Adjusting method for postwelding local heat treatment temperature

Abstract

A postwelding local heat treatment temperature adjusting method is used for enabling the highest temperature of heat treatment to be located on a weld joint to be treated and comprises the following steps that a heat treatment heater is arranged, and a weld joint area to be subjected to heat treatment is covered; in the heat treatment process, the temperatures of one side of the weld joint to be subjected to heat treatment, the weld joint to be subjected to heat treatment and the other side of the weld joint to be subjected to heat treatment are obtained in real time and recorded as T1, T2 and T3; comparing T1 and T2 as well as T2 and T3: if T1 is less than T2 and T3 is less than T2, indicating that the highest temperature of heat treatment is on the weld joint to be treated, and at the moment, not adjusting a heater; if T1 is larger than T2 or T3 is larger than T2, it is indicated that the highest temperature of heat treatment is located outside the weld joint to be treated, at the moment, a heater needs to be adjusted to achieve temperature adjustment of T1 and / or T3, and the steps are repeated till T1 is smaller than T2 and T3 is smaller than T2.

Description

Technical Field

[0001] The invention relates to the technical field of welding heat treatment, and in particular to a temperature regulating method for local heat treatment after welding. Background Art

[0002] In recent years, my country's power industry has developed rapidly. In order to meet the requirements of high efficiency, energy saving and environmental protection, the unit capacity of power station units has become larger and larger, and the unit parameters have become higher and higher. Large-diameter thick-walled high-alloy pipes have been widely used. During the installation and maintenance process at the construction site, some asymmetric special-shaped pipe fittings are often encountered, such as reducers, tees, valves, headers, or pipe fittings with other obstacles on the pipes. For on-site heat treatment, these are the difficulties of heat treatment quality control, but they are also the focus. When performing post-weld heat treatment on the welds of special-shaped pipe fittings at the construction site, the weld temperature often fails to rise to the set temperature or the hardness of the parent material is low due to overheating, resulting in unqualified metallographic structure and other problems, which seriously affect the weld quality and the service life of the unit. Therefore, studying the problem of post-weld local heat treatment of welded joints caused by large-scale equipment, high-end materials and refined temperature control will become a hot technical problem in the field of welding heat treatment.

[0003] The description of heterogeneous structural weldments in the "Technical Regulations for Welding Heat Treatment in Thermal Power Plants", "Regulations for Post-weld Heat Treatment of Pressure Equipment", "Regulations for Local Post-weld Heat Treatment of Pressure Equipment", etc. is: During post-weld heat treatment and post-heat treatment, measures should be taken to ensure that the highest temperature of the weldment is located on the weld being heat treated. There should be at least three thermocouples, one of which is located on the weld for temperature control, and the other two thermocouples (for monitoring temperature) are located on the same line of the outer wall of the same busbar of the pipe 20mm away from the edge of the weld. For the arrangement of heaters, it is advisable to arrange more zone-controlled heating devices on the side with larger metal material volume, and adjust their heating power according to the actual situation and temperature distribution of the weldment. The use of three thermocouples can monitor whether the highest temperature point during post-weld heat treatment is on the weld. If the highest temperature is not found on the weld, the heater on the larger side needs to be readjusted. If this method is adopted, it will not only waste time but also have a great impact on the heat treatment quality of the weld. By consulting relevant information, specific data may be obtained through experiments or experience on specific specifications and structural forms, but the specifications and forms of special-shaped structures on construction sites vary greatly, and the summarized and accumulated data cannot meet the needs of the construction site. It is urgent to find a set of post-weld heat treatment processes suitable for various forms of special-shaped pipe fittings.

