KR20030012140A - Apparatus and method for cooling hot-forged parts - Google Patents

Abstract

PURPOSE: A method and an apparatus for cooling hot forged products are provided to maximize cooling efficiency of the forged products after hot forging by adopting water cooling process along with flowing direction of air supplied into each chambers. CONSTITUTION: The method for cooling hot forged products comprises the processes of transferring the hot forged products(100) through a plurality of chambers(20a to 20d) by controlling speed of a conveyor(10); water cooling the forged products by spraying water onto the forged products in each of the chambers while the forged products are being transferred; and controlling flow rate and ejecting direction of air ejected from each of the chambers along with water cooling type cooling process, wherein a blower driven by a controller is used in the air cooling process to independently vary control direction of air, and a distance between the blower for generating air in the air cooling process and the hot forged products is 30 to 50 cm. The apparatus for cooling hot forged products comprises chambers(20a to 20d) a plurality of which are adjacently formed to each other; and a conveyor(10) for transferring the forged products(100) by passing through each of the chambers, wherein each of the chambers comprise a water cooling means(40) for spraying water onto the forged products by receiving signals from a controller and an air cooling means(50) which are rotationally controlled in both directions, wherein the water cooling means comprises a plurality of water spraying nozzles(41) installed in each of the chambers, a pump(42) for supplying water to the water spraying nozzles and a water collector(43) mounted on the lower part of the conveyor in the chambers, and the air cooling means is blowers mounted on each of the chambers and independently rotated forward and reversely by control of the controller.

Description

Apparatus and method for cooling hot-forged parts

The present invention relates to a method and a cooling apparatus for cooling a hot forging. More particularly, the forging may be cooled by a feed rate of a forging, a direction of inflow / outflow of cooling air, and a water cooling or a combination thereof in a plurality of chambers. The present invention relates to a cooling method and a cooling device for a hot forging product, which is configured to refine the grains to improve physical properties after final carburization, particularly fatigue strength.

In general, a material that requires high strength and high toughness, such as a transmission gear for an automobile, is subjected to a hot forging process. The manufacturing process of the transmission gear is shown in Figure 2, the material → hot forging → cooling (air cooling or cooling) → heat treatment before processing (ISO annealing or Normarlizing) → processing (shaving & Hobbing) → carburizing heat treatment → After finishing (Honing) process.

As described above, the finished material forging is subjected to a cooling process at about 1200 ° C. or more. The crystal grain size of the material cooled in this way is GS No. It has a value of about 7 to 8, if the carburizing process after cooling the material is GS No. It will have a value of about 6-7.

A cooling device to improve this has already been filed under the name of the Korean Patent No. 2000-73091 "cooling device for hot forging products". Figure 3 shows such a conventional cooling device. The cooling device includes a conveyor 10 for transporting the forged product in a horizontal direction, a plurality of chambers 20a to 20d for separating and separating the conveyor, and mounted in each chamber to cool the forged product by supplying / discharging air. The main is composed of cooling means 30.

In particular, the cooling means 30 is a supply blower 31 mounted in each of the chambers 20a to 20d to supply outside air, and the air thus supplied cools the forged product and then outside the chambers 20a to 20d. It is composed of a discharge fan 32 mounted on the upper portion so as to be discharged to the controller, and a controller 33 for controlling the blowers 31.

Cooling means 30 made as described above by controlling the feed speed of the conveyor 10, the blowing speed of the blower 31 and the discharge fan 32 and the discharge speed by the control of the controller 33 to cool the forged product Given.

As a result, the GS No. Fine grains of 10 or more were obtained.

However, the conventional cooling apparatus has raised the following problems and needs to be improved.

1) Small quantity is suitable for forging like the prototype, but when mass production by mass production of parts, many forgings are placed on the conveyor and the belt stretches when cooling, causing problems in the durability of equipment autonomy.

2) In order to improve this, if the belt is made strong, the durability can be improved, but it causes a problem that the cooling efficiency is reduced by friction with the cooling air blown through the blower.

3) Since cooling is carried out by air only, there is a limit in cooling the forged product.

The present invention has been made in view of this point, and by adopting a water-cooling cooling method together with the flow direction of the air provided in each chamber, the cooling method and cooling apparatus for hot forgings that can maximize the cooling efficiency of the forgings after hot forging The purpose is to provide.

