Brinell hardness testing device and method for fasteners

Abstract

The application relates to the technical field of hardness detection, and discloses a Brinell hardness detection device and method for fasteners. The Brinell hardness detection device for fasteners comprises a pressure head, an indentation collection device, a middle groove body, a bottom groove body connected to the groove bottom of the middle groove body, an upper groove body connected to the opening, a lifting mechanism with a driving element and a movable supporting arm, the supporting arm being provided with a slot, a pressure sensing device arranged in the slot, a pressure control device arranged on the supporting arm, the pressure control device being electrically connected to the driving element, and the pressure head being detachably inserted into the slot or the indentation collection device being detachably inserted into the slot. The Brinell hardness detection device for fasteners and the Brinell hardness detection method relying on the same can accurately and quickly obtain the hardness value of a small fastener on site, and solve the defect that the accurate hardness value cannot be obtained due to the limitation of the size and shape of the fastener in the Rockwell hardness on-site detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hardness detection, in particular to a Brinell hardness detection device and method for fasteners. BACKGROUND

[0002] In wind power generation and thermal power generation equipment, the performance of fasteners is reduced and the problem of fracture occurs frequently, which poses a serious threat to the stable operation of the unit.

[0003] As an important indicator for evaluating mechanical properties, the on-site inspection of fasteners usually uses a Leeb hardness tester.

[0004] However, the Leeb hardness testing method has the following problems, on the one hand, the Leeb hardness value needs to be converted into a Brinell hardness value for further analysis, and this conversion process is easy to cause the accuracy of the detection result to decrease; on the other hand, the Leeb hardness tester is difficult to effectively test small size and small mass fasteners, affecting the use.

[0005] Although the Brinell hardness test has many advantages such as high measurement accuracy, accurate value, and large indentation area, the current Brinell hardness test is limited by the size of the test piece and the test instrument, and only large fasteners can be tested on site, which has certain limitations and affects the use. SUMMARY

[0006] Therefore, the present application provides a Brinell hardness detection device and method for fasteners to solve the problem that it is difficult to directly measure the Brinell hardness of small size fasteners on site.

[0007] In a first aspect, the present application provides a Brinell hardness detection device for fasteners, comprising: a pressure head adapted to load pressure on the fastener; an indentation collection device adapted to collect indentation information on the surface of the fastener; a clamp having a limiting groove, the limiting groove having a middle groove body, the groove bottom of the middle groove body being connected with a bottom groove body, and the opening being connected with an upper groove body; the shape of the middle groove body and the upper groove body is a double V-shaped groove, and the opening angle of the upper groove body is greater than that of the middle groove body; the shape of the bottom groove body is a ring-shaped groove; a lifting mechanism having a driving member and a movable support arm, the support arm being provided with a slot; a pressure sensing device is arranged on the upper part of the slot, and the pressure sensing device is electrically connected with a pressure control device; the pressure control device is arranged on the support arm, and the pressure control device is electrically connected with the driving member; wherein the pressure head is detachably inserted into the slot and cooperates with the pressure sensing device; or the indentation collection device is detachably inserted into the slot.

[0008] In an alternative embodiment, the middle groove is outwardly open, and the opening of the middle groove is connected with the upper groove; the upper groove is outwardly open from the connection with the middle groove; and the cross section of the bottom groove is semicircular.

[0009] In an alternative embodiment, the opening of the insertion groove is opposite to the slot of the limiting groove.

[0010] In an alternative embodiment, the opening angle of the upper groove is A1, where 145 degrees≤A1≤155 degrees; and the opening angle of the middle groove is A2, where 55 degrees≤A1≤65 degrees.

[0011] In an alternative embodiment, the lifting mechanism further comprises a screw rod, a screw hole is provided on the support arm, the screw hole is connected with the screw rod and cooperates with the screw thread of the screw rod; the screw rod is connected with a driving member, the driving member is adapted to drive the screw rod to rotate, and the rotation of the screw rod drives the support arm to move up and down.

