阅读说明：本技术 一种棒状材料连续温度梯度热处理装置和方法 (Continuous temperature gradient heat treatment device and method for rod-shaped material ) 是由 黄太文 刘林 郭敏 苏海军 张军 杨文超 刘哲良 郭一诺 昌花婷 申辉 李邵颖 于 2020-06-28 设计创作，主要内容包括：本发明涉及热处理技术领域,尤其涉及一种棒状材料连续温度梯度热处理装置和方法。本发明的装置炉体内包括上加热区和下加热区,分别利用上加热电源和下加热电源进行独立控温,且上加热区和下加热区均为封闭加热区,封闭隔热板可防止热量散失,确保上加热区和下加热区温度的精确控制,从而实现棒状材料标样段温度梯度的精确控制。本发明的装置包括抽真空设备,使棒状材料在真空下进行传热,避免热对流；在上加热区和下加热区之间设置环状辐射屏,能抑制标样段侧向散热,使传热沿纵向传递；且棒状材料与环状辐射屏不接触,避免了热传导；三方面共同作用使棒状材料沿轴向一维传热,确保了棒状材料表面和中心温度一致。(The invention relates to the technical field of heat treatment, in particular to a device and a method for continuous temperature gradient heat treatment of a rod-shaped material. The device comprises an upper heating area and a lower heating area in a furnace body, wherein the upper heating area and the lower heating area are respectively used for independently controlling the temperature, and the upper heating area and the lower heating area are both closed heating areas. The device comprises a vacuumizing device, so that the rod-shaped material is subjected to heat transfer in vacuum, and heat convection is avoided; an annular radiation screen is arranged between the upper heating zone and the lower heating zone, so that the lateral heat dissipation of the standard sample section can be inhibited, and the heat transfer is transmitted along the longitudinal direction; the rod-shaped material is not contacted with the annular radiation screen, so that heat conduction is avoided; the three aspects act together to lead the rod-shaped material to transfer heat along the axial direction in one dimension, thus ensuring the temperature of the surface and the center of the rod-shaped material to be consistent.)

1. A continuous temperature gradient heat treatment device for a rod-shaped material is characterized by comprising a furnace body, a vacuumizing device, an upper heating power supply and a lower heating power supply; the vacuumizing equipment, the upper heating power supply and the lower heating power supply are positioned outside the furnace body; an infrared thermal imaging temperature measuring window (5) and an air outlet (6) are arranged on the side wall of the furnace body; the vacuum pumping equipment is communicated with the air outlet (6);

a water-cooling joint (1), an upper heating zone (2), a lower heating zone (3) and an annular radiation screen (4) are arranged in the furnace body; the water-cooling joint (1) is fixed at the top of the furnace body;

the annular radiation screen (4) is positioned between the upper heating area (2) and the lower heating area (3), the distance from the upper end of the annular radiation screen to the bottom end of the upper heating area is 0-2 mm, and the distance from the lower end of the annular radiation screen to the top end of the lower heating area is 0-2 mm; the annular radiation screen (4) is provided with a thin seam with the width of 1-2 mm along the axial direction; the length of the thin seam is the same as the height of the annular radiation screen (4); the infrared thermal imaging temperature measurement window (5) is matched with the position of the slit;

the upper heating zone (2) is provided with an upper heating rod (71) and an upper sealing heat-insulating plate (81), and the lower heating zone (3) is provided with a lower heating rod (72) and a lower sealing heat-insulating plate (82); the upper heating power supply is connected with an upper heating rod (71) of the upper heating area (2), and the lower heating power supply is connected with a lower heating rod (72) of the lower heating area (3); the upper closed heat insulation plate (81) and the lower closed heat insulation plate (82) respectively surround the upper heating rod (71) and the lower heating rod (72) to form a closed heating zone; the upper wall and the lower wall of the upper closed heat insulation plate (81) and the upper wall of the lower closed heat insulation plate (82) are respectively provided with a channel through which a rod-shaped material passes;

the axis of the annular radiation screen (4) is superposed with the axis of the rod-shaped material and the vertical center lines of the upper heating zone (2) and the lower heating zone (3); the annular radiation screen (4) is not in contact with the rod-shaped material.

2. The apparatus for continuous thermal gradient processing of a rod-shaped material according to claim 1, wherein the annular radiation shield (4) is made of tantalum or molybdenum, the thickness of the annular radiation shield (4) is 0.3-0.6 mm, and the distance between the annular radiation shield (4) and the surface of the rod-shaped material is 10-20 mm.

3. The continuous temperature gradient heat treatment device for the rod-shaped materials according to claim 1, wherein the upper closed heat insulation board (81) and the lower closed heat insulation board (82) are made of graphite felt, and the thicknesses of the upper closed heat insulation board (81) and the lower closed heat insulation board (82) are 5-10 mm independently.

4. The apparatus for continuous thermal gradient heat treatment of rod-shaped materials according to claim 1 or 3, wherein the gaps between the passages for rod-shaped materials to pass through and the rod-shaped materials on the upper and lower closed heat-insulating plates (81, 82) are independently less than 3 mm.

5. The continuous thermal gradient heat treatment apparatus for rod-shaped materials according to any one of claims 1 to 3, wherein a moving guide (9) is further provided on the inner wall of the furnace body; at least one of the upper heating area (2) and the lower heating area (3) can move up and down along the moving guide rail (9).

