreeC, and the cooling step which cools, maintaining for 20 minutes through the said hardening step.

As shown in FIG. 3, although the acetone composition was increased to 18% than in the first embodiment, the obtained hardness was low as HRC18-19, and the CO content was still determined to be low, and the acetone ratio serving as the Enrich Gas was determined. It is necessary to raise.

Third Embodiment

In the third embodiment, the test conditions are as follows.

As can be seen in Figure 1, the preheating step of preheating the temperature to 900 ℃ 30 minutes by inserting the metal material in the carburizing furnace, the atmosphere temperature in the furnace after the preheating step is maintained at 920 ℃, methanol 80% by weight + acetone Injecting at 20% by weight, the gas generated by pyrolysis was heat treated while carburizing and diffusing for 3 hours and diffusing for 2 hours, while maintaining the temperature in the furnace at 850 ° C for 30 minutes through carburizing and diffusing. The red cast carburizing method of metal was performed by the hardening step which hardens into the cooling oil of degreeC, and the cooling step which cools, maintaining for 20 minutes through the said hardening step.

As shown in FIG. 4, the carburizing agent acetone was adjusted up than in Example 2, but the obtained hardness was low as HRC15-20, and it was determined that the ratio of acetone 0, which is still carburizing agent, was low.

Fourth Embodiment

As can be seen in Figure 1, the preheating step of preheating the temperature to 900 ℃ 30 minutes by inserting the metal material in the carburizing furnace, the atmosphere temperature in the furnace after the preheating step is maintained at 920 ℃, methanol 50% by weight + acetone Injecting at 50% by weight, the gas produced by pyrolysis is carburized for 3 hours and diffused for 2 hours at the same time, followed by heat-treatment while maintaining the temperature in the furnace at 850 ° C. for 30 minutes through the carburizing and diffusion step. The red cast carburizing method of metal was performed by the hardening step which hardens into the cooling oil of degreeC, and the cooling step which cools, maintaining for 20 minutes through the said hardening step.

As shown in Figure 5, the carburization hardness is less than HRC 58 ~ 60, the hardness required in the carburization still HRC 20 ~ 30. Although the acetone weight% was greatly increased than in Example 3, it was judged that an error occurred in the heat treatment test when it was determined that the carburization hardness was low, and it was evaluated that retesting was required under the same conditions.

Fifth Embodiment

As can be seen in Figure 1, the preheating step of preheating the temperature to 900 ℃ 30 minutes by inserting the metal material in the carburizing furnace, the atmosphere temperature in the furnace after the preheating step is maintained at 920 ℃, methanol 50% by weight + acetone Injecting at 50% by weight, the gas produced by pyrolysis is carburized for 3 hours and diffused for 2 hours at the same time, followed by heat-treatment while maintaining the temperature in the furnace at 850 ° C. for 30 minutes through the carburizing and diffusion step. The red cast carburizing method of metal was performed by the hardening step which hardens into the cooling oil of degreeC, and the cooling step which cools, maintaining for 20 minutes through the said hardening step.

As shown in Figure 6, the test was carried out under the same conditions as in the fourth embodiment, the obtained carburized hardness was the same as before in HRC 20-25. The rate of acetone, a carburizing agent, needs to be increased.

Sixth Embodiment

As can be seen in Figure 1, the preheating step of preheating the temperature to 900 ℃ 30 minutes by inserting the metal material in the carburizing furnace, the atmosphere temperature in the furnace after the preheating step is maintained at 920 ℃, methanol 30% by weight + acetone 70% by weight of the gas produced by pyrolysis was injected into a carburizing and diffusion step for 3 hours, followed by diffusion for 2 hours, and heat treatment while maintaining the temperature in the furnace at 850 ° C for 30 minutes through the carburization and diffusion step. The red cast carburizing method of metal was performed by the hardening step which hardens into the cooling oil of degreeC, and the cooling step which cools, maintaining for 20 minutes through the said hardening step.

As shown in Fig. 7, the obtained carburized hardness was less than the target value of HRC 25 ~ 35. Microscopic analysis showed that carburization was virtually impossible. Therefore, it was determined that it is necessary to further increase the ratio of acetone, which is a carburizing accelerator.

