Boron steel tube production process, boron steel tube, battery frame and vehicle

Abstract

The present invention discloses a production process of a boron steel pipe, a boron steel pipe, a battery frame and a vehicle, wherein the production process of the boron steel pipe comprises: cold bending and welding a boron steel material to obtain a preformed boron steel pipe; heating a preformed curved portion of the preformed boron steel pipe to obtain a first heat-treated boron steel pipe, wherein the first heat-treated boron steel pipe has a first heat-treated curved portion with a fillet radius smaller than the fillet radius of the preformed curved portion; heating the entire first heat-treated boron steel pipe to obtain a second heat-treated boron steel pipe having austenite; quenching the second heat-treated boron steel pipe to obtain a target boron steel pipe having martensite. The technical solution of the present invention aims to reduce the forming force required for the steel pipe during production.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a production process of a boron steel pipe, a boron steel pipe, a battery frame and a vehicle. Background Art

[0002] At present, the steel pipe is made of Q355 material and obtained through cold roll forming process. The steel pipe will encounter the problem of large forming force during the production process. Summary of the invention

[0003] The main purpose of the present invention is to provide a production process for boron steel pipes, aiming to reduce the forming force required for the steel pipes during production.

[0004] To achieve the above object, the production process of the boron steel pipe proposed in the present invention includes:

[0005] Cold bending and welding the boron steel to obtain preformed boron steel tubes;

[0006] Heating the preformed bent portion of the preformed boron steel tube to obtain a first heat-treated boron steel tube, wherein the first heat-treated boron steel tube has a first heat-treated bent portion with a fillet radius smaller than that of the preformed bent portion;

[0007] Heating the entire first heat-treated boron steel tube to obtain a second heat-treated boron steel tube having austenite;

[0008] The second heat-treated boron steel tube is quenched to obtain a target boron steel tube having martensite.

[0009] Optionally, the step of heating the preformed bent portion of the preformed boron steel tube to obtain a first heat-treated boron steel tube, wherein the first heat-treated boron steel tube has a first heat-treated bent portion having a fillet radius smaller than that of the preformed bent portion, is specifically:

[0010] The preformed bent portion is heated to between 600°C and 680°C to obtain the first heat-treated boron steel tube, wherein the value range of R1 of the first heat-treated bent portion is 1.5d to 2.5d, wherein R1 is the fillet radius of the first heat-treated bent portion, and d is the thickness of the boron steel.

[0011] Optionally, the step of heating the preformed bent portion to between 600°C and 680°C to obtain the first heat-treated boron steel tube, wherein the value range of R1 of the first heat-treated bent portion is 1.5d to 2.5d, wherein R1 is the fillet radius of the first heat-treated bent portion, and d is the thickness of the boron steel material is specifically as follows:

[0012] The preformed curved portion is heated by a linear induction heating coil.

[0013] Optionally, the step of heating the preformed curved portion by a linear induction heating coil is specifically:

[0014] The linear induction heating coil is used to heat the preformed curved portion within a distance range of 5 cm-12 cm, the heating frequency of the linear induction heating coil is controlled within a range of 10 KHz-12 KHz, and the heating current of the linear induction heating coil is controlled within a range of 200 A-250 A.

[0015] Optionally, the steps of cold bending and welding the boron steel to obtain a preformed boron steel tube are specifically as follows:

[0016] The boron steel is rolled and high-frequency induction welded to obtain the formed boron steel pipe, wherein the value range of R2 of the preformed bend is 5d to 8d, wherein the frequency of high-frequency induction welding is 50KHz-80KHz, R2 is the fillet radius of the preformed bend, and d is the thickness of the boron steel.

[0017] Optionally, the forming speed of the boron steel material to form the preformed curved portion is controlled to be 5m / min-9m / min.

