Annealing process for carbon steel vacuum chamber structural components

Abstract

The application relates to the technical field of heat treatment, and discloses an annealing process for carbon steel vacuum chamber structural members, which is used for annealing treatment of carbon steel structural members of a vacuum chamber and comprises the following steps: a preparation stage, heating, heat preservation, cooling and post-treatment. In the process parameter designation process, a correction coefficient is introduced, related parameters which have influences on target parameters are included in the correction coefficient, the variation range of the target parameters in the process designation process is compressed, the control precision of the variation range of the target parameters before and after the annealing treatment can be improved based on the designated process parameters, the qualified rate of the annealing treatment products is higher, and a too large allowance does not need to be reserved, so that the subsequent production and processing difficulty is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat treatment, in particular to an annealing process for carbon steel vacuum chamber structural parts, which is used for annealing treatment of carbon steel structural parts of vacuum chamber. BACKGROUND

[0002] Carbon steel is a kind of iron alloy containing carbon, which is a commonly used material for manufacturing various metal products and structural parts. Carbon steel structural parts refer to various structural parts made of carbon steel as raw material. These structural parts are widely used in many fields such as construction, bridge, machinery manufacturing, automobile, ship, petroleum and chemical industry, etc.

[0003] Carbon steel structural parts often need to be annealed during production. The annealing process of carbon steel structural parts is an important metal heat treatment process, which aims to improve the microstructure and macroscopic properties of the material by controlling the heating and cooling process. Common annealing processes for carbon steel structural parts include heating stage, holding stage and cooling stage, etc.

[0004] Due to the changes in various parameters of carbon steel structural parts before and after heat treatment, such as hardness, strength, plasticity, toughness, internal stress, magnetism, size, etc., although these parameter changes have certain regularity, due to the influence of many factors on parameter changes during the heat treatment process, the existing annealing process can only be determined within a larger range, and the control of related parameters is not accurate.

[0005] For example, the size parameter of carbon steel structural parts, in order to ensure that the size of the structural part after heat treatment changes still meets the size requirements in the subsequent production process, it is usually necessary to design sufficient allowance in the blank part. However, due to the inaccurate control of size change during the heat treatment process, the allowance usually needs to be reserved much larger than the upper limit of size change, and the allowance needs to be removed after heat treatment. This results in excessive allowance in the production process of parts, which not only increases the consumption of materials and the amount of waste in the processing process, but also seriously increases the processing difficulty and processing time. SUMMARY

[0006] The technical problem solved by the present application is how to more accurately determine the parameter changes before and after heat treatment, and then develop the corresponding annealing process based on the parameter changes, target parameter values and parameter values before heat treatment.

[0007] The purpose of the present application can be achieved by the following technical solutions:

[0008] An annealing process for carbon steel vacuum chamber structural parts, comprising the following steps:

[0009] Preparation stage: determine the process parameters according to the target size parameters, and perform material pretreatment. The specific process of determining the process parameters is as follows:

[0010] target parameters of the carbon steel structure;

[0011] a plurality of sets of historical data of annealing treatment, the historical data including specific values of the target parameters of the carbon steel structure before and after annealing treatment, and values of related parameters before, during and after annealing treatment;

[0012] based on the historical data, a correction coefficient is calculated and obtained, the correction coefficient being a ratio of an actual change value of the target parameters in the historical data to a theoretical change value of the target parameters, then the correction coefficient k is taken as a vertical axis and the values of the related parameters are taken as a horizontal axis for curve fitting of changes of the correction coefficient respectively, the related parameters with obvious fluctuations of the correction coefficient are selected, and after increasing the number of the historical data, the curve fitting of changes of the correction coefficient is obtained again to obtain a fitting curve of changes of the correction coefficient;

[0013] actual values of the related parameters are obtained before heat treatment, and actual correction coefficients are obtained respectively according to the fitting curve of changes of the correction coefficient;

[0014] a difference between the value before annealing treatment and the target value after annealing treatment of the target parameters is calculated as a presumed change value a, and a corrected change value b of the change of the target parameters after correction is obtained through b=ka; then process parameters are set based on the corrected change value of the change of the target parameters, and a complete process is formulated for subsequent process treatment;

[0015] heating: heating and temperature rising are performed according to the heating temperature and the heating rate set by the correction process;

[0016] holding: after reaching the process set temperature, the structure keeps at the temperature for a certain time;

[0017] cooling: after holding for the process set time, the structure is cooled, and the cooling rate is controlled according to the process requirement;

[0018] post-treatment: after cooling, the structure is post-treated to remove the surface oxide scale.