[0004] At present, there are not many guiding materials for welding heat treatment of special-shaped pipe fittings at home and abroad. Among them, the relevant standards for welding heat treatment point out the arrangement method of thermocouples and heaters. From the arrangement method of thermocouples, it can be measured whether the highest temperature is on the weld, but there is no specific explanation of what measures to take to ensure that the highest temperature point of special-shaped pipe fittings is on the weld. If the highest temperature point is only ensured on the weld by repeatedly arranging heaters, it will not only waste time, but also affect the welding quality of special-shaped pipe fittings. The relevant materials also mention the use of auxiliary heating method for pipe fittings on the side that is not easy to heat. The temperature of the auxiliary heater is generally set at 500-600℃. This method can only achieve the highest temperature close to the weld position, but cannot accurately determine the specific location of the highest temperature point. There are also studies on heat treatment experiments for special-shaped pipe fittings of a specific specification, and some data are given, but the specifications and forms of special-shaped pipe fittings at the construction site are complex and changeable, and the specific experimental data cannot meet the construction on site. Summary of the invention

[0005] In view of this, in order to overcome the defects of the prior art, an object of the present invention is to provide a method for adjusting the temperature of local heat treatment after welding.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for adjusting the temperature of a local heat treatment after welding, the method being used to make the highest temperature of the heat treatment located on the weld to be treated, the method comprising the following steps:

[0008] Arrange heat treatment heaters and cover the weld area to be heat treated;

[0009] During the heat treatment process, the temperatures of one side of the weld to be heat treated, the weld to be heat treated, and the other side of the weld to be heat treated are obtained in real time, and are recorded as T1, T2, and T3;

[0010] Compare the size between T1 and T2 and between T2 and T3:

[0011] If T1<T2 and T3<T2, it indicates that the highest temperature of heat treatment is located on the weld to be treated, and there is no need to adjust the temperature of the heater;

[0012] If T1>T2 or T3>T2, it indicates that the highest temperature of heat treatment is outside the weld to be treated. In this case, the heater needs to be adjusted to achieve temperature regulation of T1 and / or T3, and the above steps are repeated until T1<T2 and T3<T2.

[0013] According to some preferred implementation aspects of the present invention, before heat treatment, thermocouples need to be arranged on one side of the weld to be heat treated, the weld to be heat treated and the other side of the weld to be heat treated, and the above-mentioned thermocouples are all temperature monitoring thermocouples, denoted as TC1, TC2, TC3, which correspond to the obtained temperatures T1, T2, T3.

[0014] According to some preferred implementation aspects of the present invention, the temperature monitoring thermocouple is connected to the heater signal, and adjusts the temperature of the heater according to the judgment result between T1, T2, and T3.

[0015] According to some preferred implementation aspects of the present invention, the heater has a temperature control point, and the heater is controlled according to the temperature of the temperature control point.

[0016] Preferably, in some embodiments of the present invention, a temperature-controlling thermocouple is provided corresponding to the temperature-controlling point, and the temperature monitored by the temperature-controlling thermocouple of the heater controls the heater. By providing the temperature-controlling thermocouple and the temperature-monitoring thermocouple, the temperature adaptation and self-regulation can be better achieved. Specifically, the temperature of the temperature-controlling point is first set, and the heater is adjusted according to the temperature of the temperature-controlling thermocouple of the temperature-controlling point. During the adjustment process, the temperature-monitoring thermocouple continuously monitors the temperature of the corresponding position, i.e., T1, T2, and T3, and the heater adjusts the temperature according to the comparison results of T1, T2, and T3.

[0017] According to some preferred implementation aspects of the present invention, the heater is one or more of a crawler heater, a rope heater, and a medium frequency induction heater. The present invention is applicable to post-weld local heat treatment using commonly used heaters such as crawler heaters, rope heaters, and medium frequency induction heaters. During heat treatment, heaters of different specifications and powers need to be arranged according to the different shapes and sizes of the workpieces to be heat treated, and the size and power of the heaters can be arranged symmetrically or asymmetrically.

[0018] According to some preferred implementation aspects of the present invention, the heater comprises at least two groups of heaters with independently controlled temperatures.

[0019] According to some preferred implementation aspects of the present invention, when the heater is a track-type heater or a rope-type heater, the heater includes at least two separate temperature control systems.

[0020] According to some preferred implementation aspects of the present invention, the heater is a medium frequency induction heater, and the heater includes at least two separate temperature control systems with the same frequency.

[0021] When using resistance heaters such as crawler heaters or rope heaters for local heat treatment after welding, it is necessary to ensure that at least two separate temperature control systems can be realized; if medium frequency induction heating is used for local heat treatment after welding, it is necessary to ensure at least two separate temperature control systems with the same frequency.

