Reaming tool for hydrogen-induced delayed cracking of hot-formed part

Abstract

The utility model discloses a broaching tool for hydrogen-induced delayed cracking of a hot forming part, which comprises an upper die and a lower die, the upper die comprises an upper die body and a broaching cone, the lower die comprises a lower die body, the lower die body is provided with a mounting hole and a material sheet placing groove, and the material sheet placing groove divides the lower die body into a top plate and a bottom plate; a through hole located under the reaming cone is formed in the center of the bottom plate, a strip-shaped groove, a plurality of outer-ring threaded holes and a plurality of inner-ring threaded holes are formed in the middle of the top plate, and round points of a circular ring formed by the outer-ring threaded holes and the inner-ring threaded holes are all located on the central axis of the through hole. The chambering tool can take out material sheets meeting chambering requirements for hot forming parts with different molded surfaces for chambering experiments, so that the hydrogen-induced delayed cracking risk rate of the parts is judged, the application range is wide, and the requirements of hydrogen-induced delayed cracking chambering experiments of typical hot forming parts such as A columns, B columns and central channels can be met; meanwhile, the tool is simple in design, short in machining time and low in cost.

Description

TECHNICAL FIELD

[0001] The utility model relates to reaming tool technical field, concretely relates to a reaming tool for hydrogen-induced delayed cracking of hot forming parts. BACKGROUND

[0002] Due to the increase of lightweight and anti-collision demand in the automobile industry, if the traditional cold stamping material continues to be applied to safety parts, the material thickness needs to be increased to meet the anti-collision demand, which is contrary to the lightweight of automobiles.

[0003] Currently, hot forming steel is mostly used in automobile safety parts. The thickness of hot forming steel can be halved compared to cold stamping steel while ensuring strength, which can meet the requirements of lightweight and anti-collision.

[0004] Hot forming steel is divided into bare plate and aluminum-silicon plated plate. The use of aluminum-silicon plated plate to produce parts may have the risk of hydrogen-induced delayed cracking. The mechanism is as follows: during the heating process in the roller hearth furnace, the aluminum-silicon plated layer melts due to its melting point of about 600℃ (material heating temperature of 880℃-950℃), in addition, the plated layer reacts with water vapor in the furnace to generate hydrogen gas and penetrate into the material matrix, resulting in an increase in hydrogen content in the material, which increases the risk of hydrogen-induced delayed cracking during the subsequent die cold forming process.

[0005] In view of the risk of hydrogen-induced delayed cracking in the production of aluminum-silicon plated plate parts, the existing detection methods include HTDS, hydrogen charging experiment, slow tensile test, etc. These experiments are high in cost and time-consuming, and do not have the effect of rapid detection in the field of production, therefore, the national standard GB / T24524-2021 reaming experiment combined with T / CSAE332-2023 is generally used to detect the risk of hydrogen-induced delayed cracking of hot forming steel.

[0006] However, in existing hole expansion experiments, most toolings are only suitable for GB / T24524-2021 flat sheet, the size of which is 100*100mm, and only very special hot-formed parts can take out such a large plane, which cannot be applied to most hot-formed parts, and the hydrogen-induced delayed cracking risk rate of the parts cannot be determined. For example, patent CN 206772711 U discloses a pressing device for hole expansion test of sheet forming test machine, which is a new device for pressing sheet during hole expansion test of sheet forming test machine. The pressing device comprises an upper screw, an upper pressing device, a concave clamping device, a convex clamping device, a lower pressing device and a lower screw. However, this device can only be used for hole expansion experiment of fixed size sheet, and cannot be used for hole expansion experiment of different hot-formed parts. Patent CN 116895347 A discloses a high-strength steel edge crack sensitivity evaluation method based on limit hole expansion. This method is still based on the size standard in GB / T24524-2021 metal material sheet and thin strip hole expansion test method, and cannot be applied to hole expansion experiment of most hot-formed parts.

[0007] At the same time, the existing hole expansion tooling is complex in design. If different hole expansion experiments of different hot-formed parts are to be met, different tooling lower molds need to be customized, which will cause high manufacturing cost and maintenance difficulty. Practical new type content

[0008] The utility model discloses to the prior art's deficiency provides a kind of hole expansion tooling for hydrogen-induced delayed cracking of hot-formed part, and the application range is wide, and it is not necessary to special size (100*100mm) sheet, can be extracted according to different profile hot-formed part sheet that meets hole expansion requirement to carry out hole expansion experiment, to determine the hydrogen-induced delayed cracking risk rate of the part.