[0019] In one scheme of the present application: the carbon steel structure is placed on a support assembly during annealing treatment, the support assembly including a support body and a power structure, the power structure being used to drive the support body to move linearly and reciprocally, the top surface of the support body being provided with a plurality of protruding structures, and the two sides of the protruding structure being inclined surfaces.

[0020] In one scheme of the present application: the inclined surface can be a straight surface or a curved surface.

[0021] In one scheme of the present application: the longitudinal cross-sectional profile of the protruding structure is a triangle, an arc or a trapezoid.

[0022] In one aspect of the present application: a planar gap is arranged between two protruding structures, the gap size is smaller than the structure size.

[0023] In one aspect of the present application: the protruding structure arranged on the support body is provided with a notch along the advancing direction of the support body, a roller column is arranged above the support body, and a push rod matching the notch is arranged on the roller column.

[0024] In one aspect of the present application: the number of groups of historical data is more than 50 groups.

[0025] In one aspect of the present application: the pretreatment includes cleaning the surface of the material and removing oil stains and rust.

[0026] In one aspect of the present application: during the heating process, the workpiece is heated in a protective atmosphere or vacuum.

[0027] The beneficial effects of the present application are:

[0028] In the process parameter specification process of the present application, a correction coefficient is introduced, and related parameters that have an influence on the target parameter are included in the correction coefficient, thereby compressing the variation range of the target parameter in the process specification process. Based on the specified process parameters, the control accuracy of the variation range of the target parameter before and after annealing can be improved, the qualified rate of the annealed product is higher, and there is no need to reserve a large amount of excess, thereby reducing the difficulty of subsequent production and processing.

[0029] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter in the description of the application. BRIEF DESCRIPTION OF DRAWINGS

[0030] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the description of the embodiments, taken in conjunction with the following drawings in which:

[0031] Figure 1 is a process flowchart of the present application;

[0032] Figure 2 is a structure schematic diagram of the protruding structure with a triangular cross-sectional profile of the present application;

[0033] Figure 3 is a structure schematic diagram of the protruding structure with an arc-shaped cross-sectional profile of the present application;

[0034] Figure 4 is a structure schematic diagram of the protruding structure with a trapezoidal cross-sectional profile of the present application;

[0035] Figure 5 is a structure schematic diagram of the present application Figure 4 from the perspective view.

[0036] The reference signs in the drawings are as follows: 1, support body; 2, convex structure; 3, lever. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0038] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0039] In the description of the present application, the meaning of several is one or more, and the meaning of multiple is two or more. Greater than, less than, more than, etc. are understood as not including the number, and above, below, etc. are understood as including the number. If the first and the second are described, they are only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0040] Please refer to Figure 1 The present application is an annealing process for carbon steel vacuum chamber structural parts, comprising the following steps:

[0041] Preparation stage: According to the target size parameters, process parameters are formulated, and the material is pretreated to clean the surface of the material and remove oil stains, rust, etc. to ensure the annealing effect. Avoid forming uneven oxide layers during heating. Check the size and shape of the material to ensure that they are suitable for loading into the annealing furnace.

[0042] The specific process of formulating process parameters is as follows:

[0043] The target parameters of the carbon steel structural parts are selected, which can be hardness, strength, plasticity, toughness, internal stress, magnetism, size, etc.

[0044] Obtain more than 50 sets of historical data of annealing treatment, the historical data including specific values of target parameters of carbon steel structural parts before and after annealing treatment, and values of related parameters before, after and during annealing treatment; the related parameters can be temperature and humidity of environment before and after heat treatment and during the process, material composition, heating rate, annealing temperature, holding time, cooling rate, initial size of workpiece, etc.

[0045] Based on the historical data, a correction coefficient is calculated, which is the ratio of the actual change value of the target parameter in the historical data to the theoretical change value of the target parameter. Then k is taken as the vertical axis and the related parameters are taken as the horizontal axis to perform curve fitting of the change of the correction coefficient. The related parameters with obvious fluctuation of the correction coefficient are selected, and after increasing the number of historical data, the correction coefficient change fitting curve is obtained by curve fitting again.