6. The apparatus for continuous thermal gradient treatment of a rod-shaped material according to any one of claims 1 to 3, further comprising a water circulating means, wherein the water circulating means is connected to the water cooling joint.

7. A method for continuous thermal treatment of a rod-shaped material by using the apparatus for continuous thermal treatment of a rod-shaped material according to any one of claims 1 to 5, comprising the steps of:

the rod-shaped material sequentially passes through the upper wall of the lower heating area (3), the annular radiation screen (4) and the lower wall and the upper wall of the upper heating area (2) from bottom to top, and the upper end of the rod-shaped material is fixed on the water-cooling joint (1); taking the corresponding part of the rod-shaped material between the upper heating area (2) and the lower heating area (3) as a standard sample section;

vacuumizing the furnace body by using vacuumizing equipment, then starting an upper heating power supply and a lower heating power supply, heating the part of the rod-shaped material, which is positioned in an upper heating area (2), by using an upper heating rod (71), heating the part of the rod-shaped material, which is positioned in a lower heating area (3), by using a lower heating rod (72), and conducting heat transfer along the axial direction of the rod-shaped material, so that a continuous temperature gradient is formed in a standard sample section of the rod-shaped material; the heating temperatures set by the upper heating zone (2) and the lower heating zone (3) correspond to the end point temperature of the temperature gradient of the standard sample section of the rod-shaped material;

and measuring the continuous temperature gradient distribution condition of the standard sample section through an infrared thermal imaging temperature measurement window (5), and preserving heat after the continuous temperature gradient distribution is stable.

8. The method according to claim 7, wherein the apparatus further comprises a circulating water unit, and the circulating water unit is turned on before heating.

9. The method according to claim 7 or 8, wherein the evacuation is performed to a vacuum of 3.3 × 10^-2Pa or less.

10. The method according to claim 7 or 8, wherein the method further comprises a step of installing a thermocouple on an outer wall of the standard sample section of the rod-shaped material before the rod-shaped material is heated, and the continuous temperature gradient measured by the infrared thermography is corrected by the thermocouple after the stable continuous temperature gradient is obtained.

Technical Field

The invention relates to the technical field of heat treatment, in particular to a device and a method for continuous temperature gradient heat treatment of a rod-shaped material.

Background

The heat treatment is a process of heating, insulating and cooling a material in a certain medium, and the performance of the material is controlled by changing the tissue structure on the surface or in the material, which is a very important link in material research and application. At present, the conventional method for studying the correlation between the heat treatment temperature and the material structure property is to prepare a large number of alloy samples with the same components, and change the heat treatment temperature under the condition of ensuring the same other heat treatment conditions, and although the method is simple and easy to operate, the method has the following defects: 1. the preparation quantity of samples is large, and the experimental period is long. Generally, a plurality of temperature point data are needed to be obtained in a heat treatment experiment, so that a certain number of samples need to be prepared to meet the requirement; and each sample must go through the complete heat treatment process, so the workload is large and the experimental period is long. 2. Setting the temperature discretely may not observe abnormal behavior during the experiment, for example, many metallic materials are extremely sensitive to temperature, and slight temperature changes may cause large changes in phase or structure.

The gradient heat treatment can realize continuous temperature gradient in the same sample, and the work which can be finished by a plurality of heat treatment experiments in the past can be finished by the temperature gradient once, so that the experiment efficiency can be improved, the labor and material resource consumption of the experiment can be reduced, and the method has important significance for improving the research and development speed of new materials, new products and new processes. Ningyonggu et al, northwest university of industry, proposed a gradient heat treatment apparatus for rod-shaped materials and a method for treating rod-shaped materials using the same (grant publication No. CN 102912086B). In the method, the upper end of a rod-shaped material is inductively heated by an upper furnace body of the device, and the lower end of the rod-shaped material is subjected to water cooling and heat conduction by a lower furnace body, so that the axial temperature gradient of the material from top to bottom is obtained. In this invention, the temperature of each region of the sample cannot be precisely controlled, resulting in uncontrollable temperature gradients. Zhoufeng et al propose a mold temperature gradient control device (grant No. CN203356572U), which ensures the designed temperature gradient by controlling the opening and closing of the cooling air duct through the cooperation of a thermocouple and a temperature sensor. However, the patent is limited to the mold temperature control in the casting process and has certain limitation in the field of material heat treatment. Although the technology generates a continuous temperature gradient, the temperature of the surface of the material is different from that of the interior of the material due to factors such as lateral heat dissipation, and the accuracy of experimental data is affected. The university of the south-China proposes a material continuous temperature gradient heat treatment method (granted patent number ZL104451090), gradient change of a resistor is realized by adopting a trapezoidal graphite cylinder heating body, and direct current is applied to two ends of a thermal simulator to obtain gradient heating and temperature control of a sample in a cylinder. However, because the temperature can be controlled only by a single point, the temperature of the sample deviating from the temperature control point can fluctuate all the time, and the experimental result is influenced.

