A method and system for compensating for heat treatment temperature of a special-shaped welded joint

Abstract

This invention provides a method for compensating the heat treatment temperature of irregular welded joints. It obtains a first distance between the first point where the temperature gradient change of the irregular part is greatest and the center of the first weld. The first weld is the weld between the irregular part and the first end of a first straight pipe. A second weld exists between any two straight pipes of the same specifications as the first straight pipe. A temperature cycle curve is obtained at a second point at a first distance from the center of the second weld. This temperature cycle curve is the temperature cycle curve during heat treatment using a normal welding process. The temperature curve of the first heating device at the first point is controlled to match the temperature cycle curve. This invention reduces or eliminates the influence of uncontrollable factors on welding by rationally arranging the heating device, thermocouples, insulation width, and heat treatment curve, ensuring the quality of the welding heat treatment and thus achieving a reasonable distribution of the heat treatment temperature field, thereby improving the heat treatment pass rate.

Description

Technical Field

[0001] This invention relates to the field of welding temperature control technology, and in particular to a method and system for compensating for heat treatment temperature of irregularly shaped welded joints. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With the improvement of power plant boiler efficiency and the continuous increase of its temperature and pressure parameters, high-alloy steel is often used for key high-temperature and high-pressure components. For example, new heat-resistant steels such as T91 / P91, T92 / P92, 122, super304H, SA213-TP347HFG, SA213-TP310HCBN or HR3C are often used in superheaters and main steam components. The performance of these alloy steels is an important guarantee for the safe and stable operation of boilers, and the heat treatment process is a key factor affecting the performance of high alloy steel.

[0004] In conventional heat treatment, the heat conduction conditions are usually the same on both sides of the weld (such as the weld of a straight pipe). The temperature control thermocouple is placed in the center of the weld, the temperature measurement thermocouple is placed at the edge of the weld at a distance of 1 wall thickness, and the heating device is symmetrically arranged on both sides of the weld.

[0005] The above method has limitations when used for heat treatment of the following types of non-shaped joints:

[0006] (1) Transverse unidirectional heat conduction irregular welded joints. When the joint is locally heat-treated after welding, the heat is conducted from one side of the weld to the other side. The highest temperature point in the heating area is theoretically located at the end of the structure. The weld only has a temperature gradient in the thickness direction and the transverse direction. Typical structural forms of this type of joint include: manhole end cover joint, manhole and container manhole cover joint, structural end or near end joint, such as support joints of headers, pipes and containers.

[0007] (2) Transverse bidirectional heat conduction non-conductive welded joints. When the joint is partially heat-treated after welding, the heat energy is conducted to both sides in the transverse direction of the weld. However, due to the influence of the joint structure and material, the rate of heat conduction to both sides of the weld is not necessarily the same. The transverse temperature field on both sides of the weld is asymmetrically distributed. Typical structural types of this type of joint include: reducing pipe connection joints, dissimilar steel welded joints, container and manifold pipe seat butt joints, plate-plate butt joints of unequal thickness and corner joints.

[0008] (3) Transverse and longitudinal heat-conducting irregular welded joints. When the joints are partially heat-treated after welding, in addition to the heat energy being conducted to both sides in the transverse direction of the weld, there is also heat conduction along the longitudinal direction of the weld. The temperature field on both sides of the transverse direction of the weld is asymmetrically distributed, and there is also a temperature gradient in the longitudinal direction of the weld. Typical structural types of this type of joint include: tee main pipe welded joint, tee branch pipe welded joint, welded tee welded joint and large valve body pipe welded joint.

[0009] When the above three irregular structures are heat-treated, the temperature field on both sides of the weld is asymmetrically distributed, and the highest temperature point is not at the weld. If conventional heat treatment methods are used, it may lead to local overheating on both sides of the weld, which may result in a weak weld. Summary of the Invention

[0010] To address the shortcomings of existing technologies, this invention provides a method and system for compensating for the heat treatment temperature of irregularly shaped welded joints. By rationally arranging the heating device, thermocouple, insulation width, and heat treatment curve, the influence of uncontrollable factors on welding is reduced or eliminated, ensuring the quality of welding heat treatment. This achieves a rational distribution of the heat treatment temperature field and improves the heat treatment pass rate.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] The first aspect of this invention provides a method for compensating the heat treatment temperature of irregularly shaped welded joints.

