CN204711008U - A kind of 22MnB5 boron steel U-shaped heat stamping and shaping cooling experiment mould - Google Patents

Abstract

A 22MnB5 boron steel U-shaped piece hot stamping forming cooling experiment mold, including a punch, a punch cooling water pipe, a die, a die cooling water pipe, a cooling water circulation system, a hydraulic pump and a cooling water tank, is characterized in that the convex A punch cooling water pipe is arranged inside the mold, a die cooling water pipe is arranged in the die, a hydraulic pump is connected at the entrance of the die cooling water pipe and the punch cooling water pipe, the die cooling water pipe and the punch The outlet of the cooling water pipe is communicated with a cooling water circulation system, the outlet of the cooling water circulation system is communicated with the cooling water tank, and the inlet of the hydraulic pump extends into the inside of the cooling water tank. The utility model adopts the method of setting cooling water passages in the convex mold and the concave mold to reduce the mold temperature, thereby ensuring the quality of the prepared mold.

Description

A 22MnB5 boron steel U-shaped hot stamping forming cooling experimental mold

technical field

The utility model belongs to a hot stamping forming cooling experiment device, in particular to a 22MnB5 boron steel U-shaped piece hot stamping forming cooling experiment mold.

Background technique

22MnB5 boron steel U-shaped hot stamping experiment. By analyzing the geometric dimensions, microstructure and mechanical properties of hot stamping parts, the feasibility and reliability of the hot stamping forming process are verified, and meaningful exploratory research is carried out for the wide application of hot stamping forming technology.

At present, the structural parts of high-strength steel hot stamping parts widely used in automobiles mainly include A-pillar and B-pillar. In the experiment, the simplified model U-shaped part of B-pillar was taken as an example, and 22MnB5 boron steel was used for hot stamping experiments.

The hot stamping process includes the following four steps:

The first step: heating and heat preservation stage

It is the first step in the hot stamping experiment to put the sheet into the heating furnace for heating and heat preservation to make it completely austenitized. Heating temperature and holding time will affect the hot stamping forming process and the quality of formed parts, so an appropriate temperature and holding time should be selected.

The basis for selecting the austenitization temperature: first, the austenitization temperature of the steel plate is above the complete austenite structure, which provides conditions for the subsequent quenching to obtain martensite; the second is to choose the temperature at which the metal will undergo a strong oxidation reaction The following is to avoid defects caused by material oxidation; the third is to consider the heat loss in the subsequent blank transfer process. In order to ensure the starting temperature of forming, the heating temperature selected in this experiment is 950 °C. Set the temperature of the holding furnace to 950°C, and put the sheet into it after the furnace temperature is stable.

In order to achieve the purpose of obtaining more martensite structure after stamping and quenching, the billet must be heated and then kept warm to fully dissolve the residual cementite and obtain a uniform austenite structure. At the same time, since the original structure has a great influence on the quality of stamping parts, too long holding time will cause grain growth and reduce the quality of stamping parts, so the holding time is 5 minutes.

Step Two: The Transfer Process

Quickly transfer the sheet from the furnace to the mold. During the process of transferring the 950°C sheet from the heating furnace to the stamping die, due to contact with the 20°C air, heat exchange will occur between the sheet and the air. According to the simulation results, in order to ensure that the sheet has good fluidity during the stamping process and obtain more martensitic structure during the quenching process, it is best to ensure that the initial temperature of stamping is above 800°C. The heat loss of the sheet is very large, so the transfer time should be kept as short as possible. The average transfer time in this experiment is 8s.

The third step: stamping forming process

According to the simulation results, it can be seen that 25mm/s-45mm/s is the appropriate range of stamping speed. In this experiment, the stamping speed of 25mm/s was selected for the hot stamping experiment.

The fourth step: holding pressure setting stage

After the hot stamping process is over, the sheet is not taken out, and it continues to cool in the mold. According to the simulation results, it can be known that the temperature of the martensitic transformation can be reached below the starting temperature of the martensitic transformation after holding the pressure for 3 seconds. However, in order to ensure the amount of martensite transformation, the experimental After the temperature of the material drops below the Mf temperature (about 200°C), the holding pressure is ended, and the holding time selected in this experiment is 1min.

The hot stamping process of high-strength steel is very different from the traditional cold stamping. Since the blank is in a high temperature state, and there are certain requirements for the cooling speed of the blank during the forming process, the hot stamping die must integrate sheet metal forming and quenching. High-strength steel hot stamping dies have strict requirements in terms of material selection and structural design, which mainly include:

(1) Hot stamping is a process with complex temperature changes, so not only the mold is required to have high rigidity, hardness and fatigue strength, but also the mold must be able to resist the heat between the blank and the blank under severe alternating cold and hot conditions. Friction, so hot stamping has high requirements on the surface of the mold.

(2) In order to meet the quenching requirements of hot stamping parts, the hot stamping die must have good thermal conductivity, or design a cooling system in the die to meet the cooling speed requirements of the hot forming process. If the cooling capacity of the mold is not enough, it will not only affect the strength of the formed part, but also cause thermal cracks of the mold caused by high temperature during the forming process, which will affect the dimensional accuracy of the part.

Contents of the invention

The purpose of the utility model is to provide a 22MnB5 boron steel U-shaped piece hot stamping forming cooling experiment mold, which can meet the cooling speed requirement in the hot stamping process.