[0022] According to some preferred implementation aspects of the present invention, adjusting the heater includes adjusting a heating parameter of the heater, including one or more of heating power, current density and frequency.

[0023] According to some preferred implementation aspects of the present invention, the adjusting the heater includes adjusting the position of the heater. Specifically, if after N adjustments, T1<T2 and T3<T2 cannot be satisfied, the arrangement of the heater needs to be readjusted, and the above steps need to be repeated, so that T1<T2 and T3<T2; if over-temperature or over-power occurs, the heat treatment is stopped.

[0024] In order to realize the above-mentioned post-weld local heat treatment temperature adjustment method, the present invention realizes intelligent adjustment of the post-weld local heat treatment temperature according to the temperature feedback information T1, T2 and T3 of the above-mentioned thermocouple, so that the highest temperature is located at the center of the weld to be treated. While being suitable for post-weld local heat treatment of pipeline butt welds, it is also applicable to post-weld local heat treatment of asymmetric special-shaped pipe fittings such as reducers, tees, valves, headers, and pipe seats, and pipe fittings with other obstacles on the pipes (such as: reducer welds, pipe seat welds, tee welds, and welding flanges, etc.).

[0025] The present invention is not limited to the use of three thermocouples to obtain temperature information of characteristic points in the weld area. During the implementation of the present invention, a larger number of temperature measurement and feedback points can be set in the weld area to accommodate post-weld local heat treatment of welds of the above-mentioned various special-shaped pipe fittings and pipe fittings with other obstacles on the pipes.

[0026] Due to the adoption of the above technical scheme, compared with the prior art, the advantages of the present invention are: the method for adjusting the post-weld heat treatment temperature of the present invention can effectively control the distribution of the highest temperature point of the post-weld heat treatment constant temperature on the weld, effectively ensuring the heat treatment quality of the weld, avoiding the overburning of the parent material caused by the high hardness of the parent material, and at the same time ensuring that the weld heat treatment is successful once, avoiding the phenomenon of re-heat treatment, improving the heat treatment construction efficiency, and achieving considerable economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 It is a schematic diagram of the principle of temperature field superposition in the present invention;

[0029] Figure 2Schematic diagrams for comparing temperature field zone temperature control in the present invention, a) is a schematic diagram for one-way temperature control, and b) is a schematic diagram for multi-way temperature control;

[0030] Figure 3 It is a schematic diagram of the process of the temperature adjustment method in the present invention;

[0031] Figure 4 The schematic diagrams of the structures of the crawler heaters in the preferred embodiments of the present invention are as follows: a) is a schematic diagram of the structure A of the crawler heater, and b) is a schematic diagram of the structure B of the crawler heater;

[0032] Figure 5 Schematic diagrams of the arrangement structures of the crawler heater in the preferred embodiment of the present invention, a) is a schematic diagram of the arrangement of the crawler heater structure A, b) is a schematic diagram of the arrangement of the crawler heater structure B;

[0033] Figure 6 Schematic diagram of the structure of the medium frequency induction heater in the preferred embodiment of the present invention, a) is a schematic diagram of the structure A of the medium frequency induction heater, b) is a schematic diagram of the structure B of the medium frequency induction heater;

[0034] Figure 7 Schematic diagrams of the arrangement structure of the medium frequency induction heater in the preferred embodiment of the present invention, a) is a schematic diagram of the arrangement of the medium frequency induction heater structure A, b) is a schematic diagram of the arrangement of the medium frequency induction heater structure B;

[0035] Figure 8 It is a schematic diagram of the arrangement structure of the fillet weld heater to be processed in the preferred embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the technical solution of the present invention and apply it to actual local heat treatment after welding, the principle of the temperature adjustment method for local heat treatment after welding of the present invention and the technical solution in the embodiment will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the protection scope of the present invention.

[0037] The principle of the automatic adjustment method of the local heat treatment temperature after welding of the present invention is as follows:

[0038] 1) Temperature field superposition

[0039] like Figure 1As shown, the temperature regulation method of the present invention realizes the superposition of the entire temperature field by separately controlling the temperature fields on both sides of the weld to be treated, and feeds back information in real time through the temperature control point thermocouples and controls the heater to realize automatic regulation of the temperature field so that the highest temperature is located on the weld to be treated.