[0018] Optionally, the step of heating the entire first heat-treated boron steel tube to obtain a second heat-treated boron steel tube having austenite is specifically:

[0019] The first heat-treated boron steel tube is heated to between 650 degrees Celsius and 750 degrees Celsius to obtain the second heat-treated boron steel tube, wherein the metallographic structure of the second heat-treated boron steel tube is austenite.

[0020] Optionally, the step of heating the first heat-treated boron steel tube to 650 degrees Celsius to 750 degrees Celsius to obtain the second heat-treated boron steel tube, wherein the metallographic structure of the second heat-treated boron steel tube is austenite, is specifically:

[0021] The first heat-treated boron steel pipe is heated by a heating furnace device.

[0022] Optionally, the step of quenching the second heat-treated boron steel tube to obtain a target boron steel tube having martensite is specifically:

[0023] The second heat-treated boron steel pipe is fed into a cooling mold at a speed of 8m / min-12m / min, and the second heat-treated boron steel pipe is quenched at a cooling rate of 3°C / s-5°C / s to obtain the target boron steel pipe, wherein the metallographic structure of the target boron steel pipe is martensite.

[0024] Optionally, the step of quenching the second heat-treated boron steel pipe at a cooling rate of 3°C / s-5°C / s to obtain the target boron steel pipe, wherein the metallographic structure of the target boron steel pipe is martensite is specifically:

[0025] The temperature of the cooling mold is controlled between 50°C and 100°C.

[0026] The present invention also provides a boron steel pipe, which is produced by the above-mentioned boron steel pipe production process.

[0027] The present invention also provides a battery frame, which is made of the aforementioned boron steel tube.

[0028] The present invention further provides a vehicle, which includes a vehicle body and the aforementioned battery frame installed on the vehicle body.

[0029] In the technical solution of the present invention, the boron steel is cold bent and welded to obtain a preformed boron steel pipe, and the preformed bent portion of the preformed boron steel pipe is heated to obtain a first heat-treated boron steel pipe. When the preformed boron steel pipe is locally heated, the forming force required for the first heat-treated boron steel pipe is reduced, the resilience of the first heat-treated boron steel pipe is reduced, and the forming stress of the first heat-treated boron steel pipe is reduced to avoid work hardening. The first heat-treated boron steel pipe has a first heat-treated bent portion with a fillet radius smaller than the fillet radius of the preformed bent portion. The entire first heat-treated boron steel pipe is heated to obtain a second heat-treated boron steel pipe having austenite, and the second heat-treated boron steel pipe is quenched to obtain a target boron steel pipe having martensite. This production process reduces the forming force of the steel pipe during the production process, and the produced boron steel pipe has a higher structural strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0031] Figure 1 This is a schematic diagram of the production process of the boron steel pipe of the present invention;

[0032] Figure 2 This is a performance comparison table of different target boron steel pipes under four process parameters;

[0033] Figure 3 This is a performance table of various profiles of the target boron steel pipe according to one embodiment of the present invention;

[0034] Figure 4 This is a welding performance table of a target boron steel pipe according to an embodiment of the present invention;

[0035] Figure 5 This is a bending performance analysis table of a target boron steel pipe and a Q355 steel pipe according to an embodiment of the present invention.

[0036] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or abutment, and it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0041] The invention provides a production process of a boron steel pipe.

[0042] Reference Figure 1 In one embodiment of the present invention, the production process of the boron steel pipe includes:

[0043] Step S100, cold bending and welding the boron steel to obtain a preformed boron steel tube;