[0046] The actual values of the related parameters are obtained before heat treatment, and the actual correction coefficients are obtained according to the correction coefficient change fitting curve; if there are multiple related parameters, there are multiple fitting curves, at this time the average value of the multiple actual correction coefficients is used for the next step;

[0047] The difference between the value of the target parameter before annealing treatment and the target value after annealing treatment is calculated as the estimated change value a, and the corrected change value of the target parameter change is obtained through b=ka. Then the process parameters are set based on the obtained corrected change value of the target parameter change, and the completed process is used for subsequent process treatment. Specifically, the correction coefficient can be obtained by automatic calculation through a computer terminal, or a factor correlation model can be established based on existing deep learning. After deep learning, the model outputs the values of the related parameters to obtain the values of the correction coefficients.

[0048] Heating: According to the heating temperature and heating rate set by the correction process, heating is carried out. In this process, the workpiece is heated in a protective atmosphere or vacuum to prevent oxidation and decarburization. The structural part is heated to the temperature set by the process, which is usually higher than the recrystallization temperature (Ac3 or Ac1) of carbon steel. The heating rate should be determined according to the size of the structural part and the material properties to avoid deformation caused by overheating or thermal stress.

[0049] Holding: After reaching the required temperature, the structural part needs to be kept at this temperature for a certain time to ensure uniformization of the material internal organization. The holding time depends on the thickness of the material, the chemical composition and the required degree of organization refinement. Precise control of heating and holding temperature is crucial to ensure the expected organization transformation.

[0050] Cooling: After soaking, the structural member is cooled at an appropriate rate. For full annealing, slow cooling, sometimes controlled cooling, is usually used to promote the transformation of austenite into fine pearlite structure. According to the thickness of the material and the required performance, the cooling rate is controlled to avoid the generation of new internal stress or uneven microstructure.

[0051] Post-processing: After cooling is completed, the structural member may need some post-processing, such as removing the surface scale or surface cleaning.

[0052] Please refer to Figures 2-5 In one embodiment of the present application, when the process is used for heat treatment of large vacuum chamber structural members, the carbon steel large vacuum chamber structural member is placed on a support assembly during the annealing process. The support assembly includes a support body 1 and a power structure for driving the support body 1 to move linearly back and forth (left and right shaking), and the top surface of the support body 1 is provided with a plurality of protruding structures 2, which are used to support the structural member and reduce the contact area with the structural member, so as to avoid uneven heating of the structural member during annealing. At the same time, the reciprocating shaking of the support assembly driven by the power structure can avoid the regional defects caused by the continuous contact between the structural member and the support structure. The support body 1 is provided with blocking structures at both ends, which can be used to block the shaking limit position of the structural member to avoid falling off. When used for large vacuum chamber structural members, the power structure uses a heavy driving mechanism to provide sufficient driving force.

[0053] Please refer to Figures 2-5 In one embodiment of the present application, the process can also be used for heat treatment of small parts on the vacuum chamber in addition to being used for heat treatment of large vacuum chamber structural members. The specific process parameters need to be adjusted according to the specific situation. For example, for large vacuum chamber structural members, the stepwise heating method is used, that is, multiple heating and soaking are used, and each time the temperature is raised by a fixed temperature, such as 50℃, and then maintained for a period of time, so as to avoid uneven heating of the large vacuum chamber structural member due to its large size, weight and high thickness, and to avoid deformation or other defects caused by rapid heating.

[0054] Please refer to Figures 2-5In one of the embodiments of the present application, when the device is used for small structure heat treatment on the vacuum chamber, the two sides of the convex structure 2 are inclined surfaces, which can be straight or curved surfaces. The longitudinal section profile of the convex structure 2 can be triangular, arc-shaped or trapezoidal. The structure is located between the two inclined surfaces, and swings between the two inclined surfaces during the left and right shaking of the support structure, avoiding the continuous contact of the structure with the support structure during the annealing process. At the same time, the collision of the structure with the inclined surface can also remove the surface impurities. Further, a planar gap can be provided between the two convex structures 2, and the gap size is smaller than the structure size, so that the structure can be in an upright state between the two convex structures 2. When the support body 1 shakes left and right, the structure shakes left and right, and the bottom end will slide with the contact position of the plane. At the same time, during the shaking process, the structure also swings between the two inclined surfaces, which effectively avoids the continuous contact of a certain point of the structure with the support body 1, and prevents the occurrence of defective spots. Further, the convex structure 2 provided on the support body 1 is provided with a notch along the forward direction of the support body 1, and a roller is provided above the support body 1, and a push rod 3 matched with the notch is provided on the roller. During the process that the support body 1 carries the structure into the annealing furnace, the roller is driven to rotate to drive the push rod 3 to rotate, so that the structure is separated, avoiding the accumulation of the structure to cause quality problems. The size between the two notches can match the size of the structure to fully ensure the independence of the structure.