[0040] 2) Temperature field zone control

[0041] like Figure 2 As shown, similar to the finite element principle, when a weld is locally heat treated, it can be treated by one heater or by coordinated temperature control by multiple heaters. Multiple heaters can realize zoned temperature control at different positions and thus realize secondary distribution of the entire temperature field. Resistance wires of different powers can also be designed on the same heater for temperature control. Figure 2 Different colors in the diagram represent heaters in different paths, and the temperature field is adjusted together according to different heaters.

[0042] Based on the above principle, the present invention can realize adaptive adjustment of the temperature field near the weld to be treated, ensure that the highest temperature of the post-weld heat treatment is located on the weld to be treated, and ensure the heat treatment quality of the weld. The post-weld local heat treatment temperature adjustment method of the present invention can effectively solve the problem of post-weld heat treatment of special-shaped pipe fittings, ensure the post-weld heat treatment quality of special-shaped pipe fittings, and has a very broad application prospect, and can be widely used in the fields of electric power, petrochemical, aerospace, shipbuilding, rail trains and nuclear power.

[0043] The method for adjusting the post-weld local heat treatment temperature in this embodiment is used to make the highest temperature of the heat treatment located on the weld to be treated, such as Figure 3 As shown. In view of the fact that the method for adjusting the temperature of the local heat treatment after welding of the present invention has similar operation procedures when different numbers of temperature measurement and feedback points are set, only a simple case of three temperature measurement and feedback points is taken as an example. Figure 3 The process of the temperature adjustment method is described in detail.

[0044] The method for adjusting the post-weld local heat treatment temperature in this embodiment specifically includes the following steps:

[0045] Step 1: Before heat treatment, select the type of heat treatment heater and arrange it in the weld area to be heat treated.

[0046] The heater type adopts crawler heater, rope heater, medium frequency induction heater and other common heaters for local heat treatment after welding. During heat treatment, heaters of different specifications and powers should be arranged according to the different shapes and sizes of the workpieces to be heat treated. The size and power of the heater can be arranged symmetrically or asymmetrically.

[0047] When using resistance heaters such as crawler heaters or rope heaters for local heat treatment after welding, it is necessary to ensure that at least two separate temperature control systems can be realized; if medium frequency induction heating is used for local heat treatment after welding, it is necessary to ensure at least two separate temperature control systems with the same frequency.

[0048] Preferably, each heater is provided with a temperature-controlling thermocouple, which corresponds to a temperature-control point. The temperature-controlling thermocouple can control the temperature of the feedback heater and further adjust the parameters of the heater.

[0049] Step 2: Arrange thermocouples at a position ≥50mm on one side of the weld to be heat treated, at a position ≥50mm on the weld to be heat treated, and at a position ≥50mm on the other side of the weld to be heat treated. The above thermocouples are all temperature monitoring thermocouples, denoted as TC 1, TC2, and TC3. The temperature monitoring thermocouples continuously monitor the temperature at the corresponding positions, and the position of the temperature monitoring thermocouple does not overlap with the position of the temperature controlling thermocouple.

[0050] Step 3: During the heat treatment process, the temperatures of one side of the weld to be heat treated, the weld to be heat treated and the other side of the weld to be heat treated are obtained in real time, and are recorded as T1, T2 and T3.

[0051] Step 4: Compare the values ​​between T1 and T2 and between T2 and T3, and adjust the temperature of the heater according to the comparison results:

[0052] If T1<T2 and T3<T2, it indicates that the highest temperature of heat treatment is located on the weld to be treated, and there is no need to adjust the heater at this time;

[0053] If T1>T2 or T3>T2, it indicates that the highest temperature of heat treatment is outside the weld to be treated. In this case, the parameters of the heater need to be adjusted to adjust T1 and / or T3, and repeat the above steps until T1<T2 and T3<T2.

[0054] When adjusting the temperature, the temperature is monitored by the thermocouple feedback, and the parameters of the heater are adjusted to adjust the temperature field. The parameters of the heater include one or more of heating power, current density and frequency.

