CN101486061A - Thermoforming, hole-punching and edge-cutting integrated technique and mold of high-duty steel part - Google Patents

Abstract

The invention provides hot-forming, punching and edge-cutting integral technology and a hot-forming, punching and edge-cutting integral die for high strength steel parts. The integral technology comprises the following steps: arranging an edge-cutting and punching tool on a hot-forming die of the high strength steel parts; placing high strength steel plate materials which is heated to be completely austenized into the hot-forming die for punching before hot stamping forming of the high strength steel plate materials; utilizing the edge-cutting and punching tool on the hot-forming die to perform edge-cutting and punching operations on workpieces subjected to stamping after the hot-forming die is closed; cooling the hot-forming die after the operations are over; and utilizing die components which contact formed parts to quench the formed parts. The integral die comprises a forming convex die, a forming concave die, an upper punching tool, a lower punching tool, an upper edge-cutting tool and a lower edge-cutting tool. The integral technology and the integral die reduce the production cost of the hot-formed parts, and shorten the production period of the hot-formed parts; and the hot-formed parts have high edge-cutting and punching quality and high dimension precision and shape precision.

Description

Hot forming, punching and trimming integrated process and mold for high-strength steel parts

technical field

The invention relates to hot stamping forming, punching, trimming process and mold of high-strength steel, advanced high-strength steel and ultra-high-strength steel stamping parts, and belongs to the technical field of forming high-strength steel plate gold parts.

Background technique

At present, in the field of automobile manufacturing, people's demand for high safety, low dead weight and good fuel economy has become an important driving factor for technological progress. Manufacturers are making consumers' wishes come true by introducing new safety concepts and lightweight body structures. Especially in terms of body structure, through the use of high-strength steel, advanced high-strength steel and ultra-high-strength steel, the crash performance of the car is improved and the requirement of lightweight is also achieved. However, with the increase of steel strength, the elongation rate decreases, and the formability of the material is also greatly reduced. During the forming process, problems such as cracking, wrinkling, difficult to control the size and poor shape are prone to occur. The traditional cold stamping forming process can no longer meet the technical requirements. and production development needs.

In recent years, scholars at home and abroad have developed a new hot stamping process for high-strength and ultra-high-strength steel sheets, which heats high-strength steel and ultra-high-strength steel sheets to the austenitizing temperature ( 900～950℃), and keep it in the austenite zone for 5 minutes, then transfer the sheet to the press, and perform stamping forming and quenching in the stamping die at the same time, so that the formed parts can obtain 100% martensite structure. The process can reduce the weight of automotive structural parts while improving crash performance and fatigue strength.

Chinese patent document CN101288889 discloses a "ultra-high-strength steel plate hot stamping die", which includes an upper mold base and a punch fixed on the upper mold base, a lower mold base and a concave mold fixed on the lower mold base, and A cooling water channel is arranged in the mold, and the cooling water channel is connected with a cooling water circulation system.

Chinese patent document CN1829813 discloses a kind of "hot forming method and hot forming member". After heating a steel plate with a specific composition above the austenite point temperature (Ac3) and maintaining it, the final product shape is formed. During forming or from When cooling the forming temperature after forming, the cooling rate to the Martens point temperature (Ms point) of the formed component is above the critical cooling rate, and the average cooling rate from the Ms point to 200 °C is 25~150 °C/ s cooling and quenching treatment.

In the case of high dimensional accuracy requirements, through-holes on thermoformed parts or press flanges on thermoformed parts, secondary processing of thermoformed parts is necessary. In the cold stamping process, the stamping die is generally used for secondary processing such as punching and trimming, but it is extremely difficult to use a conventional die structure for secondary processing in the hot stamping process; Trimming or punching of components requires a large processing load, and the metal die will be damaged or its life shortened. For hot-formed parts of ultra-high-strength steel plates, it is even impossible to process with cold stamping dies.

In order to make hot-formed high-strength parts meet the corresponding dimensional accuracy and shape requirements, five-axis laser cutting technology is currently used for punching and trimming. However, the efficiency of laser trimming or cutting holes is low, and a hot stamping production line often requires several A set of laser edge trimming or hole cutting line is matched with it. In addition, each set of laser edge trimming or hole cutting line needs corresponding fixtures to position and clamp the parts, so the equipment occupies a large area, equipment investment is large, and production costs are high. . In addition, after laser trimming or hole cutting, the trimming or hole edge of the thermoformed part will have some metal particles formed after the solidification of molten metal, which requires a subsequent grinding process to remove the metal waste, resulting in a production cycle of thermoformed parts Long, which limits the popularization and application of hot stamping technology. When using laser trimming or hole cutting, the completion time is limited by the size of the part and the number of holes. The simplest part takes more than 30 seconds from the part to the trimming fixture to the completion of cutting. It may take several minutes for complex parts.