[0013] A method for compensating the heat treatment temperature of irregularly shaped welded joints includes the following steps:

[0014] Obtain the first distance between the first point where the temperature gradient change of the irregular part is the largest and the center of the first weld; wherein, the first weld is the weld between the irregular part and the first end of the first straight pipe;

[0015] A second weld is found between any two straight pipe fittings of the same specifications as the first straight pipe fitting. The temperature cycle curve of a second point at a first distance from the center of the second weld is obtained; wherein, the temperature cycle curve is the temperature cycle curve when the normal welding process is heat treated.

[0016] The temperature curve of the first heating device at the first point is controlled to be consistent with the temperature cycle curve.

[0017] As a further limitation of the first aspect of the invention, the first point and the second point are located at the same circumferential position on the pipeline.

[0018] As a further limitation of the first aspect of the present invention, the layout of the second temperature control device at the location of the first weld and the third temperature control device at the location of the second weld are the same or similar.

[0019] As a further limitation of the first aspect of the present invention, both the second temperature control device and the third temperature control device use the same heat treatment method as in normal welding processes for temperature control.

[0020] As a further limitation of the first aspect of the present invention, a first thermocouple is arranged at the location of the first point, a second thermocouple is arranged at the location of the first weld, and a third thermocouple is arranged on the irregular part between the first thermocouple and the second thermocouple.

[0021] A fourth thermocouple is arranged at the location of the second weld, a sixth thermocouple is arranged at the location of the second point, and a fifth thermocouple is arranged on the straight pipe between the fourth and sixth thermocouples.

[0022] As a further limitation of the first aspect of the invention, the distance between the second thermocouple and the third thermocouple is the third distance, and the distance between the fourth thermocouple and the fifth thermocouple is the fourth distance, wherein the third distance and the fourth distance are the same.

[0023] As a further limitation of the first aspect of the present invention, if the temperature deviation between the two curves at any given moment is within a set range when comparing the thermal cycle curves of the fifth thermocouple and the third thermocouple, then the temperature field gradient distribution on both sides of the first weld and the second weld layer is symmetrical.

[0024] A second aspect of the present invention provides a heat treatment temperature compensation system for irregularly shaped welded joints.

[0025] A heat treatment temperature compensation system for irregularly shaped welded joints, comprising:

[0026] The first weld data acquisition module is configured to: acquire the first distance between the first point where the temperature gradient change of the irregular part is the largest and the center of the first weld; wherein, the first weld is the weld between the irregular part and the first end of the first straight pipe;

[0027] The second weld data acquisition module is configured to: acquire the temperature cycle curve of a second point at a first distance from the center of the second weld if there is a second weld between any two straight pipe fittings of the same specification as the first straight pipe fitting; wherein, the temperature cycle curve is the temperature cycle curve when the normal welding process is heat treated;

[0028] The temperature control module is configured to control the temperature curve of the first heating device at the first point so that it is consistent with the temperature cycle curve.

[0029] As a further limitation of the first aspect of the present invention, a first thermocouple is arranged at the location of the first point, a second thermocouple is arranged at the location of the first weld, and a third thermocouple is arranged on the irregular part between the first thermocouple and the second thermocouple.

[0030] A fourth thermocouple is arranged at the location of the second weld, a sixth thermocouple is arranged at the location of the second point, and a fifth thermocouple is arranged on the straight pipe between the fourth and sixth thermocouples.

[0031] As a further limitation of the first aspect of the invention, the distance between the second thermocouple and the third thermocouple is the third distance, and the distance between the fourth thermocouple and the fifth thermocouple is the fourth distance, wherein the third distance and the fourth distance are the same.

[0032] As a further limitation of the first aspect of the present invention, if the temperature deviation between the two curves at any given moment is within a set range when comparing the thermal cycle curves of the fifth thermocouple and the third thermocouple, then the temperature field gradient distribution on both sides of the first weld and the second weld layer is symmetrical.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. This invention innovatively proposes a method and system for compensating the heat treatment temperature of irregular welded joints. By rationally arranging the heating device, thermocouple, insulation width and heat treatment curve, the influence of uncontrollable factors on welding is reduced or eliminated, ensuring the quality of welding heat treatment, thereby achieving a reasonable distribution of the heat treatment temperature field and improving the heat treatment qualification rate.

