Crack arrest steel cutting method

Abstract

The invention provides a crack arrest steel cutting method. The crack arrest steel cutting method comprises the following steps that S1, flame cutting equipment is adjusted to be in a preheating mode; s2, the two sides of the workpiece cutting line are preheated for the first time to reach the first target temperature; s3, the two sides of the workpiece cutting line are preheated for the second time to reach the second target temperature; and S4, cutting operation is conducted on the workpiece. According to the crack arrest steel cutting method provided by the invention, the cutting effect of the groove (the thickness t is greater than 30mm) meets the process requirement by increasing the heat conduction range under the condition of ensuring that the structure property of the material is not changed. Meanwhile, the method has the characteristics of lowest cost, high operability and the like. The cutting method is easy to operate, suitable for external field operation and not limited by fields, large equipment and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of crack arrest steel cutting, and in particular relates to a crack arrest steel cutting method. Background Art

[0002] As the name implies, crack arrest steel has crack arrest performance. The crack arrest performance of BCA1 crack arrest steel is: -10℃ crack arrest toughness Kca≥6000N / mm3 / 2 (NDTT, P2, Side, -35℃ NO BRECK), and the carbon equivalent specification allows it to reach 0.49. It has high requirements for heat input control, high requirements for thermal deformation control, and is difficult to adjust after deformation. Especially for thick plates (t>50mm), the requirements for cutting and cutting are very high. Conventional flame cutting methods are prone to defects such as incomplete bevel cutting or bevel jagged, which cannot meet the subsequent assembly and welding requirements.

[0003] In the working environment of field cutting operation (without large plasma cutting equipment), conventional flame cutting can only be used to cut parts or open on-site bevels for crack arrest steel, which is very easy to cause the following problems: bevels are jagged, straightness is poor, and the root retention does not meet the requirements. Especially for opening X bevels, thick plate bevel cutting research and quality control are required to reduce the impact on the next process. Due to the large thickness of the material, it is very easy to not cut through. You can use the method of cutting the bevel to leave a margin, and then machine the parts to the specified size requirements, which takes a long time and costs a lot. Summary of the invention

[0004] The present invention provides a method for cutting crack arrest steel, comprising the following steps:

[0005] S1: Set the flame cutting equipment to preheating mode;

[0006] S2: Preheating both sides of the workpiece cutting line for the first time to a first target temperature;

[0007] S3: preheating both sides of the workpiece cutting line for the second time to a second target temperature;

[0008] S4: Cutting the workpiece.

[0009] Further: In S2, both sides of the cutting line of the workpiece are preheated for the first time at a speed of 20 mm / min.

[0010] Further: In S2, the first preheating is performed on the range of 80 mm on both sides of the cutting line of the workpiece.

[0011] Further: in S2, an infrared temperature measuring gun is used to monitor the temperature of the first preheating flame travel path.

[0012] Further: in said S2, preheating to a first target temperature is such that the surface temperature of the workpiece cutting line is between 80°C and 120°C.

[0013] Further: In S3, both sides of the cutting line of the workpiece are preheated for a second time at a speed of 20 mm / min.

[0014] Further: In S3, a second preheating is performed on the range of 80 mm on both sides of the cutting line of the workpiece.

[0015] Further: in S3, an infrared temperature measuring gun is used to monitor the temperature of the second preheating flame travel path.

[0016] Further: in said S3, preheating to a second target temperature is such that the surface temperature of the workpiece cutting line is between 110°C and 180°C.

[0017] Further: in said S4, the flame cutting equipment is switched from a preheating mode to a cutting mode.

[0018] The beneficial effects brought by the present invention are as follows:

[0019] It can be seen from the above scheme that the present invention provides a method for cutting crack arrest steel. By increasing the heat conduction range without changing the material structure and performance, the cutting effect of the groove (thickness t>30mm) meets the process requirements. At the same time, this method has the characteristics of lowest cost and strong operability. The cutting method is simple to operate and is suitable for field operations, and is not subject to restrictions such as site and large equipment. It can cover the cutting of plates with process requirements such as 45-degree groove, single-sided groove, and X-shaped groove of large thick plates. There is no need to add additional equipment or tooling to ensure the quality of crack arrest steel, and it has strong operability. Only conventional oxygen and acetylene are required as flame sources, and no large plasma cutting machine is required, which reduces the cost of handling and transporting workpieces. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A flow chart of a crack arrest steel cutting method provided by the present invention is shown. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] like Figure 1 As shown: A method for cutting crack arrest steel provided by the present invention comprises the following steps:

[0023] S1: Set the flame cutting equipment to preheating mode;

[0024] S2: Preheating both sides of the workpiece cutting line for the first time to a first target temperature;

[0025] S3: preheating both sides of the workpiece cutting line for the second time to a second target temperature;

[0026] S4: Cutting the workpiece.

[0027] The present invention provides a method for cutting crack arrest steel. By increasing the heat conduction range without changing the material's organizational properties, the cutting effect of the groove (thickness t>30mm) meets the process requirements. At the same time, the method has the characteristics of lowest cost and strong operability. The cutting method is simple to operate and is suitable for field operations without being restricted by site, large equipment and other restrictions. It can cover the cutting of plates with process requirements such as 45-degree grooves, single-sided grooves, and X-shaped grooves of large thick plates. There is no need to add additional equipment or tooling to ensure the process quality of the crack arrest steel, and the operability is strong. Only conventional oxygen and acetylene are required as flame sources, and no large plasma cutting machine is required, which reduces the cost of handling and transporting workpieces.

