Method capable of quickly judging cracking damage of self-preheating burner heat exchanger

Abstract

The invention relates to a method capable of quickly judging cracking and damage of a self-preheating burner heat exchanger, which quickly judges the cracking and damage condition of the self-preheating burner heat exchanger during the normal quenching production period of a heat treatment furnace, and timely treats and replaces three types of heat exchangers on line, so that the intact utilization rate of burners is improved, and the production efficiency is improved. And the tempering production heating capacity of the heat treatment furnace is recovered, the problem that the furnace temperature for heating the tempered steel plate does not reach the standard is solved, and the tapping temperature of the steel plate and the set temperature are controlled within 10 DEG C. According to the method, the problem that the heating cycle time of heat treatment is too long is solved, the heating coefficient is averagely reduced by 0.5-1.0 min / mm, the production efficiency is improved, the production cost is reduced, the product performance and mechanical property indexes reach the standard, the unevenness of the quenched and tempered steel plate is successfully controlled within 4 mm, and the problem that white spots appear due to abnormal oxidation on the surface of the quenched and tempered steel plate is solved in time. According to the scheme, the production efficiency is greatly improved, gas potential safety hazards are eliminated, and various quality indexes of the quenched and tempered steel plate are remarkably improved.

Description

TECHNICAL FIELD

[0001] The patent application belongs to the technical field of maintenance of heat treatment furnace equipment, and more particularly to a method for quickly determining cracking damage of a heat exchanger of a self-preheating burner, and especially to a method for quickly and online determining cracking damage of a heat exchanger of a core component of a self-preheating burner applied to a heat treatment quenching furnace. BACKGROUND

[0002] In the mechanism of the heat treatment quenching furnace, the combustion control system mainly consists of four parts, namely, the self-preheating burner, the burner front coal gas valve and pipeline accessories, the radiation pipe and the burner controller. The high-efficiency air self-preheating gas burner of the heat treatment furnace is a core component for heating the steel plate of the heat treatment furnace. The unique burner structure consists of three parts, namely, the burner shell, the burner core and the heat exchanger.

[0003] 1. Burner shell: The multifunctional compact shell has functions of burner installation, combustion-supporting air supply, shell cooling and flue gas discharge, and the burner is easy to equip and install. The aluminum alloy shell can greatly reduce the weight of the burner. The shell has a double-layer structure, and the combustion-supporting air enters the burner through the annular gap of the outer layer to ensure normal combustion of the burner and cool the shell, thereby reducing heat loss. The inner wall of the air shell and the smoke exhaust pipe are provided with heat insulation materials.

[0004] 2. Burner core: The burner core consists of a gas connection flange, a gas guide pipe, an air guide pipe, a mixed combustion chamber, a flame monitoring device and an ignition electrode.

[0005] 3. Heat exchanger: The metal fin heat exchanger has a large heat exchange area, and high heat exchange efficiency can be obtained even in a low-temperature furnace. The core component of the high-efficiency air self-preheating gas burner is the heat exchanger, and damage of the heat exchanger will cause the burner to malfunction and cannot be used normally. In special cases, the burner may spray fire, burn red, and cause accidents such as burning of the circuit. Normal use of the heat exchanger is the main reason affecting the furnace temperature control of the production of quenched and tempered steel plate.

[0006] In the production of the quenching furnace, when the pressure of the coal gas heat value suddenly rises, the coal gas impurities are abnormal, and the like, the combustion is insufficient and the flame is abnormal, which causes damage of the heat exchanger of the core component of multiple burners and cannot be used normally. In severe cases, the heat exchanger of the burner cracks and the radiation pipe is damaged by excessive load, and the radiation pipe of the burner is forced to stop working and cannot heat the steel plate. When heating the quenched and tempered steel plate, the furnace temperature of each furnace zone in the heating section does not meet the standard, the furnace temperature in the holding section is low, and the holding time is set too long, which leads to a long heat treatment period of the quenched and tempered steel plate, low production efficiency, high production cost, abnormal product performance, uneven quenched and tempered steel plate, white spots on the surface and other production quality problems. At the same time, there are serious equipment safety hazards such as coal gas leakage, fire and explosion.