[0044] Boron steel has the characteristics of high strength and low density. The target boron steel tube formed by boron steel, the battery frame having the target steel tube, and the vehicle having the battery frame all have the advantages of high strength and light weight, which is conducive to the lightweight of the vehicle. Specifically, the boron steel is mainly based on C-MN material, which is a low-carbon microalloy steel containing alloy elements such as Ti, Cr, Mo, Cu, and Ni. In addition, it also contains boron elements. Boron elements are beneficial to improving the quenching performance of boron steel. In one embodiment, the mass percentage of boron elements in boron steel is 0.001 to 0.005. The microstructure of this boron steel before heat treatment is ferrite and pearlite, the hardness is 170HV-200HV, the yield strength is about 280 to 450MPa, and the tensile strength is greater than 450MPa. Boron steel is formed into a preformed curved portion under the action of cold bending. Taking the preformed rectangular steel tube as an example, the preformed rectangular steel is a steel tube with a rectangular or approximately rectangular cross section. The transition part between two adjacent planes of the preformed rectangular steel tube is the preformed curved portion. It is worth mentioning that the plane can also be called a profile. For the preformed rectangular steel tube, it has four curved portions. Of course, the preformed boron steel tube can also be a preformed special-shaped tube, such as but not limited to a preformed triangular special-shaped steel tube. It can be understood that at least one preformed curved portion is formed by welding.

[0045] The preformed boron steel tube formed by cold bending and welding still has large stress that needs to be eliminated. For this reason, in step S200, the preformed bent portion of the preformed boron steel tube is heated to obtain a first heat-treated boron steel tube, wherein the first heat-treated boron steel tube has a first heat-treated bent portion with a fillet radius smaller than the fillet radius of the preformed bent portion. It can be understood that heating the preformed bent portion is to heat the local part of the preformed boron steel tube, so that the yield strength of the preformed bent portion is lower than the two planes connecting the preformed bent portion, and the preformed bent portion is softened, so that the forming performance of the preformed bent portion is improved. High, so that the cold bending pressure is transmitted to the preformed bending part, and the preformed bending part undergoes plastic deformation. In this way, the process of forming the first heat-treated boron steel tube is controllable, which is beneficial to improving the forming quality of the first heat-treated boron steel tube, reducing the forming force of the first heat-treated boron steel tube, reducing the resilience of the first heat-treated boron steel tube, reducing the forming stress of the first heat-treated boron steel tube, and avoiding work hardening. It is worth mentioning that in the prior art, the whole preformed rectangular steel tube will be heated, and overall deformation will occur. It is very likely that a first heat-treated boron steel tube with a diamond-shaped cross-section will be obtained, and the forming quality of the first heat-treated boron steel tube is low. In addition, the first heat-treated boron steel tube of the present scheme has a first heat-treated bending part with a fillet radius smaller than the fillet radius of the preformed bending part. The first heat-treated boron steel tube is less likely to crack after the fillet radius becomes smaller, and the strength of the first heat-treated boron steel tube is higher.

[0046] Step S300, heating the entire first heat-treated boron steel tube to obtain a second heat-treated boron steel tube having austenite;

[0047] Step S400, quenching the second heat-treated boron steel tube to obtain a target boron steel tube with martensite. In one embodiment, the target boron steel tube has a yield strength of 950 MPa or more, a tensile strength of 1300 MPa or more, a hardness of more than 400 HV, and an elongation of more than 5%.

[0048] Optionally, in one embodiment, step S200 is specifically:

[0049] Step S210, heating the preformed bent portion to between 600°C and 680°C to obtain the first heat-treated boron steel tube. The first heat-treated boron steel tube obtained at this temperature has a higher quality. The value range of R1 of the first heat-treated bent portion is 1.5d to 2.5d, wherein R1 is the fillet radius of the first heat-treated bent portion, and d is the thickness of the boron steel. It can be understood that if R1 is greater than 2.5d, the stress in the first heat-treated boron steel tube is not released thoroughly enough. If R1 is less than 1.5d, the first heat-treated boron steel tube is over-formed and the formed quality is poor. When the value range of R1 is 1.5d to 2.5d, it is ensured that the stress in the first heat-treated boron steel tube is released more thoroughly and the forming quality of the first heat-treated boron steel tube is higher.