[0035] 2. This invention innovatively proposes a method and system for compensating the temperature of heat treatment of irregular welded joints, which makes the temperature field on both sides of the weld uniformly distributed, and the highest temperature point appears in the center of the weld, realizing precise control of the temperature field center and avoiding scrapping caused by local overheating of the joint or the surrounding base material due to temperature center deviation.

[0036] 3. This invention innovatively proposes a method and system for compensating the heat treatment temperature of irregular welded joints, which makes the distribution of the temperature gradient on both sides of the weld of irregular parts as similar as possible to the distribution of the temperature gradient on both sides of the weld of straight pipes, keeps the uniform temperature zone within a reasonable width, and does not expand or shrink excessively, thereby reducing the adverse effects of the heat cycle during heat treatment on the base material around the weld.

[0037] 4. This invention innovatively proposes a method and system for compensating the heat treatment temperature of irregular welded joints. According to the different materials and specifications of the pipeline, a database of heat treatment temperature control curves can be formed, thereby improving the first-pass yield of heat treatment and saving electricity, manpower and time.

[0038] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0039] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0040] Figure 1 This is a schematic flowchart of a heat treatment temperature compensation method for irregular welded joints provided in Embodiment 1 of the present invention;

[0041] Figure 2 This is a schematic diagram showing the relative positions of points A and B in Embodiment 1 of the present invention;

[0042] Figure 3 This is a schematic diagram of the principle of a heat treatment temperature compensation system for irregular welded joints provided in Embodiment 2 of the present invention;

[0043] Wherein, 1-Irregular part; 2-First straight pipe; 3-Second straight pipe; 4-Third straight pipe; 5-First heating device; 6-Second heating device; 7-Third heating device; 8-First weld; 9-Second weld. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0045] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0046] 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.

[0047] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0048] Example 1:

[0049] like Figure 1 As shown, Embodiment 1 of the present invention provides a method for compensating the heat treatment temperature of irregular welded joints. The irregular welded joints described in this embodiment refer to welded joints in which the heat conduction on both sides of the weld is asymmetrical due to structural and material reasons during local post-weld heat treatment, and include the following processes:

[0050] S1: Based on the shape and specifications of the irregular part requiring heat treatment, analyze the point with the largest temperature gradient change (i.e., the area near this point dissipates heat the fastest), such as... Figure 1 Point A (i.e., the first point) is located, and the distance from point A to the center of the first weld 8 is measured, such as... Figure 1 L1 in the middle.

[0051] In this embodiment, the first weld 8 is used to connect the irregular part 1 and the first straight pipe 2, that is, the first weld 8 is used to fix one end of the straight pipe of the irregular part 1 (the irregular part 1 includes a part of the straight pipe section) to the first end of the first straight pipe 2.

[0052] S2: Near the weld of a straight pipe section of the same specification (i.e., the second weld 9), find point B (i.e., the second point) at a distance L1 from the center of the second weld 9. Point B should be at the same position as point A on the pipe cross-section (e.g., ...). Figure 2 As shown, points A and B are both at the 12 o'clock position. A temperature measuring thermocouple f (i.e., the sixth thermocouple) is placed at point B.

[0053] In this embodiment, point B is located on the straight pipe 3, and the second weld 9 is used to fix the second end of the second straight pipe 3 to the first end of the third straight pipe 4. It can be understood that the second straight pipe 3 and the third straight pipe 4 are any two straight pipe fittings with the same specifications (including diameter, wall thickness, etc.) as the first pipe fitting 2. Optionally, the second straight pipe 3 and the first pipe fitting can be a single pipe fitting, or multiple pipe fittings can be spaced apart in between, which will not be elaborated here.

[0054] S3: The welded joint of the straight pipe section is heat-treated according to the normal process, and the temperature cycle curve F(t) of point B is obtained from the thermocouple f.

[0055] Understandably, the normal process here refers to the heat treatment process set according to the welding requirements, which is the commonly used process for welding straight pipe sections. The welding process may vary depending on the material or type of pipe section. Those skilled in the art can set the process according to the specific working conditions, and no specific limitation is made here.

[0056] S4: When processing irregular weld seams, set a temperature-controlled thermocouple a (i.e., the first thermocouple) at point A and control the temperature curve of the independent heating device (i.e., the first heating device 5) set around it. Arrange the second heating device 6 and thermocouple b (the second thermocouple) and thermocouple c (the third thermocouple) around the first weld seam according to the normal process.