[0012] In an alternative embodiment, the base is further provided, the clamp and the lifting mechanism are arranged on the base; the lifting mechanism further comprises a housing, the housing is connected with the base, and part of the screw rod is arranged inside the housing; a slot is provided on the housing, the support arm extends through the slot, and the slot extends along the axial direction of the screw rod; and the screw rod is rotatably connected with the base.

[0013] In a second aspect, the application further provides a method for detecting the Brinell hardness of a fastener, which is suitable for the fastener Brinell hardness detection device as described in any one of the above embodiments, and comprises the following steps: S1, pretreating the fastener to be detected; S2, placing the fastener in the limiting groove of the clamp, and abutting the inner wall of the limiting groove to fix the fastener; wherein the limiting groove is composed of the bottom groove, the middle groove and the upper groove in sequence to adapt to the size of the fastener; S3, installing a pressure head in the insertion groove, driving the support arm to move downward, and pressing the pressure head to obtain a indentation on the surface of the fastener; S4, removing the pressure head, installing a indentation collection device in the insertion groove, and collecting indentation information by the indentation collection device; and S5, obtaining the Brinell hardness value of the fastener based on the indentation information by the indentation analysis device.

[0014] In an alternative embodiment, step S3 further comprises the following steps: S31, moving the pressure head downward until it contacts the detection site of the fastener; and S32, controlling the pressure head to apply pressure to the fastener by the driving member and the pressure control device; when the pressure applied by the pressure head to the fastener reaches a predetermined stress, maintaining the current pressure state for a period of time T to obtain the indentation.

[0015] In an alternative embodiment, the indentation analysis device is electrically connected with the indentation collection device.

[0016] The Brinell hardness detection device and the Brinell hardness detection method provided by the application can accurately and quickly obtain the hardness value of a small fastener on site, and solve the defect that the accurate hardness value cannot be obtained due to the limitation of the size and shape of the fastener in the Rockwell hardness on-site detection.

[0017] In one aspect, by sequentially connecting and continuously arranging the upper groove body, the middle groove body and the bottom groove body, the limiting groove is characterized by gradually opening outward, and the groove wall spacing of the limiting groove is arranged in stages to adapt to the limiting and fixing of various small fasteners and preliminarily meet the requirements of small fastener on-site detection and Brinell hardness detection.

[0018] On the other hand, by arranging the pressure head that can be flexibly assembled and disassembled and the indentation collection device, the Brinell hardness tester pressure head or the indentation collector can be installed at the insertion slot in the different processes of Brinell hardness detection, and the limiting groove is cooperated to smoothly complete the key task of pressure loading and indentation detection of the small fastener, and the purpose of Brinell hardness detection of the small fastener on site is achieved.

[0019] In summary, the Brinell hardness detection device and method provided by the application are fast and efficient in the detection process, and the detection result is accurate. By arranging the Brinell hardness tester pressure head, the indentation collection device and the indentation analysis device, the Brinell hardness of the fastener is detected, and the defect that the existing Rockwell hardness detection method cannot accurately detect the hardness due to the limitation of the size, quality and shape of the fastener is solved. At the same time, the fastener is fixed by using the double V-shaped support tool, which is simple to operate, convenient and fast to load, stable in loading speed, high in force value accuracy, so as to achieve the purpose of accurately, reliably and quickly detecting the real hardness value of the small size and small weight fastener on site. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the application, the drawings needed in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 It is a schematic view of the Brinell hardness detection device of the fastener of the application;

[0022] Figure 2 It is a side view of the Brinell hardness detection device of the fastener of the application;

[0023] Figure 3 The top view of the Brinell hardness detection device of the fastener of the present application;

[0024] Figure 4 The front view of the Brinell hardness detection device of the fastener of the present application;

[0025] Figure 5 The schematic view of the limiting groove of the present application;

[0026] Figure 6 The partial structure view of the Brinell hardness detection device of the fastener of the present application;

[0027] Figure 7 The schematic view of the electrical connection between the indentation collection device and the indentation analysis device of the present application;

[0028] Figure 8 The schematic view of the indenter of the present application.

