CN108817200A - Improve the processing method and application of hole expansibility - Google Patents

Abstract

The processing method and application provided by the invention for improving hole expansibility, is related to reaming processing technique field.A kind of processing method improving hole expansibility, including：The diameter in hole to be processed is A, and diameter is selected to carry out first time punching processing for the first punch-pin of (A- Ф 0.60)~(A- Ф 0.56) mm, the first cavity plate that diameter is (A- Ф 0.36)~(A- Ф 0.32) mm.It selects diameter to carry out second of reaming punch press process for the second punch-pin of A, the second cavity plate that diameter is (A+0.03)~(A+0.07) mm, the notch that first time punching is formed is processed as smooth kerf.The processing method simple process, controllability is strong, processes available smooth notch section to high strength steel.

Description

Processing method and application for improving hole expansion rate

technical field

The invention relates to the technical field of hole reaming, and in particular to a processing method and application for improving the hole reaming rate.

Background technique

In order to solve the endurance problem of new energy vehicles, the lightweight of the vehicle body has become an inevitable issue. Cold-rolled high-strength steel (generally refers to steel with a tensile strength above 580MPa, which can maintain very high strength even if it is very thin.) While achieving weight reduction, it can also ensure its safety.

In the process of processing the body, the plate is porous to install screws and further reduce weight. The processing of these holes is generally mechanical punching. Generally speaking, the notch surface of the blanking process is preferably a smooth cross section. High-strength steel has low ductility and is difficult to process. Compared with ordinary mild steel, high-strength steel has low formability. Especially, secondary processing such as hole expansion will cause fracture of the section and reduce the formability of the material.

Contents of the invention

The object of the present invention is to provide a processing method for improving the hole expansion rate. The processing method is simple in process and strong in controllability, and can obtain a smooth cut section for processing high-strength steel.

Another object of the present invention is to provide the application of the above processing method for improving hole expansion rate in automobile production and processing.

The present invention solves its technical problem and adopts the following technical solutions to realize:

A processing method for improving hole expansion rate, comprising:

The diameter of the hole to be processed is A, select the first punch with a diameter of (A-Ф0.60)～(A-Ф0.56)mm, and a diameter of (A-Ф0.36)～(A-Ф0.32) mm of the first die for the first punching process.

Select the second punch with a diameter of A and the second die with a diameter of (A+0.03)~(A+0.07)mm to carry out the second hole expansion and punching process, and process the incision formed by the first punching as Smooth cuts.

Application of the above-mentioned processing method for improving hole expansion rate in automobile production and processing.

The beneficial effects of the processing method and application for improving the hole expansion rate of the embodiment of the present invention are:

The present invention adopts two hole-enlarging processing methods. In the first punching process, the first concave die and the first punch with suitable apertures are selected for hole-enlarging punching, and the cut surface after processing under a certain process is uneven. Then, after selecting the second concave die with suitable aperture and the second coating, carry out the second reaming punching on the incision surface, so that the incision surface is smooth and tidy, and a hole with qualified process quality is obtained. In this processing method, the size of the die and the punch for each punching is particularly important. Due to the high strength and low ductility of the processed steel, there is an important relationship between the process parameters of the two reaming punches. The processing method improves the damage of the high-strength steel during hole expansion, increases the rate of hole expansion, and improves the formability of the high-strength steel.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following will briefly introduce the drawings used in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the invention and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained based on these drawings without creative effort.

Fig. 1 is the processing structure schematic diagram that the embodiment of the present invention provides;

Fig. 2 is the hole expansion rate figure provided by the present invention;

Fig. 3 is a microstructure diagram provided by the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all conventional products that could be purchased from the market.

The processing method and application for improving the hole expansion rate of the embodiments of the present invention will be described in detail below.

A processing method for improving hole expansion rate provided by an embodiment of the present invention includes:

Please refer to Fig. 1, select the plate to be processed, and set it between the first die and the pressing plate. The pressing plate is arranged below, and the first die is arranged above. The plate is punched from bottom to top with the first punch. After punching for the first time, the above board is placed between the second die and the pressing plate. The pressing plate is arranged below, and the second die is arranged above. The plate is reamed and punched from bottom to top by using the second punch.

In the embodiment of the present invention, the plate to be processed is mainly high-strength steel. Due to the low ductility of high-strength steel, it is difficult to process, and compared with mild steel, the new type is very low, so it is easy to cause cross-sectional fracture during processing. In the method provided by the present invention, in order to improve the damage of high-strength steel during hole reaming, in the first punching process, the first die and the first punch with a suitable aperture are selected for reaming and punching. The cut surface after lower processing is uneven. Then, after selecting the second concave die with suitable aperture and the second coating, carry out the second reaming punching on the incision surface, so that the incision surface is smooth and tidy, and a hole with qualified process quality is obtained. This processing method increases the machining rate of hole expansion and improves the formability of high-strength steel materials.

