An economical and high-precision end-quenching experimental device and its usage method

Abstract

This invention provides an economical and high-precision end-quenching experimental device and its usage method. It includes an end-quenching sample clamping block, an upper crossbeam, a support, a lower crossbeam, a cooling medium constraint plate, a cooling medium injection pipe, and a base. The support is mounted on the ground, and the upper crossbeam, lower crossbeam, and base are arranged from top to bottom within the support. The end-quenching sample clamping block has a central hole in its center to match the end-quenching sample. The end-quenching sample clamping block is detachably mounted on the upper crossbeam. The positional relationship between the upper and lower crossbeams and the support is adjustable. After the end-quenching sample clamping block is positioned on the upper crossbeam, the central hole of the end-quenching sample clamping block is aligned with the through hole of the cooling medium constraint plate. The cooling medium injection pipe passes through the base to uniformly cool the quenched end of the sample. This invention, with its simple structure and low cost, reliably solves the problem of various factors affecting the accuracy of evaluation results during the end-quenching process.

Description

Technical Field

[0001] This invention relates to the field of steel hardenability testing technology, and more particularly to an economical, high-precision end-quenching experimental device and its usage method. Background Technology

[0002] Currently, the Jominy end-quench test method is commonly used in the industry to determine the hardenability of steel, and it is also the standard method for hardenability testing in many countries. The general procedure is as follows: the steel is heated to its austenitizing temperature and held for a period of time. It is then removed from the furnace and placed inside a circular hole in a metal component. Water is sprayed onto the lower end of the end-quenched sample to create a cooling rate gradient inside the sample. Two parallel surfaces are then machined on the sample surface. Hardness is tested at regular intervals from the quenched end to different locations inside the sample, forming an end-quenched hardness curve based on the hardness versus the distance from the end. This method is quite simple, but several factors can affect the accuracy of the results, including: 1. The influence of the clamping tool on the temperature of the clamping position when the sample is removed from the furnace; 2. Inconvenient sample placement, with the time required to transfer the sample to the end-quenching support depending on the operator's skill; 3. Direct contact between the metal support and the non-quenched end of the sample, leading to heat transfer and potentially establishing a reverse cooling rate gradient at the non-quenched end; 4. The uniformity of cooling of the sample end face by the water (or other medium) flow at the quenched end; 5. The parallelism of the parallel surfaces of the end-quenched sample to the sample axis; 6. Machining depth, etc. The last two factors are mainly related to sample fixation and processing. Technical personnel have developed many related fixation and processing methods, which will not be elaborated upon here. To address the impact of each factor on the accuracy of the evaluation results, scientists have developed some devices or technologies, but none can simultaneously resolve the adverse effects of all the aforementioned factors on the accuracy of the evaluation results.

[0003] For example, the invention patent with application number CN02136430.3, "End Quenching Device and Quenching Determination Method for Medium and High Hardenability Steel", reduces the cooling rate of the non-quenched end by placing the sample in a hole filled with refractory insulation material, thereby reducing the adverse effects of factor 3 mentioned above. However, this method still requires the use of a clamp to manually hold the sample into the device, and the quenched end still uses the traditional test method, which cannot solve the effects of factors 1, 2 and 4.

[0004] The invention patent application number CN201611164378.0, entitled "An End-Quenching Experimental Device", uses a moving and tilting heating furnace to make the sample automatically fall into the end-quenching experimental device, thus eliminating the influence of factors 1 and 2. However, it still adopts the traditional end-quenching method and cannot solve the adverse effects of factors 3 and 4. At the same time, the experimental device has a complex structure and may have problems with reliability and cost.

[0005] The utility model patent with application number CN88215671.3, "Manipulator-type end-effector quenching test machine", automatically completes the sample clamping and water spraying process through photoelectric sensing. However, it only solves the problems of sample centering (factor 4) and the consistency of the time from sample placement to water spraying. It does not help solve factors 1, 2, and 3.

[0006] The utility model patent "Multi-purpose end quenching test machine" with application number CN200620085107.1 solved the problems of the cooling medium not being reusable and the water jet height being affected by water pressure. In fact, it reduced the adverse effects of factor 4, but did not solve the effects of factors 1, 2 and 3.