1 is a side view showing the configuration of a cooling device according to the present invention;

Figure 2 is a manufacturing process showing an example of passing through a conventional hot forging (transmission gear for automobiles),

Figure 3 is a side view showing the configuration of a conventional cooling device,

[Description of Symbols for Main Parts of Drawing]

10: conveyor 20a-20d: chamber

30: cooling means 31: blower

32: discharge fan 33: controller

40: water cooling means 41: water spray nozzle

42: pump 43: water collector

50: air cooling means 100: hot forging

The present invention for realizing this process is to control the speed of the conveyor to transfer the forged hot forged through a plurality of chambers, the process of cooling the water by cooling the water in each chamber during the transfer of the forging, and water-cooled In addition to the cooling process characterized in that consisting of a process for adjusting the flow rate and the blowing direction of the air ejected from each chamber.

In a preferred embodiment of the present invention, the air cooling process is characterized by using a blower driven under the control of the controller to independently change the control direction.

In addition, the distance between the blower for generating air in the air cooling process and the hot forging is characterized in that the 30 to 50 cm.

The apparatus for cooling a hot forging product according to the present invention includes a plurality of adjacently formed chambers and a conveyor for transferring the forgings across each chamber, wherein each chamber is sprayed with water under the control of a controller. Air cooling means capable of controlling the rotation in both directions with the water cooling means is characterized in that it is provided.

In a preferred embodiment of the present invention, the water cooling means comprises a plurality of water spray nozzles installed in each chamber, a pump for supplying water thereto, and a water collector mounted on the lower part of the conveyor in the chamber. .

In addition, the water spray nozzles are used by installing a total of four water jet nozzles, one between the first chamber and the second chamber, two between the second chamber and the third chamber, and one between the third chamber and the fourth chamber. It is preferable to.

In addition, the air cooling means is mounted to each chamber is characterized in that the blower capable of independent forward and reverse rotation independently of the control of the controller.

In addition, the controller is characterized in that for controlling the air cooling means as shown in Table 1 to be described later.

Hereinafter, with reference to the accompanying drawings, the configuration and effect of the present invention will be described.

1 is a side view showing the configuration of a cooling device according to the present invention. Here, about the same element as the conventional structure, the same code | symbol is used as it is.

The present invention realizes miniaturization of grains by a cooling method and a cooling device which are performed immediately after hot forging, thereby suppressing grain growth through rapid cooling in a recrystallized region, and fast structure in austenite and ferrite abnormal regions. ) To suppress the formation of ferrite aggregates.

In more detail, the present invention is to transfer the hot forging 100 through the conveyor (10). The conveyor 10 is configured to transport the hot forging 100 to traverse the four chambers (20a-20d) as in the preferred embodiment of the present invention, in particular the drive configured in this conveyor (100) The motor is controlled by the controller 33 which in turn controls the conveying speed of the conveyor 10, ie the hot forging 100.

In addition, the present invention includes a water cooling means 40 installed in each of the chamber (20a-20d), the water-cooled hot forging product (100) sequentially passing through each chamber (20a-20d) through the conveyor 10 Will be cooled.

The water cooling means 40 is composed of a water spray nozzle 41 mounted in each chamber 20a-20d, a pump 42 for generating water pressure, and a water collector 43 for collecting the sprayed water. It is.

Here, in the preferred embodiment of the present invention, the water spray nozzles 41 are illustrated as being installed in each of the two chambers 20a-20d and are supplied with water pressure from the pump 42. The water spray nozzle 41 hardens the tissue because it accelerates the cooling rate of the hot forging 100 according to the amount of water sprayed. Preferably, the water is sprayed into each chamber 20a-. 20d).

In a preferred embodiment of the invention, the water spray nozzle 41 is one between the first chamber 20a and the second chamber 20b, two between the second chamber 20b and the third chamber 20c. It is preferable to install and use four dogs, one each between the dog and the third chamber 20c and the fourth chamber 20d.

In addition, the pump 42 is preferably controlled to control the water pressure supplied to the water spray nozzle 41 under the control of the controller 33, as shown in the accompanying drawings in the lower portion of each chamber (20a-20d) As it is configured to recycle the water collected through the water collector 43.

Therefore, when the hot forging 100 reaches the austenite + ferrite abnormality region during cooling, cooling is slowed down due to energy (latent heat) required for precipitation, and the quenching effect can be further increased through the water cooling means. Of course, this effect is obtained with the air cooling means as well as the water cooling means.

Finally, the present invention increases the cooling effect of the hot forging 100 with the air cooling means 50 as well as the water cooling effect of the water cooling means 40.

The air cooling means 50 is a blower driven under the control of the controller 33 and is mounted in each of the chambers 20a-20d. In particular, the air-cooling means 50 is selectively driven as shown in Table 1 under the control of the controller 33 as a blower rotatable in the forward and reverse directions.

