Temperature control method for on-line heat treatment of cold-drawn seamless steel pipe

Abstract

The invention discloses a cold-drawn seamless steel tube online heat treatment temperature control method which comprises the following steps: randomly selecting one cold-drawn steel tube, uniformly attaching a plurality of thermocouple temperature sensors to the outer surface of the cold-drawn steel tube, then integrally entering a heat treatment furnace, uniformly distributing a plurality of heat treatment units in the heat treatment furnace, and automatically adjusting the temperature of each heat treatment unit; the average section temperature of the cold-drawn steel pipe below each heat treatment unit is obtained by setting a fitting function, the average section temperature is compared with the set rated temperature, and the cold-drawn steel pipe of each section is compensated in a classified compensation and cyclic compensation mode, so that the final temperature of the cold-drawn steel pipe is infinitely close to the rated temperature; therefore, the temperature of the whole cold-drawn steel pipe is balanced. According to the method, the whole cold-drawn steel pipe can be subjected to uniform heat treatment, so that the heat treatment quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of cold-drawn steel pipe production technology, and in particular to an online heat treatment temperature control method for a cold-drawn seamless steel pipe. Background Art

[0002] At present, cold-drawn steel pipes are widely used in many fields, such as the automotive industry, machinery industry, oil and gas industry, energy industry, electronics and communications industry, and medical equipment. As a high-precision, high-quality steel pipe product, the production process of cold-drawn steel pipe is a complex process involving multiple processes, usually including raw material preparation, pre-treatment, cold drawing process, heat treatment, straightening and flaw detection, quality inspection and marking, and warehousing. The main function of the heat treatment process is to eliminate the residual stress inside the steel pipe and improve the mechanical properties of the steel pipe, which plays an important role in whether the cold-drawn steel pipe can be put into use. The current heat treatment method for cold-drawn steel pipes has the following shortcomings:

[0003] 1. The cold-drawn steel pipes currently produced are relatively long, and the temperature sensors are only arranged at the inlet and outlet of the heat treatment furnace. The temperature of the cold-drawn steel pipe cannot be accurately known at the temperature measured by a limited number of temperature sensors, and the temperature distribution of the entire steel pipe cannot be known;

[0004] 2. The existing heat treatment furnace adjusts the temperature of the cold-drawn steel pipe by simply raising or lowering the temperature based on the temperature measured by a limited number of temperature sensors, without considering the actual temperature of a certain area of ​​the cold-drawn steel pipe. As a result, the performance of the cold-drawn steel pipe produced in different areas is different. Summary of the invention

[0005] In order to overcome the defects in the prior art, the present invention provides an online heat treatment temperature control method for a cold-drawn seamless steel pipe, which can achieve uniform temperature of the entire cold-drawn steel pipe.

[0006] The technical solution adopted by the present invention is: a method for controlling the temperature of a cold-drawn seamless steel pipe by online heat treatment, comprising the following steps:

[0007] Step S1, before the cold-drawn steel pipe is heat-treated, a cold-drawn steel pipe is randomly selected from the cold-drawn steel pipes, and n thermocouple temperature sensors are pasted on the outer surface of the cold-drawn steel pipe, one thermocouple temperature sensor is arranged at each end of the selected cold-drawn steel pipe, and the rest are evenly arranged; from the inlet of the heat treatment furnace to the outlet of the heat treatment furnace is taken as the direction, the thermocouple temperature sensor pasted on the cold-drawn steel pipe is recorded as temperature sensor k, where k = 1, 2, 3...n;

[0008] Place the cold-drawn steel pipe with the thermocouple temperature sensor in the middle of all the cold-drawn steel pipes, and then put them into the heat treatment furnace side by side; the heat treatment furnace area corresponding to the position of the cold-drawn steel pipe is composed of m heat treatment units, each heat treatment unit can adjust the temperature separately, and the length of each heat treatment unit is l. After the heat treatment furnace works for t0 time, proceed to step S2;