[0007] The utility model patent with application number CN201820593219.0, entitled "A test device for hardenability test of steel end", can ensure that the sprayed water column is in uniform contact with the end of the steel, but it does not solve the influence of factors 1, 2, and 3, and the structure is relatively complex.

[0008] The utility model patent with application number CN201921493677.8, entitled "A device for testing the hardenability of metallic materials", is functionally no different from an ordinary end-quenching test machine and does not help solve factors 1, 2, 3, and 4.

[0009] The utility model patents CN202020754431.8, entitled "An Automated End-Quenching Device", and CN202123243612.8, entitled "An End-Quenching Test Device for Steel Hardenability", can automate the end-quenching process and eliminate the influence of human factors, but they do not solve the adverse effects of factors 1, 2, 3, and 4 on the accuracy of the evaluation results. Summary of the Invention

[0010] In view of the above-mentioned technical problems, this invention provides an economical and high-precision end-quenching experimental device and method of use. This invention can fundamentally solve the adverse effects of various factors in the end-quenching process on the accuracy of evaluation results at a lower cost.

[0011] The technical means employed in this invention are as follows:

[0012] An economical and high-precision end-quenching experimental device includes: an end-quenching sample clamping block, an upper crossbeam, a support, a lower crossbeam, a cooling medium constraint plate, a cooling medium injection pipe, and a base. The support is set on the ground, and the upper crossbeam, lower crossbeam, and base are arranged sequentially from top to bottom inside the support. The end-quenching sample clamping block is detachably connected to the upper crossbeam, and the cooling medium constraint plate is detachably connected to the lower crossbeam. The center of the end-quenching sample clamping block is provided with a central hole matching the end-quenching sample. The positional relationship between the upper and lower crossbeams and the support is adjustable, and the relative height between the end-quenching sample clamping block and the upper crossbeam is adjustable, so that after the end-quenching sample clamping block is set on the upper crossbeam, the lower surface of the end-quenching sample is in just contact with the upper part of the through hole of the cooling medium constraint plate. The cooling medium injection pipe passes through the base and can uniformly cool the quenched end of the sample.

[0013] Furthermore, the end-quenched sample clamping block has a central hole, and positioning holes are provided on both sides of the central hole. Each section of the upper crossbeam is equipped with a matching positioning post at its end.

[0014] Furthermore, the upper section of the positioning hole is cylindrical with a diameter of at least 5 mm, and the lower section is conical with a maximum diameter of at least 1.5 times that of the upper section.

[0015] Furthermore, the end-quenched sample clamping block has a stepped combined clamping platform located away from the central hole.

[0016] Furthermore, the bracket has several holes of different heights, and the upper and lower crossbeams are connected to the bracket by bolts.

[0017] Furthermore, the cooling medium constraint plate has a conical hole at its center, with a hole diameter of at least 25 mm on the upper surface and at least 40 mm on the lower surface.

[0018] Furthermore, it also includes a pressure switch, which is mounted on the upper crossbeam and connected to a water spray motor, which is connected to the cooling medium injection pipe.

[0019] The present invention also discloses a method for determining hardenability using the above-described apparatus, comprising the following steps:

[0020] 1) For the end-quenched specimen, the positional relationship between the upper and lower crossbeams is adjusted based on the specifications of the end-quenched specimen so that after the clamping block is placed on the upper crossbeam, the quenched end of the specimen is in contact with the cooling medium constraint plate.

[0021] 2) Place the combination of the clamping block and the end-quenched sample into an electric furnace filled with a protective atmosphere and heat for no less than 20 minutes. After heating to the specified temperature, hold it at that temperature for a certain period of time.

[0022] 3) After the heat preservation time is reached, use a tool to clamp the assembly clamping platform on the clamping block, take out the assembly of the clamping block and the sample, align the positioning hole on the clamping block with the positioning post on the upper crossbeam, and let the sample fall freely to complete the positioning of the sample. Close the pressure switch, and the cooling medium spray pipe sprays water until the sample is completely cooled.

[0023] 4) Process the end-quenched sample and measure its hardness, plot the hardness-distance curve from the quenched end, and complete the determination of hardenability.