Chinese patent document CN2617549 discloses a "new hot punching and trimming die", which is used for hot punching and trimming dies for forgings. The die disclosed in this patent can only use the slide block movement of the press to complete a single Punching, trimming, but not for forming, trimming or punching compound, in addition, the mold structure is used for steel block forging, belongs to the field of volume forming, and cannot be used for high-strength sheet metal belonging to the field of sheet metal forming Punch or trim.

Chinese patent document CN101326022 discloses a "combined punch for hydraulic punching", which is used to form holes in hydraulic bulging components. After the hydraulic bulging of the part is completed, the combined punch retreats the punch to the inside of the mold, and uses the high-pressure liquid as power to cut the part to be punched into several pieces to complete the punching process. This process and structure are only suitable for hydraulic bulging low-strength steel plates, and cannot be used for forming and punching high-strength steel parts.

Contents of the invention

The present invention aims at the problems existing in the secondary processing technology used in hot forming, edge trimming and punching of high-strength or ultra-high-strength steel stamping parts, and provides a high-strength steel part with simple structure, high production efficiency and good quality. An integrated process of thermoforming, punching and edge trimming, and a mold for realizing the process is provided at the same time.

The hot forming, punching and trimming integrated process of the high-strength steel parts of the present invention are:

First, trimming and punching tools are set on the hot forming die of high-strength steel parts. Before the high-strength steel sheet is hot-stamped, the high-strength steel sheet heated to complete austenitization is placed in the hot-forming die for stamping , after the thermoforming mold is closed, then use the trimming and punching tools on the thermoforming mold to trim and punch the stamped workpiece. After the completion, the thermoforming mold is cooled, and the mold that is in contact with the formed part Components Quenching of formed parts.

The integrated mold for hot forming, punching and edge trimming of high-strength steel parts that realizes the above-mentioned integrated process adopts the following technical solutions:

The integrated mold includes a forming punch, a forming die, an upper punching tool, a lower punching tool, an upper trimming tool and a lower trimming tool, the forming punch and the forming die are provided with a cooling water channel, and the forming punch The outer contour of the bottom end is consistent with the shape of the part, the inner cavity contour of the forming die is consistent with the outer shape of the part; the forming punch is equipped with a binder plate, and the forming punch is provided with a through hole corresponding to the punching position of the part. The through hole is equipped with a push rod, and the upper end of the forming punch is equipped with an upper punching cylinder. The piston rod of the upper punching cylinder extends into the through hole of the forming punch and is connected with the upper end of the push rod. The punching tool is connected, and the upper trimming cylinder is installed on the top surface of the pressing plate, and the piston rod of the upper trimming oil cylinder is connected with the upper trimming tool; there is also a through hole in the forming die, which is connected with the forming The through holes of the die are on the same axis; the lower end of the forming die is equipped with a lower trimming cylinder and a lower punching cylinder, and the piston rod of the lower punching cylinder extends into the through hole of the forming die and is connected with the lower punching tool. The piston rod of the edge trimming oil cylinder is connected with a push rod, and the push rod is connected with the edge trimming tool.

The upper trimming tool and the lower trimming tool are segmented according to the outer shape of the part, and the upper trimming tool and the lower trimming tool have the same number of segments.

The thickness of the upper trimming tool and the lower trimming tool is 1.5~4.0 times of the wall thickness of the processed part.

The present invention uses trimming and punching tools inside the mold that do not rely on the energy of the press to trim and punch hot formed parts after hot stamping and before in-mold quenching of the formed parts. After punching, the parts are quenched in the mold. This process reduces the equipment investment for hot forming, reduces the floor area of the equipment, reduces the production cost of hot forming parts, shortens the production cycle of hot forming parts, and hot forming The trimming and punching quality of the parts is high, and the dimensional accuracy and shape accuracy of the parts are high. Using the edge trimming and punching process of the present invention, the time to complete the edge trimming and punching process is 1-2 seconds, and is not limited by the size and shape of the parts.

Description of drawings

Fig. 1a is a structural schematic diagram of a part that requires thermoforming, punching, and edge trimming.

Figure 1b is a cross-sectional view of Figure 1a.

Fig. 2 is a structural schematic diagram of a thermoforming, trimming and punching composite mold for the part shown in Fig. 1 (the state before trimming and punching, cut along the A-A cutting line in Fig. 3).