[0050] Optionally, in one embodiment, step S210 is specifically:

[0051] Step S211, heating the preformed curved portion by a linear induction heating coil, which is easy to manipulate and convenient for controlling the heating temperature of the preformed curved portion. Of course, in other embodiments, the preformed curved portion may also be heated by other means.

[0052] Optionally, in one embodiment, step S211 is specifically:

[0053] Step S222, heating is performed by the linear induction heating coil within a distance range of 5 cm-12 cm from the preformed curved portion, the heating frequency of the linear induction heating coil is controlled to be within a range of 10 KHz-12 KHz, and the heating current of the linear induction heating coil is controlled to be within a range of 200 A-250 A.

[0054] Optionally, in one embodiment, step S100 is specifically:

[0055] Step S110, rolling and high-frequency induction welding are performed on the boron steel to obtain the formed boron steel pipe. The technologies of rolling and high-frequency induction welding are mature and easy to apply. The value range of R2 of the preformed bend is 5d to 8d, the frequency of high-frequency induction welding is 50KHz-80KHz, R2 is the fillet radius of the preformed bend, and d is the thickness of the boron steel.

[0056] Optionally, in one embodiment, the forming speed of the boron steel material to form the preformed curved portion is controlled to be 5m / min-9m / min, which is more suitable.

[0057] Optionally, in one embodiment, step S300 is specifically:

[0058] Step S310: heating the first heat-treated boron steel pipe to between 650 degrees Celsius and 750 degrees Celsius to obtain the second heat-treated boron steel pipe, wherein the metallographic structure of the second heat-treated boron steel pipe is austenite.

[0059] Optionally, in one embodiment, step S310 is specifically:

[0060] The first heat-treated boron steel tube is heated by a heating furnace. Of course, in other embodiments, the first heat-treated boron steel tube can also be heated by other heating methods.

[0061] Optionally, in one embodiment, step S400 is specifically:

[0062] Step S410, feeding the second heat-treated boron steel pipe into a cooling mold at a speed of 8m / min-12m / min, and quenching the second heat-treated boron steel pipe at a cooling rate of 3°C / s-5°C / s to obtain the target boron steel pipe, wherein the metallographic structure of the target boron steel pipe is martensite, so that the metallographic structure is relatively uniform, and the tensile strength of the target boron steel pipe reaches 1500MPa, and the elongation is between 5% and 7%.

[0063] Optionally, in one embodiment, step S410 is specifically:

[0064] Step S411, controlling the temperature of the cooling mold to be between 50°C and 100°C.

[0065] like Figure 2 As shown, combined with the performance results of the embodiment and the product performance, it can be seen that: with the increase of the heating current and the heating frequency, the heating power increases, the temperature rise of the preformed boron steel pipe accelerates, and the preformed bend is affected by the temperature, so that the yield strength of the preformed bend is lower than the two planes connecting the preformed bend, and the forming performance of the preformed bend is improved, so that the pressure of the cold bending is transmitted to the preformed bend, and the preformed bend undergoes plastic deformation, and a first heat-treated bend with a smaller fillet radius can be obtained; when the temperature in the heating furnace equipment reaches 600°C, the banded structure has been basically eliminated, and only a small amount of ferrite grains are elongated along the rolling direction, and the matrix ferrite is recrystallized; when the temperature is raised to 650°C, the ferrite is completely recrystallized, and the lath-like bainite is replaced by granular bainite. At this time, the strength and elongation of the high-strength steel reach a better match; when the forming temperature continues to be raised to 700°C, the polygonal ferrite grains grow, and the granular bainite content decreases, and the mechanical properties reflected by the elongation are greatly improved, but the strength drops sharply. At the same time, the cooling rate directly affects the number of martensite transformations. When the cooling rate is faster, it is easy to form lath-shaped martensite structure in the material structure, inhibiting the formation of pearlite and bainite, thereby improving the tensile properties of the material.