Disclosure of Invention

The invention aims to provide a device and a method for continuous temperature gradient heat treatment of a rod-shaped material.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a continuous temperature gradient heat treatment device for a rod-shaped material, which comprises a furnace body, a vacuumizing device, an upper heating power supply and a lower heating power supply, wherein the furnace body is provided with a plurality of heating holes; the vacuumizing equipment, the upper heating power supply and the lower heating power supply are positioned outside the furnace body; an infrared thermal imaging temperature measuring window 5 and an air outlet 6 are arranged on the side wall of the furnace body; the vacuum pumping equipment is communicated with the air outlet 6;

a water-cooling joint 1, an upper heating zone 2, a lower heating zone 3 and an annular radiation screen 4 are arranged in the furnace body; the water-cooling joint 1 is fixed at the top of the furnace body;

the annular radiation screen 4 is positioned between the upper heating area 2 and the lower heating area 3, the distance from the upper end of the annular radiation screen to the bottom end of the upper heating area is 0-2 mm, and the distance from the lower end of the annular radiation screen to the top end of the lower heating area is 0-2 mm; the annular radiation screen 4 is provided with a thin slit with the width of 1-2 mm along the axial direction; the length of the thin slit is the same as the height of the annular radiation screen 4; the infrared thermal imaging temperature measurement window 5 is matched with the position of the slit;

the upper heating zone 2 is provided with an upper heating rod 71 and an upper closed heat insulation plate 81, and the lower heating zone 3 is provided with a lower heating rod 72 and a lower closed heat insulation plate 82; the upper heating power supply is connected with an upper heating rod 71 of the upper heating zone 2, and the lower heating power supply is connected with a lower heating rod 72 of the lower heating zone 3; the upper closed heat insulation plate 81 and the lower closed heat insulation plate 82 respectively surround the upper heating rod 71 and the lower heating rod 72 to form a closed heating zone; the upper wall and the lower wall of the upper closed heat insulation board 81 and the upper wall of the lower closed heat insulation board 82 are respectively provided with a channel through which a rod-shaped material passes;

the axis of the annular radiation screen 4 is superposed with the axis of the rod-shaped material and the vertical center lines of the upper heating zone 2 and the lower heating zone 3; the annular radiation screen 4 is not in contact with the rod-shaped material.

Preferably, the annular radiation screen 4 is made of tantalum or molybdenum, the thickness of the annular radiation screen 4 is 0.3-0.6 mm, and the distance between the annular radiation screen 4 and the surface of the rod-shaped material is 10-20 mm.

Preferably, the upper sealing heat insulation board 81 and the lower sealing heat insulation board 82 are made of graphite felts, and the thicknesses of the upper sealing heat insulation board 81 and the lower sealing heat insulation board 82 are independently 5-10 mm.

Preferably, the gaps between the passages for the rod-shaped materials to pass through and the rod-shaped materials on the upper and lower closed heat insulation boards 81 and 82 are independently less than 3 mm.

Preferably, a moving guide rail 9 is further arranged on the inner wall of the furnace body; at least one of the upper heating zone 2 and the lower heating zone 3 can move up and down along the moving guide 9.

Preferably, the water-cooling device also comprises a water circulating device, and the water circulating device is communicated with the water-cooling joint.

The invention provides a continuous temperature gradient heat treatment method for a rod-shaped material, which utilizes the continuous temperature gradient heat treatment device for the rod-shaped material to carry out heat treatment and comprises the following steps:

the rod-shaped material sequentially passes through the upper wall of the lower heating area 3, the annular radiation screen 4 and the lower wall and the upper wall of the upper heating area 2 from bottom to top, and the upper end of the rod-shaped material is fixed on the water-cooling joint 1; taking the corresponding part of the rod-shaped material between the upper heating area 2 and the lower heating area 3 as a standard sample section;

vacuumizing the furnace body by using vacuumizing equipment, then starting an upper heating power supply and a lower heating power supply, heating the part of the rod-shaped material, which is positioned in the upper heating area 2, by using an upper heating rod 71, heating the part of the rod-shaped material, which is positioned in the lower heating area 3, by using a lower heating rod 72, and conducting heat transfer along the axial direction of the rod-shaped material, so that a continuous temperature gradient is formed in the standard sample section of the rod-shaped material; the heating temperatures set by the upper heating zone 2 and the lower heating zone 3 correspond to the end point temperature of the temperature gradient of the standard sample section of the rod-shaped material;

and measuring the continuous temperature gradient distribution condition of the standard sample section through an infrared thermal imaging temperature measurement window 5, and preserving heat after the continuous temperature gradient distribution is stable.

Preferably, when the continuous temperature gradient heat treatment device for rod-shaped materials further comprises a circulating water device, the method further comprises opening the circulating water before heating.

It is preferable thatSaid evacuation is to 3.3 × 10^-2Pa or less.

Preferably, before the rod-shaped material is heated, a thermocouple is arranged on the outer wall of the standard sample section of the rod-shaped material, and after a stable continuous temperature gradient is obtained, the continuous temperature gradient measured by infrared thermal imaging is corrected by the thermocouple.

