KR102258477B1 - Manufacturing Method of Injector Clamp with Improved Rust-preventing Properties - Google Patents

Abstract

The present invention relates to a method of manufacturing an injector clamp for supporting an injector applied to a diesel engine, and to a method of manufacturing an injector clamp having improved toughness and improved rust prevention by controlling the microstructure of the component.
According to the present invention for solving the problems of the prior art described above, the present invention is a molding and sintering step (S110) in which an iron-based powder is molded and sintered to become a part, and a carburizing heat treatment step in which the parts subjected to the molding and sintering step are carburized and heat treated ( S130), a steam heat treatment step (S150) in which the parts subjected to the carburization heat treatment step are heat treated by steam, and a coating step (S170) in which the parts subjected to the heat treatment step are coated (S170). to provide.

Description

Manufacturing Method of Injector Clamp with Improved Rust-preventing Properties}

The present invention relates to a method of manufacturing an injector clamp for supporting an injector applied to a diesel engine, and to a method of manufacturing an injector clamp having improved toughness and improved rust prevention by controlling the microstructure of the component.

An injector is a device that injects fuel into the combustion chamber of an engine. The role of the injector is to inject the correct amount of fuel calculated by the electronic control unit (ECU) during all driving conditions.

In this way, in order to inject the correct amount of fuel according to each driving condition, the ECU calculates the opening time of the injector in relation to the fuel pressure, and consequently, the exact amount of fuel injection is guaranteed.

Supporting such an injector is called an injector clamp, and requires high strength to support the injector, and for this, it must have corrosion resistance and rust resistance that does not corrode for a long time.

For high mechanical properties, corrosion resistance, and rust prevention, in the prior art, a special steel is hot forged and processed, and then a nitride layer is formed through nitriding heat treatment, and then a phosphate film for rust prevention coating is performed to manufacture an injector clamp. In this case, phosphate coating is one of the chemical conversion methods of steel, which chemically reacts the metal with dilute phosphoric acid to make the surface of the metal poorly soluble crystalline phosphate, thereby changing the intrinsic properties of the metal.

However, in the case of the prior art, in the process of processing and heat treatment, numerous pores are generated, and the mechanical properties of the parts after the phosphate coating treatment on the surface having such pores are significantly deteriorated.

In addition, in the case of the prior art, when the salt spray test on a part subjected to nitriding heat treatment and phosphate coating, the time for rust to occur is 2 hours, and there is a problem that corrosion resistance and rust prevention are significantly inferior to application to an injector clamp.

Accordingly, the present invention was invented to manufacture an injector clamp having excellent mechanical properties, corrosion resistance, and rust prevention in order to solve the above problems.

The present invention was conceived to solve the problems of the prior art, and a coating step for forming a zinc-based composite film on the surface of the part is applied after carburizing heat treatment on the part and then heat treatment with steam. . As described above, according to the present invention, a steam heat treatment step with steam is performed before the part coating step, thereby preventing exposure of pores generated by the processing and carburizing heat treatment steps, thereby providing a method of manufacturing an injector clamp having excellent rust prevention properties. There is this.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems that are not mentioned will be clearly understood by those of ordinary skill in the art from the description of the present invention. .

According to the present invention for solving the problems of the prior art described above, the iron-based powder is molded and sintered to form a part by molding and sintering step; A carburizing heat treatment step in which the parts subjected to the molding and sintering step are carburized and heat treated; A steam heat treatment step in which the parts subjected to the carburization heat treatment step are heat treated by steam; And it provides a method of manufacturing an injector clamp having excellent anti-rust properties; and a coating step in which the parts that have undergone the heat treatment step are coated.

The iron-based powder in the present invention comprises 3.6 to 4.4% by weight of nickel (Ni), 1.3 to 1.7% by weight of copper (Cu), 0.4 to 0.6% by weight of molybdenum (Mo), more than 0 and up to 0.9% by weight of carbon ( It is preferable to contain C), the remainder of iron (Fe) and unavoidable impurities.

It is preferable that the carburizing heat treatment step in the present invention further includes an oil etch step in which the parts subjected to the carburization heat treatment step are oil dubbed.

The temperature of the carburizing heat treatment step in the present invention is preferably 800 ℃ to 900 ℃.

It is preferable that the surface structure of the part that has undergone the carburization heat treatment step in the present invention includes martensite and austenite.