[0028] Specifically, S1: adjusting the flame cutting equipment to a preheating mode;

[0029] Conventional oxygen and acetylene are used as flame sources.

[0030] S2: Preheating both sides of the workpiece cutting line for the first time to a first target temperature;

[0031] Furthermore, the first preheating is performed on both sides of the workpiece cutting line at a speed of 20 mm / min. The first preheating is performed within 80 mm on both sides of the workpiece cutting line. The temperature of the first preheating flame travel path is monitored by an infrared temperature measuring gun. The first target temperature is preheated to a surface temperature of the workpiece cutting line between 80°C and 120°C.

[0032] Specifically, the first preheating is performed on the workpiece within 80mm on both sides of the cutting line at a speed of 20mm / minute. During the first preheating process, an infrared temperature measuring gun is used to monitor the temperature of the first preheating flame path. The first preheating requires the surface temperature of the workpiece cutting line to be between 80℃-120℃, and the interval temperature is adjusted by fine-tuning the cutting machine travel speed.

[0033] S3: preheating both sides of the workpiece cutting line for the second time to a second target temperature;

[0034] Furthermore, the second preheating is performed on both sides of the workpiece cutting line at a speed of 20 mm / min. The second preheating is performed within 80 mm on both sides of the workpiece cutting line. The temperature of the second preheating flame travel path is monitored by an infrared temperature measuring gun. The second target temperature is preheated to a surface temperature of the workpiece cutting line between 110°C and 180°C.

[0035] Specifically, the second preheating is performed on the 80mm range on both sides of the workpiece cutting line at a speed of 20mm / minute. During the second preheating process, an infrared temperature measuring gun is used to monitor the temperature of the second preheating flame walking path. The second preheating requires the surface temperature of the workpiece cutting line to be between 110℃-180℃, and the interval temperature is adjusted by fine-tuning the cutting machine walking speed.

[0036] S4: Cutting the workpiece.

[0037] Further, the flame cutting equipment is switched from the preheating mode to the cutting mode, and the workpiece is cut according to the conventional process.

[0038] The present invention provides a method for cutting crack arrest steel. By increasing the heat conduction range without changing the material structure and performance, the cutting effect of the groove (thickness t>30mm) meets the process requirements. At the same time, the method has the characteristics of lowest cost and strong operability. The cutting method is simple to operate and is suitable for field operations, and is not restricted by site, large equipment and other restrictions. It can cover the cutting of plates with process requirements such as 45-degree grooves, single-sided grooves, and X-shaped grooves of large thick plates. No additional equipment or tooling is required to ensure the quality of crack arrest steel, and the operability is strong. Only conventional oxygen and acetylene are required as flame sources, and no large plasma cutting machine is required, which reduces the cost of handling and transporting workpieces. The operation is flexible, and the equipment can be moved with the position of the workpiece, and there is no need to move the steel plate to other large equipment sites. There is no need to change the working environment of the workers, only simple technical training is required, and the operation can be carried out according to the process requirements.

[0039] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for cutting crack arrest steel, characterized in that: The following steps are involved: S1: Set the flame cutting equipment to preheating mode; S2: Preheating both sides of the workpiece cutting line for the first time to a first target temperature; S3: preheating both sides of the workpiece cutting line for the second time to a second target temperature; S4: Cutting the workpiece.

2. The method for cutting crack arrest steel according to claim 1, characterized in that: In S2, both sides of the cutting line of the workpiece are preheated for the first time at a speed of 20 mm / min.

3. The method for cutting crack arrest steel according to claim 1, characterized in that: In S2, the first preheating is performed on the area within 80 mm on both sides of the cutting line of the workpiece.

4. The method for cutting crack arrest steel according to claim 1, characterized in that: In S2, an infrared temperature measuring gun is used to monitor the temperature of the first preheating flame travel path.

5. The method for cutting crack arrest steel according to claim 1, characterized in that: In S2, the workpiece is preheated to a first target temperature, which is a surface temperature of the cutting line of the workpiece between 80°C and 120°C.

6. The method for cutting crack arrest steel according to claim 1, characterized in that: In S3, both sides of the cutting line of the workpiece are preheated for the second time at a speed of 20 mm / min.

7. The method for cutting crack arrest steel according to claim 1, characterized in that: In S3, a second preheating is performed on the area within 80 mm on both sides of the cutting line of the workpiece.

8. The method for cutting crack arrest steel according to claim 1, characterized in that: In S3, an infrared temperature measuring gun is used to monitor the temperature of the second preheating flame travel path.

9. The method for cutting crack arrest steel according to claim 1, characterized in that: In S3, the workpiece is preheated to a second target temperature, which is a surface temperature of the cutting line of the workpiece between 110°C and 180°C.

10. The method for cutting crack arrest steel according to claim 1, characterized in that: In S4, the flame cutting equipment is switched from a preheating mode to a cutting mode.

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