The invention provides a continuous temperature gradient heat treatment device for a rod-shaped material, which comprises a furnace body, a vacuumizing device, an upper heating power supply and a lower heating power supply, wherein the furnace body is provided with a plurality of heating holes; the vacuumizing equipment, the upper heating power supply and the lower heating power supply are positioned outside the furnace body; an infrared thermal imaging temperature measuring window 5 and an air outlet 6 are arranged on the side wall of the furnace body; the vacuum pumping equipment is communicated with the air outlet 6; a water-cooling joint 1, an upper heating zone 2, a lower heating zone 3 and an annular radiation screen 4 are arranged in the furnace body; the water-cooling joint 1 is fixed at the top of the furnace body; the annular radiation screen 4 is positioned between the upper heating area 2 and the lower heating area 3, the distance from the upper end of the annular radiation screen to the bottom end of the upper heating area is 0-2 mm, and the distance from the lower end of the annular radiation screen to the top end of the lower heating area is 0-2 mm; the annular radiation screen 4 is provided with a thin slit with the width of 1-2 mm along the axial direction; the length of the thin slit is the same as the height of the annular radiation screen 4; the infrared thermal imaging temperature measurement window 5 is matched with the position of the slit; the upper heating zone 2 is provided with an upper heating rod 71 and an upper closed heat insulation plate 81, and the lower heating zone 3 is provided with a lower heating rod 72 and a lower closed heat insulation plate 82; the upper heating power supply is connected with an upper heating rod 71 of the upper heating zone 2, and the lower heating power supply is connected with a lower heating rod 72 of the lower heating zone 3; the upper closed heat insulation plate 81 and the lower closed heat insulation plate 82 respectively surround the upper heating rod 71 and the lower heating rod 72 to form a closed heating zone; the upper wall and the lower wall of the upper closed heat insulation board 81 and the upper wall of the lower closed heat insulation board 82 are respectively provided with a channel through which a rod-shaped material passes; the axis of the annular radiation screen 4 is superposed with the axis of the rod-shaped material and the vertical center lines of the upper heating zone 2 and the lower heating zone 3; the annular radiation screen 4 is not in contact with the rod-shaped material.

The device comprises an upper heating area 2 and a lower heating area 3 which are respectively used for independent temperature control, wherein the upper heating area 2 and the lower heating area 3 are both closed heating areas, a closed heat insulation plate can prevent heat dissipation, the temperature of the upper heating area and the temperature of the lower heating area are accurately controlled, the temperature difference between the upper heating area and the lower heating area is the temperature gradient of the middle standard sample section of the rod-shaped material, and the temperature gradient is accurately controlled by accurately controlling the temperature of the upper heating area and the lower heating area.

The device comprises a vacuumizing device, and the heat transfer of the rod-shaped material can be realized under vacuum, so that the heat convection is avoided; an annular radiation screen 4 is arranged between the upper heating zone and the lower heating zone, so that the lateral heat dissipation of the standard sample section of the rod-shaped material between the upper heating zone 2 and the lower heating zone 3 can be inhibited, and the heat transfer is transmitted along the longitudinal direction (the axial direction of the rod-shaped material); the rod-shaped material is not contacted with the annular radiation screen 4, so that heat conduction is avoided; the three aspects act together to enable the standard sample section of the rod-shaped material between the upper heating area and the lower heating area to transfer heat along the axial direction in one dimension, so that the surface temperature and the central temperature of the standard sample section of the rod-shaped material are ensured to be consistent.

Further, the apparatus of the present invention further comprises a moving guide 9; at least one of the upper heating area 2 and the lower heating area 3 can move up and down along the moving guide rail 9, so that the sample preparation device can adapt to samples with different specifications.

Furthermore, the device also comprises a circulating water device, and the circulating water device can reduce the temperature of the water-cooling joint 1 to protect the water-cooling joint 1, and can adjust the temperature gradient range and regulate and control the heat balance.

The invention provides a continuous temperature gradient heat treatment method for a rod-shaped material, which can obtain data which can be obtained by a plurality of samples in the traditional method in one sample, greatly improves the experimental efficiency, and reduces the manpower, material resource investment and energy consumption.

Furthermore, before the rod-shaped material is heated, a thermocouple is arranged on the outer wall of the standard sample section of the rod-shaped material, and after a stable continuous temperature gradient is obtained, the continuous temperature gradient measured by infrared thermal imaging is corrected through the thermocouple, so that the precision of temperature control can be further improved.

Drawings

FIG. 1 is a schematic structural diagram of a continuous temperature gradient heat treatment apparatus for a rod-shaped material according to the present invention;

the device comprises a water-cooling joint, 2-an upper heating zone, 3-a lower heating zone, 4-an annular radiation screen, 5-an infrared thermal imaging temperature measuring window, 6-an air outlet, 71-an upper heating rod, 72-a lower heating rod, 81-an upper closed heat insulation plate, 82-a lower closed heat insulation plate, 9-a moving guide rail, 10-a thermocouple, 11-an electrode and 12-a water-cooling rod, wherein the water-cooling joint is arranged on the upper heating zone;

FIG. 2 is a graph of a continuous temperature gradient profile of a section of a standard sample obtained by thermocouple coupled infrared thermography;

FIG. 3 is a graph showing the temperature change with time during the heating process at different points of the upper heating zone, the lower heating zone and the standard sample section;

fig. 4 is a temperature profile calculated by numerical simulation of heat transfer to a standard section using ProCast software.