The temperature of the steam heat treatment step in the present invention is preferably 400 ℃ to 600 ℃.

The steam heat treatment step in the present invention is preferably heat-treated at 400° C. for 20 minutes or more.

The steam heat treatment step in the present invention is preferably heat-treated at 500° C. for 10 minutes or more.

The steam heat treatment step in the present invention is preferably heat-treated at 600° C. for 10 minutes or more and less than 30 minutes.

In the present invention, the steam heat treatment step is preferably heat treated at 500° C. for 20 minutes or more.

The steam heat treatment step in the present invention is preferably heat-treated at 600° C. for 20 minutes or more and less than 30 minutes.

It is preferable that the surface structure of the part that has undergone the steam heat treatment step in the present invention includes bainite and austenite.

It is preferable that _{Fe 3} O ₄ is generated in the surface structure of the rough part in the steam heat treatment step in the present invention.

It is preferable that the surface of the part that has undergone the coating step in the present invention contains a zinc-based composite film.

According to the manufacturing method of the injector clamp of the present invention, heat treatment by steam is performed before the coating step, thereby preventing pores generated by processing and carburizing heat treatment, so that it has excellent rust resistance, and toughness is enhanced through microstructure control. There is an effect of providing a method of manufacturing this excellent injector clamp.

1 is a photograph of an injector clamp in which rust has occurred after a nitriding heat treatment and a coating step according to Comparative Example 1.
2 is a photograph of an injector clamp in which rust occurs after heat treatment by steam according to Comparative Example 2.
3 is a photograph of an injector clamp in which rust has occurred after a carburization heat treatment step and a coating step according to Comparative Example 3.
4 is a photograph of an injector clamp in which rust has occurred after a carburizing heat treatment step, a steam heat treatment step, and a coating step according to an embodiment of the present invention.
Figure 5 is a photograph showing the step of forming and sintering iron-based powder according to an embodiment of the present invention.
6 is a schematic view showing a carburizing heat treatment step of a component according to an embodiment of the present invention.
Figure 7 is an enlarged photograph of the surface texture of the part after the carburizing heat treatment step according to an embodiment of the present invention.
8 is an enlarged photograph of the surface texture of a part in which tempered bainite is generated after a steam heat treatment step by steam according to an embodiment of the present invention.
9 is an enlarged photograph of the surface texture of the part after the coating step according to an embodiment of the present invention.
10 is a flow chart of a method of manufacturing an injector clamp according to the present invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail. Prior to this, terms or words used in the specification and claims should not be construed as being limited to their usual or dictionary meanings, and the inventors appropriately explain the concept of terms in order to explain their own invention in the best way. Based on the principle that it can be defined, it should be interpreted as a meaning and concept consistent with the technical idea of the present invention. Accordingly, the embodiments described in the present specification are only the most preferred embodiments of the present invention and do not represent all the technical spirit of the present invention, and various equivalents and modifications that can replace them at the time of the present application are It should be understood that there may be.

Hereinafter, the present invention will be described in detail. The present invention relates to a method of manufacturing a component excellent in rust prevention.

More specifically, the present invention relates to a method of manufacturing an injector clamp for supporting an injector applied to a diesel engine, and an object of the present invention is to strengthen toughness and improve rust-prevention coating through control of the microstructure of the component.

1, 2, 3, and 4 are photographs showing that rust has occurred by applying a salt spray test to an injector clamp. FIG. 1 is a photographic view of an injector clamp in which rust has occurred after a nitridation heat treatment and a coating step according to Comparative Example 1, and FIG. 2 is a photographic view of an injector clamp in which rust has occurred after heat treatment by steam according to Comparative Example 2, and FIG. 3 Is a photograph of an injector clamp in which rust has occurred after passing through the carburizing heat treatment step and coating step according to Comparative Example 3, and FIG. 4 is a steam heat treatment step (S150) and a coating step (S170) by steam according to an embodiment of the present invention. It is a photograph of the injector clamp where rust occurred after passing through.