In this processing method, the size of the die and the punch for each punching is particularly important. Due to the high strength and low ductility of the processed steel, there is an important relationship between the process parameters of the two reaming punches. Specifically, the diameter of the hole to be processed is A, and the first punch with a diameter of (A-Ф0.60)～(A-Ф0.56)mm is selected and the diameter is (A-Ф0.36)～(A- The first die of Ф0.32) mm is made of a press, under the conditions of a pressurization pressure of 440-460KN, a processing speed of 70-80spm, a processing range of 195-255mm, and a pressurized total length of 100mm. secondary punching process.

After the first punching process, the plate is processed with holes. However, the cut surface of the hole is uneven and needs to be processed further. However, during the second processing, the section of the high-strength steel is easily broken, so the setting of process parameters for the second processing is particularly important. Select the second punch with a diameter of A and the second die with a diameter of (A+0.03)～(A+0.07)mm, use a press, pressurize at a pressure of 440～460KN, and a processing speed of 70～80spm , The processing range is 195 ~ 255mm, and the pressurized total length is 100mm, and the second reaming punching process is carried out.

Further, in a preferred embodiment of the present invention, the diameter of the first punch is (A-Ф0.59) ~ (A-Ф0.57) mm, the diameter of the first die is (A-Ф0.35 )～(A-Ф0.33)mm; the diameter of the second die is (A+0.04)～(A+0.06)mm. The pressing pressure is 445-455KN, the processing speed is 72-78spm, the processing range is 210-240mm, and the total press length is 100mm.

Further, in a preferred embodiment of the present invention, the diameter of the first punch is (A-Ф0.58) mm, the diameter of the first die is (A-Ф0.34) mm; the diameter of the second die The diameter is (A+0.05) mm. In the present invention, the diameter of the first punch is the outer diameter of the first punch, and the diameter of the second punch is the outer diameter of the second punch; the diameter of the first die is the inner diameter of the first die, and the diameter of the second punch is the inner diameter of the first die. The diameter of the second die is the inner diameter of the second die.

The processing method for improving the hole expansion rate provided by the present invention has better processing effect for the hole expansion processing of high-strength steel, improves the hole expansion processing rate, improves the formability of high-strength steel, and can be applied in automobile production and processing .

The characteristics and performance of the present invention will be described in further detail below in conjunction with the examples.

Example 1

This embodiment provides a processing method for improving the hole expansion rate, including:

The diameter of the hole to be processed is 10 mm, and the first punch with a diameter of 10 mm and the first concave die with a diameter of 10.24 mm are selected. Select the 1200MPa grade high-strength steel plate to be processed, and set it between the first die and the pressing plate. The pressing plate is arranged below, and the first die is arranged above. The plate is punched from bottom to top with the first punch. Among them, the pressing pressure is 450KN, the processing speed is 75spm, the processing range is 195-255mm, and the total press length is 100mm.

Example 2

This embodiment provides a processing method for improving the hole expansion rate, including:

The diameter of the hole to be processed is 10 mm, and the first punch with a diameter of 9.81 mm and the first concave die with a diameter of 10.05 mm are selected. Select the 1200MPa grade high-strength steel plate to be processed, and set it between the first die and the pressing plate. The pressing plate is arranged below, and the first die is arranged above. The plate is punched from bottom to top with the first punch. Among them, the pressing pressure is 450KN, the processing speed is 75spm, the processing range is 195-255mm, and the total press length is 100mm.

Select a second punch with a diameter of 10 mm and a second die with a diameter of 10.05 mm, and place the above-mentioned plate between the second die and the pressing plate. The pressing plate is arranged below, and the second die is arranged above. The plate is reamed and punched from bottom to top by using the second punch. Among them, the pressing pressure is 450KN, the processing speed is 75spm, the processing range is 195-255mm, and the total press length is 100mm.

Example 3

This embodiment provides a processing method for improving the hole expansion rate, including:

The diameter of the hole to be processed is 10 mm, and the first punch with a diameter of 9.76 mm and the first concave die with a diameter of 10 mm are selected. Select the 1200MPa grade high-strength steel plate to be processed, and set it between the first die and the pressing plate. The pressing plate is arranged below, and the first die is arranged above. The plate is punched from bottom to top with the first punch. Among them, the pressing pressure is 450KN, the processing speed is 75spm, the processing range is 195-255mm, and the total press length is 100mm.

Select a second punch with a diameter of 10 mm and a second die with a diameter of 10.05 mm, and place the above-mentioned plate between the second die and the pressing plate. The pressing plate is arranged below, and the second die is arranged above. The plate is reamed and punched from bottom to top by using the second punch. Among them, the pressing pressure is 450KN, the processing speed is 75spm, the processing range is 195-255mm, and the total press length is 100mm.