[0009] Step S2, taking the location of the thermocouple temperature sensor 1 as the coordinate origin, taking the heat treatment furnace inlet to the heat treatment furnace outlet as the positive direction, recording the distance from the remaining positions of the cold-drawn steel pipe to the coordinate origin as the x value, recording the temperature measured by the thermocouple temperature sensor k as t k , where k = 1, 2, 3 ... n, and the temperature t k is the y value; according to the arrangement of the thermocouple temperature sensor on the selected cold-drawn steel tube, the temperature sensor k position-temperature coordinate is recorded as A k , A k The expression is Where k = 1, 2, 3...n;

[0010] Step S3: The fitting function T(x) is used to reflect the temperature distribution of the complete cold-drawn steel tube. The expression of T(x) is T(x)=Cx (n-1) +Dx (n-2) +Ex (n-3) +…+Gx+H, where C, D, E…H are coefficients, and the position-temperature coordinate A k Substitute into the fitting function T(x) to obtain the values ​​of all coefficients; according to the temperature distribution of the complete cold-drawn steel pipe T(x), the specific temperature of the cold-drawn steel pipe corresponding to the length of each heat treatment unit is obtained, and the average temperature of the cold-drawn steel pipe corresponding to the length of the i-th heat treatment unit is recorded as T i , where: i = 1, 2, 3...m;

[0011] Step S4: according to the average temperature T of the cold-drawn steel pipe of the corresponding length of each heat treatment unit i Perform temperature compensation and record the rated temperature of heat treatment as T 额 , calculate the average temperature T of the cold-drawn steel pipe of the corresponding length of the heat treatment unit i With the required rated temperature T 额 The temperature difference ΔT i , ΔT i The calculation formula is ΔT i =T 额 -T i , where i = 1, 2, 3...m; calculate the temperature difference ΔT i and rated temperature T 额 The relative difference ratio τ, the calculation formula of τ is Based on the relative difference ratio τ, the temperature of the cold-drawn steel pipe is compensated by adjusting the temperature of the heat treatment unit so that all parts of the cold-drawn steel pipe are heated evenly.

[0012] As a further improvement of the present invention, in step S4, the specific steps of temperature compensation are:

[0013] Step S41: Set is the first boundary point, when And ΔT i >0, the temperature compensation function ΔT of the heat treatment unit is given 偿 =-k1t+b1, where k1 is the value of ΔT i constant coefficients, and k1>0, b1 is related to ΔT i The relevant constant coefficients are b1>0, t is a time variable, and the cut-off time of t is δ1; the judgment condition t≠T, where T is the period of temperature compensation of the heat treatment unit. If the condition t≠T is satisfied, continue to execute this step. If the condition t=T is satisfied, return to step S2;

[0014] Step S42: And ΔT i When <0, the temperature compensation function ΔT of the heat treatment unit is given 偿 =k1t-b1, where k1 is the value of ΔT i constant coefficients, and k1>0, b1 is related to ΔT i The relevant constant coefficients are b1>0, t is the time variable, and the cutoff time of t is δ1; the judgment condition is t≠T. If the condition t≠T is met,

[0015] Then continue to execute this step, and if the condition t=T is met, return to step S2;

[0016] Step S43: Set is the second boundary point, when And ΔT i >0, the temperature compensation function ΔT of the heat treatment unit is given 偿 =-k2t+b2, where k2 is the same as ΔT i constant coefficients related to ΔT, and k2>0, k1>k2, b2 is i The relevant constant coefficient and b2>0, the cut-off time of t is δ2; the judgment condition t≠T, if the condition t≠T is met, continue to execute this step, if the condition t=T is met, return to step S2;

[0017] Step S44: And ΔT i When <0, the corresponding heat treatment unit temperature compensation function ΔT is given 偿 =k2t-b2, where k2 is the value of ΔTi The constant coefficients are related to k2>0, k1>k2, and b2 is related to ΔT i The relevant constant coefficient, and b2>0, the cut-off time of t is δ2; the judgment condition t≠T, if the condition t≠T is satisfied, then continue to execute this step, if the condition t=T is satisfied, then return to step S2;