[0007] The heat exchanger of the burner core component is installed inside the furnace wall of the heat treatment furnace, and the damage of the heat exchanger cannot be directly observed when the burner is abnormal during normal production. Therefore, it is necessary to invent a method for quickly judging the cracking damage of the heat exchanger of the self-preheating burner, which can restore the damaged burner heat exchanger in time to ensure production and quality. SUMMARY

[0008] The technical problem to be solved by the present application is to provide a method for quickly judging the cracking damage of the heat exchanger of the self-preheating burner.

[0009] To solve the above problems, the technical scheme adopted by the present application is: A method for quickly judging the cracking damage of the heat exchanger of the self-preheating burner, first, through the abnormal burner fault report of the combustion system, the electrical control burner control fault frequency and code statistical analysis, the calibration of air-fuel ratio pressure, combined with the observation of abnormal flame in the furnace, the heat exchanger cracking can be judged; Then, the burner shell and the burner core of the unique burner structure are simply disassembled, and the heat exchanger of the burner core component is directly checked by naked eye and mechanically impacted by special tools to determine the crack width of the heat exchanger cracking; the crack width of the heat exchanger cracking is 1.5-5cm; Finally, use special tools to ignite a fire, and observe whether the smoke pipe of the burner is spouting fire under the reasonable mechanical impact in the heat exchanger combined with the negative pressure suction principle, which can judge the heat exchanger cracking, the crack width is 0.5-1.5cm. In the case of heat exchanger cracking with crack width less than 0.5cm, the air-fuel ratio pressure is not changed by calibration during normal production, the external coal gas slightly fluctuates, and the burner often appears red and spouts fire.

[0010] Due to the adoption of the above technical scheme, the present application has the following beneficial effects: The application can judge the cracking of the heat exchanger by observing the abnormal situation of the flame in the furnace, observing the state of the smoke pipe of the burner whether it is spouting fire, and judging the cracking of the heat exchanger and the crack width of 0.5-1.5 cm. In the case of cracking of the heat exchanger and the crack width of less than 0.5 cm, the air-fuel ratio pressure is not changed, the external gas slightly fluctuates, and the burner often appears the condition of red spouting fire.

[0011] The application can judge the cracking of the heat exchanger by observing the abnormal situation of the flame in the furnace, observing the state of the smoke pipe of the burner whether it is spouting fire, and judging the cracking of the heat exchanger and the crack width of 0.5-1.5 cm. In the case of cracking of the heat exchanger and the crack width of less than 0.5 cm, the air-fuel ratio pressure is not changed, the external gas slightly fluctuates, and the burner often appears the condition of red spouting fire.

[0012] The application can judge the cracking of the heat exchanger by observing the abnormal situation of the flame in the furnace, observing the state of the smoke pipe of the burner whether it is spouting fire, and judging the cracking of the heat exchanger and the crack width of 0.5-1.5 cm. In the case of cracking of the heat exchanger and the crack width of less than 0.5 cm, the air-fuel ratio pressure is not changed, the external gas slightly fluctuates, and the burner often appears the condition of red spouting fire. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a structural schematic diagram of the high-efficiency air self-preheating gas burner; Figure 2 is a practical diagram of the burner heat exchanger of Example 1; Figure 3 Cracking of burner heat exchanger for Example 2, crack width is 1.5-5cm; Figure 4 Cracking of burner heat exchanger for Example 3, crack width is 0.5-1.5cm; Figure 5 Cracking of burner heat exchanger for Example 4, crack width is less than 0.5cm; Figure 6 Cracking of burner heat exchanger for Example 3, Example 4, crack width is 0.5-1.5cm, less than 0.5cm special tool;

[0014] Figure 7 Flow chart of the basic invention. DETAILED DESCRIPTION

[0015] The application will be further described in detail below with examples.

[0016] A method for quickly determining the cracking damage of a self-preheating burner heat exchanger, as shown in the structure diagram of a high-efficiency air self-preheating gas burner, Figure 1 the flow chart. Figure 7

[0017] Comprising the following steps: S1, through the abnormal burner of the combustion system, statistical analysis of burner controller fault parameters; S2, calibrate the air-gas pressure difference parameters of the burner when burning normally; S3, observe and determine the flame abnormality when the burner is ignited manually; S4, disassemble the burner shell and the burner core, leak out the heat exchanger of the core components of the burner, directly check the inside of the heat exchanger with the naked eye, and at the same time use special tools to check and determine the inside of the heat exchanger by mechanical impact, to determine the crack width of the heat exchanger cracking; S5, according to the reasonable mechanical impact inside the heat exchanger, combined with the principle of negative pressure suction, observe whether the burner exhaust pipe is in the state of flame spouting; S6, when the external gas fluctuates slightly, determine the probability and frequency of the burner exhaust pipe burning red and spouting.