Detailed Description

As shown in FIG. 1, the invention provides a continuous temperature gradient heat treatment device for a rod-shaped material, which comprises a furnace body, a vacuum pumping device, an upper heating power supply and a lower heating power supply; the vacuumizing equipment, the upper heating power supply and the lower heating power supply are positioned outside the furnace body; an infrared thermal imaging temperature measuring window 5 and an air outlet 6 are arranged on the side wall of the furnace body; the vacuum pumping equipment is communicated with the air outlet 6;

a water-cooling joint 1, an upper heating zone 2, a lower heating zone 3 and an annular radiation screen 4 are arranged in the furnace body; the water-cooling joint 1 is fixed at the top of the furnace body;

the annular radiation screen 4 is positioned between the upper heating area 2 and the lower heating area 3, the distance from the upper end of the annular radiation screen to the bottom end of the upper heating area is 0-2 mm, and the distance from the lower end of the annular radiation screen to the top end of the lower heating area is 0-2 mm; the annular radiation screen 4 is provided with a thin slit with the width of 1-2 mm along the axial direction; the length of the thin slit is the same as the height of the annular radiation screen 4; the infrared thermal imaging temperature measurement window 5 is matched with the position of the slit;

the upper heating zone 2 is provided with an upper heating rod 71 and an upper closed heat insulation plate 81, and the lower heating zone 3 is provided with a lower heating rod 72 and a lower closed heat insulation plate 82; the upper heating power supply is connected with an upper heating rod 71 of the upper heating zone 2, and the lower heating power supply is connected with a lower heating rod 72 of the lower heating zone 3; the upper closed heat insulation plate 81 and the lower closed heat insulation plate 82 respectively surround the upper heating rod 71 and the lower heating rod 72 to form a closed heating zone; the upper wall and the lower wall of the upper closed heat insulation board 81 and the upper wall of the lower closed heat insulation board 82 are respectively provided with a channel through which a rod-shaped material passes;

the axis of the annular radiation screen 4 is superposed with the axis of the rod-shaped material and the vertical center lines of the upper heating zone 2 and the lower heating zone 3; the annular radiation screen 4 is not in contact with the rod-shaped material.

The continuous temperature gradient heat treatment device for the rod-shaped materials comprises vacuumizing equipment, wherein the vacuumizing equipment is used for vacuumizing a furnace body to a vacuum state. The present invention does not require special vacuum equipment, which is well known in the art.

The continuous temperature gradient heat treatment device for the rod-shaped materials comprises an upper heating power supply and a lower heating power supply. The upper heating power supply and the lower heating power supply respectively provide heat sources for the upper heating rod 71 in the upper heating zone 2 and the lower heating rod 72 in the lower heating zone 3, and then the rod-shaped materials are heated by utilizing the heat radiated by the heating rods, so that the independent temperature control of the upper heating zone 2 and the lower heating zone 3 is realized. The invention has no special requirements on the structure of the upper heating power supply and the lower heating power supply, and the heating power supply which is well known in the field can be adopted. In the embodiment of the present invention, the upper heating power supply and the lower heating power supply respectively include a thermocouple 10, an electrode 11, and a control unit; the temperature is measured by a thermocouple and fed back to a control unit of a power supply, so that the temperature is controlled.

The continuous temperature gradient heat treatment device for the rod-shaped materials comprises a furnace body, wherein an infrared thermal imaging temperature measurement window 5 and an air outlet 6 are arranged on the side wall of the furnace body; the vacuum pumping equipment is communicated with the air outlet 6; the infrared thermal imaging temperature measurement window 5 is matched with the position of the slit on the annular radiation screen 4. In the invention, the infrared thermal imaging temperature measurement window 5 is matched with the slit on the annular radiation screen 4, so that the measurement of the continuous temperature gradient of the standard sample section between the upper heating zone and the lower heating zone is realized.

The continuous temperature gradient heat treatment device for the rod-shaped materials is characterized in that a water cooling joint 1, an upper heating zone 2, a lower heating zone 3 and an annular radiation screen 4 are arranged in a furnace body.

In the invention, the water-cooling joint 1 is fixed at the top of the furnace body. The invention has no special requirements on the fixing mode of the water-cooling joint 1, and the water-cooling joint 1 can be fixed at the top of the furnace body. The water-cooled joint 1 is used for fixing rod-shaped materials. In the embodiment of the invention, the water-cooled joint 1 is in a nut shape, and the rod-shaped material is connected with the water-cooled joint 1 through a screw thread. In the invention, the water-cooling joint 1 can fix a rod-shaped material with the diameter of 7-16 mm.

As an embodiment of the invention, the continuous temperature gradient heat treatment device for the rod-shaped materials also comprises a water circulating device; the water circulating device is communicated with the water-cooling joint 1. In the embodiment of the invention, the water circulating device is communicated with the water-cooling joint through a water-cooling rod 12 penetrating through the top of the furnace body. The water-cooling rod 12 is preferably fixedly communicated with the water-cooling joint 1 through threads. In the invention, the water-cooling rod 12 is of a hollow structure, and the invention has no special requirements on the material and the size of the water-cooling rod 12 and can be matched with the water-cooling joint 1 and a circulating water device. The circulating water device is not particularly limited in the present invention, and any device capable of supplying circulating water is well known in the art. The invention utilizes the circulating water device to reduce the temperature of the water-cooling joint and protect the water-cooling joint, and is favorable for adjusting the temperature gradient range and regulating and controlling the heat balance.