[0009] To solve the above technical problems, the utility model provides a kind of hole expansion tooling for hydrogen-induced delayed cracking of hot-formed part, including upper die and lower die;

[0010] The upper die includes an upper die body and a hole expansion cone arranged at the bottom of the upper die body, and the upper die body is used to connect the driving mechanism of the hole expansion testing machine;

[0011] The lower die includes a lower die body, and a mounting hole is arranged on the lower die body for connecting the base of the hole expansion testing machine. A sheet placing groove is arranged in the lower die body for inserting the hole expansion sheet. The sheet placing groove divides the lower die body into a top plate and a bottom plate.

[0012] A through hole is arranged at the center of the bottom plate, which is located directly below the hole expansion cone. A strip-shaped groove is arranged in the middle of the top plate, which is in communication with the sheet placing groove and located directly above the through hole.

[0013] The top plate is provided with a plurality of outer ring threaded holes and a plurality of inner ring threaded holes for fixing different sizes of the material pieces to be expanded, and the center points of the outer ring threaded holes and the inner ring threaded holes forming a ring are located on the central axis of the through hole.

[0014] The upper die body of the expanding tool upper die is fixedly connected with the driving mechanism of the expanding test machine, and the expanding cone of the upper die is driven to press down and expand; the lower die is fixedly connected with the base of the expanding test machine through the mounting hole, the material piece to be expanded is inserted into the material piece placing groove, and the bolt is screwed through the outer ring threaded hole and / or the inner ring threaded hole to press the material piece to be expanded, and a pressure of about 50kN is generated after locking to ensure that the material piece to be expanded remains stationary during the expanding process and ensures the accuracy of the experiment.

[0015] The tool is provided with outer ring threads and inner ring threaded holes to match the fixation of different sizes of the material pieces to be expanded, and can realize the expansion of material pieces with sizes of 30*30mm to 100*100mm, has a wide application range, and does not need to replace the lower die for the expanding experiment of different hot-formed parts, and has low cost and simple structure.

[0016] Further, the height of the material piece placing groove is 8-20mm, and the width of the material piece placing groove perpendicular to the insertion direction of the material piece is 100-110mm, so that the insertion of material pieces with sizes of 100*100mm and below can be realized.

[0017] Further, the number of the inner ring threaded holes is two, which are symmetrically distributed on both sides of the strip-shaped groove, and the distance d1 between the two is less than 30mm, so that the fixation of material pieces with sizes of 30*30mm and above can be realized.

[0018] Further, the number of the outer ring threaded holes is four, which are symmetrically distributed on both sides of the strip-shaped groove, and the distance d2 between the two outer ring threaded holes symmetrically distributed on both sides of the strip-shaped groove is: 50mm

[0019] Further, the upper die body is in a cylindrical structure, and the upper part of the upper die body is provided with a insertion hole for fixing the upper die body by a pin.

[0020] Further, the lower part of the upper die body is threadedly connected with a locking block for locking the upper die body and the driving mechanism of the expanding test machine.

[0021] When the upper die is fixed, the upper die body is inserted into the output end of the driving mechanism of the expanding test machine, and is fixed by a pin, and the locking block is screwed upward to lock the upper die.

[0022] Further, the installation hole penetrates the material piece placing groove, the installation hole comprises a threaded hole arranged at the lower end of the bottom plate, and a round hole arranged at the upper end of the bottom plate and the top plate, the diameter of the round hole is larger than the diameter of the threaded hole.

[0023] Further, the height of the round hole on the bottom plate is 40-60mm.

[0024] When the lower die is fixed, the bolt is inserted into the round hole at the upper part of the lower die and screwed in the threaded hole to be fixed with the base of the hole expansion testing machine, and the top of the bolt is embedded in the round hole of the bottom plate to avoid affecting the insertion of the material piece.

[0025] Further, the length direction of the strip-shaped groove is consistent with the insertion direction of the material piece to be hole expanded.

[0026] Further, the diameter of the inner ring threaded hole is smaller than the diameter of the outer ring threaded hole.