[0018] In step S1, the burner controller model is SCU460, which feeds back the abnormality of the combustion system through the fault code, specifically: Fault 13, abnormal flame signal, unable to detect flame signal, flame current less than 2uA, heat exchanger fracture, eight probability of body separation, heat exchanger cracking, crack width is 1.5-5cm two probability; ​Fault 14, flame check abnormal, unstable flame signal, flame current less than 10uA, heat exchanger cracking, crack width in 1.5-5cm five probability, crack width in 0.5-1.5cm five probability; Fault 15, flame abnormal, unstable flame signal, flame current less than 12uA, heat exchanger cracking, crack width in 0.5cm below five probability, crack width in 0.5-1.5cm five probability.

[0019] In step S2, specifically refers to: the burner includes three models, respectively SINMAX 5M model, SINMAX 4M model, SINMAX 3M model, SINMAX 5M model, SINMAX 4M model, SINMAX 3M model quantity decreases in turn; SINMAX 5M model of the burner normal combustion, control air gas pressure difference parameters are: gas pressure 30 (millibar), gas pressure 2 (millibar), air pressure 27 (millibar), air pressure difference 4 (millibar); SINMAX 4M model of the burner normal combustion, control air gas pressure difference parameters are: gas pressure 28 (millibar), gas pressure 2 (millibar), air pressure 25 (millibar), air pressure difference 4 (millibar); SINMAX 3M model of the burner normal combustion, control air gas pressure difference parameters are: gas pressure 40 (millibar), gas pressure 3 (millibar), air pressure 28 (millibar), air pressure difference 4 (millibar).

[0020] Burner heat exchanger damage, parameter abnormality, need to be re calibrated.

[0021] Heat exchanger cracking, crack width in three ranges: 1.5-5cm, 0.5-1.5cm, crack width below 0.5cm.

[0022] In S3, the flame abnormal condition includes flame color, temperature, and degree of aggregation, which can be divided into the following categories: Dark red, about 600 degrees Celsius, diffuse shapeless; Dark red, about 700 degrees Celsius, weak flame; Orange red, about 1000 degrees Celsius, gather no stiffness; Orange red, about 1000 degrees Celsius, gather stiffness small; Normal conditions of the fuel flame color and temperature for blue white, about 1400 degrees Celsius, gather with stiffness.

[0023] In S4, the tool mechanically impacts the inside of the heat exchanger to determine whether it is cracked or broken. If no cracks are found, the tool uses a 400 Newton hammer to impact the heat exchanger. If the heat exchanger is still not cracked or broken under the impact of the 400 Newton hammer, it is determined that the heat exchanger is normal and not damaged. If the impact is further increased, it will cause damage to the steel structure of the furnace wall and the refractory system of the heat treatment furnace.

[0024] In combination Figure 6 The tool is a special tool, including a tool body made of a steel pipe, a flat part provided at the end of the tool body, and grease applied on the flat part. The steel pipe is a DN25 seamless steel pipe with a thickness of 4.5 and a length of 1.35 meters. The flat part is 5 centimeters.

[0025] In S5, 0.1 kg of grease is applied on the flat part, which is placed inside the heat exchanger. A clear fire is generated by using high-temperature ignition oil. A 250 Newton hammer is used to repeatedly impact the heat exchanger along the edge of the fin to check for cracks. At this time, the induced draft fan exhaust pressure is adjusted to -1 kp to increase the suction. The state of the burner exhaust pipe is observed to determine whether the heat exchanger is cracked. In this scheme, the grease is No. 2 lithium-based grease of the Great Wall brand.