[0029] Explanation of reference signs:

[0030] 1. Indenter

[0031] 2. Indentation collection device

[0032] 3. Clamp

[0033] 4. Limiting groove; 41, upper groove body; 42, middle groove body; 43, bottom groove body

[0034] 5. Lifting mechanism; 51, driving piece; 52, screw rod; 53, shell; 54, strip hole; 55, battery

[0035] 6. Support arm; 61, insertion slot; 62, pressure control device; 621, timer; 622, collector; 623, controller; 624, display; 625, switch; 64, pressure sensing device

[0036] 7. Base

[0037] 8. Fastener

[0038] 9. Indentation analysis device DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments of the present application. 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.

[0040] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0042] In addition, the technical features involved in the different embodiments of the application described below can be combined with each other as long as there is no conflict.

[0043] The embodiments of the present application will be described below. Figures 1 to 8

[0044] According to the embodiments of the present application, in one aspect, a Brinell hardness detection device for fasteners is provided, comprising: a pressure head 1 adapted to load pressure on the fastener 8, the pressure head 1 being a Brinell hardness tester pressure head; a indentation collection device 2 adapted to collect indentation information on the surface of the fastener 8, the indentation collection device 2 being an optical indentation collector.

[0045] A clamp 3 is used as a supporting tool, and a limiting groove 4 is arranged at the clamp 3. The limiting groove 4 has a middle groove body 42. The groove bottom of the middle groove body 42 is connected with a bottom groove body 43, and the opening is connected with an upper groove body 41. The shape of the middle groove body 42 and the upper groove body 41 is a double-V-shaped groove, and the opening angle of the upper groove body 41 is greater than that of the middle groove body 42. The shape of the bottom groove body 43 is a ring-shaped groove.

[0046] Specifically, the middle groove body 42 is outwardly open, and the open end of the middle groove body 42 is connected with and continuously arranged with the upper groove body 41. The upper groove body 41 is outwardly open from the connection with the middle groove body 42. The cross-sectional shape of the bottom groove body 43 is semicircular.

[0047] ​In this embodiment, by setting the upper groove body 41, the middle groove body 42 and the bottom groove body 43 which are sequentially connected and continuously arranged, the limiting groove 4 is gradually outwardly opened, and the groove wall spacing of the limiting groove 4 is arranged in a stepwise manner to adapt to the limiting and fixing of various small fasteners and preliminarily meet the requirements of small fasteners, on-site detection and Brinell hardness detection.

[0048] The lifting mechanism 5 has a driving member 51 and a movable support arm 6 provided with a slot 61; a pressure sensing device 64 is arranged at the upper part of the slot 61. In this embodiment, the pressure sensing device 64 can be, but is not limited to, a compression stress test piece. The compression stress test piece is arranged in the slot of the slot 61. When the indenter 1 is inserted into the slot 61, the indenter 1 abuts against the pressure sensing device 64, so that the pressure at the indenter 1 can be transmitted to the pressure sensing device 64, and the pressure sensing device 64 senses the compression stress at the indenter 1. A pressure control device 62 is arranged on the support arm 6, and the pressure control device 62 is electrically connected with the driving member 51, which is used to set the start-stop or rotating speed of the motor according to the stress and time of the indenter 1 acting on the fastener 8.

[0049] Specifically, the indenter 1 is detachably inserted into the slot 61 and cooperates with the pressure sensing device 64. The detachable connection can be, but is not limited to, interference fit, threaded connection or buckle connection. The pressure sensing device 64 is electrically connected with the pressure control device 62. Alternatively, the indentation collecting device 2 is detachably inserted into the slot 61, and the detachable connection can be, but is not limited to, interference fit, threaded connection or buckle connection.