Surface treatment process Time for rust to occur during salt spray test Comparative Example 1 (nitridation + phosphate coating) 2 hours Comparative Example 2 (Steam heat treatment) Less than 1 hour Comparative Example 3 (carburizing + zinc-based composite film) Less than 1 hour Example (carburizing + steam heat treatment + zinc-based composite film) More than 3,000 hours

Table 1 is a comparison of the rust prevention performance according to the surface treatment process by applying the salt spray test, and corresponding to Comparative Example 1, Comparative Example 2, Comparative Example 3, and Examples in order from the top of Table 1, Fig. 1, Fig. 2, Fig. 3, Fig. 4 shows. In this way, after performing the salt spray test on the part, the time when rust occurred was 2 hours, 1 hour or less, 1 hour or less, and 3000 hours or more, respectively.

When rust occurs in parts, not only the corrosion resistance and strength are deteriorated, but when applied to a vehicle, there may be various problems such as noise of a vehicle body during driving and a decrease in corrosion resistance. Therefore, it means that corrosion resistance, that is, rust resistance, is significantly lowered when rust occurs more quickly.

More specifically, FIG. 1 is a photographic view of a part in which rust has occurred after undergoing a nitriding heat treatment and a coating step according to Comparative Example 1. FIG. In Comparative Example 1, after processing a special steel by hot forging, a nitride layer was formed through nitriding heat treatment, and then a phosphate film for rust prevention coating was performed to prepare an injector clamp. In this case, in the processing and heat treatment process, numerous pores are generated, and it can be seen that the mechanical properties of the parts after the phosphate coating treatment on the surface having such pores are significantly deteriorated.

As can be seen from FIG. 1, it can be seen that rust is generated on the part after the nitridation heat treatment and the coating step according to the prior art, and the color is black. It was confirmed that the time when rust occurred in the part according to FIG. 1 was 2 hours when the salt spray test was applied.

In addition, FIG. 2 is a photographic view of a part in which rust has occurred after heat treatment by steam according to Comparative Example 2. As shown in FIG. Unlike FIG. 1, FIG. 2 is a photographic view of a part in which rust occurs when only heat treatment by steam is applied. As can be seen through FIG. 2, rust did not occur much than that of FIG. 1, but it can be seen that the color partially changed due to rust. As such, the time when rust occurred on the part according to FIG. 2 was 1 hour or less when the salt spray test was applied.

In addition, FIG. 3 is a photographic view of a part in which rust has occurred after the molded and sintered part according to Comparative Example 3 undergoes carburization heat treatment and then a coating step. 3 is a photographic view of a component in which a zinc-based composite film is formed through a coating step after heat treatment is not performed by steam, and after carburization heat treatment, unlike FIG. 2. 3, it can be seen that rust did not occur much than that of FIG. 2, but the color changed due to rust. The time when rust occurred in the part according to FIG. 3 was 1 hour or less.

Meanwhile, FIG. 4 is a photographic view of a part in which rust has occurred after a carburizing heat treatment step, a steam heat treatment step, and a coating step according to an embodiment of the present invention. The time when rust occurred on the part according to FIG. 4 was 3000 hours or more. As such, it can be seen that, in FIG. 4, when compared with the photographic diagram of the comparative example, the portion where rust has occurred is significantly less, and the time when the rust occurs is also significantly different when compared with the comparative example.

Therefore, it is preferable that the method for manufacturing a component according to the present invention includes a steam heat treatment step (S150) and a coating step (S170) using steam. As in the case of FIGS. 2 and 3, when the heat treatment and coating treatment by steam are individually performed, it can be seen that the rust generation time is significantly faster, and the area of the rust generation area is larger.

As such, the reason why rust does not occur in the part according to the present invention is that the heat treatment by steam serves to fill the pores in the surface structure of the part. In addition, as the surface structure changes from martensite to tempered bainite due to heat treatment by steam, it has an effect of enhancing toughness.

Therefore, it can be seen that it is preferable to proceed with the steam heat treatment step (S150) by steam before the coating step (S170) of the part, and the heat treatment by this steam serves to fill the pores of the surface structure, and the coating step (S170) ) To help.

In the end, the method of manufacturing a part according to the present invention includes a molding and sintering step (S110) in which iron-based powder is molded and sintered to become a part, a carburizing heat treatment step (S130) in which the parts subjected to the molding and sintering step are carburized heat treatment (S130), and the carburizing heat treatment step. It includes a steam heat treatment step (S150) in which the parts that have been subjected to heat treatment by steam, and a coating step (S170) in which the parts that have undergone the heat treatment step are coated (S170), and provides a method of manufacturing a part having excellent rust prevention properties. In addition, it is preferable that the carburizing heat treatment step (S130) in the present invention further includes an oil-quenching step in which the parts that have undergone the carburization heat treatment step (S130) are oil-called.