[0018] Step S45: And ΔT i When <0, the corresponding heat treatment unit temperature compensation function is given Where k3 is related to ΔT i constant coefficients related to ΔT, and k3>0, and k1>k3, b3 is i The relevant constant coefficient, and b3>0, the cut-off time of t is δ3; the judgment condition t≠T, if the condition t≠T is satisfied, then continue to execute this step, if the condition t=T is satisfied, then return to step S2;

[0019] Step 46: And ΔT i >0, the temperature compensation function of the heat treatment unit is given Where k3 is related to ΔT i constant coefficients related to ΔT, and k3>0, and k1>k3, b3 is i The relevant constant coefficients are b3>0, and the cut-off time of t is δ3; the judgment condition t≠T is met. If the condition t≠T is met, continue to execute this step. If the condition t=T is met, return to step S2.

[0020] As a further improvement of the present invention, the number of the thermocouple temperature sensors is 5 to 7.

[0021] As a further improvement of the present invention, the working time t0 before measurement is 120s or 180s.

[0022] As a further improvement of the present invention, the period T of the temperature compensation performed by the heat treatment unit is 120s or 180s.

[0023] As a further improvement of the present invention, the first boundary point The value range is

[0024] As a further improvement of the present invention, the second boundary point The value range is

[0025] As a further improvement of the present invention, the value range of the cut-off time δ1 is 0.4T<δ1<0.6T.

[0026] As a further improvement of the present invention, the value range of the cut-off time δ2 is 0.8T<δ2<1T.

[0027] As a further improvement of the present invention, the value range of the cut-off time δ3 is 0.45T<δ3<0.55T.

[0028] The beneficial effects of the present invention are:

[0029] (1) The present invention evenly distributes a plurality of heat treatment units above the heat treatment furnace, each heat treatment unit can automatically adjust the temperature, and evenly arranges a plurality of thermocouple temperature sensors on the calibrated cold-drawn steel pipe. The heat treatment unit collects the temperature of the cold-drawn steel pipe section below it, and then adopts the classification compensation and circulation compensation method to make the temperature of the entire cold-drawn steel pipe evenly distributed, release the residual stress inside it, and thus improve the heat treatment quality of the cold-drawn steel pipe;

[0030] (2) The present invention can perform refined compensation for the temperature of the cold-drawn steel pipe and implement different compensation schemes under different conditions, so that the temperature of each section of the entire cold-drawn steel pipe can be close to the rated temperature, ensuring the temperature uniformity of the entire cold-drawn steel pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Figure 1 It is a heating schematic diagram of a heat treatment furnace of the present invention;

[0033] Figure 2 is a flow chart of temperature compensation for cold drawn steel pipe according to the present invention;

[0034] Figure 1 Among them, 1-cold drawn steel pipe, 2-thermocouple temperature sensor, 3-heat treatment unit, 4-support device, 5-heat treatment furnace. DETAILED DESCRIPTION

[0035] Please refer to Figure 1 and Figure 2 The present invention provides a method for controlling the online heat treatment temperature of a cold-drawn seamless steel pipe, comprising the following steps:

[0036] Step S1, before the cold-drawn steel pipe is heat-treated, a cold-drawn steel pipe 1 is randomly selected from the cold-drawn steel pipes, and n thermocouple temperature sensors 2 are pasted on its outer surface, one thermocouple temperature sensor is arranged at each end of the selected cold-drawn steel pipe, and the rest are evenly arranged; with the direction from the inlet of the heat treatment furnace 5 to the outlet of the heat treatment furnace, the thermocouple temperature sensor pasted on the cold-drawn steel pipe is recorded as temperature sensor k, where k = 1, 2, 3...n. Specifically, the number of thermocouple temperature sensors is 5 to 7.