[0050] In this embodiment, the indenter 1 and the indentation collecting device 2 can be flexibly assembled and disassembled, so that the Brinell hardness tester indenter or the indentation collector 622 can be installed at the slot 61 in different processes of Brinell hardness detection, and cooperates with the limiting groove 4 to smoothly complete the key tasks of pressure loading and indentation detection of small fasteners, and achieve the purpose of Brinell hardness detection of small fasteners on site.

[0051] The Brinell hardness detection method of the fastener 8 is to pretreat the fastener to be detected, then place the fastener 8 in the limiting groove 4 of the clamp 3, make the Brinell hardness tester indenter obtain an indentation on the surface of the fastener to be detected by the lifting device, then replace the Brinell hardness tester indenter with the optical indentation collector to collect the indentation, transmit the collection result to the indentation analysis device 9, and obtain the Brinell hardness value of the fastener 8 to be detected by the indentation analysis device 9.

[0052] In the field detection, taking a small fastener with a specification of M36*3*204mm as an example, the detection steps are as follows: first, polish the to-be-detected part of the fastener 8 rod to make the surface roughness parameter Ra not greater than 1.6 microns; second, install a pressure head 1 with a diameter of 2.5mm, the diameter of the pressure head 1 is selected according to the specification of the fastener 8 to be detected; install the clamp 3 to the base 7, place the pretreated fastener 8 in the limiting groove 4 of the clamp 3, and make the to-be-detected part of the fastener 8 face the Brinell hardness pressure head 1; turn on the switch 625 at the support arm 6, so that the pressure control device 62 is in a working state, the pressure control device 62 is electrically connected with the driving part 51, the driving part 51 can control the action of the support arm 6 of the lifting mechanism 5, thereby driving the pressure head 1 to ascend or pressurize; the pressure sensing device 64, the pressure control device 62 and the driving part 51 cooperate to control the loading force to be 187.5Kg, and the loading time is 10s, after completing one loading, the fastener 8 is rotated by 90° for secondary loading, the above operation is repeated to complete the third and fourth loadings; after completing all the loading procedures, remove the pressure head 1, install the indentation collecting device 2 into the insertion slot 61, use the indentation collecting device 2 to identify the four indentations respectively, and transmit the collection results to the indentation analysis device 9 to obtain the real Brinell hardness values of the fastener 8 as follows:

[0053] 289HB, 288HB, 291HB, 289HB;

[0054] The field detection of the fastener 8 uses a portable Leeb hardness tester, and the hardness values are as follows:

[0055] 269HB, 259HB, 265HB, 271HB.

[0056] Then, the fastener 8 is sent to the laboratory, processed and tested by a desktop Brinell hardness tester, and the hardness values are as follows:

[0057] 289HB, 288HB, 290HB, 289HB.

[0058] As can be seen from the above, through data comparison, the Brinell hardness values detected on site by the method are almost the same as the actual hardness values obtained by laboratory detection, while the hardness values detected on site by the Leeb hardness tester have a large difference from the actual hardness values, and the detection accuracy is much lower than that of the method.

[0059] Therefore, the Brinell hardness detection device and the Brinell hardness detection method relying thereon provided by the embodiment can accurately and quickly obtain the hardness value of the small fastener on site, and solve the defect that the accurate hardness value cannot be obtained due to the limitation of the size and shape of the fastener 8 in the Leeb hardness on-site detection.

[0060] Optionally, the pretreatment process is to polish the rod detection part of the fastener 8 to be detected, remove the surface oxide skin, surface treatment layer, etc., and expose the metal luster; in the polishing process, the rod detection part of the fastener 8 to be detected is polished by a grinding wheel sheet, a sandpaper sheet and a polishing sheet.