In this way, before the coating step (S170) of the part according to the present invention, the steam heat treatment step (S150) by steam is performed, thereby preventing exposure of the pores generated due to the processing and carburization heat treatment, and a method of manufacturing a part having excellent rust resistance. It has the effect it provides. In addition, an injector clamp having a bainite structure excellent in toughness is obtained due to the heat treatment by steam.

Further, the zinc-based composite film in the coating step applied to the present invention does not contain chromium, which is a heavy metal material at all, and in general, when metal and other metals meet, double metal contact corrosion occurs to accelerate corrosion, but the zinc component Since it has a similar tendency to ionization as aluminum, if corrosion occurs finely, all zinc is corroded due to the self-sacrificing action of zinc, thereby maintaining corrosion resistance.

In addition, the zinc-based composite film enables stable coating even on products with complex shapes and difficult structures, and since there is no process that can cause hydrogen embrittlement during the coating process, injector clamps of stable quality can be manufactured, and the film has excellent adhesion. There is an effect of further increasing the effect of. In addition, the zinc-based composite film is excellent in corrosion prevention, cost reduction effect, and friction characteristics. Accordingly, the injector clamp according to the present invention having a zinc-based composite film may include all of the above characteristics.

On the other hand, Figure 5 is a photographic diagram showing the step of forming and sintering iron-based powder according to an embodiment of the present invention. 5 shows that the iron-based powder according to the present invention is introduced into a mold to be molded and sintered.

The iron-based powder may be any iron-based powder, but more preferably, 3.6 to 4.4% by weight of nickel (Ni), 1.3 to 1.7% by weight of copper (Cu), 0.4 to 0.6% by weight of molybdenum (Mo), It is preferable to contain more than 0 and 0.9% by weight or less of carbon (C), the balance iron (Fe) and unavoidable impurities.

6 is a schematic diagram showing a carburizing heat treatment step (S130) of a part according to an embodiment of the present invention, and FIG. 7 is an enlarged photograph of the surface texture of a part after the carburizing heat treatment step (S130) according to an embodiment of the present invention. . The temperature of the carburizing heat treatment step (S130) of the part according to the present invention is 800°C to 900°C, and after maintaining for a certain time, the stiffness is strengthened while going through the oil?

Therefore, it can be seen that the surface structure of the part according to the present invention after passing through the carburization heat treatment step (S130) is a structure of martensite and austenite through FIG. 7. Martensite has a fine needle-like shape, and austenite has a polygonal shape. The structure of martensite refers to a hard structure due to partial inhibition of transformation from austenite stable at high temperature to a structure composed of α iron and cementite stable at room temperature when iron is quenched, and it is the hardest structure among steel structures. That is, austenite is a high-temperature phase, and martensite is a structure that is formed when austenite is referred to as high-temperature austenite. As a result, it can be seen that the part to which the carburizing heat treatment step S130 according to the present invention is applied has improved rigidity due to the martensite structure.

In addition, Figure 8 is an enlarged photograph of the surface structure of the part after the heat treatment step (S150) by steam according to an embodiment of the present invention. It can be seen from FIG. 8 that a tempered bainite structure is generated in the surface structure of the part after the heat treatment step (S150). Bainite is one of the cooling transformation products of austenite, which occurs in the middle temperature range between the pearlite formation temperature and the martensite formation temperature, and it has the shape of a bird's feather or needle when checked through an enlarged photograph. In addition, since bainite has strong toughness, it can be seen that the surface of the part according to the present invention has properties of strengthening toughness due to the bainite structure.