[0024] Compared with the prior art, the present invention has the following advantages in use:

[0025] 1. The structure of the clamping block with a central hole and a stepped combined clamping platform with a central hole on the end-quenched sample clamping block away from the central hole ensures that when the sample is removed after heating, the clamping position is located on the sample clamping block away from the sample, thus avoiding the influence of the clamping tool on the sample temperature.

[0026] 2. The lower side of the positioning hole of the clamping block is conical, which facilitates the entry of the positioning post on the upper crossbeam. The upper side of the positioning hole is cylindrical, which can play the role of positioning the sample. When placing the sample, you only need to slightly align it and then release the sample and clamping block assembly. The assembly will fall freely to complete the positioning of the sample, avoiding the sample placement time being too long.

[0027] 3. Since the sample holder block is heated together with the sample and has considerable thickness and width, during the end quenching process, the sample will not transfer heat to the support due to the low temperature of the support. Instead, it will provide a certain temperature compensation to the non-quenched end of the sample, thereby establishing a more stable cooling rate gradient inside the sample and avoiding the influence of the sample support on the sample temperature.

[0028] 4. The upper surface of the cooling medium constraint plate is in direct contact with the sample. The conical hole in the middle can guide the water flow to the surface of the sample quenching end, while preventing water droplets from splashing onto the cylindrical surface of the sample. Even if the angle or height of the water column changes slightly, uniform cooling of the sample quenching end can be achieved.

[0029] In summary, this invention, through the above design, reliably solves the problem of the influence of various factors on the accuracy of evaluation results during end quenching with a simple structure and low cost. Compared with existing end quenching test devices and methods, it improves the accuracy of end quenching test results. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0032] Figure 2 This is a cross-sectional view of the sample clamping block of the present invention, wherein (a) is the front view; (b) is the top view; and (c) is the side view.

[0033] Figure 3 This is a schematic diagram of the shape of the upper beam and the position of the positioning column of the present invention, wherein (a) is the front view; (b) is the top view; and (c) is the side view.

[0034] Figure 4 This is a schematic diagram of the cooling medium constraint plate structure of the present invention, wherein (a) is the front view; (b) is the top view; and (c) is the side view.

[0035] In the figure: 1. Sample clamping block; 2. Upper crossbeam; 3. Support; 4. Cooling medium constraint plate; 5. Lower crossbeam; 6. Positioning column; 7. Pressure switch; 8. Cooling medium injection pipe; 9. Base; 10. Central hole; 11. Positioning hole; 12. Assembly clamping platform. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0039] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0040] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0041] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0042] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0043] like Figure 1 As shown, this invention discloses an economical and high-precision end-quenching experimental device, comprising: an end-quenching sample clamping block 1, an upper crossbeam 2, a support 3, a lower crossbeam 5, a cooling medium constraint plate 4, a cooling medium injection pipe 8, and a base 9. The support is set on the ground, and the upper crossbeam, lower crossbeam, and base are arranged sequentially from top to bottom inside the support. The end-quenching sample clamping block is detachably connected to the upper crossbeam, and the cooling medium constraint plate is detachably connected to the lower crossbeam. The center of the end-quenching sample clamping block is provided with a central hole matching the end-quenching sample. The positional relationship between the upper crossbeam, lower crossbeam, and support is adjustable, and the relative height between the end-quenching sample clamping block and the upper crossbeam is adjustable, so that after the end-quenching sample clamping block is set on the upper crossbeam, the lower surface of the end-quenching sample is in just contact with the upper part of the through hole of the cooling medium constraint plate. After the cooling medium injection pipe passes through the base, it can uniformly cool the quenching end of the sample (i.e., the lower end in the figure). In this embodiment, the cooling medium is water. In other optional embodiments, the cooling medium may be other media that meet the experimental requirements.