[0037] The cold-drawn steel pipe with the thermocouple temperature sensor 2 is placed in the middle of all the cold-drawn steel pipes, and then placed side by side in the heat treatment furnace 5 and placed on the supporting device 4; the heat treatment furnace area corresponding to the position of the cold-drawn steel pipe is composed of m heat treatment units 3, each heat treatment unit 3 is used for heating, and the heat treatment unit 3 and the thermocouple temperature sensor 2 are connected to the controller, and the controller collects the real-time temperature of the thermocouple and adjusts the temperature of the heat treatment unit.

[0038] The length of each heat treatment unit is 1, and step S2 is executed after the heat treatment furnace has been working for t0 time, and t0 is 120s or 180s. In this step, a cold-drawn steel pipe is used as a marker, and multiple thermocouple temperature sensors are set on it, so that the sensed temperature can be generalized to the temperature measurement of other cold-drawn steel pipes entering the heat treatment furnace. The present invention first heats the cold-drawn steel pipe entering the heat treatment furnace for a period of time, that is, t0 time period, so that its overall temperature is around the rated temperature and then compensated.

[0039] Step S2, take the position of temperature sensor 1 as the coordinate origin, take the direction from the heat treatment furnace inlet to the heat treatment furnace outlet as the positive direction, record the distance from the other positions of the cold-drawn steel pipe to the coordinate origin as the x value, record the temperature measured by temperature sensor k as t k , where k = 1, 2, 3...n, and the temperature t k is the y value; according to the arrangement of the thermocouple temperature sensor on the selected cold-drawn steel tube, the temperature sensor k position-temperature coordinate is recorded as A k , A k The expression is Where k = 1, 2, 3...n;

[0040] Step S3: The fitting function T(x) is used to reflect the temperature distribution of the complete cold-drawn steel tube. The expression of T(x) is T(x)=Cx (n-1) +Dx (n-2) +Ex (n-3) +...+Gx+H, where C, D, E...H are coefficients, and the position-temperature coordinate A k Substitute into the fitting function T(x) to obtain the values ​​of all coefficients; according to the temperature distribution of the complete cold-drawn steel pipe T(x), the specific temperature of the cold-drawn steel pipe corresponding to the length of each heat treatment unit is obtained, and the average temperature of the cold-drawn steel pipe corresponding to the length of the i-th heat treatment unit is recorded as T i , where: i = 1, 2, 3...m.

[0041] Specifically, by using the property of function area integral, the average temperature of the cold-drawn steel pipe corresponding to the length of the i-th heat treatment unit can be obtained as T i , T i The calculation formula is Where: i = 1, 2, 3...m.

[0042] Step S4: according to the average temperature T of the cold-drawn steel pipe of the corresponding length of each heat treatment unit i Perform temperature compensation and record the rated temperature of heat treatment as T 额 , calculate the average temperature T of the cold-drawn steel pipe of the corresponding length of the heat treatment unit i With the required rated temperature T 额 The temperature difference ΔT i , ΔT i The calculation formula is ΔT i =T 额 -T i , where i = 1, 2, 3...m; calculate the temperature difference ΔT i and rated temperature T 额 The relative difference ratio τ, the calculation formula of τ is Based on the relative difference ratio τ, the temperature of the cold-drawn steel pipe is compensated by adjusting the temperature of the heat treatment unit so that all parts of the cold-drawn steel pipe are heated evenly.

[0043] Specifically, the specific steps for temperature compensation are:

[0044] Step S41: Set is the first boundary point, when And ΔT i >0, the temperature compensation function ΔT of the heat treatment unit is given 偿 =-k1t+b1, where k1 is the value of ΔT i constant coefficients, and k1>0, b1 is related to ΔT i The constant coefficients are related, and b1>0, t is the time variable, and the cut-off time of t is δ1; the judgment condition t≠T, where T is the period of temperature compensation of the heat treatment unit. If the condition t≠T is satisfied, continue to execute this step; if the condition t=T is satisfied, return to step S2. The first boundary point The value range is The value range of the cut-off time δ1 is 0.4T<δ1<0.6T, and the cycle T of the temperature compensation of the heat treatment unit is 120S or 180S. The time of the T cycle in the following steps is the same. In this compensation function, when the time t of the function runs to the cut-off time δ1, the compensation of this situation is stopped. t continues to run, and when it reaches T, that is, t=T, it returns to step S2 for cyclic compensation. The operation cut-off principle of the following compensation functions is the same. Regarding setting the cycle T, since the temperature compensation of the heat treatment furnace is a repetitive cycle process, the thermocouple temperature sensor will measure the temperature once every cycle T, and then perform temperature compensation again based on this temperature; when a cycle is completed, it is measured again and temperature compensation is performed again, which can not only detect whether the last temperature compensation is effective, but also make the actual temperature of the entire cold-drawn steel pipe closer to the rated temperature through cyclic compensation.