[0066] Example 2 is based on Example 1, the temperature in the heating furnace equipment is increased from the original 600℃ to 650℃, and it is found that the yield strength and tensile strength of the material are improved, the ferrite is completely recrystallized, and the lath bainite is replaced by granular bainite. At this time, the strength of the high-strength steel develops in a more favorable direction, which can well improve the mechanical properties of the material, and the fillet radius is also improved to a certain extent. Example 3 is based on Example 2, the heating frequency and heating current are reduced, and it is found that the mechanical properties of the material are reduced, mainly because the heating power is reduced, the preformed bending part is affected by the temperature, so that the yield strength of the preformed bending part and the temperature difference between the two planes connecting the preformed bending part are small, so that the forming performance of the preformed bending part is reduced, so the fillet radius of the first heat treatment bending part is increased, and the heat treatment effect of the material will be correspondingly uneven, so that the strength shown is also reduced; Example 4 is based on Example 3, the cooling rate is reduced, thereby affecting the transformation of the material organization. The initial transformation from bainite to martensite organization is insufficient, resulting in reduced material performance, poor forming performance of the material, and a certain increase in the fillet radius.

[0067] The present invention also provides a boron steel pipe, which is produced by the above-mentioned boron steel pipe production process.

[0068] Mechanical analysis of the target boron steel pipe was carried out, and the test results are as follows: Figure 3 As shown, the results show that the tensile strength of the target boron steel pipe on each side is greater than 1500MPa, the yield strength is greater than 1200MPa, the elongation is greater than 7%, and the maximum error value of the performance of each section is less than 5%. Next, MAG is used to weld the target boron steel pipe and other profiles, and the welding strength of different materials is evaluated. The test results Figure 4 As shown, the results show that: the welding strength of Q355 materials reaches 15.1KN; the welding strength of boron steel materials reaches 18.1KN; the welding strength of Q355 and boron steel materials reaches 15.9KN; through comparison, it is found that the welding performance of boron steel is more than 5% higher than that of Q355. At the same time, the influence of the same cross-sectional specifications and different thicknesses of boron steel replacing Q355 materials on the bending effect is analyzed, and the influence of lightweight on the bending strength is evaluated. The test results are shown in Figure 5 As shown, the results show that: Q355 material uses a rectangular tube of 80mmx40mmx3mm, and after being bent in the direction of the section 80, its bending strength is 29.3KN, while using boron steel material, a rectangular tube of 80mmx40mmx3mm, after being bent in the direction of the section 80, its bending strength is 30.3KN; in terms of lightweighting, the weight can be reduced by more than 36%, and the bending strength can be increased by more than 4%.

[0069] The present invention also proposes a battery frame, which is made of the aforementioned boron steel tube, and is used to carry a battery module, and the battery module is used to provide electrical energy for the vehicle. The battery frame can also be designed by topological optimization to obtain a lightweight battery frame. Specifically, an initial model of the battery frame is established; the initial model is topologically optimized to obtain a topological model; a design model is obtained according to the material density distribution of the topological model; the material properties and structural parameters of the design model are configured according to the target weight; and the design model is output. Furthermore, the step of obtaining the design model according to the material density distribution of the topological model includes: setting a first reinforcement and / or increasing the cross-sectional size of the profile of the initial model in the area where the material density distribution of the initial model is large, and reducing the cross-sectional size of the profile of the initial model in the area where the material density distribution of the initial model is small, so as to obtain the design model. It can be understood that the area with large material density distribution represents the need to withstand greater forces. By setting the first reinforcement or increasing the cross-sectional size of the profile of the initial model, the strength of the area can be effectively improved. The area with small material density distribution represents the need to withstand smaller forces. By reducing the cross-sectional size of the profile of the initial model, the weight of the designed battery frame can be reduced. In this way, the material distribution of the obtained design model is more reasonable.

[0070] The present invention also proposes a vehicle, which includes the aforementioned battery frame. The vehicle includes a vehicle body and a battery frame. The battery frame is installed on the vehicle body. The vehicle body includes basic components that enable the vehicle to operate normally, such as a vehicle body, a battery module, etc., which will not be elaborated herein.

