A method for synchronous flame cutting of narrow and long steel plates using two cutting torches

Abstract

A method for synchronous dual-torch flame cutting of narrow, long steel plates employs two torches. The two torches utilize identical flame cutting process parameters, including cutting speed, torch model and nozzle size, gas type and pressure, and the angle between the nozzle and the steel plate surface. However, the distance between the torch nozzles and the steel plate surface is adjusted based on the temperature difference between the two sides of the narrow, long steel plate after cutting, maintaining the temperature difference within 10°C or even 5°C. An empirical control model for the distance difference between the two torch nozzles and the steel plate surface is established. The method provided by the present invention can rapidly adjust the temperature difference between the two sides of the narrow, long steel plate during flame cutting, effectively alleviating the problem of lateral bending during flame cutting of the narrow, long steel plate. The method is simple to operate and implement, and has potential for widespread application.

Description

Technical Field

[0001] The invention belongs to the technical field of steel plate processing and relates to a double-torch synchronous flame cutting method for narrow and long strip steel plates. Background Art

[0002] When torch cutting narrow, long steel plates, uneven thermal stress along the two long sides often causes lateral bowing. Public literature indicates that using dual-torch simultaneous torch cutting on both long sides can effectively reduce the thermal stress differential and alleviate the lateral bowing problem. However, the dual-torch torch cutting process parameters significantly impact thermal stress, especially for the side and center torches, which are affected by factors such as ambient temperature and plate thickness. Therefore, setting these process parameters is crucial for minimizing thermal stress and preventing lateral bowing in narrow, long steel plates. Summary of the Invention

[0003] The object of the present invention is to provide a method for synchronous flame cutting of narrow and long strip steel plates using dual cutting torches, and to significantly improve the side bending problem of narrow and long strip steel plates by optimizing the flame cutting process using dual cutting torches.

[0004] The technical solution of the present invention:

[0005] A method for synchronous flame cutting of narrow and long steel plates with two cutting torches, the key process steps include:

[0006] (1) Level the steel plate to be cut;

[0007] (2) Two flame cutting torches are set in the length direction of the steel plate and arranged in parallel in the width direction with a distance between them equal to the required width of the narrow strip steel plate after cutting. At the same time, a thermometer is set 100 mm behind each cutting torch to measure the temperature of the edge of the narrow strip steel plate 5 mm away from the cutting seam;

[0008] (3) During the flame cutting process, the two cutting torches are controlled to use the same cutting speed for synchronous, uniform and parallel movement. At the same time, the selected torch model and cutting nozzle size, gas type and pressure, inclination angle between the cutting nozzle and the steel plate surface and other flame cutting process parameters are consistent, but the distance between the cutting nozzle and the steel plate surface will be adjusted according to the temperature difference measured by the two thermometers: Assuming that the temperature difference is ΔT, the corresponding distance difference between the cutting nozzle and the steel plate surface is Δh0, then the distance between the cutting nozzle on the side with higher temperature and the steel plate surface is Δh=Δh0+0.1ΔT(1-exp(-0.1ΔT)), where Δh and Δh0 are measured in mm, and ΔT is measured in ℃, which are positive numbers; give priority to adjusting the edge cutting torch, but ensure that the distance between the flame core and the steel plate surface should be no less than 3mm; continuously adjust the appropriate Δh during the cutting process to make ΔT≤10℃ until the cutting is completed.

[0009] Preferably, in step (3), the appropriate Δh is continuously adjusted during the cutting process to make ΔT ≤ 5°C.

[0010] Furthermore, when the flame cutting starts, the distance between the edge cutting torch nozzle and the steel plate surface is adjusted to be Δh greater than the distance between the middle cutting torch nozzle and the steel plate surface. 00 =0.3T R +0.1t-3, where t is the thickness of the steel plate, T R is room temperature, Δh 00 and t in mm, T R Measure in °C and then make appropriate adjustments based on ΔT.

[0011] The present invention has the following beneficial effects: When performing simultaneous dual-torch torch cutting of narrow, long steel plates, the present invention uses measured data on the temperature difference between the side edges of the narrow, long steel plates under different torch cutting conditions, such as steel plate thickness and ambient temperature, to control the temperature difference range by adjusting the distance between the torch nozzle and the steel plate surface. This allows for the development of an empirical control model. The method provided by the present invention allows for rapid adjustment of the temperature difference between the two sides of the narrow, long steel plate during torch cutting, effectively alleviating the problem of lateral bending during torch cutting. The method is simple to operate and implement, and has potential for widespread application. DETAILED DESCRIPTION

[0012] The present invention will be further described with reference to the following examples.