[0045] Step S42: And ΔT i When <0, the temperature compensation function ΔT of the heat treatment unit is given 偿 =k1t-b1, where k1 is the value of ΔT i constant coefficients, and k1>0, b1 is related to ΔT i The relevant constant coefficients and b1>0, the cut-off time of t is δ1; the judgment condition t≠T, where T is the period of temperature compensation of the heat treatment unit. If the condition t=T is met, continue to execute this step; if the condition t≠T is not met, return to step S2; during compensation, ΔT i >0, indicating that the overall temperature of this section of cold-drawn steel pipe is higher than the set temperature, and ΔT i <0, it means that the overall temperature of this section of cold-drawn steel pipe is lower than the rated temperature.

[0046] Step S43: Set is the second boundary point, when And ΔT i >0, the temperature compensation function ΔT of the heat treatment unit is given 偿 =-k2t+b2, where k2 is the same as ΔT i constant coefficients related to ΔT, and k2>0, k1>k2, b2 is i The relevant constant coefficient and b2>0, the cut-off time of t is δ2; the judgment condition t≠T, where T is the period of temperature compensation of the heat treatment unit. If the condition t≠T is met, continue to execute this step. If the condition t=T is met, return to step S2; the second boundary point The value range is

[0047] Step S44: And ΔT iWhen <0, the corresponding heat treatment unit temperature compensation function ΔT is given 偿 =k2t-b2, where k2 is the value of ΔT i The constant coefficients are related to k2>0, k1>k2, and b2 is related to ΔT i The relevant constant coefficients, and b2>0, the cut-off time of t is δ2; if the judgment condition t≠T, continue to execute this step; if the condition t=T is satisfied, return to step S2; the value range of the cut-off time δ2 is 0.8T<δ2<T.

[0048] Step S45: And ΔT i When <0, the corresponding heat treatment unit temperature compensation function is given

[0049] Where k3 is related to ΔT i constant coefficients related to ΔT, and k3>0, and k1>k3, b3 is i The relevant constant coefficients, and b3>0, the cut-off time t is δ3; the judgment condition t≠T, if the condition t≠T is met, continue to execute this step, if the condition t≠T is not met, return to step S2; the value range of the cut-off time δ3 is 0.45T<δ3<0.55T.

[0050] Step 46: And ΔT i >0, the temperature compensation function of the heat treatment unit is given Where k3 is related to ΔT i constant coefficients related to ΔT, and k3>0, and k1>k3, b3 is i The relevant constant coefficients are b3>0, and the deadline of t is δ3; the judgment condition t≠T is met. If the condition t≠T is met, continue to execute this step. If the condition t≠T is not met, return to step S2.

[0051] This temperature compensation uses the absolute value ratio of the temperature difference to the rated temperature for classification compensation, which is divided into three cases for separate processing:

[0052] In the first case, the actual temperature deviates very little from the desired temperature (including positive deviation and negative deviation), corresponding to step 41 and step 42 of the method;

[0053] In the second case, the actual temperature does not deviate much from the desired temperature, corresponding to steps 43 and 44 of the method;

[0054] In the third case, the actual temperature deviates greatly from the required temperature, which corresponds to step 45 and step 46 of the method.