[0026] In the S5 step, slight fluctuations in external gas refer to the determination of the probability and frequency of the burner exhaust pipe burning red and spouting fire when the gas pressure is greater than 23 kpa. Specifically: When the heat value pressure of the gas used suddenly increases by 10% during the production of the high-efficiency air self-preheating gas burner in the quenching furnace, the flame burns inside the smoke pipe, and multiple burner non-metal exhaust pipes spout flames. The state of the burner exhaust pipe is observed to determine whether the heat exchanger is cracked. Embodiment 1

[0027] The embodiment is a method for quickly determining the cracking of the self-preheating burner heat exchanger of the heat treatment quenching furnace, which includes the following steps: Figure 6 The method includes controller fault parameter statistical analysis, air and gas pressure difference parameter calibration, observation and determination of abnormal flame of the burner manual control ignition, simple disassembly of the burner shell and burner core, direct naked eye inspection of the inside of the heat exchanger, and mechanical impact inspection determination of the special tool. The specific process steps are as follows: (1) Controller fault parameter statistical analysis process: the burner controller model is SCU460. SCU460 feeds back the abnormality of the combustion system through the fault code. SCU460 burner controller feeds back the fault code of the abnormality of the combustion system. Fault 13 flame signal abnormality, unable to detect the flame signal, flame current less than 2uA.

[0028] (2) Calibration process for air and gas pressure difference parameters: Three models of high-efficiency air self-preheating gas burners. 5M control parameters are gas pressure 30 (mbar), gas pressure 2 (mbar), air pressure 27 (mbar), and air pressure difference 4 (mbar). 4M control parameters are gas pressure 28 (mbar), gas pressure 2 (mbar), air pressure 25 (mbar), and air pressure difference 4 (mbar). 3M control parameters are gas pressure 40 (mbar), gas pressure 3 (mbar), air pressure 28 (mbar), and air pressure difference 4 (mbar).

[0029] (3) Observation and judgment process of abnormal flame conditions: The abnormal flame conditions of high-efficiency air self-preheating gas burner are dark red, around 600 degrees Celsius, and have no divergent shape; deep red, around 700 degrees Celsius, and the divergent flame is weak.

[0030] (4) Mechanical impact inspection and judgment process: The high-efficiency air self-preheating gas burner is disassembled to reveal the heat exchanger body. If the flame is abnormal and is dark red, around 600 degrees Celsius, and has no shape, the burner heat exchanger is directly observed to be broken. If the flame is abnormal and is dark red, around 700 degrees Celsius, and has a weak flame, use a special tool to use a 100 Newton impact force to inspect the heat exchanger to observe whether it is broken.

[0031] This embodiment quickly and accurately determines that the self-preheating burner heat exchanger is broken. Example 2

[0032] This embodiment provides a method for quickly determining cracks in a self-preheating burner heat exchanger of a heat treatment quenching furnace, wherein the crack width is 1.5-5 cm. Figure 3 , including statistical analysis of controller fault parameters; calibration of air and gas pressure difference parameters; observation and judgment of abnormal conditions of burner manual control ignition flame; simple disassembly of burner shell and burner core, direct visual inspection of the interior of the heat exchanger and mechanical impact inspection and judgment process using special tools. The specific process steps are as follows: (1) Statistical analysis process of controller fault parameters: SCU460 burner controller feedbacks the fault code of the combustion system abnormality, fault 13 flame signal abnormality, flame signal cannot be detected, flame current is less than 2uA, 35% probability; fault 14 flame calibration abnormality, flame signal is unstable, flame current is less than 10uA, 65% probability.

[0033] (2) Air gas pressure difference parameter calibration process: three models of high-efficiency air self-preheating gas burner. The 5M control parameters are gas pressure 30 (millibar), gas pressure 2 (millibar), air pressure 27 (millibar), and air pressure difference 4 (millibar). The 4M control parameters are gas pressure 28 (millibar), gas pressure 2 (millibar), air pressure 25 (millibar), and air pressure difference 4 (millibar). The 3M control parameters are gas pressure 40 (millibar), gas pressure 3 (millibar), air pressure 28 (millibar), and air pressure difference 4 (millibar).

[0034] (3) Flame abnormality observation and determination process: the flame of the high-efficiency air self-preheating gas burner is deep red, about 700 degrees Celsius, with weak scattered sparks; orange-red, about 1000 degrees Celsius, with flame gathering without rigidity.

[0035] (4) Mechanical impact inspection and determination process: the high-efficiency air self-preheating gas burner is disassembled and the heat exchanger body leaks out. When the flame observation is deep red, about 700 degrees Celsius, with weak scattered sparks, use a specially designed tool to impact the heat exchanger with an impact force of 100 Newton to observe cracking and shaking. When the flame observation is orange-red, about 1000 degrees Celsius, with flame gathering without rigidity, use a specially designed tool to impact the heat exchanger with an impact force of 400 Newton to observe cracking and shaking.