FIG. 3 is a top view of FIG. 2 .

Fig. 4 is a left side view of Fig. 2 (the state before trimming and punching, cut along the center of the trimming tool).

Fig. 5 is a schematic diagram of the state after trimming and punching of the thermoforming, trimming and punching composite mold shown in Fig. 2 .

Fig. 6 is a schematic diagram of the state after trimming and punching of the thermoforming, trimming and punching composite mold shown in Fig. 4 .

Among them: 1. Binder, 2. Upper trimming tool, 3. Lower trimming tool, 4. Ejector, 5. Forming die, 6. Lower trimming oil cylinder, 6a, upper oil hole, 6b, lower oil hole, 6c, piston rod, 7, lower punching cylinder, 7a, upper oil hole, 7b, lower oil hole, 7c, piston rod, 8, lower punching tool, 9, thermoformed parts, 10, lower trimming oil cylinder, 10a, Upper oil hole, 10b, lower oil hole, 10c, piston rod, 11, ejector rod, 12, lower trimming tool, 13, upper trimming tool, 14, upper trimming oil cylinder, 14a, upper oil hole, 14b, lower oil Hole, 14c, piston rod, 15, upper punching tool, 16, ejector rod, 17, upper punching cylinder, 17a, upper oil hole, 17b, lower oil hole, 17c, piston rod, 18, forming punch, 19 , Upper trimming oil cylinder, 19a, upper oil hole, 19b, lower oil hole, 19c, piston rod, 20, trimming waste, 21 punching waste, 22, forming parts.

Detailed ways

The hot forming, punching and trimming integrated process of the high-strength steel parts of the present invention, firstly, corresponding trimming and punching are arranged on the punch, die or binder plate of the hot-forming mold of the high-strength steel parts. Hole tools for mounting trimming and punching devices on punches, dies or binders. The flow of the process is that the sheet heated to the austenitic state is placed on the die of the thermoforming mold → driven by the press, the pressing plate first presses the thermoforming sheet, and then the punch and die are closed , to complete the thermoforming of the part → trimming and punching device movement in the punch, die or binder plate, complete trimming and punching → pass cooling medium into the punch, die or binder plate to cool the mold Cooling to achieve quenching of high-strength parts, while the trimming and punching tools are reset, and the waste formed by trimming and punching is ejected → Driven by the press, the punch and die are opened, and the thermoformed parts, trimming and Waste formed by punching. Hot forming, edge trimming and punching of high-strength steel parts can be completed at the same time in one stamping.

Figure 2, Figure 3 and Figure 4 show the structure of an integrated mold for thermoforming, punching and edge trimming for the parts shown in Figure 1a and Figure 1b, Figure 2 and Figure 4 show the parts after thermoforming The state of the mold before punching and edge trimming, and Figure 5 and Figure 6 show the state of the part after punching and edge trimming. The thermoforming, trimming and punching integrated mold includes a binder plate 1, an upper trimming tool 2, a lower trimming tool 3, a lower trimming tool 12, an upper trimming tool 13, a lower punching tool 8, and an upper punching tool 15. Lower trimming oil cylinder 6, lower trimming oil cylinder 10, upper trimming oil cylinder 14, upper trimming oil cylinder 19, lower punching oil cylinder 7, upper punching oil cylinder 17, ejector rod 4, ejector rod 11, ejector rod 16, forming convex Die 18 and forming die 5. Forming punch 18 and forming die 5 adopt the disclosed technology of CN101288889, and are provided with cooling water channel (not drawn among Fig. 2) in forming punch 18 and forming die 5. The outer profile of the forming punch 18 is consistent with the internal shape of the part, and the inner cavity profile of the forming die 5 is consistent with the outer shape of the part. The upper trimming oil cylinder 19 and the upper trimming oil cylinder 14 are installed on the top surface of the binder plate 1, the upper punching oil cylinder 17 is installed on the upper end of the forming punch 18, and the lower trimming oil cylinder 6 and the lower trimming oil cylinder 6 are installed on the forming die 5. Oil cylinder 10 and lower punching oil cylinder 7. The piston rod 19c of the upper trimming oil cylinder 19 is connected together with the upper trimming tool 2 by threads, the piston rod 14c of the upper trimming oil cylinder 14 is connected together with the upper trimming tool 13 by threads, and the piston rod 6c of the lower trimming oil cylinder 6 Connect together with ejector rod 4 by screw thread, ejector rod 4 is connected together with lower trimming tool 3 by thread, piston rod 10c of lower trimming oil cylinder 10 is connected together with ejector rod 11 by thread, and ejector rod 11 is connected with lower trimming tool by thread Tools 12 are connected together. The piston rod 17c of the upper punching oil cylinder 17 is connected together with the push rod 16 by threads, the push rod 16 is connected together with the upper punching tool 15 by threads, and the piston rod 7c of the lower punching oil cylinder 7 is connected with the lower punching tool by threads. 8 connected together. The forming punch 18 and the binder plate 1 are fixed on the upper template (not shown in the figure) by screws and pins, and the upper template is fixed on the slide block of the press, and the forming die 5 is fixed on the lower template (not shown) by screws and pins. Not drawn among the figure) upper and lower formwork is fixed on the workbench of press again.

