CN102319835A - Forming method of variable strength hot stamped piece and die - Google Patents

Abstract

Automobile structural parts need to have high strength to ensure collision safety, and at the same time, relatively low strength and relatively high toughness are required in specific parts to achieve high comprehensive performance to achieve energy absorption and better comprehensive protection functions. The existing structural parts either have the same overall performance and cannot meet the actual use requirements, or realize the performance difference by splicing, the process is complicated, and there are performance concerns at the joint. According to the different local performance requirements of parts, the present invention designs a hot stamping die including different cooling efficiency modules, which is used to manufacture high-performance, lightweight, and low-cost body safety structural parts. The hot stamping die involved in the present invention has only specific die inserts containing cooling pipes, or the position, size, and arrangement of each sub-block cooling pipe are designed according to performance requirements, and the produced thermoformed structural parts such as the B-pillar reinforcement plate reduce the original The overall weight of the parts improves the car's ability to resist deformation in side collisions, and at the same time can better absorb collision energy.

Description

Forming method and mold for variable strength hot stamping parts

technical field

The invention relates to the field of hot stamping, and specifically relates to a hot stamping die that can manufacture a part that can not only ensure the safety of automobiles, but also improve the structural strength and effectively absorb energy. the

Background technique

Automobile lightweight and safety have become the forefront and hot spot of automobile technology in the 21st century. Studies have shown that if the weight of the vehicle is reduced by 10%, the fuel efficiency can be increased by 6% to 8%. Since the oil crisis in 1973, the lightweight of automobiles has been gradually paid attention to. However, the needs of safety, comfort, and intelligence have caused the weight of automobiles, especially passenger cars, to fluctuate. With the advancement of materials and manufacturing technology, automobile weight reduction has been continuously realized. Automobile lightweight is very important to save energy, reduce exhaust emissions, and realize the sustainable development of my country's automobile industry. the

Automobile structural parts need to have high strength to ensure collision safety, and at the same time, relatively low strength and relatively high toughness are required in specific parts to achieve high comprehensive performance to achieve energy absorption and better comprehensive protection functions. For complex structural parts, such as automobile B-pillar, A-pillar, etc., its mechanical properties, especially strength, are the fundamental factors affecting its function. Since there is no airbag on the side of the car, when a side collision occurs, the B-pillar needs to be both anti-collision and energy-absorbing. Double effect, that is, the strength of each part of the B-pillar reinforcement plate should be different, while the traditionally manufactured B-pillar reinforcement plate is a whole structure punched from the same steel plate with uniform thickness. This structure is simple to manufacture and can be compared The overall flatness and dimensional accuracy of the parts are well guaranteed, but the thickness of the steel plate is designed according to the maximum thickness required for strength, so it is not conducive to the lightweight of the body, and the energy absorption effect of the B-pillar is poor. the

The existing automotive variable-strength B-pillar reinforcement plates mainly include the following three forms:

One is that the front and rear sections of the B-pillar reinforcement plate are formed separately by steel plates of different thicknesses, and then connected by welding to form a block structure. This structure has improved the lightweight of the car body, but it increases the number of parts and the amount of processing. Moreover, the flatness of the surface of the part cannot be guaranteed, and the dimensional accuracy of the part will also be reduced.

The second is that the B-pillar reinforcement plate blanks are connected by butt welding and laser spot welding of steel plates of different thicknesses, and then stamped to form the B-pillar, which can achieve light weight and ensure the overall flatness of the structure, but the process is complicated and the processing performance is poor. The manufacturing cost is high, and the structure and performance of the welded part are poor. the

The third is a variable cross-section B-pillar reinforcement plate mentioned in patent ZL201020574844.4. This structure needs to be made into a required thickness in advance, and then hot stamped to form a variable cross-section part. This method requires a special rolling mill, which increases the cost of forming parts. the

The above three B-pillars cannot simultaneously have the characteristics of high anti-collision performance, energy-absorbing effect, light weight and low cost. This paper proposes a forming method and mold for variable-strength hot stamping parts, which are used to make local hot-formed B-pillars. The strength of each part of the B-pillar is different, which can have good anti-collision performance and energy absorption effect, and reduce the manufacturing cost compared with the variable cross-section B-pillar while ensuring light weight. the

Contents of the invention

The existing structural parts either have the same overall performance and cannot meet the actual use requirements, or realize the performance difference by splicing, the process is complicated, and there are performance concerns at the joint. The invention provides a forming method and mold for variable-strength hot stamping parts, which can manufacture high-performance hot stamping parts, solve the problems of high manufacturing cost and complicated process of existing parts, and realize the light weight, safety and reliability of parts application. The integration of economy and high energy absorption effect. the

The hot stamping die involved in the present invention has only specific die inserts containing cooling pipes, or the position, size, and arrangement of each sub-block cooling pipe are designed according to performance requirements, and the produced thermoformed structural parts such as the B-pillar reinforcement plate reduce the original The overall weight of the parts improves the car's ability to resist deformation in side collisions, and at the same time can better absorb collision energy. the

The method for realizing the above-mentioned object of the present invention takes the B-pillar of the car door as an example, and is explained as follows in conjunction with the accompanying drawings. the