[0057] The third heating device 7 and thermocouples d (fourth thermocouple) and e (fifth thermocouple) are arranged around the second weld according to the normal process. The distance from thermocouple c to thermocouple b is the same as the distance from thermocouple e to thermocouple d.

[0058] The arrangement of the second heating device 6 is similar to or the same as that of the third heating device 7 during the heat treatment of the straight pipe section, but the insulation thickness and width can be appropriately increased around the irregular parts that dissipate heat quickly.

[0059] S5: Set the cyclic curve F(t) obtained from point B in S3 as the temperature control curve of thermocouple a, and set the temperature control curve of thermocouple b according to the normal process. Perform heat treatment on irregular parts.

[0060] S6: Compare the thermal cycle curves of thermocouple e at the straight pipe section and thermocouple c at the irregular part. If the temperature deviation between the two curves is within ±5℃ at any time, it proves that the temperature field gradient distribution on both sides of the weld is symmetrical. Then archive the thermal cycle curve F(t).

[0061] S7: If heat treatment is required for irregular parts with similar thermal conductivity and pipe specifications but different conditions, simply repeat S4-S5.

[0062] Example 2:

[0063] like Figure 2 As shown, Embodiment 2 of the present invention provides a heat treatment temperature compensation system for irregularly shaped welded joints, comprising:

[0064] The first weld data acquisition module is configured to: acquire the first distance between the first point where the temperature gradient change of the irregular part is the largest and the center of the first weld; wherein, the first weld is the weld between the irregular part and the first end of the first straight pipe;

[0065] The second weld data acquisition module is configured to: acquire the temperature cycle curve of a second point at a first distance from the center of the second weld if there is a second weld between any two straight pipe fittings of the same specification as the first straight pipe fitting; wherein, the temperature cycle curve is the temperature cycle curve when the normal welding process is heat treated;

[0066] The temperature control module is configured to control the temperature curve of the first heating device at the first point so that it is consistent with the temperature cycle curve.

[0067] More specifically, the operating method of the system includes:

[0068] Based on the shape and specifications of the irregular parts requiring heat treatment, analyze the point where the temperature gradient changes the most (i.e., the area near this point dissipates heat the fastest), such as... Figure 1 Point A (i.e., the first point) is located, and the distance from point A to the center of the first weld 8 is measured, such as... Figure 1 L1 in the middle.

[0069] In this embodiment, the first weld 8 is used to connect the irregular part 1 and the first straight pipe 2, that is, the first weld 8 is used to fix one end of the straight pipe of the irregular part 1 (the irregular part 1 includes a part of the straight pipe section) to the first end of the first straight pipe 2.

[0070] Near the weld seam of a straight pipe section of the same specification (i.e., the second weld seam 9), find point B (i.e., the second point) at a distance L1 equidistant from the center of the second weld seam 9. Point B should be located at the same position as point A on the pipe cross-section (e.g., ...). Figure 2 As shown, points A and B are both at the 12 o'clock position. A temperature measuring thermocouple f (i.e., the sixth thermocouple) is placed at point B.

[0071] In this embodiment, point B is located on the straight pipe 3, and the second weld 9 is used to fix the second end of the second straight pipe 3 to the first end of the third straight pipe 4. It can be understood that the second straight pipe 3 and the third straight pipe 4 are any two straight pipe fittings with the same specifications (including diameter, wall thickness, etc.) as the first pipe fitting 2. Optionally, the second straight pipe 3 and the first pipe fitting can be a single pipe fitting, or multiple pipe fittings can be spaced apart in between, which will not be elaborated here.

[0072] The welded joint of the straight pipe section was heat-treated according to the normal process, and the temperature cycle curve F(t) of point B was obtained from the thermocouple f.

[0073] Understandably, the normal process here refers to the heat treatment process set according to the welding requirements, which is the commonly used process for welding straight pipe sections. The welding process may vary depending on the material or type of pipe section. Those skilled in the art can set the process according to the specific working conditions, and no specific limitation is made here.

[0074] When processing irregular welds, a temperature-controlled thermocouple a (i.e., the first thermocouple) is set at point A to control the temperature curve of an independent heating device (i.e., the first heating device 5) set around it. A second heating device 6 and thermocouples b (the second thermocouple) and c (the third thermocouple) are arranged around the first weld according to the normal process.

[0075] The third heating device 7 and thermocouples d (fourth thermocouple) and e (fifth thermocouple) are arranged around the second weld according to the normal process. The distance from thermocouple c to thermocouple b is the same as the distance from thermocouple e to thermocouple d.