[0013] Example 1:

[0014] A method for synchronous flame cutting of narrow strip steel plates with two cutting torches, the thickness of the steel plate is 30 mm, and the ambient temperature is T R The temperature is 10℃, and the key process steps include:

[0015] (1) Level the steel plate to be cut;

[0016] (2) Two flame cutting torches are set in the length direction of the steel plate and arranged in parallel in the width direction with a distance between them equal to the required width of the narrow strip steel plate after cutting. At the same time, a thermometer is set 100 mm behind each cutting torch to measure the temperature of the edge of the narrow strip steel plate 5 mm away from the cutting seam;

[0017] (3) During the flame cutting process, the two cutting torches were controlled to move synchronously and uniformly at a cutting speed of 420 mm / min. At the same time, 3# cutting torches were used, the cutting nozzle aperture was 1.0 mm, propane and oxygen cutting were used, the cutting oxygen pressure was 0.6 MPa, the cutting nozzles were tilted backwards from the steel plate surface, and the tilt angle was 15°. Other flame cutting process parameters remained the same. At the beginning of the flame cutting, the difference Δh between the distance between the edge cutting torch nozzle and the steel plate surface and the distance between the middle cutting torch nozzle and the steel plate surface was 00 =0.3T R+0.1t-3 empirical formula, adjust the distance between the cutting nozzle of the edge cutting torch and the steel plate surface to 10mm, the distance between the cutting nozzle of the middle cutting torch and the steel plate surface to 7mm, and then adjust the distance between the cutting nozzle and the steel plate surface according to the temperature difference ΔT measured by the two thermometers: when the flame cutting is about 150mm, the temperature measured by the thermometer behind the edge cutting torch is 8℃ lower than the temperature measured by the thermometer behind the middle cutting torch. At this time, the distance difference between the cutting nozzle of the middle cutting torch and the steel plate surface is ΔT. Δh0=-3mm. According to the empirical formula Δh=Δh0+0.1ΔT(1-exp(-0.1ΔT)), the distance between the cutting nozzle of the side with higher temperature and the surface of the steel plate is different from that between the cutting nozzle of the side with lower temperature. The distance between the cutting nozzle of the side cutting torch and the surface of the steel plate is adjusted to 9.6mm, and the distance between the cutting nozzle of the middle cutting torch and the surface of the steel plate remains unchanged at 7mm. After the adjustment, the temperature difference ΔT measured by the two thermometers is 2°C. Then, the adjusted flame cutting parameters are followed until the cutting is completed.

[0018] After flame cutting, the side bending of the narrow strip steel plate was measured to be within 2mm.

[0019] Example 2:

[0020] A method for synchronous flame cutting of narrow strip steel plates with two cutting torches, the thickness of the steel plate is 50 mm, and the ambient temperature is T R The temperature is -10℃, and the key process steps include:

[0021] (1) Level the steel plate to be cut;

[0022] (2) Two flame cutting torches are set in the length direction of the steel plate and arranged in parallel in the width direction with a distance between them equal to the required width of the narrow strip steel plate after cutting. At the same time, a thermometer is set 100 mm behind each cutting torch to measure the temperature of the edge of the narrow strip steel plate 5 mm away from the cutting seam;

[0023] (3) During the flame cutting process, the two cutting torches are controlled to move synchronously, uniformly and in parallel at a cutting speed of 350 mm / min. At the same time, 4# cutting torches are used, the cutting nozzle aperture is 1.25 mm, acetylene and oxygen cutting are used, and the cutting oxygen pressure is 0.6 MPa. The cutting nozzles are perpendicular to the surface of the steel plate. Other flame cutting process parameters remain the same, but the distance between the cutting nozzle and the surface of the steel plate will be adjusted according to the temperature difference measured by the two thermometers: at the beginning of the flame cutting, the distance between the cutting nozzles of the edge cutting torch and the middle cutting torch and the surface of the steel plate is set to 4 mm. When the flame cutting is about 150 mm, the temperature measured by the thermometer behind the edge cutting torch is higher than that behind the middle cutting torch. The temperature measured by the thermometer is 15°C lower. According to the empirical formula of the distance difference between the cutting nozzle on the side with higher temperature and the steel plate surface compared with the distance difference between the cutting nozzle on the side with lower temperature and the steel plate surface Δh=Δh0+0.1ΔT(1-exp(-0.1ΔT)) (at this time, the distance difference between the cutting nozzle of the middle cutting torch and the steel plate surface and the distance between the cutting nozzle of the side cutting torch and the steel plate surface Δh0=0mm), the distance between the cutting nozzle of the middle cutting torch and the steel plate surface is adjusted to 5mm, and the distance between the cutting nozzle of the side cutting torch and the steel plate surface is adjusted to 3.8mm. After adjustment, the temperature difference ΔT measured by the two thermometers is 5°C. Then, the adjusted flame cutting parameters are followed until the cutting is completed.