Seventh Embodiment

As can be seen in Figure 1, the preheating step of preheating the temperature to 900 ℃ 30 minutes by inserting a metal material in the carburizing furnace, the atmosphere temperature in the furnace after the preheating step is maintained at 920 ℃, methanol 20% by weight + acetone 80% by weight of the gas produced by pyrolysis was injected into a carburizing and diffusing step for 3 hours, followed by diffusing for 2 hours, followed by heat treatment while maintaining the temperature in the furnace at 850 ° C. for 30 minutes through 65 The red cast carburizing method of metal was performed by the hardening step which hardens into the cooling oil of degreeC, and the cooling step which cools, maintaining for 20 minutes through the said hardening step.

As shown in Fig. 8, the carburization hardness obtained from the experiment was far lower than the target carburization hardness of HRC14-16. As a result of reviewing whether acetone is suitable as a carburizing accelerator, acetone is a mild carburizing accelerator. We could reaffirm that we had enough C for carburization. The experiment using 100% acetone was decided to be carried out in the next test order.

Eighth Embodiment

As can be seen in Figure 1, the preheating step of preheating the temperature to 900 ℃ for 30 minutes by inserting a metal material in the carburizing furnace, the atmosphere temperature in the furnace after the preheating step is maintained at 920 ℃, methanol 10% by weight + acetone 90% by weight of the gas produced by pyrolysis by carburizing and diffusing for 2 hours and carburizing and diffusing for 2 hours, followed by heat-treatment while maintaining the temperature in the furnace at 850 ° C for 30 minutes through 65 The red cast carburizing method of metal was performed by the hardening step which hardens into the cooling oil of degreeC, and the cooling step which cools, maintaining for 20 minutes through the said hardening step.

As shown in FIG. 9, the hardness obtained in this experiment was close to the target hardness HRC 58-60 as HRC52-56. On the microscopic structure, good carburized tissue was produced by carburized tissue. Slightly low hardness was considered to be a slight delay in oil quenching.

< Ninth Embodiment >

As can be seen in Figure 1, the preheating step of preheating the temperature to 900 ℃ for 30 minutes by inserting the metal material in the carburizing furnace, the atmosphere temperature in the furnace after the preheating step is maintained at 920 ℃, injected in 100% by weight acetone Through the carburizing and diffusion step of diffusing the gas produced by pyrolysis for 3 hours and the same time for 2 hours, heat treatment while maintaining the temperature in the furnace at 850 ° C for 30 minutes through the carburizing and diffusion step, and quenched in cooling oil at 65 ° C. The red stock carburizing method of the metal was performed by the cooling step of cooling while maintaining for 20 minutes through the hardening step, the hardening step.

As shown in FIG. 10, the carburized layer hardness was accurately obtained at the target carburizing hardness of HRC 58 to 61, and the microstructure of the carburized layer was also a very good tissue.

As a result of this experiment, when acetone is used as a carburizing accelerator, the target carburizing hardness and carburizing structure can be obtained when the composition ratio is maintained above 90%.

Tenth Embodiment

As can be seen in Figure 1, the preheating step of preheating the temperature to 900 ℃ 30 minutes by inserting the metal material in the carburizing furnace, the atmosphere temperature in the furnace after the preheating step is maintained at 920 ℃, methanol 95% by weight + paraffin 5% by weight of oil was injected into the pyrolysis gas for 3 hours, followed by carburization and diffusion for 2 hours, followed by carburization and diffusion, and the heat treatment while maintaining the temperature in the furnace at 850 ° C for 30 minutes. The red stock carburizing method of metal was performed by the hardening step of hardening to 65 degreeC cooling oil, and the cooling step which keeps cooling for 20 minutes through the said hardening step.

As shown in FIG. 11, the obtained hardness was HRC 9,10, which was largely insufficient in the target hardness, and it was determined that an upward adjustment of paraffin oil, a carburizing accelerator, was required.

< Eleventh embodiment >

As can be seen in Figure 1, by inserting the metal material in the carburizing furnace preheating step of preheating temperature to 900 ℃ for 30 minutes, the atmosphere temperature in the furnace after the preheating step is maintained at 920 ℃, methanol 10% by weight + paraffin 90% by weight of oil was injected to heat the gas generated by pyrolysis by carburizing and diffusing for 3 hours and diffusing for 2 hours while maintaining the temperature in the furnace at 850 ° C. for 30 minutes through carburizing and diffusing. The red stock carburizing method of metal was performed by the hardening step of hardening to 65 degreeC cooling oil, and the cooling step which keeps cooling for 20 minutes through the said hardening step.