[0076] The arrangement of the second heating device 6 is similar to or the same as that of the third heating device 7 during the heat treatment of the straight pipe section, but the insulation thickness and width can be appropriately increased around the irregular parts that dissipate heat quickly.

[0077] Set the cycle curve F(t) obtained from point B by S3 as the temperature control curve of thermocouple a, and set the temperature control curve of thermocouple b according to the normal process. Perform heat treatment on irregular parts.

[0078] Comparing the thermal cycle curves of thermocouple e at the straight pipe section and thermocouple c at the irregular part, if the temperature deviation between the two curves is within ±5℃ at any given moment, it proves that the temperature field gradient distribution on both sides of the weld is symmetrical. Then, the thermal cycle curve F(t) is archived.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for compensating the heat treatment temperature of irregularly shaped welded joints, characterized in that, Includes the following processes: Obtain the first distance between the first point where the temperature gradient change of the irregular part is the largest and the center of the first weld; wherein, the first weld is the weld between the irregular part and the first end of the first straight pipe; A second weld is found between any two straight pipe fittings of the same specification as the first straight pipe fitting. The temperature cycle curve of a second point at a first distance from the center of the second weld is obtained. The temperature cycle curve is the temperature cycle curve during heat treatment of normal welding process. The first point and the second point are located at the same circumferential position of the pipe. Control the temperature curve of the first heating device at the first point to make it consistent with the temperature cycle curve; A first thermocouple is placed at the location of the first point, a second thermocouple is placed at the location of the first weld, and a third thermocouple is placed on the irregular part between the first and second thermocouples. A fourth thermocouple is arranged at the location of the second weld, a sixth thermocouple is arranged at the location of the second point, and a fifth thermocouple is arranged on the straight pipe between the fourth and sixth thermocouples. Comparing the temperature cycle curves of the fifth thermocouple and the third thermocouple, if the temperature deviation between the two curves is within the set range at any given moment, then the temperature field gradient distribution on both sides of the first and second welds is symmetrical.

2. The method for compensating for heat treatment temperature of irregular welded joints as described in claim 1, characterized in that, The layout of the second temperature control device at the location of the first weld and the third temperature control device at the location of the second weld is the same or similar.

3. The method for compensating the heat treatment temperature of irregular welded joints as described in claim 1, characterized in that, Both the second and third temperature control devices use the same heat treatment method as in normal welding processes for temperature control.

4. The method for compensating for heat treatment temperature of irregular welded joints as described in claim 1, characterized in that, The distance between the second thermocouple and the third thermocouple is the third distance, and the distance between the fourth thermocouple and the fifth thermocouple is the fourth distance. The third distance and the fourth distance are the same.

5. A heat treatment temperature compensation system for irregularly shaped welded joints, characterized in that, include: The first weld data acquisition module is configured to: acquire the first distance between the first point where the temperature gradient change of the irregular part is the largest and the center of the first weld; wherein, the first weld is the weld between the irregular part and the first end of the first straight pipe; The second weld data acquisition module is configured to: acquire the temperature cycle curve of a second point at a first distance from the center of the second weld if there is a second weld between any two straight pipe fittings of the same specification as the first straight pipe fitting; wherein, the temperature cycle curve is the temperature cycle curve when the normal welding process is heat treated; The temperature control module is configured such that: the first point and the second point are located at the same circumferential position on the pipeline; and the temperature curve of the first heating device at the first point is controlled to be consistent with the temperature cycle curve. A first thermocouple is placed at the location of the first point, a second thermocouple is placed at the location of the first weld, and a third thermocouple is placed on the irregular part between the first and second thermocouples. A fourth thermocouple is arranged at the location of the second weld, a sixth thermocouple is arranged at the location of the second point, and a fifth thermocouple is arranged on the straight pipe between the fourth and sixth thermocouples. Comparing the temperature cycle curves of the fifth thermocouple and the third thermocouple, if the temperature deviation between the two curves is within the set range at any given moment, then the temperature field gradient distribution on both sides of the first and second welds is symmetrical.

6. The heat treatment temperature compensation system for irregular welded joints as described in claim 5, characterized in that, The distance between the second thermocouple and the third thermocouple is the third distance, and the distance between the fourth thermocouple and the fifth thermocouple is the fourth distance. The third distance and the fourth distance are the same.

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