The furnace body of the invention comprises an upper heating zone 2 and a lower heating zone 3. In the present invention, the upper heating zone 2 is provided with an upper heating rod 71 and an upper closing insulation board 81; the lower heating zone 3 is provided with a lower heating rod 72 and a lower closing insulation plate 82. In the present invention, the material of the heating rod is preferably a silicon carbide rod. The maximum heating temperature of the silicon carbide rod used as the heating rod can reach 1450 ℃, and the accumulated working time can reach more than 1000 hours. The invention has no special requirement on the number of the heating rods in the heating area and can realize uniform heating. In an embodiment of the invention, the heating rods are symmetrically distributed in the heating zone, and the heating rods do not contact with the rod-shaped materials when heating, and are heated by radiation. In the invention, the upper heating power supply is connected with the heating rod of the upper heating zone; the lower heating power supply is connected with the heating rod of the lower heating area.

In the present invention, the upper and lower enclosed heat insulation boards 81 and 82 respectively surround the upper and lower heating rods 71 and 72 to form enclosed heating zones (i.e. both the upper and lower heating zones are enclosed heating zones); a channel through which the bar-shaped material passes is respectively provided on the upper and lower walls of the upper closed heat-insulating board 81 and the upper wall of the lower closed heat-insulating board 82. As an embodiment of the present invention, the lower wall of the lower closed heat insulation plate 82 may or may not be provided with a channel through which the rod material passes. In the present invention, the gap between the channel and the rod-shaped material is preferably 3mm or less independently, and more preferably, the channel and the rod-shaped material are in a gap-free matching contact to prevent heat loss and influence on temperature accuracy. In the invention, the upper closed heat insulation board 81 and the lower closed heat insulation board 82 are in a cylindrical structure, and the formed closed heating area is a cylindrical heating area, which is beneficial to realizing the symmetrical heating of the sample. In the invention, the upper closed heat insulation board 81 and the lower closed heat insulation board 82 are preferably made of graphite felt, and the thicknesses of the upper closed heat insulation board 81 and the lower closed heat insulation board 82 are preferably 5-10 mm independently. The invention has no special requirements on the sizes of the upper closed heat insulation board 81 and the lower closed heat insulation board 82, and can play a role in preventing heat loss. In the present invention, the upper closed heat insulation plate has a size ofThe lower closed heat insulation plate has the following specific size(i.e., heating zone size). The invention adopts the closed heat insulation board to prevent heat loss and ensure the accurate control of the temperature of the upper heating area and the lower heating area, and the invention is matched withThe independent temperature control of the upper heating power supply and the lower heating power supply enables the temperature gradient of the middle standard sample section of the rod-shaped material to be accurately controlled according to the temperature setting of the upper heating area and the lower heating area.

The device of the invention comprises an annular radiation screen 4. In the invention, the annular radiation screen is a hollow tubular structure. In the invention, the annular radiation screen 4 is positioned between the upper heating area 2 and the lower heating area 3, and the distance between the upper end of the annular radiation screen 4 and the bottom end of the upper heating area 2 is 0-2 mm, preferably 0 mm; the distance between the lower end of the annular radiation screen 4 and the top end of the lower heating area 3 is 0-2 mm, and preferably 0 mm; the annular radiation screen 4 is provided with a slit with the width of 1-2 mm along the axial direction, and the length of the slit is the same as the height of the annular radiation screen 4 and is used for infrared thermal imaging temperature measurement.

In the invention, the material of the annular radiation screen 4 is preferably tantalum or molybdenum, and the thickness of the annular radiation screen 4 is preferably 0.3-0.6 mm. The annular radiation screen made of the material and the thickness is beneficial to reducing heat radiation, so that one-dimensional heat transfer of the standard sample section is promoted, and the surface temperature and the central temperature of the standard sample section are ensured to be consistent.

In the invention, the rod-shaped material sequentially passes through the upper wall of the lower heating zone 3, the annular radiation screen 4 and the upper wall and the lower wall of the upper heating zone 2 from bottom to top, and the upper end of the rod-shaped material is fixed on the water-cooling joint 1; the axis of the annular radiation screen 4 coincides with the axis of the rod-shaped material and the vertical center lines of the upper heating zone 2 and the lower heating zone 3. In the present invention, the annular radiation screen 4 is not in contact with a rod-shaped material; the distance between the annular radiation screen and the surface of the rod-shaped material is preferably 10-20 mm. The rodlike material does not contact with the annular radiation screen 4, so that heat conduction is avoided, one-dimensional heat transfer along the axial direction of the standard sample section of the rodlike material in the upper heating area and the lower heating area is facilitated, and the consistency of the surface temperature and the central temperature of the standard sample section is further ensured.

As an embodiment of the invention, a moving guide rail 9 is further arranged on the inner wall of the furnace body; at least one of the upper heating area 2 and the lower heating area 3 can move up and down along the moving guide rail 9; preferably, the upper heating zone 2 is fixed, and the lower heating zone 3 can move up and down along the moving guide rail 9, so that the heating of samples with different specifications is adapted. The invention has no special limitation on the movable guide rail and the connection relationship between the movable guide rail and the heating area, and can realize the up-and-down movement of the upper heating area and/or the lower heating area. Specifically, the movable guide rail is provided with a slide block capable of moving axially, and the slide block is connected with the lower heating area.