Process parameters of the steam heat treatment step After steam heat treatment step and coating step
Anti-rust After steam heat treatment step and coating step surface
Hardness (HV10) Impact value (J/cm ² ) Remark Temperature(℃) Time (minutes) Density (g/cm ³ ) Porosity 300 10 X (less than 1 hour) 7.127 9.92% 194 15.9 Fe ₂ O ₃ (red-green) production 20 X (less than 1 hour) 7.131 9.87% 189 16.7 Fe ₂ O ₃ (red-green) production 30 X (less than 1 hour) 7.129 9.90% 197 18.5 Fe ₂ O ₃ (red-green) production 400 10 X (less than 1 hour) 7.124 9.96% 209 18.5 Fe ₂ O ₃ (red and green) production 20 O (1-2 hours) 7.227 8.66% 214 24.5 Fe ₃ O ₄ generation 30 O (1-2 hours) 7.231 8.61% 216 26.5 Fe ₃ O ₄ generation 500 10 O (1-2 hours) 7.226 8.67% 218 25.3 Fe ₃ O ₄ generation 20 ◎
(More than 2 hours) 7.278 8.01% 224 36.8 Fe ₃ O ₄ generation 30 ◎
(More than 2 hours) 7.269 8.13% 223 35.9 Fe ₃ O ₄ generation 600 10 O (1-2 hours) 7.247 8.40% 212 36.9 Fe ₃ O ₄ generation 20 ◎
(More than 2 hours) 7.304 7.68% 224 37.5 Fe ₃ O ₄ generation 30 X (less than 1 hour) 7.224 8.70% 216 36.4 FeO generation

Table 2 shows the microstructure fraction and rust prevention properties according to the process parameters of heat treatment by steam. From Table 2 above, it can be seen that during heat treatment by steam, the phase and physical properties generated on the surface vary according to the variables of the holding time and temperature at a high temperature.

In addition, according to the present invention, it is preferable to generate _{Fe 3} O _{4 than to generate Fe 2} O ₃ (red rust) in the surface structure. When rust is generated, not only the corrosion resistance and strength are lowered, but also when applied to automobile parts, there may be various problems such as vehicle body noise while driving and corrosion resistance decrease when applied to automobiles. Fe ₂ O ₃ (red rust) The generation of is undesirable. On the contrary, according to the present invention, Fe ₃ O ₄ fills the pores during heat treatment by steam on the part, and the generation of _{Fe 3} O ₄ improves the performance in the next coating step (S170). desirable.

In addition, when FeO is generated, it is a phase that occurs at high temperature and _{may be deteriorated to Fe 2} O ₃ (red green) at room temperature. As mentioned above, when applied to automobile parts, red and green may cause a decrease in vehicle quality such as vehicle body noise and corrosion resistance. Therefore, production of _{Fe 3} O ₄ is preferred according to the present invention.

Therefore, in the method of manufacturing an injector clamp having excellent rust resistance according to the present invention, in the steam heat treatment step (S150) by steam, the temperature is preferably from 400°C to 600°C, and heat treatment at 400°C for 20 minutes or more is preferable. Preferably, heat treatment is preferably performed at 500° C. for 10 minutes or more, and heat treatment is preferably performed at 600° C. for 10 minutes or more and less than 30 minutes.

Even more preferably, the steam heat treatment step (S150) in the present invention is heat-treated at 500° C. for 20 minutes or more, and is preferably heat-treated at 600° C. for 20 minutes or more and less than 30 minutes.

On the other hand, the rust-prevention measurement in Table 2 is applied to the salt spray test, and when the rust generation time is less than 1 hour, it is determined that the rust-prevention is deteriorated, and thus the injector clamp according to the present invention is not applied.

Further, the porosity in Table 2 is that the porosity of the surface has a large error depending on the measurement, and thus the porosity of the cross section is measured by cutting the part into a cross section. In addition, it can be seen that as the porosity decreases, the density increases.

In addition, it can be seen that the impact value in Table 2 refers to the energy required to cut the test piece, and generally increases as the heat treatment time increases. This increase in the impact value indicates that the toughness increases, and according to the present invention, it represents the fraction of the tempered bainite phase. Therefore, it can be seen that the phase fraction of bainite generally increases as the heat treatment time increases.

More specifically, FIG. 8 is an enlarged photograph of the surface texture of a part in which tempered bainite is generated after the steam heat treatment step (S150) with steam according to an embodiment of the present invention. It can be seen from FIG. 8 that a tempered bainite structure is generated in the surface structure of the part after the heat treatment step (S150). Bainite is one of the cooling transformation products of austenite, which occurs in the middle temperature range between the pearlite formation temperature and the martensite formation temperature, and it has the shape of a bird's feather or needle when checked through an enlarged photograph. In addition, since bainite has strong toughness, it can be seen that the surface of the part according to the present invention has properties of strengthening toughness due to the bainite structure.