[0061] Optionally, after the pretreated fastener 8 is stably placed in the clamp 3, the pressure sensing device 64 and the pressure control device 62 are in a working state, the Brinell hardness tester indenter contacts the detection part, the pressure is loaded, and until the predetermined stress is reached, the current stress state is maintained for 10s, and the indentation is obtained.

[0062] Optionally, the diameter of the Brinell hardness tester indenter 1 is selected in the range of 1mm to 5mm, and the unit is mm; the loading force is selected in the range of 25Kg to 250Kg, and the unit is Kg.

[0063] Optionally, the indentation collection device 2 is electrically connected with the indentation analysis device 9, the indentation collection device 2 can be built-in Bluetooth module or WIFI module, and the indentation data is transmitted to the indentation analysis device 9 through Bluetooth connection or WIFI connection.

[0064] The Brinell hardness detection device provided in the embodiment has a fast and efficient detection process and accurate detection result; the Brinell hardness detection device is used for detecting the fastener 8 by setting the Brinell hardness tester indenter, the indentation collection device 2 and the indentation analysis device 9, and the defects that the existing Leeb hardness detection method is limited by the size, mass and shape of the fastener 8 and cannot accurately detect the hardness are solved; meanwhile, the fastener 8 is fixed by using the double V-shaped support tool, the operation is simple, the pressure loading is convenient and fast, the loading speed is stable, and the force value accuracy is high, so that the purpose of accurately, reliably and quickly detecting the real hardness value of the small-size and small-weight fastener 8 on site is achieved.

[0065] In some embodiments, in combination with Figure 1 As shown in the figure, the opening of the slot 61 is arranged opposite to the slot opening of the limiting groove 4, so as to ensure that the indenter 1 is aligned with the fastener 8.

[0066] In some embodiments, in combination with Figure 5 As shown in the figure, the opening angle of the upper groove body 41 is A1, and 145 degrees≤A1≤155 degrees; the opening angle of the middle groove body 42 is A2, and 55 degrees≤A1≤65 degrees; in the embodiment, the opening angle of the upper groove body 41 is 150 degrees, and the opening angle of the middle groove body 42 is 60 degrees.

[0067] In some embodiments, in combination with Figure 1As shown, the lifting mechanism 5 also has a screw rod 52, the support arm 6 is provided with a screw hole which is connected to the screw rod 52 and matches with the screw thread of the screw rod 52; the screw rod 52 is connected with a driving member 51 which is suitable for driving the screw rod 52 to rotate, and the screw rod 52 rotates to drive the support arm 6 to move up and down, and the support arm 6 drives the pressure head 1 to move, when the pressure head 1 abuts against the fastener 8, the lifting mechanism 5 continues to control the support arm 6 to move downward, so that the pressure head 1 exerts pressure on the fastener 8.

[0068] In some embodiments, in combination with Figure 1 As shown, the base 7 is also provided, and the clamp 3 and the lifting mechanism 5 are arranged on the base 7; the base 7 is provided with a rectangular slot which is matched with the clamp 3 in size, and the clamp 3 is put into and fitted in the rectangular slot to be fixed; the lifting mechanism 5 also has a shell 53 which is connected with the base 7, and part of the rod body of the screw rod 52 is arranged inside the shell 53; the shell 53 is provided with a strip hole 54, the support arm 6 extends out through the strip hole 54, and the strip hole 54 extends along the axial direction of the screw rod 52 to provide space for the movement of the support arm 6.

[0069] In some embodiments, in combination with Figure 1 As shown, the driving member 51 can be a motor which is connected with a battery 55; the pressure control device 62 includes a timer 621, a collector 622 and a controller 623 which are electrically connected with each other, and the pressure control device 62 is also electrically connected with a display 624 and a switch 625; the timer 621 is used to record and monitor the duration of pressure loading; the collector 622 is used to collect pressure information and transmit data to the controller 623; the controller 623 is electrically connected with the driving member 51, and is used to adjust the start-stop or rotating speed of the motor according to the size and time of stress.