Condition Progress direction of forgings Direction of air movement in the chamber Chamber 1 Chamber 2 Chamber 3 Chamber 4 Condition A → ↓ ↓ ↓ ↑ Condition B → ↓ ↓ ↓ ↑ Condition C → ↓ ↑ ↓ ↓ Condition D → ↓ ↑ ↑ ↓ Condition E → ↓ ↓ ↑ ↓

Here, the conditional classification is classified according to the advancing direction of the air in each chamber 20a-20d, so that the best cooling capacity can be obtained in the case of condition C.

In addition, the cooling means 50 is preferably used to be mounted so as to maintain an interval of about 30 to 50 cm with the hot forging 100 in mounting in each chamber (20a-20d). This is because the hot forging 100 is a high-temperature body of 1200 ° C or more, so if the distance is shorter than this, the durability of the cooling means 50 and the equipment is lowered, if it is farther than this to prevent the cooling capacity is lowered.

For example, when the cooling means 50 is installed so that the distance from the hot forging product 100 is positioned at 40 cm and 70 cm, the cooling rate is measured.

Hereinafter, a description will be given of an embodiment experimented with the transmission gears (counter cluster gear) for a small commercial vehicle.

Table 2 shows the results of manufacturing the gear through a process according to hot forging → cooling → heat treatment before processing → carburizing. Here, the cooling process of Comparative 1 proceeds to air cooling / air cooling, which is a conventional cooling method, and in Comparative 2, cooling is performed according to control cooling (Korean Patent Application No. 20001-73091), and the embodiment is cooled according to the present invention. will be.

Example and Comparative Example (Material: SCM822HVSi) Comparison 1 Comparison 2 practice Final grain size (GS No after carburizing) 7.3 10.08 10.7 Improvement effect - 38% improvement over comparison 1 46% improvement compared to comparison 1 6% improvement compared to comparison 2

From these results, it can be seen that the present invention is improved by about 46% compared to the conventional cooling method and about 6% compared to the control cooling method, which according to the academic report, GS No. When increased by 1, it is known that the micronization effect is improved by 6 to 8% as fatigue strength, thereby improving the durability of automobile parts.

As described above, the present invention obtains the following effects by transporting the hot forged product through a conveyor at a predetermined speed and controlling cooling of the hot forged product by water cooling and air cooling in each chamber.

1) It is easier to manufacture transmission gears and shafts that require higher torque because the grain size is smaller than general hot forging products.

2) The physical properties of the forged parts, especially the bending fatigue strength, are increased by about 20%, the contact fatigue (fitting resistance) is also improved by 2 to 2.5 times, and the impact energy is 1.5 times larger.

3) It is possible to replace the existing materials that are difficult to process (SNCM-based materials) with materials that are easy to process in order to obtain properties above a certain value, thereby improving the processability and lowering the unit cost.

Claims (9)

Controlling the speed of the conveyor to transfer the hot forged products through a plurality of chambers, During the transfer of the forged product by spraying water in each chamber to cool by water cooling; Cooling of the hot forging product, characterized in that the process consisting of controlling the flow rate and the direction of the ejected air from each chamber in addition to the water-cooled cooling process. The method of claim 1, wherein the air cooling process uses a blower driven by a controller to independently change a control direction. 3. The method of claim 1 or 2, wherein a distance between the blower for generating air in the air cooling process and the hot forging product is 30 to 50 cm. It is composed of a plurality of adjacently formed chambers and a conveyor for transferring the forged product across each chamber, Cooling device for hot forgings, characterized in that each chamber is provided with water cooling means for injecting water under the control of the controller and air cooling means capable of rotation control in both directions. 5. The hot forging according to claim 4, wherein the water cooling means includes a plurality of water spray nozzles installed in each chamber, a pump for supplying water thereto, and a water collector mounted on the lower part of the conveyor in the chamber. Cooling system. 5. The apparatus of claim 4, wherein the air cooling means is a blower mounted in each chamber and capable of independent forward and reverse rotation under the control of a controller. 7. The apparatus for cooling hot forging according to claim 4 or 6, wherein the air cooling means is capable of position adjustment so that the distance from the hot forging is between 30 and 50 cm. 5. The apparatus of claim 4, wherein the controller controls the air cooling means as follows. division Progress direction of forgings Direction of air movement in the chamber Chamber 1 Chamber 2 Chamber 3 Chamber 4 Condition A → ↓ ↓ ↓ ↑ Condition B → ↓ ↓ ↓ ↑ Condition C → ↓ ↑ ↓ ↓ Condition D → ↓ ↑ ↑ ↓ Condition E → ↓ ↓ ↑ ↓ 5. The water spray nozzle according to claim 4, wherein one water spray nozzle is one between the first chamber 20a and the second chamber 20b, two between the second chamber 20b and the third chamber 20c, and a third. A cooling device for hot forgings, characterized in that a total of four are provided, one each between the chamber (20c) and the fourth chamber (20d).