As shown in FIG. 12, the carburized layer hardness was HRC35-37, which was less than the target carburizing hardness, but was greatly improved than the tank test. In order to achieve the target carburizing stiffness, we believe it is necessary to raise C.P's Enrich oil.

As a result, it was evaluated that the target carburizing hardness and carburizing structure can be obtained when paraffin oil is used as a carburizing accelerator when the composition ratio is maintained above 90%.

< Twelfth Embodiment >

As can be seen in Figure 1, the preheating step of preheating the temperature to 900 ℃ 30 minutes by inserting a metal material in the carburizing furnace, the atmosphere temperature in the furnace after the preheating step is maintained at 920 ℃, paraffin oil 100% by weight Injecting and pyrolysis of the gas produced by pyrolysis for 3 hours and at the same time to diffuse for 2 hours, the heat treatment while maintaining the temperature in the furnace at 850 ℃ for 30 minutes through the carburizing and diffusion step, and then to the cooling oil of 65 ℃ The red stock carburizing method of metal was performed by the hardening step of hardening, and the cooling step of cooling while maintaining for 20 minutes through the hardening step.

As shown in FIG. 13, the carburized layer hardness was accurately obtained at the target carburized hardness of HRC 58 to 61. The microstructure of the carburized layer is also an ideal one and a very good one.

As a result of this experiment, when acetone is used as a carburizing accelerator, the target carburizing hardness and carburizing structure can be obtained when maintaining the composition ratio over 90%.

Therefore, the method of carburizing the metal deep feed (Drip Feed) of the metal according to the first to eleventh embodiments is the eighth, ninth, eleventh, and twelfth embodiments.

 However, the present invention is not limited to the preferred embodiments of the above-described features, and various modifications can be made by those skilled in the art without departing from the gist of the present invention as claimed in the claims. Of course, such changes will fall within the scope of the claims.

As described above, the present invention was suitable as a carburizing agent that can replace acetone-based or paraffinic oil, and solved the environmental problem. Particularly, the appropriate amount of acetone which is an organic solvent in methanol base was decomposed in the furnace. The carburized layer hardness can be obtained by infiltration with elastic gas and HRC58 ~ 61 carburized hardness can be obtained, and the microstructure of the carburized layer is also an ideal structure and has a very good effect.

In addition, by mixing the acetone solvent and the carburizing agent methol at various ratios, there is also an effect that does not occur soot (sooting) that can appear when using benzene in general.

Claims (4)

In the carburizing furnace, acetone in a methanol base is pyrolyzed while maintaining the atmospheric temperature of the furnace at 920 ° C. to produce a carburized gas and infiltrate the drip feed carburizing method of the metal. Preheating step of preheating the temperature to 900 ℃ 30 minutes by inserting a metal material in the carburizing furnace, Carburizing and diffusion step of mixing and spraying 10% by weight of methanol and 90% by weight of acetone after the preheating step to diffuse the gas produced by pyrolysis for 3 hours and at the same time for 2 hours, A hardening step of maintaining the temperature in the furnace at 850 ° C. for 30 minutes through the carburizing and diffusion step and quenching it in cooling oil at 65 ° C., Red metal carburizing method of the metal material characterized in that the hardness of the metal material is HRc 58 ~ 61 by the cooling step of cooling while maintaining for 20 minutes through the quenching step. In the method of carburizing the drip feed of metal in which the acetone is maintained at 920 ° C. in the carburizing furnace and pyrolyzed to generate and infiltrate the carburizing gas, Preheating step of inserting the metal material in the carburizing furnace to preheat the temperature to 900 ℃ 30 minutes Carburizing and diffusion step of injecting 100% by weight of acetone after the preheating step and diffusing the gas generated by pyrolysis for 2 hours while simultaneously carburizing for 3 hours; A hardening step of maintaining the temperature in the furnace at 850 ° C. for 30 minutes through the carburizing and diffusion step and quenching it in cooling oil at 65 ° C., Red metal carburizing method of the metal material characterized in that the hardness of the metal material is HRc 58 ~ 61 by the cooling step of cooling while maintaining for 20 minutes through the quenching step. delete delete

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