During the thermoforming process, the forming punch 18 and the binder plate 1 move downwards driven by the press slider and the upper die plate, and the binder plate 1 first contacts the austenitic steel plate placed on the upper surface of the lower mold 5. The high-strength steel plate, the elastic pressing device (not shown in the figure) provided on the top surface of the pressing plate 1 will compress the high-strength sheet to avoid defects such as wrinkles during the forming process of the sheet. As the press slider continues to descend, the forming punch 18 presses the high-strength steel plate heated to the austenitic state into the forming die 5, so that the high-strength plate is formed in the mold to form an untrimmed and punched steel plate. Thermoformed parts9.

After the parts are formed, the auxiliary hydraulic system controls the piston rod 19c of the upper trimming cylinder 19 to drive the upper trimming tool 2 to move downward, and at the same time the hydraulic system controls the piston rod 6c of the lower trimming cylinder 6 to drive the ejector rod 6 and the lower trimming tool 3 Downward movement; the auxiliary hydraulic system controls the piston rod 14c of the upper trimming cylinder 14 to drive the upper trimming tool 13 to move downward, while the hydraulic system controls the piston rod 10c of the lower trimming oil cylinder 10 to drive the ejector rod 11 and the lower trimming tool 12 Move downward; under the combined action of the upper surface of the forming die 5, the upper trimming tool 2, the lower trimming tool 3, the upper trimming tool 13, and the lower trimming tool 12, the waste material 20 formed by the eager trimming is thermally formed from the edge to be trimmed Part 9 is separated, thereby completing the process of edge trimming inside the mold. The auxiliary supporting hydraulic system controls the piston rod 7c of the lower punching cylinder 7 to drive the lower punching tool 8 to move upward, while the hydraulic system controls the piston rod 17c of the upper punching cylinder 17 to drive the ejector rod 16 and the upper punching tool 15 to move upward. Under the joint action of the lower surface of the forming punch 18, the upper punching tool 15, and the lower punching tool 8, the waste 21 formed by hot punching is separated from the hot forming part 9 to be punched, thereby completing the hot punching inside the mold process. In the process of hot punching and edge trimming of high-strength steel parts, the hot punching process and the edge trimming process are carried out simultaneously inside the mold.

After the edge trimming and hot punching are completed, a cooling medium is introduced into the cooling channels of the forming male die 18 and the forming die 5 to cool the dies, thereby quenching the formed parts. While feeding cooling water into the mould, the auxiliary supporting hydraulic system controls the lower edge trimming cylinder 6, the lower edge trimming oil cylinder 10, the upper edge trimming oil cylinder 14, and the upper edge trimming oil cylinder 19 to drive the corresponding edge trimming tool along the direction opposite to the edge trimming. The lower punching cylinder 7 and the upper punching cylinder 17 drive the punching tool to run in the opposite direction to the punching, and the trimming waste 20 formed by trimming is ejected from the forming die 5, and the punching The formed punching waste 21 is ejected from the forming punch 18 . After the formed parts are cooled, the slide block of the press moves upwards, driven by the upper platen, the forming punch 18 and the pressing plate 1 move upwards, the mold is opened, and the trimming waste 20, punching waste 21 and forming parts 22 are taken out mold, and then enter the next working cycle.