[0055] Step 5: If after N adjustments, T1 < T2 and T3 < T2 cannot be satisfied, the arrangement of the heaters needs to be adjusted and the above steps need to be repeated to make T1 < T2 and T3 < T2; if over-temperature or over-power occurs, the heat treatment is stopped and the heaters are reselected or re-arranged. N can preferably be 5-10.

[0056] When using the above temperature adjustment method to perform local heat treatment of structural parts after welding, it can be divided into the following situations according to the type of heater, the structure to be heat treated and the form of the weld:

[0057] Implementation case 1: Heating with crawler heater

[0058] For pipe butt welds, a crawler heater can be used for local heat treatment after welding. The structural and layout diagrams of crawler heaters are shown in the figure below. Figure 4 and Figure 5 According to the principle of temperature field superposition and zone temperature control, the crawler heater can be designed as a parallel type ( Figure 4 a. Crawler heater structure type A) or cross ( Figure 4 b. Track-type heater structure B) type heater, and each heater has at least two temperature control systems, which means two heaters can be adjusted separately. Through the arrangement of the heaters and the temperature adjustment method, the temperature field at the temperature monitoring point can be automatically adjusted as needed, thereby ensuring that the highest temperature is located at the center of the weld to be processed, which specifically includes the following steps:

[0059] Step 1: Install the crawler heater as follows: Figure 5 As shown, in parallel ( Figure 5 a、Crawler heater structure type A layout diagram) or cross ( Figure 5 b. Schematic diagram of the arrangement of crawler heater structure B) is arranged in the weld area to be heat treated, and are defined as heater A and heater B respectively.

[0060] Step 2: Arrange temperature-controlled thermocouples on both sides of the weld to be heat treated (heater A side and heater B side), respectively, denoted as TCA and TCB, which correspond to temperature control point A and temperature control point B, and the corresponding temperature is denoted as T A 、T B The temperature-controlled thermocouple can control the feedback temperature and thus adjust the parameters of the heater.

[0061] Step 3: Arrange temperature monitoring thermocouples on one side of the weld to be heat treated (heater A side), the weld to be heat treated and the other side of the weld to be heat treated (heater B side), respectively, and record them as TC 1, TC2, and TC3.

[0062] During the heat treatment adjustment process, the temperature monitoring thermocouples TC1, TC2, and TC3 obtain the temperatures of one side of the weld to be heat treated, the weld to be heat treated, and the other side of the weld to be heat treated in real time, and the corresponding temperatures are recorded as T1, T2, and T3.

[0063] Step 4: Compare the values ​​between T1 and T2 and between T2 and T3, and adjust the temperature of the heater according to the comparison results:

[0064] If T1<T2 and T3<T2, it indicates that the highest temperature of heat treatment is located on the weld to be treated, and there is no need to adjust the temperature of the heater;

[0065] If T1>T2 or T3>T2, it indicates that the highest temperature of heat treatment is outside the weld to be treated. At this time, it is necessary to adjust the heating power of the heater through the temperature control point to adjust T1 and / or T3, and repeat the above steps until T1<T2 and T3<T2.

[0066] Through the above steps 1 to 4, the temperature adaptive adjustment of the post-weld local heat treatment of the pipeline butt weld can be achieved by using the crawler heater.

[0067] Implementation case 2: Heating with medium frequency induction heater

[0068] For the butt weld of the pipeline, a medium frequency induction heater can also be used for local heat treatment after welding. The structural diagram and layout diagram of the medium frequency induction heater are shown in the figure. Figure 6 and Figure 7 According to the principle of temperature field superposition and zone temperature control, the medium frequency induction heater can be designed as a parallel type ( Figure 6 a. Medium frequency induction heater structure type A) or cross type ( Figure 6 b. Medium frequency induction heater structure B), and each heater has at least two temperature control systems, which means that the two heaters can be adjusted separately. Induction heating must also ensure the same frequency design of the temperature control system. Through the arrangement of the heater and the temperature adjustment method, the temperature field at the temperature monitoring point can be automatically adjusted according to the needs, thereby ensuring that the highest temperature is located at the center of the weld to be processed. Specifically, the following steps are included:

[0069] Step 1: Install the medium frequency induction heater as follows: Figure 7 , in parallel ( Figure 7 a、Medium frequency induction heater structure type A layout diagram) or cross ( Figure 7 b. Schematic diagram of the arrangement of medium frequency induction heater structure B) is arranged in the weld area to be heat treated, and is defined as heater A and heater B respectively.