[0036] This embodiment quickly and accurately determines the cracking of the self-preheating burner heat exchanger, with a crack width of 1.5-5 cm. Example 3

[0037] This embodiment is a method for quickly determining the cracking of the self-preheating burner heat exchanger in a heat treatment quenching furnace, with a crack width of 0.5-1.5 cm, which comprises controller fault parameter statistical analysis; air gas pressure difference parameter calibration; burner manual control ignition flame abnormality observation and determination; simple disassembly of the burner shell and burner core, direct visual inspection of the heat exchanger inside, and mechanical impact inspection and determination of the specially designed tool; and reasonable mechanical impact combined with negative pressure suction principle to observe the state of the jet determination process. Figure 4 (1) Controller fault parameter statistical analysis process: the SCU460 burner controller feeds back abnormal fault codes of the combustion system. Fault 14: flame verification abnormality, unstable flame signal, flame current less than 10uA, 50% probability; fault 15: flame working abnormality, unstable flame signal, flame current less than 12uA, 50% probability.

[0038] ​(2) Calibration process for air and gas pressure difference parameters: Three models of high-efficiency air self-preheating gas burners. 5M control parameters are gas pressure 30 (mbar), gas pressure 2 (mbar), air pressure 27 (mbar), and air pressure difference 4 (mbar). 4M control parameters are gas pressure 28 (mbar), gas pressure 2 (mbar), air pressure 25 (mbar), and air pressure difference 4 (mbar). 3M control parameters are gas pressure 40 (mbar), gas pressure 3 (mbar), air pressure 28 (mbar), and air pressure difference 4 (mbar).

[0039] (3) Observation and judgment process of abnormal flame: The abnormal flame of high-efficiency air self-preheating gas burner is orange-red, around 1000 degrees Celsius, and has weak aggregation stiffness.

[0040] (4) Mechanical impact inspection and judgment process: The high-efficiency air self-preheating gas burner is disassembled to reveal the heat exchanger body. When the flame is abnormally orange-red, around 1000 degrees Celsius, and the aggregate stiffness is weak, use a special tool to use a 100 Newton impact force to check the heat exchanger to observe if there is any shaking. Use a special tool to use a 400 Newton impact force to check if there is any shaking.

[0041] (5) Reasonable mechanical impact combined with the principle of negative pressure suction and injection to observe the flame state judgment process: The high-efficiency air self-preheating gas burner is disassembled to leak out the heat exchanger. Direct observation combined with mechanical impact cannot determine whether the heat exchanger is broken or cracked. Use a special tool, apply 0.1kg of ordinary grease on the flat end, place it inside the heat exchanger, ignite it at high temperature to generate an open flame, and use a 250 Newton impact force to repeatedly impact along the edge of the heat exchanger fin. At the same time, adjust the exhaust pressure of the induced draft fan to -1kp, increase the suction force, and observe the state of the burner exhaust pipe with flame negative pressure suction and air ejection.

[0042] This embodiment quickly and accurately determines whether a self-preheating burner heat exchanger is cracked, and the crack width is 0.5-1.5 cm. Example 4

[0043] This embodiment provides a method for quickly determining cracks in a self-preheating burner heat exchanger of a heat treatment quenching furnace, wherein the crack width is less than 0.5 cm. Figure 5 , including statistical analysis of controller fault parameters; calibration of air and gas pressure difference parameters; observation and judgment of abnormal conditions of manual control ignition flame of burner; simple disassembly of burner shell and burner core, direct visual inspection of the interior of heat exchanger and mechanical impact inspection and judgment using special tools; reasonable mechanical impact inside the heat exchanger combined with the principle of negative pressure suction and injection to observe the state of flame spraying; and combined with the judgment of the red-hot flame spraying condition of exhaust pipe caused by gas fluctuation. The specific process steps are as follows: (1) Controller failure parameter statistical analysis process: SCU460 burner controller feedback combustion system abnormal fault code, fault 14 flame check abnormal, unstable flame signal, flame current less than 10uA, 10% probability; fault 15 flame working abnormally, unstable flame signal, flame current less than 12uA, 50% probability.