[0055] The present invention first divides the cold-drawn steel pipe into sections, and sets a thermocouple temperature sensor and a heat treatment unit for each section. Then, temperature compensation is performed on each section of the cold-drawn steel pipe, and the temperature difference is classified to implement refined compensation, and multi-cycle compensation is performed until the temperature of each section of the cold-drawn steel pipe approaches the rated temperature. Compared with the prior art, the present invention can effectively release the residual stress of the cold-drawn steel pipe and improve the overall heat treatment quality.

[0056] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited thereto. Various changes that can be made within the knowledge scope of technicians in the relevant technical field without departing from the spirit of the present invention are all within the protection scope of the claims of the present invention.

Claims

1. A method for controlling the online heat treatment temperature of a cold-drawn seamless steel pipe, characterized in that: The following steps are involved: Step S1, before the cold-drawn steel pipe is heat-treated, a cold-drawn steel pipe is randomly selected from the cold-drawn steel pipes, and n thermocouple temperature sensors are pasted on the outer surface of the cold-drawn steel pipe, one thermocouple temperature sensor is arranged at each end of the selected cold-drawn steel pipe, and the rest are evenly arranged; from the inlet of the heat treatment furnace to the outlet of the heat treatment furnace is taken as the direction, the thermocouple temperature sensor pasted on the cold-drawn steel pipe is recorded as temperature sensor k, where k = 1, 2, 3...n; Place the cold-drawn steel pipe with the thermocouple temperature sensor in the middle of all the cold-drawn steel pipes, and then put them into the heat treatment furnace side by side; the heat treatment furnace area corresponding to the position of the cold-drawn steel pipe is composed of m heat treatment units, each heat treatment unit can adjust the temperature separately, and the length of each heat treatment unit is l. After the heat treatment furnace works for t0 time, proceed to step S2; Step S2, taking the location of the thermocouple temperature sensor 1 as the coordinate origin, taking the heat treatment furnace inlet to the heat treatment furnace outlet as the positive direction, recording the distance from the remaining positions of the cold-drawn steel pipe to the coordinate origin as the x value, recording the temperature measured by the thermocouple temperature sensor k as t k , where k = 1, 2, 3...n, and the temperature t k is the y value; according to the arrangement of the thermocouple temperature sensor on the selected cold-drawn steel tube, the temperature sensor k position-temperature coordinate is recorded as A k , A k The expression is Where k = 1, 2, 3...n; Step S3: The fitting function T(x) is used to reflect the temperature distribution of the complete cold-drawn steel tube. The expression of T(x) is T(x)=Cx (n-1) +Dx (n-2) +Ex (n-3) +…+Gx+H, where C, D, E…H are coefficients, and the position-temperature coordinate A k Substitute into the fitting function T(x) to get the values ​​of all coefficients; According to the temperature distribution of the complete cold-drawn steel pipe T(x), the specific temperature of the cold-drawn steel pipe corresponding to the length of each heat treatment unit is obtained, and the average temperature of the cold-drawn steel pipe corresponding to the length of the i-th heat treatment unit is recorded as T i , where: i = 1, 2, 3...m; Step S4: according to the average temperature T of the cold-drawn steel pipe of the corresponding length of each heat treatment unit i Perform temperature compensation and record the rated temperature of heat treatment as T 额 , calculate the average temperature T of the cold-drawn steel pipe of the corresponding length of the heat treatment unit i With the required rated temperature T 额 The temperature difference ΔT i , ΔT i The calculation formula is ΔT i =T 额 -T i , where i = 1, 2, 3...m; calculate the temperature difference ΔT i and rated temperature T 额 The relative difference ratio τ, the calculation formula of τ is Based on the relative difference ratio τ, the temperature of the cold-drawn steel pipe is compensated by adjusting the temperature of the heat treatment unit so that all parts of the cold-drawn steel pipe are heated evenly.