[0070] In some embodiments, in combination with Figure 1 As shown, the screw rod 52 is rotatably connected with the base 7, wherein the base 7 is provided with a connecting slot, and the end of the screw rod 52 is provided with a protruding part which matches with the connecting slot to realize the rotatable connection between the screw rod 52 and the base 7; specifically, the structure shape of the protruding part can be disc-shaped, and the protruding part is arranged around the rod part, and the cross-sectional shape of the protruding part and the rod part is T-shaped; the slot body shape of the connecting slot is matched with the protruding part, and has a disc-shaped slot body which can accommodate the rotation of the protruding part.

[0071] In some embodiments, in combination with Figure 7 And Figure 8 As shown, the pressure head 1 and the periphery of the indentation collecting device 2 are provided with a connecting sleeve which is connected with the insertion slot 61 through interference fit clamping to realize the detachable connection between the pressure head 1, the indentation collecting device 2 and the insertion slot 61.

[0072] According to the embodiment of the present application, in another aspect, a method for detecting the Brinell hardness of a fastener 8 is also provided, which is suitable for the Brinell hardness detection device of any one of the above-mentioned embodiments, and comprises the following steps: S1, pretreating the fastener 8 to be detected to ensure that the surface of the fastener 8 is clean, free of oil stains and oxide layers, so as to obtain accurate indentation and hardness values; S2, placing the fastener 8 in the limiting groove 4 of the clamp 3, and abutting the fastener 8 with the inner wall surface of the limiting groove 4 to fix it, so as to ensure that it will not move or deform during the detection process; wherein the limiting groove 4 is composed of the bottom groove body 43, the middle groove body 42 and the upper groove body 41 in sequence, so as to adapt to the size of the fastener 8; S3, installing the indenter 1 in the insertion groove 61, and controlling the lower movement of the support arm 6 by the driving member 51, so as to press down the indenter 1 and obtain an indentation on the surface of the fastener 8; S4, removing the indenter 1, and installing the indentation collecting device 2 in the insertion groove 61, so as to collect indentation information by the indentation collecting device 2; and S5, obtaining the Brinell hardness value of the fastener 8 based on the indentation information by the indentation analysis device 9.

[0073] Further, step S3 further comprises the following steps: S31, moving down the indenter 1 until it contacts the part to be detected of the fastener 8; and S32, controlling the indenter 1 to apply pressure to the fastener 8 by the driving member 51 and the pressure control device 62; when the pressure applied by the indenter 1 to the fastener 8 reaches a predetermined stress, maintaining the current pressure state for a time period T, which can be 10 seconds, to obtain an indentation; and the predetermined stress is pre-set according to the material and the expected hardness range of the fastener 8.

[0074] In some embodiments, the method further comprises the following steps: Figure 7 As shown in the drawings, the indentation analysis device 9 is electrically connected with the indentation collecting device 2.

[0075] Obviously, the above-mentioned embodiments are only examples for clearly illustrating the present application, and are not intended to limit the implementation modes. Although the embodiments of the present application are described in conjunction with the drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations all fall within the scope of the present application.