[0044] (2) Air-gas pressure difference parameter calibration process: three models of high-efficiency air self-preheating gas burner. The control parameters of 5M are gas pressure 30 (millibar), gas pressure 2 (millibar), air pressure 27 (millibar), and air pressure difference 4 (millibar). The control parameters of 4M are gas pressure 28 (millibar), gas pressure 2 (millibar), air pressure 25 (millibar), and air pressure difference 4 (millibar). The control parameters of 3M are gas pressure 40 (millibar), gas pressure 3 (millibar), air pressure 28 (millibar), and air pressure difference 4 (millibar).

[0045] (3) Flame abnormality observation and determination process: high-efficiency air self-preheating gas burner flame abnormality observation orange, about 1000 degrees Celsius, and weak aggregation stiffness.

[0046] (4) Mechanical impact check and determination process: high-efficiency air self-preheating gas burner disassembly leaks heat exchanger body. When the flame abnormality observation is orange, about 1000 degrees Celsius, and weak aggregation stiffness, use 100 Newton impact force to impact the heat exchanger with special tools, and observe no shaking. Use 400 Newton impact force to impact the heat exchanger with special tools, and observe no shaking.

[0047] (5) Reasonable mechanical impact combined with negative pressure suction principle to observe the state of jet flame determination process: high-efficiency air self-preheating gas burner disassembly leaks heat exchanger, direct observation with mechanical impact cannot determine the existence of heat exchanger cracking or cracking. Use special tools, such as Figure 6 Example 3, Example 4 burner heat exchanger cracking, crack width 0.5-1.5cm, 0.5cm below special tool figure, flat one end smeared with 0.1kg ordinary grease, placed inside the heat exchanger, ignited by high temperature to produce open fire, use 250 Newton impact force along the heat exchanger fin edge repeatedly, while the induced draft fan exhaust pressure is adjusted to -1kp, increase the suction, observe the burner exhaust pipe without flame negative pressure suction jet state.

[0048] (6) The determination process of the red jet condition of the smoke exhaust pipe caused by the gas fluctuation: the high-efficiency air self-preheating gas burner is disassembled and leaks out of the heat exchanger, and the state of the jet cannot be determined by directly observing the mechanical impact without and reasonable mechanical impact combined with the principle of negative pressure suction. Combined with the close observation of the external gas fluctuation in production, when the high-efficiency air self-preheating gas burner is used in the quenching furnace production, when the heat value pressure of the gas suddenly rises by 10%, the combustion is insufficient, the flame burns inside the smoke pipe, and the flame often appears in the non-metal smoke exhaust pipe with the burner. The state of the jet of the burner smoke exhaust pipe determines the cracking of the heat exchanger.

[0049] This embodiment quickly and accurately determines the cracking of the self-preheating burner heat exchanger, and the crack width is less than 0.5 cm.

Claims

1. A method for quickly determining cracking and damage of a self-preheating burner heat exchanger, characterized by: The steps include: S1. Analyze the fault parameters of the burner controller based on the abnormal burner fault report in the combustion system; S2. Calibrate the air-gas pressure difference parameters of the burner during normal combustion; S3. Observe and determine the abnormal flame condition during manual control ignition of the burner; S4. Disassemble the burner shell and burner core to expose the heat exchanger of the burner core component. Visually inspect the interior of the heat exchanger. Use tools to perform a mechanical impact inspection to determine the width of the cracks in the heat exchanger. S5. Based on the reasonable mechanical impact inside the heat exchanger and the principle of negative pressure suction and injection, observe the burner exhaust pipe to determine whether it is spraying fire; S6. When the external gas fluctuates slightly, the probability and frequency of the exhaust pipe of the burner burning red and spitting flames are determined.

2. A method for quickly determining cracking and damage of a self-preheating burner heat exchanger according to claim 1, characterized in that: In step S1, the burner controller model is SCU460, and SCU460 feedbacks the abnormality of the combustion system through the fault code, specifically: Fault 13: Flame signal abnormality, flame signal cannot be detected, flame current is less than 2uA, heat exchanger is broken, body separation has an 80% probability, heat exchanger is cracked, crack width is 1.5-5cm has a 20% probability; Fault 14: Flame calibration abnormality, flame signal instability, flame current less than 10uA, heat exchanger cracking, crack width of 1.5-5cm with a 50% probability, crack width of 0.5-1.5cm with a 50% probability; Fault 15: abnormal flame operation, unstable flame signal, flame current less than 12uA, heat exchanger cracking, crack width less than 0.5cm with a 50% probability, crack width between 0.5-1.5cm with a 50% probability.