The invention provides a continuous temperature gradient heat treatment method for a rod-shaped material, which utilizes the continuous temperature gradient heat treatment device for the rod-shaped material to carry out heat treatment and comprises the following steps:

the rod-shaped material sequentially passes through the upper wall of the lower heating area 3, the annular radiation screen 4 and the lower wall and the upper wall of the upper heating area 2 from bottom to top, and the upper end of the rod-shaped material is fixed on the water-cooling joint 1; taking the corresponding part of the rod-shaped material between the upper heating area 2 and the lower heating area 3 as a standard sample section;

vacuumizing the furnace body by using vacuumizing equipment, then starting an upper heating power supply and a lower heating power supply, heating the part of the rod-shaped material, which is positioned in the upper heating area 2, by using an upper heating rod 71, heating the part of the rod-shaped material, which is positioned in the lower heating area 3, by using a lower heating rod 72, and conducting heat transfer along the axial direction of the rod-shaped material, so that a continuous temperature gradient is formed in the standard sample section of the rod-shaped material; the heating temperatures set by the upper heating zone 2 and the lower heating zone 3 correspond to the end point temperature of the temperature gradient of the standard sample section of the rod-shaped material;

and measuring the continuous temperature gradient distribution condition of the standard sample section through an infrared thermal imaging temperature measurement window 5, and preserving heat after the continuous temperature gradient distribution is stable.

According to the invention, a rod-shaped material sequentially passes through the upper wall of the lower heating zone 3, the annular radiation screen 4 and the lower wall and the upper wall of the upper heating zone 2 from bottom to top, and the upper end of the rod-shaped material is fixed on the water-cooling joint 1.

The invention has no special requirements on the rod-shaped material and can be selected according to actual requirements. In the present invention, the rod-like material is preferably a cylinder having a uniform diameter; the diameter of the rod-shaped material is preferably 7-18 mm.

In the present invention, when the lower wall of the lower heating zone 3 is provided with a channel through which the rod-shaped material passes, the present invention preferably further comprises passing the rod-shaped material through the lower wall of the lower heating zone 3, so as to ensure that the lower heating zone 3 is a closed heating zone, thereby facilitating the control of the temperature precision of the lower heating zone.

In the invention, the corresponding part of the rod-shaped material between the upper heating zone 2 and the lower heating zone 3 is used as a standard sample segment; the length of the standard sample section is the distance between the upper heating area and the lower heating area. When the inner wall of the furnace body of the rod-shaped material continuous temperature gradient heat treatment device is also provided with a moving guide rail 9, at least one of the upper heating zone 2 and the lower heating zone 3 can move up and down along the moving guide rail 9. The length of the standard sample segment is preferably adjusted by adjusting the upper and lower positions of the upper heating zone and/or the lower heating zone. The invention has no special requirement on the length of the standard sample segment and can select the standard sample segment according to the actual requirement. In an embodiment of the invention, the length of the standard section is 80 mm.

After the fixing of the rod-shaped materials is finished, the furnace body is vacuumized by utilizing a vacuumizing device, then an upper heating power supply and a lower heating power supply are started, the part of the rod-shaped materials, which is positioned in the upper heating area 2, is heated by the upper heating rod 71, the part of the rod-shaped materials, which is positioned in the lower heating area 3, is heated by the lower heating rod 72, heat transfer is carried out along the axial direction of the rod-shaped materials, and a continuous temperature gradient is formed in the standard sample section of the rod-shaped materials.

In the present invention, the evacuation is preferably to 3.3 × 10^-2Pa or less. The present invention utilizes vacuum to reduce thermal convection.

In the present invention, before the rod-shaped material is heated, the present invention preferably further comprises a thermocouple disposed on an outer wall of the rod-shaped material sample section, and after a stable continuous temperature gradient is formed, the continuous temperature gradient measured by infrared thermography is corrected by the thermocouple. In the present invention, the thermocouple is preferably disposed at both ends of the rod-shaped material sample section.

In the present invention, the heating temperatures set in the upper heating zone 2 and the lower heating zone 3 correspond to the end point temperature of the temperature gradient of the rod-shaped material standard sample section. If a continuous temperature gradient between 1000 and 1300 ℃ is required, the temperature of one of the upper heating zone and the lower heating zone is set to 1000 ℃, and the other is set to 1300 ℃. In the invention, the heating temperatures set by the upper heating zone and the lower heating zone are also the heat preservation temperatures corresponding to the upper heating zone and the lower heating zone in the subsequent heat preservation process.

In the present invention, the rod-shaped material forms a continuous temperature gradient between the upper heating zone and the lower heating zone due to the temperature difference between the upper heating zone and the lower heating zone. The standard sample section transfers heat under vacuum, so that heat convection is avoided; an annular radiation screen is arranged between the upper heating zone and the lower heating zone, so that the lateral heat dissipation of the standard sample section can be inhibited, and the heat transfer is transmitted along the longitudinal direction (the axial direction of the rod-shaped material); the rod-shaped material is not contacted with the annular radiation screen, so that heat conduction is avoided; the three aspects act together to enable the standard sample section of the rod-shaped material between the upper heating area and the lower heating area to transfer heat along the axial direction in one dimension, so that the surface temperature and the central temperature of the standard sample section of the rod-shaped material are ensured to be consistent.