[0044] like Figure 2 As shown, the end-quenched sample clamping block has a central hole 10, and positioning holes 11 are provided on both sides of the central hole, as shown. Figure 3As shown, each segment of the upper crossbeam is equipped with a matching positioning post 6 at its end. Positioning and sample placement are achieved through the positioning holes on both sides of the central circular hole, which cooperate with the positioning posts on the upper crossbeam. The sample clamping block has a thickness of 25mm or more, is square or circular in shape, and its side length or diameter should be 50mm or more. The clamping block is machined with two positioning holes and one clamping platform. The positioning holes are divided into two sections: the upper section is cylindrical with a diameter of 5mm or more, and the lower end is conical with a maximum diameter 1.5 times or more of the diameter of the upper section. A stepped combined clamping platform 12 is provided on the end-quenched sample clamping block away from the central hole. The clamping platform has a depth of 5mm or more and a height of 10mm or more, facilitating the removal of the combination of the clamping block and the end-quenched sample. The sample clamping block mainly serves three functions: first, to prevent direct contact between the clamping tool and the sample; second, to facilitate the positioning and placement of the sample; and third, to prevent heat transfer from the sample to the sample holder, which could affect the accuracy of the results.

[0045] The bracket has several holes of different heights, and the upper and lower crossbeams are connected to the bracket by bolts. Both the upper and lower crossbeams are two-sectioned; that is, two upper crossbeams are installed on corresponding sides of the bracket, and two lower crossbeams are installed on corresponding sides of the bracket. As an optional implementation, both upper and lower crossbeams are of the same specifications. To increase rigidity, both upper and lower crossbeams are made of square steel tubing with a width of 20mm or more. Each section of the upper crossbeam has a positioning post with a diameter of 5mm or more installed at its end. The upper and lower crossbeams are connected to the bracket by bolts, and the position of the upper crossbeam can be adjusted using different holes on the bracket.

[0046] like Figure 4 As shown, the cooling medium constraint plate is made of steel plate with a thickness of 5-10mm. It is fixed to the lower crossbeam on both sides with bolts. A tapered hole is made on the constraint plate directly opposite the end-quenched sample, with a hole diameter of 25mm on the upper surface and 40mm or more on the lower surface. The cooling medium constraint plate has two functions: first, it guides the water flow to concentrate on the lower surface of the quenched end of the sample, ensuring uniform cooling even under water pressure fluctuations or directional deviations; second, it prevents splashing water droplets from falling onto the cylindrical surface of the sample. The distance from the upper surface of the cooling medium constraint plate to the lower surface of the sample clamping block is equal to the length of the sample protruding from the clamping block.

[0047] It also includes a pressure switch 7, which is mounted on the upper crossbeam and connected to the water spray motor, which is connected to the cooling medium injection pipe.

[0048] Example 1

[0049] The following examples, using the determination of hardenability of a medium-carbon alloy tool steel as an example, are provided in conjunction with the content of this invention:

[0050] 1) The sample clamping block is 25mm thick, circular in shape, and 50mm in diameter. A clamping platform is machined on the clamping block, with a depth of 10mm and a height of 15mm. Two positioning holes are machined on the clamping block, each divided into two sections: the upper section is cylindrical with a diameter of 5mm, and the lower section is conical with a maximum diameter of 10mm. The purpose of these parameters is to allow the sample clamping block to provide heat to the sample while reducing its weight, thus facilitating the removal and placement of the sample clamping block and the sample assembly.

[0051] 2) Both the upper and lower crossbeams are made of square steel tubing, with a tubing width of 30mm. The diameter of the positioning post at the end of the upper crossbeam is 5mm.

[0052] 3) The cooling medium constraint plate is made of 10mm thick steel plate. A conical hole is opened on the constraint plate opposite the end-quenched sample. The hole diameter on the upper surface is 25mm and the hole diameter on the lower surface is 50mm.

[0053] The specific method for conducting hardenability determination using the test apparatus described in this invention is as follows:

[0054] 1) Process standard end-quenched specimens according to GB / T 225-2006. In this embodiment, the end-quenched specimen length is 125mm, and the position of the upper crossbeam is adjusted according to the specimen length. In other optional embodiments, it is recommended to appropriately extend the specimen for medium and high hardenability steel.

[0055] 2) Place the assembly of the clamping block and the end-quenched sample together in an electric furnace filled with a protective atmosphere and heat it to 880°C for 20 minutes. After heating to the specified temperature, hold it at that temperature for 30 minutes.