Example 4

This embodiment provides a processing method for improving the hole expansion rate, including:

The diameter of the hole to be processed is 10 mm, and the first punch with a diameter of 9.66 mm and the first concave die with a diameter of 9.9 mm are selected. Select the 1200MPa grade high-strength steel plate to be processed, and set it between the first die and the pressing plate. The pressing plate is arranged below, and the first die is arranged above. The plate is punched from bottom to top with the first punch. Among them, the pressing pressure is 450KN, the processing speed is 75spm, the processing range is 195-255mm, and the total press length is 100mm.

Select a second punch with a diameter of 10 mm and a second die with a diameter of 10.05 mm, and place the above-mentioned plate between the second die and the pressing plate. The pressing plate is arranged below, and the second die is arranged above. The plate is reamed and punched from bottom to top by using the second punch. Among them, the pressing pressure is 450KN, the processing speed is 75spm, the processing range is 195-255mm, and the total press length is 100mm.

Comparative example 1

In this comparative example, the existing cutting processing method is used to process the holes of the 1200MPa grade high-strength steel plate.

The 1200MPa grade high-strength steel plates in Examples 1 to 4 and Comparative Example 1 are all steel products of the same production batch, and the process mechanical characteristics of the steel products are tested, and the results are as follows:

Table 1 Test results of mechanical properties

Measure the hole expansion rate to the hole that embodiment 1～4, comparative example 1 make, the hole expansion rate where d is the critical pore diameter and d1 is the initial diameter _of the pore. Use the punch to press the test piece into the concave die, so that the prefabricated hole of the test piece continues to expand. When the edge of the hole or the material near the hole begins to shrink or crack, the test is stopped, and the hole diameter at this time is the critical hole diameter. The results are shown in Figure 2, where the punching process corresponds to Example 1, the obtained value 0.095mm corresponds to Example 2, the obtained value 0.12mm corresponds to Example 3, the obtained value 0.17mm corresponds to Example 4, and the cutting process corresponds to Comparative Example 1. It can be seen from Figure 2 that the hole expansion rate of Examples 2-4 is similar to that of cutting machining. Compared with Example 1, it shows that the processing method used in Examples 2-4 to improve the hole expansion rate can increase the hole expansion rate.

The pore diameters of Examples 2-4 and Comparative Example 1 were selected, and the microscopic morphology was detected, and the results are shown in Figure 3. It can be seen from Figure 3 that compared with the cutting process of Comparative Example 1, the surfaces of Examples 2-4 are smoother, indicating that the hole quality obtained by the processing method of improving the hole expansion rate is higher.

The embodiments described above are some, not all, embodiments of the present invention. The detailed description of the embodiments of the invention is not intended to limit the scope of the claimed invention but to represent only selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Claims (10)

1. A processing method for improving hole expansion rate, characterized in that, comprising: The diameter of the hole to be processed is A, select the first punch with a diameter of (A-Ф0.60)～(A-Ф0.56)mm, and a diameter of (A-Ф0.36)～(A-Ф0.32) The first die of mm is punched for the first time; Select the second punch with a diameter of A and the second die with a diameter of (A+0.03)~(A+0.07)mm to carry out the second hole expansion and punching process, and process the incision formed by the first punching as Smooth cuts. 2. The processing method for improving hole expansion rate according to claim 1, characterized in that, the diameter of the first punch is (A-Ф0.59) to (A-Ф0.57) mm, and the diameter of the first punch is The diameter of the first die is (A-Ф0.35)˜(A-Ф0.33) mm; the diameter of the second die is (A+0.04)˜(A+0.06) mm. 3. The processing method for improving hole expansion rate according to claim 1 or 2, characterized in that, the diameter of the first punch is (A-Ф0.58) mm, and the diameter of the first die is (A-Ф0.34) mm; the diameter of the second die is (A+0.05) mm. 4. The processing method for improving hole expansion rate according to claim 1, characterized in that, the diameter of the first punch is the outer diameter of the first punch, and the diameter of the second punch is the Describe the outer diameter of the second punch. 5. The processing method for improving hole expansion rate according to claim 1, characterized in that, the diameter of the first die is the inner diameter of the first die, and the diameter of the second die is the The inner diameter of the second die. 6. The processing method for improving the hole expansion rate according to claim 1, characterized in that, the pressing pressure for the first punching is 440-460KN. 7. The processing method for improving hole expansion rate according to claim 1 or 6, characterized in that the processing speed of the first punching is 70-80 spm. 8. The processing method for improving hole expansion rate according to claim 1, characterized in that the processing range of the first punching is 195-255 mm. 9. The processing method for improving the hole expansion rate according to claim 1, further comprising: placing the plate to be processed between the die and the pressing plate, and using a punch to move along the pressing plate to the die The direction of the plate is expanded and punched. 10. Application of the processing method for improving hole expansion rate as claimed in claims 1 to 9 in automobile production and processing.