[0027] The utility model discloses the beneficial effect:

[0028] The hole expansion tool can take out the material piece meeting the hole expansion requirement for different profile hot forming parts to carry out hole expansion experiment, thereby determining the hydrogen-induced delayed cracking risk rate of the parts, and the utility model has wide application range and can solve the requirements of the hydrogen-induced delayed cracking hole expansion experiment of typical hot forming parts such as A column, B column and central passage. ACCURATE DRAWINGS

[0029] In order to more clearly illustrate the technical scheme of the utility model, the following will be briefly introduced to the drawings needed to be used in the embodiment, and obviously, the drawings in the following description are only the embodiment of the utility model, and for the ordinary skilled in the art, other drawings can be obtained according to these drawings without creating labor.

[0030] Figure 1 It is the upper die exploded view of the hole expansion tool for hydrogen-induced delayed cracking of hot forming parts of the utility model;

[0031] Figure 2 It is the lower die perspective view of the hole expansion tool for hydrogen-induced delayed cracking of hot forming parts of the utility model;

[0032] Figure 3 It is the lower die top view of the hole expansion tool for hydrogen-induced delayed cracking of hot forming parts of the utility model;

[0033] Figure 4 It is Figure 3 A-A direction section view in the embodiment;

[0034] Figure 5 It is Figure 3 B-B direction section view in the embodiment;

[0035] Explanation of reference numerals in the drawing: 11, upper die body, 12, hole expansion cone, 13, insertion hole, 14, locking block, 20, lower die body, 21, mounting hole, 22, tablet placement groove, 23, top plate, 24, bottom plate, 25, through hole, 26, strip-shaped groove, 27, outer ring threaded hole, 28, inner ring threaded hole. DETAILED DESCRIPTION

[0036] The technical scheme of the present application will be described clearly and completely below in combination with the embodiments of the present application and the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0037] Reference Figures 1-5 The present application provides a hole expansion tool for hydrogen-induced delayed cracking of hot-formed parts, comprising an upper die and a lower die.

[0038] The upper die comprises an upper die body 11 and a hole expansion cone 12 arranged at the bottom of the upper die body 11, as shown in Figure 1 The upper die body 11 is used to connect the driving mechanism of the hole expansion testing machine.

[0039] As shown in Figure 2 The lower die comprises a lower die body 20, a mounting hole 21 is arranged on the lower die body 20 for connecting the base of the hole expansion testing machine, a tablet placement groove 22 is arranged in the lower die body 20 for inserting the hole expansion tablet, and the tablet placement groove 22 divides the lower die body 20 into a top plate 23 and a bottom plate 24.

[0040] As shown in Figure 3 The bottom plate 24 is provided with a through hole 25 at the center, which is located directly below the hole expansion cone 12, and the cone is pressed down and the bottom end enters the through hole 25 during hole expansion operation, a strip-shaped groove 26 is arranged in the middle of the top plate 23, which is in communication with the tablet placement groove 22 and located directly above the through hole 25, the length direction of the strip-shaped groove 26 is consistent with the insertion direction of the hole expansion tablet, and the strip-shaped groove 26 facilitates the movement of the tablet in the tablet placement groove 22.

[0041] A plurality of outer ring threaded holes 27 and a plurality of inner ring threaded holes 28 are arranged on the top plate 23 for fixing hole expansion tablets of different sizes, and the center points of the outer ring threaded holes 27 and the inner ring threaded holes 28 forming a circle are located on the center axis of the through hole 25.

[0042] In this embodiment, the upper die of the reaming fixture is fixedly connected to the drive mechanism of the reaming test machine via the upper die body 11. The drive mechanism drives the upper die to press down. The lower die is fixedly connected to the base of the reaming test machine via the mounting hole 21. The piece to be reamed is inserted into the piece placement slot 22, and the bolts are screwed through the outer ring threaded hole 27 and / or the inner ring threaded hole 28 to press the piece to be reamed. After locking, a pressure of about 50kN is generated to ensure that the piece to be reamed remains stationary during the reaming process, ensuring the accuracy of the experiment. In this embodiment, the fixture is equipped with an outer ring threaded hole 27 and an inner ring threaded hole 28 to match the fixing of pieces to be reamed of different sizes. It can realize the reaming of pieces ranging from 30×30mm to 100×100mm in size, with a wide range of applications. For reaming experiments on different thermoformed parts, there is no need to change the lower die, resulting in low cost and simple structure.