In addition, in the heat treatment time and temperature according to the present invention, it can be seen from Table 2 that the surface hardness also increases. This surface hardness is due to the effect of strengthening the stiffness obtained by maintaining the temperature in the carburizing heat treatment step (S130) from 800°C to 900°C, and then through the oil??qing step.

As such, Figure 6 is a schematic diagram showing a carburizing heat treatment step (S130) of a component according to an embodiment of the present invention, Figure 7 is an enlarged photograph of the surface texture of the component after the carburizing heat treatment step (S130) according to an embodiment of the present invention It is a degree. The temperature of the carburizing heat treatment step (S130) of the part according to the present invention is 800°C to 900°C, and after maintaining for a certain time, the stiffness is strengthened while going through the oil?

In addition, FIG. 8 is an enlarged photograph of the surface structure of a part in which tempered bainite is generated after the steam heat treatment step (S150) by steam according to an embodiment of the present invention. It can be seen from FIG. 8 that a tempered bainite structure is generated in the surface structure of the part after the steam heat treatment step S150. Since bainite has strong toughness, it can be seen that the surface of the part according to the present invention has properties of strengthening toughness due to the bainite structure.

On the other hand, Figure 9 is an enlarged photograph of the surface texture of the part after the coating step (S17) according to an embodiment of the present invention. According to the present invention, after the steam heat treatment step, Fe 3 O 4 is generated in the surface structure of the part to block pores, and at the same time, bainite is generated to increase toughness, which can be confirmed through FIG. 9. In addition, the coating step (S170) according to the present invention can be confirmed through FIG. 9 that a zinc-based composite film is formed on the surface of a component made of bainite and austenite. As described above, due to the zinc-based composite film, there is an effect of improving rust prevention, that is, corrosion resistance.

In addition, the present invention applies a steam heat treatment step (S150) with steam, which is a step prior to the coating step (S170), to the pores created in the part due to the carburization heat treatment step (S130) and the oil?? _{Fe 3} O ₄ was created by filling the pores, _{and such Fe 3} O ₄ Can be confirmed through FIG. 9. Such Fe ₃ O ₄ By preventing the pores from being exposed, it serves to improve the rust prevention properties of the parts according to the present invention. Therefore, it is preferable that _{Fe 3} O ₄ is generated in the surface structure of the part by the steam heat treatment step (S150).

Like this, Fe ₃ O ₄ end By blocking the pores, there is an effect of making it smoother when the coating step (S170), which is a later step, is applied. On the contrary, if the coating step (S170) is performed while a number of pores remain, the effect of rust prevention is remarkably deteriorated, which can be confirmed from Table 1.

10 is a flow chart of a method for manufacturing a component according to the present invention. Finally, the method for manufacturing a part according to the present invention includes a molding and sintering step (S110) in which iron-based powder is molded and sintered to become a part, a carburizing heat treatment step (S130) in which the parts subjected to the molding and sintering step are carburized heat treatment (S130), and the carburizing heat treatment It includes a steam heat treatment step (S150) in which the parts passed through the step are heat treated by steam, and a coating step (S170) in which the parts subjected to the heat treatment step are coated (S170), and a method of manufacturing a part having excellent rust prevention properties is provided. In addition, it is preferable that the carburization heat treatment step in the present invention further includes an oil treatment step in which the parts subjected to the carburization heat treatment step are called oil.

The iron-based powder may be any iron-based powder, but more preferably, 3.6 to 4.4% by weight of nickel (Ni), 1.3 to 1.7% by weight of copper (Cu), 0.4 to 0.6% by weight of molybdenum (Mo), It is preferable to contain more than 0 and 0.9% by weight or less of carbon (C), the balance iron (Fe) and unavoidable impurities.

In addition, the temperature of the carburizing heat treatment step (S130) is preferably 800 ℃ to 900 ℃.

Further, the temperature of the steam heat treatment step (S150) in the present invention is 400° C. to 600° C., preferably heat-treated at 400° C. for 20 minutes or more, and preferably heat-treated at 500° C. for 10 minutes or more, and 600 It is preferable to heat-treat for 10 minutes or more and less than 30 minutes at ℃. Even more preferably, the steam heat treatment step (S150) in the present invention is heat-treated at 500° C. for 20 minutes or more, and is preferably heat-treated at 600° C. for 20 minutes or more and less than 30 minutes.