[0024] After flame cutting, the side bending of the narrow strip steel plate was measured to be within 2mm.

[0025] Example 3: A method for synchronous cutting of a narrow strip of steel plate with two torches, the thickness of the steel plate is 100 mm, and the ambient temperature is T R The temperature is 30°C, and the key process steps include:

[0026] (1) Level the steel plate to be cut;

[0027] (2) Two flame cutting torches are set in the length direction of the steel plate and arranged in parallel in the width direction with a distance between them equal to the required width of the narrow strip steel plate after cutting. At the same time, a thermometer is set 100 mm behind each cutting torch to measure the temperature of the edge of the narrow strip steel plate 5 mm away from the cutting seam;

[0028] (3) During the flame cutting process, the two cutting torches were controlled to move synchronously and uniformly at a cutting speed of 200 mm / min. At the same time, 6# cutting torches were used, the cutting nozzle aperture was 1.75 mm, acetylene and oxygen cutting were used, the cutting oxygen pressure was 0.7 MPa, the cutting nozzles were perpendicular to the steel plate surface, and other flame cutting process parameters were kept consistent; at the beginning of the flame cutting, the difference Δh between the distance between the edge cutting torch nozzle and the steel plate surface and the distance between the middle cutting torch nozzle and the steel plate surface was calculated. 00 =0.3T R+0.1t-3 empirical formula, adjust the distance between the cutting nozzle of the side cutting torch and the steel plate surface to 23mm, the distance between the cutting nozzle of the middle cutting torch and the steel plate surface to 7mm, when the flame cutting is about 150mm, the temperature measured by the thermometer behind the side cutting torch is 4℃ higher than the temperature measured by the thermometer behind the middle cutting torch. At this time, the distance between the cutting nozzle and the steel plate surface is no longer adjusted according to the temperature difference ΔT measured by the two thermometers, and the flame cutting parameters are followed until the cutting is completed.

[0029] After flame cutting, the side bending of the narrow strip steel plate was measured to be within 1mm.

Claims

1. A method for synchronous flame cutting of narrow strip steel plates with two cutting torches, characterized in that The key process steps include: (1) Level the steel plate to be cut; (2) Two flame cutting torches are set in the length direction of the steel plate and arranged in parallel in the width direction with a distance between them equal to the required width of the narrow strip steel plate after cutting. At the same time, a thermometer is set 100 mm behind each cutting torch to measure the temperature of the edge of the narrow strip steel plate 5 mm away from the cutting seam; (3) During the flame cutting process, the two cutting torches are controlled to move synchronously, uniformly and parallelly at the same cutting speed. At the same time, the selected cutting torch model, cutting nozzle size, gas type and pressure, and the inclination angle between the cutting nozzle and the steel plate surface are consistent. However, the distance between the cutting nozzle and the steel plate surface will be adjusted according to the temperature difference measured by the two thermometers: Assume that the temperature difference is , the distance difference between the cutting nozzle and the steel plate surface is , the distance between the cutting nozzle on the side with higher temperature and the steel plate surface is greater than the distance between the cutting nozzle on the side with lower temperature and the steel plate surface. ,in and In mm, It is measured in degrees Celsius and is a positive number. Prioritize adjusting the edge cutting torch, but ensure that the distance between the flame core and the steel plate surface is not less than 3mm. Continuously adjust the appropriate ,make , until the cutting is completed.

2. The method for synchronous twin-torch flame cutting of narrow strip steel plates according to claim 1, characterized in that: In step (3), when the flame cutting starts, the distance between the edge cutting torch nozzle and the steel plate surface is adjusted to be slightly different from the distance between the middle cutting torch nozzle and the steel plate surface. ,in t is the thickness of the steel plate, T R is room temperature, and t In mm, T R In °C, then according to Make appropriate adjustments.

3. The method for synchronous twin-torch flame cutting of narrow strip steel plates according to claim 1, characterized in that: In step (3), the appropriate ,make .