Claims

1. A device for measuring the Brinell hardness of a fastener, characterized by, The utility model relates to a kind of press head, press mark collection device, clamp and the method for detecting fastener. It includes: Press head (1); Press mark collection device (2); Clamp (3) with limiting slot (4), the limiting slot (4) has mid-slot body (42);The slot bottom of the mid-slot body (42) is connected with bottom slot body (43), and the opening is connected with upper slot body (41); The shape of the mid-slot body (42) and upper slot body (41) is double V-shaped slot, and the shape of the bottom slot body (43) is annular slot; Lifting mechanism (5) has driving part (51) and movable support arm (6), and the support arm (6) is provided with slot (61); Pressure control device (62) is provided on the support arm (6), and the pressure control device (62) is electrically connected with the driving part (51); Pressure sensing device (64) is provided on the upper part of the slot (61), and the pressure sensing device (64) is electrically connected with the pressure control device (62); Wherein, the press head (1) can be detachably inserted into the slot (61), and is matched with the pressure sensing device (64); Or, the press mark collection device (2) can be detachably inserted into the slot (61); The opening angle of the upper slot body (41) is greater than that of the mid-slot body (42); The mid-slot body (42) is outwardly open, and the opening of the mid-slot body (42) is connected with the upper slot body (41) and is continuously arranged; The upper slot body (41) is outwardly open from the connection with the mid-slot body (42); 2. The apparatus for Brinell hardness testing of fasteners according to claim 1, wherein The cross-sectional shape of the bottom slot body (43) is semicircular.

3. The apparatus for Brinell hardness testing of fasteners according to claim 2, wherein The opening of the slot (61) is oppositely arranged with the slot opening of the limiting slot (4). The opening angle of the upper slot body (41) is A1, wherein: 145 degrees ≤ A1 ≤ 155 degrees; 4. The apparatus for Brinell hardness testing of fasteners according to claim 3, wherein The opening angle of the mid-slot body (42) is A2, wherein: 55 degrees ≤ A2 ≤ 65 degrees. The lifting mechanism (5) further has a screw rod (52), and the support arm (6) is provided with a screw hole which is penetrated by the screw rod (52) and cooperates with the screw thread of the screw rod (52); 5. The apparatus for Brinell hardness testing of fasteners according to claim 4, wherein The screw rod (52) is connected with the driving part (51), and the driving part (51) is suitable for driving the screw rod (52) to rotate, and the screw rod (52) rotates to drive the support arm (6) to move up and down. Further including, base (7), the clamp (3) and lifting mechanism (5) are arranged at the base (7); The lifting mechanism (5) further has a housing (53), and the housing (53) is connected with the base (7), and part of the rod body of the screw rod (52) is arranged inside the housing (53); A strip hole (54) is formed in the housing (53), the support arm (6) extends through the strip hole (54), and the strip hole (54) extends along the axial direction of the screw rod (52); 6. A method of measuring Brinell hardness of a fastener using the fastener Brinell hardness measuring device according to any one of claims 1 to 5, characterized by, The screw rod (52) is rotatably connected with the base (7). Including: S1: pretreating the fastener (8) to be detected; S2: placing the fastener (8) in the limiting slot (4) of the clamp (3), and the fastener (8) abuts against the inner wall surface of the limiting slot (4) to be fixed. The limiting groove (4) is composed of a bottom groove body (43), a middle groove body (42) and an upper groove body (41) in sequence to adapt to the size of the fastener (8); S3: installing the pressure head (1) in the slot (61), the driving member (51) controls the lower movement of the support arm (6), the pressure head (1) is pressed down, and a pressure mark is obtained on the surface of the fastener (8); S4: removing the pressure head (1), installing the pressure mark collecting device (2) in the slot (61), and the pressure mark collecting device (2) collects the pressure mark information; S5: the pressure mark analysis device (9) obtains the Brinell hardness value of the fastener (8) based on the pressure mark information.

7. The method of Brinell hardness testing of fasteners according to claim 6, wherein, Step S3 further comprises, S31: the pressure head (1) moves downward until it contacts the part to be detected of the fastener (8); S32: the pressure head (1) applies pressure to the fastener (8) by means of the driving member (51) and the pressure control device (62); When the pressure applied by the pressure head (1) to the fastener (8) reaches a predetermined stress, the current pressure state is maintained for a time period T, and a pressure mark is obtained.

8. The method of Brinell hardness testing of fasteners according to claim 6, wherein, The pressure mark analysis device (9) is electrically connected with the pressure mark collecting device (2).

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