[0071] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A production process for a boron steel pipe, characterized in that: include: Cold bending and welding the boron steel to obtain preformed boron steel tubes; The steps of cold bending and welding the boron steel to obtain the preformed boron steel tube are specifically as follows: Rolling and high-frequency induction welding the boron steel; Heating the preformed bent portion of the preformed boron steel tube to obtain a first heat-treated boron steel tube, wherein the first heat-treated boron steel tube has a first heat-treated bent portion with a fillet radius smaller than that of the preformed bent portion; Heating the entire first heat-treated boron steel tube to obtain a second heat-treated boron steel tube having austenite; The second heat-treated boron steel tube is quenched to obtain a target boron steel tube having martensite.

2. The production process of the boron steel pipe according to claim 1, characterized in that: The step of heating the preformed bent portion of the preformed boron steel tube to obtain a first heat-treated boron steel tube, wherein the first heat-treated boron steel tube has a first heat-treated bent portion with a fillet radius smaller than that of the preformed bent portion, is specifically: The preformed bent portion is heated to between 600°C and 680°C to obtain the first heat-treated boron steel tube, wherein the value range of R1 of the first heat-treated bent portion is 1.5d to 2.5d, wherein R1 is the fillet radius of the first heat-treated bent portion, and d is the thickness of the boron steel.

3. The production process of the boron steel pipe according to claim 2, characterized in that: The preformed curved portion is heated by a linear induction heating coil.

4. The production process of the boron steel pipe according to claim 3, characterized in that: The step of heating the preformed curved portion by a linear induction heating coil is specifically as follows: The linear induction heating coil is used to heat the preformed curved portion within a distance range of 5 cm-12 cm, the heating frequency of the linear induction heating coil is controlled within a range of 10 KHz-12 KHz, and the heating current of the linear induction heating coil is controlled within a range of 200 A-250 A.

5. The production process of the boron steel pipe according to claim 1, characterized in that: The value range of R2 of the preformed curved portion is 5d to 8d, wherein the frequency of high-frequency induction welding is 50KHz-80KHz, R2 is the fillet radius of the preformed curved portion, and d is the thickness of the boron steel.

6. The production process of the boron steel pipe according to claim 5, characterized in that: The forming speed of the boron steel material to form the preformed curved portion is controlled to be 5m / min-9m / min.

7. The production process of the boron steel pipe according to claim 1, characterized in that: The step of heating the entire first heat-treated boron steel tube to obtain a second heat-treated boron steel tube having austenite is specifically as follows: The first heat-treated boron steel tube is heated to between 650 degrees Celsius and 750 degrees Celsius to obtain the second heat-treated boron steel tube, wherein the metallographic structure of the second heat-treated boron steel tube is austenite.

8. The production process of the boron steel pipe according to claim 1, characterized in that: The step of quenching the second heat-treated boron steel tube to obtain a target boron steel tube having martensite is specifically as follows: The second heat-treated boron steel pipe is fed into a cooling mold at a speed of 8m / min-12m / min, and the second heat-treated boron steel pipe is quenched at a cooling rate of 3°C / s-5°C / s to obtain the target boron steel pipe, wherein the metallographic structure of the target boron steel pipe is martensite.

9. The process for producing a boron steel pipe according to claim 8, characterized in that: After the second heat-treated boron steel tube is fed into the cooling mold at a speed of 8m / min-12m / min, the temperature of the cooling mold is controlled between 50°C and 100°C.

10. A boron steel pipe, characterized in that: The boron steel pipe is produced by the production process of the boron steel pipe according to any one of claims 1 to 9.

11. A battery frame, characterized in that: The battery frame is made of the boron steel tube as claimed in claim 10.

12. A vehicle, characterized in that: include: Vehicle body; as well as The battery frame according to claim 11 is installed on the vehicle body.

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