[0043] In a preferred embodiment, the height of the material placement groove 22 is 8-20mm, and the width of the material placement groove 22 perpendicular to the material insertion direction is 100-110mm, enabling the insertion of material pieces with a size of 100×100mm and below. The number of inner ring threaded holes 28 is two, symmetrically distributed on both sides of the strip groove 26, as shown below. Figure 4 As shown, the distance d1 between the two is less than 30mm, which facilitates the fixing of sheet materials of size 30×30mm and above. There are four outer ring threaded holes 27, symmetrically distributed on both sides of the strip groove 26. The distance d2 between the two symmetrical outer ring threaded holes 27 on both sides of the strip groove 26 is 50mm < d2 < 100mm, which facilitates the fixing of sheet materials of size 100×100mm and below. The diameter of the inner ring threaded hole 28 is smaller than the diameter of the outer ring threaded hole 27.

[0044] In a preferred embodiment, the upper mold body 11 has a cylindrical structure. An insertion hole 13 is provided at the upper part of the upper mold body 11 for fixing the upper mold body 11 with a pin. A locking block 14 is threadedly connected to the lower part of the upper mold body 11 for locking the upper mold body 11 to the drive mechanism of the reaming test machine. When fixing the upper mold, the upper mold body 11 is inserted into the output end of the drive mechanism of the reaming test machine and fixed with a pin. The locking block 14 is then screwed upwards to lock the upper mold.

[0045] As a preferred embodiment, such as Figure 5 As shown, the mounting hole 21 penetrates the material placement groove 22. The mounting hole 21 includes a threaded hole at the lower end of the base plate 24 and a circular hole at the upper end of the base plate 24 and the top plate 23. The diameter of the circular hole is larger than the diameter of the threaded hole, and the height of the circular hole on the base plate 24 is 40-60mm. When the lower mold is fixed, the bolt is inserted into the threaded hole through the circular hole at the upper part of the lower mold and screwed into the base of the hole expansion testing machine. The top of the bolt is embedded in the circular hole of the base plate 24 to avoid affecting the insertion of the material.

[0046] The following is a specific embodiment of a hydrogen-induced delayed cracking hole expansion experiment for various hot forming parts using the tooling of the above embodiment.

[0047] Embodiment 1

[0048] In this embodiment, the hydrogen-induced delayed cracking risk rate of the A-pillar is determined: several hole expansion samples (40x40mm, a circle with r2 cut in the center) are taken from the A-pillar using a five-axis three-dimensional laser machine, the hole expansion tooling is installed on a tensile testing machine, the displacement is used to control the displacement of the upper die pressing down according to the corresponding program, the sheet is placed in the center of the lower die of the tooling and locked with the inner ring threaded hole by bolts before the test, the position of the upper die cone is adjusted to repeat the hole expansion experiment, and the experiment is stopped when cracks appear in the center of the hole expansion sheet, and the hole expansion rate is determined.

[0049] Embodiment 2

[0050] In this embodiment, the hydrogen-induced delayed cracking risk rate of the threshold connecting plate is determined: several hole expansion samples (30x30mm, a circle with r1.5 cut in the center) are taken from the threshold connecting plate using a five-axis three-dimensional laser machine, the hole expansion tooling is installed on a tensile testing machine, the displacement is used to control the displacement of the upper die pressing down according to the corresponding program, the sheet is placed in the center of the lower die of the tooling and locked with the inner ring threaded hole by bolts before the test, the position of the upper die cone is adjusted to repeat the hole expansion experiment, and the experiment is stopped when cracks appear in the center of the hole expansion sheet, and the hole expansion rate is determined.

[0051] Embodiment 3

[0052] In this embodiment, the hydrogen-induced delayed cracking risk rate of the central passage is determined: several hole expansion samples (80x80mm, a circle with r4 cut in the center) are taken from the central passage using a five-axis three-dimensional laser machine, the hole expansion tooling is installed on a tensile testing machine, the displacement is used to control the displacement of the upper die pressing down according to the corresponding program, the sheet is placed in the center of the lower die of the tooling and locked with the outer ring threaded hole by bolts before the test, the position of the upper die cone is adjusted to repeat the hole expansion experiment, and the experiment is stopped when cracks appear in the center of the hole expansion sheet, and the hole expansion rate is determined.