Considering the main function of the automobile B-pillar - effective bending resistance and energy absorption effect, according to the numerical simulation results and practical experience, this invention proposes a partially cooled automobile B-pillar, the raw material is ultra-high-strength steel plate, and hot stamping is adopted. Forming technology, the mechanical properties of each part of the formed part are different, divided into four levels, the upper end of the B-pillar has the best mechanical properties, as shown in part 1 in the figure, the tensile strength is above 1500MPa, and the lower end has the worst mechanical properties, as shown in the figure Parts 3 and 4, the tensile strength is about 600~800MPa, and the mechanical properties between the two are next. For part 2 in the figure, the tensile strength is between 1000~1200MPa, and the tensile strength between different parts It belongs to the gradual form, which is beneficial to the overall performance of the B-pillar. the

The B-pillar hot stamping die is partially improved on the basis of the traditional hot stamping die. The traditional hot stamping die is generally equipped with cooling pipes under the entire part surface. The mechanical properties of the various parts of the automobile B-pillar involved in the present invention are different. Corresponding The hot stamping die only needs local cooling. Specifically, the hot stamping B-pillar die is processed and assembled in blocks. It is characterized in that only a specific die block of the hot stamping die contains cooling pipes; the pipe layout in the die block is based on The mechanical performance requirements of the formed parts are set; in the hot stamping B-pillar mold, the cooling pipes are arranged in the die block 5, and the cooling pipes are also arranged in the corresponding convex die block; the cooling pipes are arranged in the die block 6, and the corresponding No cooling pipes are arranged in the punch block; no cooling pipes are arranged in the die block 7 and the die block 8, and there are no cooling pipes arranged in the corresponding punch block. The cooling pipeline 9 described in the present invention is consistent with the traditional hot stamping cooling pipeline. the

The thermoformed parts produced by the hot stamping die proposed by the invention can significantly reduce the overall weight of the B-pillar reinforcement plate of the automobile, achieve the purpose of lightweighting the vehicle body, have good energy absorption effect, and improve the safety of the side collision of the automobile. the

Description of drawings

Figure 1 is a structural diagram of a B-pillar with different mechanical properties of each part;

Fig. 2 is the front view of the locally cooled hot stamping B-pillar die die;

Fig. 3 is an isometric view of the concave die of the hot stamping B-pillar die with partial cooling;

FIG. 4 is a schematic diagram of the die block 7 .

In Figure 1: 1 is the place with the highest mechanical properties of the B-pillar, 3 and 4 are the places with the highest mechanical properties of the B-pillar, and the mechanical properties of the B-pillar at 2 are between 1 (4) and 3;

Figure 2 (3) includes die block 5, die block 6, die block 7 and die block 8;

9 in Fig. 4 is cooling pipeline.

Detailed ways

The present invention will be further described below according to the accompanying drawings. the

In Figure 1, different parts of the B-pillar have different requirements for mechanical properties, which are divided into four levels. The upper end of the B-pillar has the best mechanical properties, as shown in part 1 in the figure. The tensile strength is above 1500MPa, and the lower end has the worst mechanical properties, as shown in the figure. Parts 3 and 4, the tensile strength is about 650~750MPa or more, and the mechanical properties between the two are next. For part 2 in the figure, the tensile strength is between 1100~1200MPa. According to this requirement, a local cooling hot stamping die is designed, and its concave die is shown in Figure 2 and Figure 3. In the hot stamping die, cooling pipes are arranged in the die block 5, and cooling pipes are also arranged in the corresponding convex die block; The cooling pipes are arranged in the die block 6, and the cooling pipes are not arranged in the corresponding male die block, and the cooling pipes (9) in the die block 6 are not arranged in the cooling pipes (9) in the die block 5 Intensive; the concave mold block 7 and the concave mold block 8 are not arranged with cooling pipes, and the corresponding convex mold blocks are not arranged with cooling pipes. The layout of the mold cooling pipeline is shown in Figure 4. The round hole is used to directly connect the cooling pipeline, which is convenient for processing and saves costs. At the same time, it can be better adapted to the shape. The mold with cooling pipeline is divided into separate water circulation. the

The B-pillar formed parts made by this mold meet the requirements of energy absorption and anti-collision, and the tensile strength between adjacent parts changes gradually, that is, the tensile strength between the first part and the second part of the B-pillar is between 1200MPa and 1500MPa The tensile strength between the second part and the third part of the B-pillar changes gradually between 750MPa and 1100MPa. the

Claims (5)

1. the manufacturing process of a grow degree heat-punch member; The mechanical property that said grow degree heat-punch member is meant the stamping parts different parts is difference to some extent; Said manufacturing process adopts hot press-formed technology, it is characterized in that said manufacturing process adopts the manufacturing of localized heat stamping technology to grow degree drip molding.

2. the manufacturing process of a kind of grow degree heat-punch member according to claim 1; It is characterized in that said localized heat stamping technology is meant carries out integral body heating and insulation to hot forming part blank, moves quickly into then to have drawing on the local refrigerating function mould.

3. the shaping dies of a grow degree heat-punch member, mould piecemeal process and assemble is characterized in that, said hot stamping die has only specific mould piecemeal to contain cooling pipe.

4. the shaping dies of a kind of grow degree heat-punch member according to claim 3 is characterized in that the pipe arrangement mode of said mould piecemeal is set according to the drip molding mechanical property requirements.

5. the shaping dies of a kind of grow degree heat-punch member according to claim 3 is characterized in that die piecemeal 5 layout cooling pipes, and corresponding with it punch piecemeal is also arranged cooling pipe; Die piecemeal 6 is arranged cooling pipe, and corresponding with it punch piecemeal is not arranged cooling pipe; Die piecemeal 7 is not arranged cooling pipe with die piecemeal 8, and corresponding with it punch piecemeal is not also arranged cooling pipe.

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