[0070] Step 2: Arrange temperature-controlled thermocouples on both sides of the weld to be heat treated (heater A side and heater B side), respectively, denoted as TCA and TCB, which correspond to temperature control point A and temperature control point B, and the corresponding temperature is denoted as T A 、T B The temperature-controlled thermocouple can control the feedback temperature and thus adjust the parameters of the heater.

[0071] Step 3: Arrange temperature monitoring thermocouples on one side of the weld to be heat treated (heater A side), the weld to be heat treated and the other side of the weld to be heat treated (heater B side), respectively, and record them as TC 1, TC2, and TC3.

[0072] During the heat treatment adjustment process, the temperature monitoring thermocouples TC1, TC2, and TC3 obtain the temperatures of one side of the weld to be heat treated, the weld to be heat treated, and the other side of the weld to be heat treated in real time, and the corresponding temperatures are recorded as T1, T2, and T3.

[0073] Step 4: Compare the values ​​between T1 and T2 and between T2 and T3, and adjust the temperature according to the comparison results:

[0074] If T1<T2 and T3<T2, it indicates that the highest temperature of heat treatment is located on the weld to be treated, and there is no need to adjust the temperature of the heater;

[0075] If T1>T2 or T3>T2, it indicates that the highest temperature of heat treatment is outside the weld to be treated. At this time, it is necessary to adjust the current density, frequency, etc. of the heater through the temperature control point to adjust T1 and / or T3, and repeat the above steps until T1<T2 and T3<T2.

[0076] Through the above steps 1 to 4, the temperature adaptive adjustment of the post-weld local heat treatment of the pipeline butt weld using the medium frequency induction heater can be achieved.

[0077] Implementation Case 3: Post-weld local heat treatment of welds of special-shaped structural parts

[0078] The temperature regulation method in this embodiment is applicable to pipe butt welds as well as welds of special-shaped structural parts (including reducer and reducer welds, pipe seat welds, tee welds, welding flanges, etc.). It is necessary to design a reasonable heater and thermocouple arrangement according to the specifications of the welds of the parts to be processed. Figure 8 The figure shows the schematic diagram of the arrangement structure of the heater for the fillet weld to be treated. For this type of weld, it is more convenient to use a rope heater for local heat treatment after welding. Through the arrangement of the heater and the temperature adjustment method, the temperature field at the temperature monitoring point can be automatically adjusted according to the needs, thereby ensuring that the highest temperature is located at the center of the weld to be treated. The specific steps include the following:

[0079] Step 1: Install the rope heater as follows: Figure 8 , arranged in parallel in the base area and branch pipe area of ​​the weld to be heat treated, and are defined as heater A and heater B respectively.

[0080] Step 2: Arrange temperature-controlled thermocouples on both sides of the weld to be heat treated (heater A side and heater B side), respectively, denoted as TCA and TCB, which correspond to temperature control point A and temperature control point B, and the corresponding temperature is denoted as T A 、T B The temperature-controlled thermocouple can control the feedback temperature and thus adjust the parameters of the heater. The temperature of the temperature-controlled point can be set first, and the heater will be adjusted according to the temperature of the temperature-controlled point.

[0081] Step 3: Arrange temperature monitoring thermocouples on one side of the weld to be heat treated (heater A side), the weld to be heat treated and the other side of the weld to be heat treated (heater B side), respectively, and record them as TC 1, TC2, and TC3.

[0082] During the heat treatment adjustment process, the temperature monitoring thermocouples TC1, TC2, and TC3 obtain the temperatures of one side of the weld to be heat treated, the weld to be heat treated, and the other side of the weld to be heat treated in real time, and the corresponding temperatures are recorded as T1, T2, and T3.