[0055] The working principle of the present application is that the correction coefficient is introduced in the process parameter specification process, the related parameters that have an influence on the target parameter are included in the correction coefficient, the variation range of the target parameter in the process specification process is compressed, and the control accuracy of the variation range of the target parameter before and after the annealing process is improved based on the specified process parameters, so that the qualified rate of the annealing product is higher, and a large excess amount does not need to be reserved, and the subsequent production and processing difficulty is reduced.

[0056] The above describes one embodiment of the present application in detail, but the content described is only the preferred embodiment of the present application, and cannot be considered as limiting the implementation range of the present application. Any equivalent changes and improvements made within the scope of the present application should still belong to the scope of the claims of the present application.

Claims

1. A carbon steel vacuum chamber structural member annealing process characterized by, The method comprises the following steps: Preparation stage: process parameters are determined according to target size parameters, and material pretreatment is performed, and the specific process of determining the process parameters is as follows: Selecting target parameters of carbon steel structural parts; Obtaining a plurality of sets of historical data of annealing treatment, the historical data comprising specific values of target parameters before and after annealing treatment of carbon steel structural parts, and values of related parameters before, during and after annealing treatment; Based on the historical data, a correction coefficient is calculated, which is the ratio of the actual change value of the target parameter in the historical data to the theoretical change value of the target parameter, and then the correction coefficient k is taken as the vertical axis and the related parameter value is taken as the horizontal axis to perform curve fitting of the correction coefficient change respectively, the related parameters with obvious fluctuation of the correction coefficient are selected, and the number of historical data is increased to perform curve fitting again to obtain a correction coefficient change fitting curve; The actual values of the related parameters before heat treatment are obtained, and the actual correction coefficients are obtained according to the correction coefficient change fitting curve respectively; The difference between the value of the target parameter before annealing treatment and the target value after annealing treatment is calculated as the estimated change value a, and the corrected change value b of the target parameter change is obtained through b=ka; then the process parameters are set based on the obtained corrected change value of the target parameter change, and the process is completed for subsequent process treatment; Heating: heating according to the heating temperature and heating rate set by the correction process; Soaking: after reaching the process set temperature, the carbon steel structural part is kept at the temperature for a certain time; Cooling: after soaking to the process set time, the carbon steel structural part is cooled, and the cooling rate is controlled according to the process requirements; Post-processing: after cooling, the carbon steel structural part is post-processed to remove the surface oxide scale; In the annealing treatment process, the carbon steel structural part is placed on a support assembly, the support assembly comprises a support body and a power structure, the power structure is used to drive the support body to move linearly back and forth, the top surface of the support body is provided with a plurality of protruding structures, and the two sides of the protruding structure are inclined surfaces; The protruding structure provided on the support body is provided with a notch along the advancing direction of the support body, and a roller column is provided above the support body, and a push rod matched with the notch is provided on the roller column.

2. The annealing process of a carbon steel vacuum chamber structural member according to claim 1, characterized in that, The inclined surface is a straight surface or a curved surface.

3. The annealing process of a carbon steel vacuum chamber structural member according to claim 2, characterized in that, The longitudinal cross-sectional profile of the protruding structure is triangular, arc-shaped or trapezoidal.

4. The annealing process of a carbon steel vacuum chamber structural member according to claim 3, characterized in that, A planar gap is provided between two protruding structures, and the size of the planar gap is smaller than the size of the carbon steel structural part.

5. The annealing process of a carbon steel vacuum chamber structural member according to claim 1, characterized in that, The number of sets of historical data is more than 50.

6. The annealing process of a carbon steel vacuum chamber structural member according to claim 1, characterized in that, The pretreatment includes cleaning the surface of the material to remove oil stains and rust.

7. The annealing process of a carbon steel vacuum chamber structural member according to claim 1, wherein, During the heating process, the workpiece is heated in a protective atmosphere or vacuum.

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