2. The method for controlling the online heat treatment temperature of a cold-drawn seamless steel pipe according to claim 1, characterized in that: In step S4, the specific steps of temperature compensation are: Step S41: Set is the first boundary point, when And ΔT i >0, the temperature compensation function ΔT of the heat treatment unit is given 偿 =-k1t+b1, where k1 is the value of ΔT i constant coefficients, and k1>0, b1 is related to ΔT i The relevant constant coefficients are b1>0, t is a time variable, and the cut-off time of t is δ1; the judgment condition t≠T, where T is the period of temperature compensation of the heat treatment unit. If the condition t≠T is satisfied, continue to execute this step. If the condition t=T is satisfied, return to step S2; Step S42: And ΔT i When <0, the temperature compensation function ΔT of the heat treatment unit is given 偿 =k1t-b1, where k1 is the value of ΔT i constant coefficients, and k1>0, b1 is related to ΔT i The relevant constant coefficients are b1>0, t is a time variable, and the cutoff time of t is δ1; the judgment condition t≠T is satisfied, if the condition t≠T is satisfied, then continue to execute this step, if the condition t=T is satisfied, then return to step S2; Step S43: Set is the second boundary point, when And ΔT i >0, the temperature compensation function ΔT of the heat treatment unit is given 偿 =-k2t+b2, where k2 is the same as ΔT i constant coefficients related to ΔT, and k2>0, k1>k2, b2 is i The relevant constant coefficient and b2>0, the cut-off time of t is δ2; the judgment condition t≠T, if the condition t≠T is met, continue to execute this step, if the condition t=T is met, return to step S2; Step S44: And ΔT i When <0, the corresponding heat treatment unit temperature compensation function ΔT is given 偿 =k2t-b2, where k2 is the value of ΔT i The constant coefficients are related to k2>0, k1>k2, and b2 is related to ΔT i The relevant constant coefficient, and b2>0, the cut-off time of t is δ2; the judgment condition t≠T, if the condition t≠T is satisfied, then continue to execute this step, if the condition t=T is satisfied, then return to step S2; Step S45: And ΔT i When <0, the corresponding heat treatment unit temperature compensation function is given Where k3 is related to ΔT i constant coefficients related to ΔT, and k3>0, and k1>k3, b3 is i The relevant constant coefficient, and b3>0, the cut-off time of t is δ3; the judgment condition t≠T, if the condition t≠T is satisfied, then continue to execute this step, if the condition t=T is satisfied, then return to step S2; Step 46: And ΔT i >0, the temperature compensation function of the heat treatment unit is given Where k3 is related to ΔT i constant coefficients related to ΔT, and k3>0, and k1>k3, b3 is i The relevant constant coefficients are b3>0, and the cut-off time of t is δ3; the judgment condition t≠T is met. If the condition t≠T is met, continue to execute this step. If the condition t=T is met, return to step S2.

3. The method for controlling the online heat treatment temperature of a cold-drawn seamless steel pipe according to claim 1, characterized in that: The number of thermocouple temperature sensors is 5 to 7.

4. The method for controlling the online heat treatment temperature of a cold-drawn seamless steel pipe according to claim 1, characterized in that: The working time t0 before measurement is 120s or 180s.

5. The method for controlling the online heat treatment temperature of a cold drawn seamless steel pipe according to claim 2, characterized in that: The period T of the temperature compensation of the heat treatment unit is 120s or 180s.

6. The method for controlling the online heat treatment temperature of a cold drawn seamless steel pipe according to claim 2, characterized in that: First boundary point The value range is 7. The method for controlling the online heat treatment temperature of a cold drawn seamless steel pipe according to claim 2, characterized in that: Second boundary point The value range is 8. The method for controlling the online heat treatment temperature of a cold drawn seamless steel pipe according to claim 2, characterized in that: The value range of the cut-off time δ1 is 0.4T<δ1<0.6T.

9. The method for controlling the online heat treatment temperature of a cold drawn seamless steel pipe according to claim 2, characterized in that: The value range of the cut-off time δ2 is 0.8T<δ2<1T.

10. The method for controlling the online heat treatment temperature of a cold drawn seamless steel pipe according to claim 2, characterized in that: The value range of the cut-off time δ3 is 0.45T<δ3<0.55T.

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