_{In addition, it is preferable that Fe 3} O ₄ is generated in the surface structure of the part by the steam heat treatment step (S150) in the present invention, and the surface structure of the part that has undergone the carburization heat treatment step (S130) in the present invention is It is preferable to include martensite and austenite, and it is preferable that the surface structure of the part subjected to the steam heat treatment step (S150) includes bainite and austenite. It is preferable that the surface of the part that has been subjected to the coating step contains a zinc-based composite film.

Therefore, according to the manufacturing method of the injector clamp of the present invention, before the coating step (S170), the steam heat treatment step (S150) by steam proceeds, thereby preventing the pores generated due to the processing and carburizing heat treatment step (S130). This excellent, there is an effect of providing a method of manufacturing a component with enhanced toughness through microstructure control.

The present invention has been described above in connection with the specific embodiments of the present invention, but this is only an example, and the present invention is not limited thereto. Those of ordinary skill in the technical field to which the present invention pertains may change or modify the described embodiments without departing from the scope of the present invention, and within the scope of the technical idea of the present invention and the claims to be described below. Various modifications and variations are possible.

S110: molding and sintering step
S130: Carburizing heat treatment step
S150: Steam heat treatment step
S170: Coating step

Claims (14)

Molding and sintering step in which the iron-based powder is molded and sintered to form parts;
A carburizing heat treatment step in which the parts subjected to the molding and sintering step are carburized and heat treated;
A steam heat treatment step in which the parts subjected to the carburization heat treatment step are heat treated by steam; And
Including; a coating step in which the parts subjected to the steam heat treatment step are coated,
The surface structure of the part subjected to the steam heat treatment step includes bainite and austenite,
A method of manufacturing an injector clamp having excellent rust prevention properties, characterized in that the surface of the part that has undergone the coating step contains a zinc-based composite film.
The method of claim 1,
The iron-based powder is 3.6 to 4.4% by weight of nickel (Ni), 1.3 to 1.7% by weight of copper (Cu), 0.4 to 0.6% by weight of molybdenum (Mo), more than 0 and up to 0.9% by weight of carbon (C), A method of manufacturing an injector clamp having excellent rust prevention properties, characterized in that it contains negative iron (Fe) and unavoidable impurities.
The method of claim 1,
The carburizing heat treatment step further comprises an oil-quenching step in which the parts subjected to the carburizing heat treatment step are oil-quenched; the method of manufacturing an injector clamp having excellent anti-rust properties.
The method of claim 1,
The temperature of the carburizing heat treatment step is 800 ℃ to 900 ℃ method of manufacturing an injector clamp excellent in rust prevention, characterized in that.
The method of claim 1,
The method of manufacturing an injector clamp having excellent rust prevention properties, characterized in that the surface structure of the part subjected to the carburization heat treatment step includes martensite and austenite.
The method of claim 1,
A method of manufacturing an injector clamp having excellent rust prevention properties, wherein the temperature of the steam heat treatment step is 400°C to 600°C.
The method of claim 1,
The steam heat treatment step is a method of manufacturing an injector clamp having excellent rust prevention properties, characterized in that the heat treatment is performed at 400° C. for 20 minutes or more.
The method of claim 1,
The steam heat treatment step is a method of manufacturing an injector clamp having excellent rust prevention properties, characterized in that the heat treatment is performed at 500° C. for 10 minutes or more.
The method of claim 1,
The steam heat treatment step is a method of manufacturing an injector clamp having excellent rust prevention properties, characterized in that heat treatment is performed at 600° C. for 10 minutes or more and less than 30 minutes.
The method of claim 1,
The steam heat treatment step is a method of manufacturing an injector clamp having excellent rust prevention properties, characterized in that the heat treatment is performed at 500° C. for 20 minutes or more.
The method of claim 1,
The steam heat treatment step is a method of manufacturing an injector clamp having excellent rust prevention properties, characterized in that the heat treatment is performed at 600° C. for 20 minutes or more and less than 30 minutes.
delete The method of claim 1,
A method of manufacturing an injector clamp having excellent rust prevention properties, characterized in that _{Fe 3} O ₄ is generated in the surface texture of the part that has undergone the steam heat treatment step. delete

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