3. The method for quickly determining cracking and damage of a self-preheating burner heat exchanger according to claim 1, characterized in that: In step S2, specifically, the burners include three models, namely SINMAX 5M, SINMAX 4M, and SINMAX 3M, and the number of SINMAX 5M, SINMAX 4M, and SINMAX 3M models decreases in sequence; When the SINMAX 5M burner is burning normally, the air and gas pressure difference parameters are: gas pressure 30 mbar, gas pressure 2 mbar, air pressure 27 mbar, and air pressure difference 4 mbar; When the SINMAX 4M burner is burning normally, the air and gas pressure difference parameters are: gas pressure 28 mbar, gas pressure 2 mbar, air pressure 25 mbar, and air pressure difference 4 mbar; When the SINMAX 3M burner is burning normally, the air and gas pressure difference parameters are controlled as follows: gas pressure 40 mbar, gas pressure 3 mbar, air pressure 28 mbar, and air pressure difference 4 mbar.

4. The method for quickly determining cracking and damage of a self-preheating burner heat exchanger according to claim 1, characterized in that: The heat exchanger is cracked, and the crack width is in three ranges: 1.5-5cm, 0.5-1.5cm, and crack width is less than 0.5cm.

5. The method for quickly determining cracking and damage of a self-preheating burner heat exchanger according to claim 1, characterized in that: In S3, flame anomalies include flame color, temperature, and concentration, which are divided into the following categories: Dark red, about 600 degrees Celsius, divergent and shapeless; Deep red, about 700 degrees Celsius, with weak radiating flames; Orange-red, around 1000 degrees Celsius, aggregated and without stiffness; Orange-red, around 1000 degrees Celsius, weak aggregation stiffness; Under normal conditions, the flame color and temperature of the fuel are bluish-white, around 1400 degrees Celsius, and are aggregated and rigid.

6. The method for quickly determining cracking and damage of a self-preheating burner heat exchanger according to claim 1, characterized in that: In S4, the tool performs a mechanical impact inspection on the inside of the heat exchanger, which means: using an impact force of 100 Newtons to check whether the heat exchanger has any breakage or cracking. If no obvious cracking is found, the tool uses an impact force of 400 Newtons to check for cracking of the heat exchanger. If there is still no breakage or cracking under the impact force of 400 Newtons, it is determined that the heat exchanger is normal and not damaged.

7. A method for quickly determining cracking and damage of a self-preheating burner heat exchanger according to claim 6, characterized in that: The tool is a special tool, including a tool body made of steel pipe, a flat part set at the end of the tool body, and grease applied to the flat part. The steel pipe is a DN25 seamless steel pipe with a thickness of 4.5, a length of 1.35 meters, and a flat part of 5 centimeters.

8. The method for quickly determining cracking and damage of a self-preheating burner heat exchanger according to claim 7, characterized in that: In S5, 0.1 kg of grease is applied to the flat portion, which is then placed inside the heat exchanger. The grease is ignited at high temperature to generate an open flame. A force of 250 Newtons is applied to the edge of the heat exchanger fins to repeatedly impact the heat exchanger to check for cracks. The exhaust pressure of the induced draft fan is adjusted to -1 kp, and the suction is increased. The burner exhaust pipe is observed to see if it is emitting flames, thereby determining whether the heat exchanger is cracked.

9. A method for quickly determining cracking and damage of a self-preheating burner heat exchanger according to claim 8, characterized in that: The grease used is Great Wall brand No. 2 lithium-based grease.

10. The method for quickly determining cracking and damage of a self-preheating burner heat exchanger according to claim 1, characterized in that: In S6, Slight fluctuation of external gas refers to the probability and frequency of the exhaust pipe of the burner often burning red and spitting fire when the gas pressure is greater than 23kPa. Specifically, it means: In the production of quenching furnaces, when the calorific value pressure of the gas suddenly increases by 10%, incomplete combustion occurs, and the flame burns inside the flue gas pipe, flames will appear in the non-metallic exhaust pipes with multiple burners. Observe the flame state of the burner exhaust pipe to determine the cracking of the heat exchanger.

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