[0083] Step 4: Compare the values ​​between T1 and T2 and between T2 and T3, and adjust the temperature according to the comparison results:

[0084] If T1<T2 and T3<T2, it indicates that the highest temperature of heat treatment is located on the weld to be treated, and there is no need to adjust the temperature of the heater;

[0085] If T1>T2 or T3>T2, it indicates that the highest temperature of heat treatment is outside the weld to be treated. At this time, it is necessary to adjust the heating power of the heater through the temperature control point to adjust T1 and / or T3, and repeat the above steps until T1<T2 and T3<T2.

[0086] Through the above steps 1 to 4, the temperature adaptive adjustment of the post-weld local heat treatment of the fillet weld using the rope heater can be achieved.

[0087] According to the above steps of implementation case 1, implementation case 2, and implementation case 3, in the actual adjustment process, the heater first adjusts the temperature according to the temperature-controlling thermocouple. During the adjustment process, the temperature-monitoring thermocouple continuously monitors the temperature of the corresponding position, i.e., T1, T2, and T3, and the heater then adjusts the parameters of the heater according to the comparison results of T1, T2, and T3 to better achieve temperature adaptation and self-regulation.

[0088] The method for adjusting the temperature of the local heat treatment after welding of the present invention can arrange the heater symmetrically or asymmetrically, mainly including: (a) symmetrical power arrangement and (a) symmetrical size arrangement; (2) it can face symmetrical butt welds such as pipelines / steel plates / steel pipes, and can face heat transfer components such as tees, reducers, pipelines, valves, etc. that will cause asymmetrical distribution of the temperature field; the superposition of the temperature fields on both sides of the weld makes the highest temperature located at the center of the weld to be treated; according to the different sizes and shapes of the workpieces to be heat treated, heaters of different specifications and powers are arranged, and adaptive adjustment is performed through the temperature feedback information of the temperature field measuring points, so that the highest temperature is located at the center of the weld to be treated; the crawler heater must ensure that at least two separate temperature control systems can be realized, and the medium frequency induction heating must ensure that at least two separate temperature control systems with the same frequency can be realized.

[0089] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for adjusting the temperature of local heat treatment after welding, characterized in that: The adjustment method is used to make the highest temperature of the heat treatment be located on the weld to be treated, and the adjustment method comprises the following steps: Arrange heat treatment heaters and cover the weld area to be heat treated; During the heat treatment process, the temperatures of one side of the weld to be heat treated, the weld to be heat treated, and the other side of the weld to be heat treated are obtained in real time, and are recorded as T1, T2, and T3; Compare the size between T1 and T2 and between T2 and T3; If T1<T2 and T3<T2, it indicates that the highest temperature of heat treatment is located on the weld to be treated, and there is no need to adjust the temperature of the heater; If T1>T2 or T3>T2, it indicates that the highest temperature of heat treatment is outside the weld to be treated. In this case, the heater needs to be adjusted to achieve temperature regulation of T1 and / or T3, and the above steps are repeated until T1<T2 and T3<T2.

2. The adjustment method according to claim 1, characterized in that: Before heat treatment, thermocouples need to be arranged on one side of the weld to be heat treated, the weld to be heat treated, and the other side of the weld to be heat treated, respectively, to obtain T1, T2, and T3, respectively.

3. The adjustment method according to claim 2, characterized in that: The thermocouple is a temperature monitoring thermocouple, which is connected to the heater signal and adjusts the temperature of the heater according to the judgment result between T1, T2, and T3.

4. The adjustment method according to claim 1, characterized in that: The heater has a temperature control point, and the heater is controlled according to the temperature of the temperature control point.

5. The adjustment method according to claim 1, characterized in that: The heater is one or more of a crawler-type heater, a rope-type heater, and a medium-frequency induction heater.

6. The adjustment method according to claim 1, characterized in that: The heater comprises at least two groups of heaters with independently controlled temperatures.

7. The adjustment method according to claim 1, characterized in that: When the heater is a track-type heater or a rope-type heater, the heater includes at least two independent temperature control systems.

8. The adjustment method according to claim 1, characterized in that: The heater is a medium frequency induction heater, and the heater includes at least two separate temperature control systems with the same frequency.

9. The adjustment method according to claim 1, characterized in that: The adjusting the heater includes adjusting a heating parameter of the heater, including one or more of heating power, current density and frequency.

10. The adjustment method according to claim 1, characterized in that: Adjusting the heater includes adjusting a position of the heater.

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