After the continuous temperature gradient is formed in the standard sample section of the rod-shaped material, the continuous temperature gradient distribution condition of the standard sample section is measured through the infrared thermal imaging temperature measurement window 5, and heat preservation is carried out after the continuous temperature gradient distribution is stable. In the invention, when the upper heating zone and the lower heating zone reach the set temperature, the standard sample section can form a stable continuous temperature gradient quickly (within 10 min). According to the invention, stable continuous temperature gradient distribution is formed after the temperature of the fixed temperature measuring point of the standard sample section is judged to be not changed through infrared thermal imaging.

After a stable continuous temperature gradient is formed, the invention keeps the temperature of the rod-shaped material. The invention has no special requirement on the heat preservation time and can be selected according to the actual requirement. After the incubation is completed, the present invention preferably further comprises cooling the heat-treated rod-shaped material. The cooling mode of the invention has no special requirement and can be selected according to the actual requirement.

After the stable continuous temperature gradient is formed, the present invention preferably further comprises correcting the obtained stable continuous temperature gradient. In the present invention, the process of correcting preferably includes: and correcting all infrared thermal imaging temperature measurement value results by using the detection difference value of the temperature measurement point by taking the temperature measurement of the thermocouple on the outer wall of the standard sample section as a standard. Because the thermocouple is in direct contact temperature measurement, the accuracy is higher, and the invention utilizes the thermocouple to correct the continuous temperature gradient measured by infrared thermal imaging, thereby ensuring the accuracy of temperature. In the present invention, the correction may be performed during the heat preservation process or after the heat preservation is completed, and the purpose is to correct the stable continuous temperature gradient (but it is necessary to read the temperature measurement result of the thermocouple after obtaining the stable continuous temperature gradient and before the heat preservation is completed).

In the present invention, when the apparatus for continuous temperature gradient heat treatment of rod-like materials further comprises a circulating water apparatus, the present invention preferably further comprises turning on the circulating water before heating until the heat treatment is completed, and other steps are the same as the above scheme, and are not described herein again. The invention has no special requirement on the flow of the circulating water, and the technicians in the field can adjust the circulating water according to the actual conditions. The invention utilizes the circulating water to reduce the temperature of the water-cooling joint and prevent the water-cooling joint from being scrapped too early due to high temperature on one hand, and can adjust the temperature gradient range and adjust and control the heat balance on the other hand.

In order to facilitate the technical solution of the present application to be better understood by those skilled in the art, the apparatus and method for continuous temperature gradient heat treatment of rod-shaped materials of the present invention will now be described with reference to fig. 1. As shown in fig. 1, a water-cooling joint 1, an upper heating zone 2, a lower heating zone 3 and an annular radiation screen 4 are arranged in the furnace body; an infrared thermal imaging temperature measuring window 5 and an air outlet 6 are arranged on the side wall of the furnace body; the upper heating zone 2 is provided with an upper heating rod 71 and an upper closed heat insulation plate 81, and the lower heating zone 3 is provided with a lower heating rod 72 and a lower closed heat insulation plate 82; the upper heating power supply (not shown) is connected with the upper heating rod 71 of the upper heating zone 2, and the lower heating power supply (not shown) is connected with the lower heating rod 72 of the lower heating zone 3; the upper closed heat insulation plate 81 and the lower closed heat insulation plate 82 respectively surround the upper heating rod 71 and the lower heating rod 72 to form a closed heating zone; the upper wall and the lower wall of the upper closed heat insulation board 81 and the upper wall of the lower closed heat insulation board 82 are respectively provided with a channel through which a rod-shaped material passes; the annular radiation screen 4 is provided with a thin slit (not shown) with the width of 1-2 mm along the axial direction; the lower heating zone in fig. 1 can move up and down along the moving guide 9; the water circulating device (not shown in the figure) is communicated with the water-cooling joint 1 through a water-cooling rod 12; the evacuation device (not shown) communicates with the air outlet 6.

According to the invention, a rod-shaped material sequentially passes through the upper wall of a lower heating zone 3, an annular radiation screen 4 and the lower wall and the upper wall of an upper heating zone 2 from bottom to top and is fixed on a water-cooling joint 1; the furnace body is vacuumized by using a vacuumizing device, then an upper heating power supply (only a part of the thermocouple 10 and the electrode 11 of the heating power supply are shown in the figure) and a lower heating power supply (only a part of the thermocouple 10 and the electrode 11 of the heating power supply are shown in the figure) are started, the part of the rod-shaped material, which is positioned in the upper heating area 2, is heated by an upper heating rod 71, and the part of the rod-shaped material, which is positioned in the lower heating area 3, is heated by a lower heating rod 72, and heat is transferred along the axial direction of the rod-shaped material; the heating temperatures set by the upper heating zone 2 and the lower heating zone 3 correspond to the end point temperature of the temperature gradient of the standard sample section of the rod-shaped material, and a continuous temperature gradient is formed in the standard sample section of the rod-shaped material; and measuring the continuous temperature gradient distribution condition of the standard sample section through an infrared thermal imaging temperature measurement window 5, and preserving heat after the continuous temperature gradient distribution is stable.

The apparatus and method for continuous temperature gradient heat treatment of rod-shaped materials according to the present invention will be described in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.