[0053] In summary, the hole expansion tooling of the present utility model can take out sheets that meet the hole expansion requirements for different types of hot forming parts to perform hole expansion experiments, thereby determining the hydrogen-induced delayed cracking risk rate of the parts, and has a wide range of applications and can solve the requirements of hydrogen-induced delayed cracking hole expansion experiments for typical hot forming parts such as A-pillars, B-pillars, central passages, etc. At the same time, the tooling of the present utility model is simple in design, short in processing time and low in cost.

[0054] The utility model has been described in detail above in combination with specific implementation manners and exemplary examples, but these descriptions cannot be understood as limitations on the utility model. Those skilled in the art understand that the technical solutions and implementation manners of the utility model can be variously replaced, modified or improved without departing from the spirit and scope of the utility model, and these all fall within the scope of the utility model. The protection scope of the utility model is subject to the appended claims.

Claims

1. A hydrogen-induced delayed cracking reaming tooling for a hot formed part, characterized in that, The upper die and the lower die are provided; The upper die comprises an upper die body and a hole-expanding cone arranged at the bottom of the upper die body, and the upper die body is used for connecting a driving mechanism of a hole-expanding testing machine; The lower die comprises a lower die body, and a mounting hole is arranged on the lower die body and used for connecting a base of the hole-expanding testing machine, and a material sheet placing groove is arranged in the lower die body and used for inserting a material sheet to be expanded, and the material sheet placing groove divides the lower die body into a top plate and a bottom plate; A through hole is arranged at the center of the bottom plate and located directly below the hole-expanding cone, and a strip-shaped groove is arranged in the middle of the top plate and located directly above the through hole and communicated with the material sheet placing groove; A plurality of outer ring threaded holes and a plurality of inner ring threaded holes are arranged on the top plate and used for fixing material sheets to be expanded with different sizes, and the centers of the outer ring threaded holes and the inner ring threaded holes are located on the central axis of the through hole.

2. The hydrogen-induced delayed cracking reaming fixture for a hot formed part of claim 1, wherein, The height of the material sheet placing groove is 8-20 mm, and the width of the material sheet placing groove perpendicular to the insertion direction of the material sheet is 100-110 mm.

3. The hydrogen-induced delayed cracking reaming tooling for a hot formed part of claim 1, wherein, The number of the inner ring threaded holes is two, and the two inner ring threaded holes are symmetrically distributed on both sides of the strip-shaped groove, and the distance d1 between the two inner ring threaded holes is less than 30 mm.

4. The hydrogen-induced delayed cracking reaming fixture for a hot formed part of claim 1, wherein, The number of the outer ring threaded holes is four, and the four outer ring threaded holes are symmetrically distributed on both sides of the strip-shaped groove, and the distance d2 between the two outer ring threaded holes symmetrically distributed on both sides of the strip-shaped groove is 50 mm 5. The hydrogen-induced delayed cracking hole flaring fixture for a hot formed part of claim 1 wherein, The upper die body is in a cylindrical structure, and an insertion hole is arranged at the upper part of the upper die body and used for fixing the upper die body by means of a bolt.

6. The hydrogen-induced delayed cracking reaming tooling for a hot formed part of claim 5, wherein, The lower part of the upper die body is threadedly connected with a locking block, and the upper die body and the driving mechanism of the hole-expanding testing machine are locked by means of the locking block.

7. The hydrogen-induced delayed cracking reaming tooling for a hot formed part of claim 1 wherein, The mounting hole penetrates the material sheet placing groove, and the mounting hole comprises a threaded hole arranged at the lower end of the bottom plate and a circular hole arranged at the upper end of the bottom plate and the top plate, and the diameter of the circular hole is greater than the diameter of the threaded hole.

8. The hydrogen-induced delayed cracking reaming tooling for a hot formed part of claim 7, wherein, The height of the circular hole on the bottom plate is 40-60 mm.

9. The hydrogen-induced delayed cracking reaming kit for a hot formed part of claim 1 wherein, The length direction of the strip-shaped groove is consistent with the insertion direction of the material sheet to be expanded.

10. The hydrogen-induced delayed cracking reaming tooling for a hot formed part of claim 1 wherein, The diameter of the inner ring threaded hole is less than the diameter of the outer ring threaded hole.

Images