[0056] 3) After the holding time is reached, use a tool to clamp the clamping platform on the clamping block to remove the combination of the clamping block and the sample. Align the clamping hole on the clamping block with the positioning post on the upper crossbeam and let the sample fall freely to complete the placement and positioning of the sample. At this time, the quenched end of the sample is in contact with the cooling medium constraint plate. Due to the pressure change, the pressure switch is closed and the cooling medium spray pipe sprays water until the sample is completely cooled.

[0057] 4) The end-quenched samples were processed according to GB / T 225-2006 and hardness measurements were performed at the specified positions. The hardness-distance curve from the quenched end was plotted. The results showed that the quenching depth was about 30 mm, but the tail of the curve tended to a fixed value. This hardness value is the normalizing hardness of this material. The curve plotted using a common end-quenching device showed an upward curve at the tail, indicating that the end-quenching sample holder of the common device increased the cooling rate on the non-quenched end side of the sample.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An economical high-precision end-quenching experimental device, characterized in that, include: The sample holder comprises an end-quenched specimen clamping block, an upper crossbeam, a support, a lower crossbeam, a cooling medium constraint plate, a cooling medium injection pipe, and a base. The support is set on the ground, and the upper crossbeam, lower crossbeam, and base are arranged sequentially from top to bottom within the support. The end-quenched specimen clamping block is detachably connected to the upper crossbeam, and the cooling medium constraint plate is detachably connected to the lower crossbeam. The center of the end-quenched specimen clamping block has a central hole for matching the end-quenched specimen. The positional relationship between the upper and lower crossbeams and the support is adjustable, and the relative height between the end-quenched specimen clamping block and the upper crossbeam is adjustable, so that after the end-quenched specimen clamping block is set on the upper crossbeam, the lower surface of the end-quenched specimen is in just contact with the upper part of the through hole of the cooling medium constraint plate. The cooling medium injection pipe passes through the base and can uniformly cool the quenched end of the specimen. Positioning holes are provided on both sides of the central hole, and a matching positioning post is installed at the end of each section of the upper crossbeam. The upper section of the positioning hole is cylindrical with a diameter of at least 5 mm, and the lower section is conical with a maximum diameter of at least 1.5 times that of the upper section. The end-quenched sample clamping block has a stepped combined clamping platform located away from the central hole. The cooling medium constraint plate has a conical hole at its center, with a hole diameter of at least 25 mm on the upper surface and at least 40 mm on the lower surface.

2. The economical high-precision end-quenching experimental device according to claim 1, characterized in that, The bracket has several holes of different heights, and the upper and lower crossbeams are connected to the bracket by bolts.

3. The economical high-precision end-quenching experimental device according to claim 1, characterized in that, It also includes a pressure switch, which is mounted on the upper crossbeam and connected to a water spray motor, which is connected to the cooling medium injection pipe.

4. A method of using the economical high-precision end-quenching experimental apparatus according to any one of claims 1 to 3, characterized in that, Includes the following steps: 1) Processing end-quenched specimens; Adjust the positional relationship between the upper and lower crossbeams based on the specifications of the end-quenched specimens so that after the clamping block is placed on the upper crossbeam, the quenched end of the specimen is in contact with the cooling medium constraint plate. 2) Place the end-quenched sample clamping block and the end-quenched sample together into an electric furnace filled with a protective atmosphere and heat for no less than 20 minutes. After heating to the specified temperature, hold for a certain period of time. 3) After the heat preservation time is reached, use a tool to clamp the assembly clamping platform on the clamping block, take out the assembly of the clamping block and the sample, align the positioning hole on the clamping block with the positioning post on the upper crossbeam, and let the sample fall freely to complete the positioning of the sample. The cooling medium spray pipe sprays out the cooling medium until the sample is completely cooled. 4) Process the end-quenched sample and measure its hardness, plot the hardness-distance curve from the quenched end, and complete the determination of hardenability.

5. The method according to claim 4, characterized in that, In step 3), the positioning hole on the clamping block is aligned with the positioning post on the upper crossbeam to allow the sample to fall freely and complete the positioning of the sample. After this, the pressure switch is closed, and the cooling medium is automatically sprayed.

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