The utility model adopts the following technical solutions to realize:

A 22MnB5 boron steel U-shaped piece hot stamping cooling experiment mold, including a punch, a punch cooling water pipe, a die, a die cooling water pipe, a cooling water circulation system, a hydraulic pump and a cooling water tank, and the inside of the punch is provided with A punch cooling water pipe, the die is provided with a die cooling water pipe, the entrance of the die cooling water pipe and the punch cooling water pipe is connected with a hydraulic pump, the outlet of the die cooling water pipe and the punch cooling water pipe The outlet of the cooling water circulation system communicates with the cooling water tank, and the inlet of the hydraulic pump extends into the cooling water tank.

In the utility model, the cooling water pipes of the punch are distributed inside the convex arc surface of the punch, and the cooling water pipes of the die are distributed inside the concave arc surface of the die.

Beneficial effects: the utility model adopts the method of arranging cooling water passages in the male die and the concave die to reduce the mold temperature, thereby ensuring the quality of the prepared model.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is the structural representation of punch and die of the present utility model;

Fig. 3 is the three-dimensional structure schematic diagram of punch of the present utility model;

Fig. 4 is a three-dimensional structural schematic view of the concave mold of the present invention.

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the utility model easy to understand, the utility model will be further elaborated below in conjunction with specific illustrations.

Referring to Fig. 1, a schematic structural diagram of a 22MnB5 boron steel U-shaped piece hot stamping forming cooling experiment mold, a 22MnB5 boron steel U-shaped piece hot stamping forming cooling experimental mold includes a punch 1, a punch cooling water pipe 2, and a die 3. Die cooling water pipe 4, cooling water circulation system 5, hydraulic pump 6 and cooling water tank 7, the punch 1 is provided with a punch cooling water pipe 2, the die 3 is provided with a die cooling water pipe 4, The inlet of the die cooling water pipe 4 and the punch cooling water pipe 2 is connected with a hydraulic pump 6, and the outlet of the die cooling water pipe 4 and the punch cooling water pipe 2 is connected with a cooling water circulation system 5, and the cooling water circulation The outlet of the system 5 communicates with the cooling water tank 7 , and the inlet of the hydraulic pump 6 extends into the inside of the cooling water tank 7 .

Referring to Fig. 2, Fig. 3, Fig. 4, a kind of schematic diagram of the structure of the punch and die of the 22MnB5 boron steel U-shaped piece hot stamping forming cooling experiment mold, the punch cooling water pipe 2 is distributed on the convex arc surface of the punch 1 Inside, the die cooling water pipes 4 are distributed inside the concave arc surface of the die 3 .

Cooling in the hot stamping process is the key to the study of high-strength steel hot stamping forming technology, and is also the key to obtaining qualified high-strength stamping parts. In the actual production, the stamping process is continuous. The high-temperature blank and the mold exchange heat. As the production progresses, the temperature of the mold will continue to rise, so that the temperature difference between the blank and the mold will decrease, and the heat exchange rate will increase. If it drops a lot, it may not be able to meet the critical cooling rate for obtaining martensitic structure. In order to meet the required cooling rate of the sheet during high-temperature forming, it is necessary to ensure that the temperature of the mold cannot be too high. At the same time, the increase of mold temperature will reduce the service life of the mold. Therefore, in the experiment, the method of setting cooling water channels in the punch and die is used to reduce the mold temperature. Water enters the mold through the hydraulic pump, flows in the channel in the mold, and flows out from the water outlet after taking away the heat. The cooling water can be recycled to save costs. During the experiment, it is necessary to ensure the sealing of the cooling water pipe interface to prevent water from contacting the billet.

During the experiment, start the hydraulic pump 6, pump the cold water in the cooling water tank 7 to the punch cooling water pipe 2 and the die cooling water pipe 4 through the hydraulic pump 6, and put the high-temperature blank into the punch 1 and the die 3, through hot stamping, the high-temperature blank is pressed into a model, and the punch cooling water pipe 2 and the die cooling water pipe 4 absorb the heat on the punch 1 and the die 3 to ensure the quality of the model. The water flowing out from the die cooling water pipe 4 enters the cooling water circulation system 5 for cooling, and then circulates to the cooling water tank 7 for recycling.

The above shows and describes the basic principles and main features of the present utility model and the advantages of the present utility model. Those skilled in the art should understand that the present utility model is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and description are only illustrations The principle of the utility model, under the premise of not departing from the spirit and scope of the utility model, the utility model also has various changes and improvements, and these changes and improvements all fall within the scope of the utility model claimed for protection. The desired protection is defined by the appended claims and their equivalents.

Claims (2)

1. a 22MnB5 boron steel U-shaped heat stamping and shaping cooling experiment mould, comprise punch, punch cooling water pipe, die, die cooling water pipe, cooling water recirculation system, hydraulic pamp and bosh, it is characterized in that, described punch inside is provided with punch cooling water pipe, die cooling water pipe is provided with in described die, the porch of described die cooling water pipe and punch cooling water pipe is communicated with hydraulic pamp, the exit of described die cooling water pipe and punch cooling water pipe is communicated with cooling water recirculation system, the outlet of described cooling water recirculation system is communicated with bosh, the entrance of described hydraulic pamp stretches into bosh inside.

2. a kind of 22MnB5 boron steel according to claim 1 U-shaped heat stamping and shaping cooling experiment mould, it is characterized in that, described punch cooling water pipe is distributed in inside the convex globoidal of punch, and described die cooling water pipe is distributed in inside the cancave cambered surface of die.