The edge trimming process needs to cut off all the waste around the high-strength steel hot-formed part 9 to be edge trimmed. In order to ensure the smooth implementation of the edge trimming process and simplify the design of the edge trimming tool, the edge trimming tool is used as shown in Figure 10. chunked form. The peripheral contour of the high-strength steel part may be an arbitrary curve. The number of segments of the lower trimming tool is determined according to the complex program of the high-strength steel part. The number of segments of the upper trimming tool is the same as that of the lower trimming tool. Several of all the blocks of the trimming tool will exceed the boundary line of the high-strength steel part (dotted line in Fig. 3), to ensure that the scrap can be divided into several pieces after trimming, so as to facilitate the removal of the scrap. The thickness of the trimming tool is generally determined according to the wall thickness of the formed high-strength parts. The thickness of the trimming tool is 1.5 to 4.0 times the wall thickness of the part. For high-strength parts formed from thin plates, the upper limit is taken. Strength parts, take the lower limit. During the trimming process, the upper trimming tool is guided through the corresponding mounting hole in the binder plate 1 , and the lower trimming tool is guided through the corresponding mounting hole in the forming die 5 .

The single-piece edge trimming tool is generally long. If an oil cylinder is used to apply the edge trimming force to the edge trimming tool, it will result in insufficient edge trimming force or the edge trimming tool will be deflected due to uneven force during the edge trimming process, and the cutting speed will be accelerated. The wear rate of edge tools and dies. In order to solve this problem, as shown in Figure 4 and Figure 6, according to the size of the upper trimming tool 2, the upper trimming tool 13 or the lower trimming tool 3, 12, more than two upper die oil cylinders or lower die oil cylinders are used as The edge trimming tool provides edge trimming force, and the oil cylinder should be evenly distributed along the edge trimming tool to ensure that it can provide enough trimming force for the edge trimming tool, and ensure that the edge trimming tool is evenly stressed to avoid deflection. The upper oil holes 19a of a plurality of upper mold oil cylinders 19 that provide power for the upper trimming tool 2 are connected together, and the lower oil holes 19b are connected together to ensure that a plurality of oil cylinders of the upper die can move simultaneously; The upper oil holes 14a of multiple upper die oil cylinders 14 for power are connected together, and the lower oil holes 14b are connected together to ensure that a plurality of oil cylinders of the upper die can move at the same time; The upper oil holes 6a are connected together, and the lower oil holes 6b are connected together to ensure that multiple lower mold cylinders can move simultaneously; the upper oil holes 10a of multiple lower mold cylinders 10 that provide power for the lower trimming tool 12 are connected together, The lower oil holes 10b are connected together to ensure that multiple lower die oil cylinders can act simultaneously.

Claims (4)

1. A hot forming, punching and trimming integrated process for high-strength steel parts, characterized in that: First, trimming and punching tools are set on the hot forming die of high-strength steel parts. Before the high-strength steel sheet is hot-stamped, the high-strength steel sheet heated to complete austenitization is placed in the hot-forming die for stamping , after the thermoforming mold is closed, then use the trimming and punching tools on the thermoforming mold to trim and punch the stamped workpiece. After the completion, the thermoforming mold is cooled, and the mold that is in contact with the formed part Components Quenching of formed parts. 2. An integrated mold for hot forming, punching and trimming of high-strength steel parts, including forming punches, forming dies, upper punching tools, lower punching tools, upper trimming tools and lower trimming tools, forming There are cooling water channels in the punch and the forming die, the outer contour of the bottom end of the forming punch is consistent with the shape of the part, and the inner cavity contour of the forming die is consistent with the outer shape of the part. The characteristics are: the forming punch is equipped with The pressing plate, the forming punch is provided with a through hole corresponding to the punching position of the part, the through hole is equipped with a ejector rod, the upper end of the forming punch is equipped with an upper punching cylinder, and the piston rod of the upper punching cylinder extends into the The through hole of the forming punch is connected with the upper end of the ejector rod, the lower end of the ejector rod is connected with the upper punching tool, the upper trimming cylinder is installed on the top surface of the pressing plate, and the piston rod of the upper trimming oil cylinder is connected with the upper cutting tool. The side tools are connected together; there is also a through hole in the forming die, which is on the same axis as the through hole of the forming die, and the lower end of the forming die is equipped with a lower trimming cylinder and a lower punching cylinder, and the lower punching The piston rod of the oil cylinder extends into the through hole of the forming die and is connected with the lower punching tool, and the piston rod of the lower trimming oil cylinder is connected with a push rod, which is connected with the lower trimming tool. 3. The hot forming, punching and trimming integrated mold for high-strength steel parts according to claim 2, characterized in that: the upper trimming tool and the lower trimming tool are divided into blocks according to the external shape of the part, and the upper The trimming tool and the lower trimming tool have the same number of segments. 4. The hot forming, punching and trimming integrated mold for high-strength steel parts according to claim 2, characterized in that: the thickness of the upper trimming tool and the lower trimming tool is 1.5% of the wall thickness of the processed part ~4.0 times.

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