Plasma cutting method for NM500 high-grade wear-resistant steel
By employing plasma cutting methods and scientific process parameters, the problems of low cutting accuracy and efficiency of NM500 wear-resistant steel have been solved, enabling high-precision cutting of complex shapes and curves, reducing the heat-affected zone and safety hazards, and improving cutting quality and safety.
Patent Information
- Application Number
- CN202511042903.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-28
- Publication Date
- 2025-11-07
AI Technical Summary
Existing technologies for cutting NM500 high-grade wear-resistant steel suffer from problems such as poor cutting accuracy, low efficiency, large heat-affected zone, and safety hazards, especially when cutting complex shapes and curves.
The plasma cutting method is adopted, combined with a remote monitoring system and scientifically reasonable cutting process parameters, including the cutting machine network structure, camera monitoring, MES system communication, and personalized cutting program design for steel plates with different alloy compositions. In particular, low alloy steel plates are not preheated, while high alloy steel plates are preheated before cutting. The Huayuan LG-200HA frequency conversion plasma cutting machine is used for cutting.
It achieves high-precision cutting of complex shapes and curves, reduces the heat-affected zone, improves cutting efficiency and safety, avoids cutting stress cracks, and ensures cutting quality and safety.
Smart Images
Figure CN120901430A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application discloses a plasma cutting method for NM500 high-grade wear-resistant steel and relates to the technical field of plasma cutting of metal materials. BACKGROUND
[0002] NM500 high-grade wear-resistant steel is widely applied to mining machinery, coal mining and transportation, engineering machinery and cement equipment and can meet the use requirements of high wear resistance, long service life, simple cold forming and welding of key wear-resistant parts of large engineering machinery working in harsh environments. The steel is commonly used for manufacturing parts such as blades, buckets, hammer heads of various crushers, electric shovels for coal mining, automatic loading and unloading mine vehicles and trough bottom lining plates of scraper conveyors. The higher the hardness of wear-resistant steel is, the better the wear resistance is, and the problem that follows is that the cutting and welding processing of the steel plate is difficult. In most cases, for 500HB-grade wear-resistant steel plates, due to the high C and high alloy component design and the martensite structure after quenching and low-temperature tempering heat treatment, the crack tendency is strong. In order to avoid cutting cracks of the steel plate, the steel plate is usually cut and processed by using warm flame cutting or preheating flame cutting. Although the warm flame cutting has simple equipment structure and low processing cost, the cutting precision is poor, the efficiency is low, the heat affected area is large, and the use of combustible gases (commonly used acetylene and propane) may cause explosion or fire safety hazards. Based on this, the application develops a plasma cutting test for NM500 high-grade wear-resistant steel, gives relevant plasma cutting process parameters under the premise of ensuring no cracks of NM500 wear-resistant steel with different alloy components after cutting and realizes industrialized popularization and application, and improves the cutting efficiency and cutting quality of 500HB high-grade wear-resistant steel. SUMMARY
[0003] The application aims to provide a plasma cutting method for NM500 high-grade wear-resistant steel. By using the method, curve or complex shape can be cut, the heat affected area can be effectively reduced, the cutting precision and cutting efficiency can be improved, the operation safety factor can be improved, the residual stress of the cutting part can be reduced, the cutting stress crack can be avoided, and thus good cutting quality can be obtained.
[0004] The technical scheme of the application is as follows. The application discloses a plasma cutting method for NM500 high-grade wear-resistant steel, and the chemical composition of the steel is as follows in percentage by mass: C=0.2%-0.3%, Si=0.20-0.35%, Mn=0.9-1.0%, P=0.007%-0.01%, S=0.0013%-0.0022%, Alt=0.035%-0.075%, Cr=0.25%-0.65%, Nb=0.016%-0.025%, Ti=0.009%-0.011%, Mo<=0.22%, Ni<=0.65%, B=0.001%-0.002%, and the rest is Fe and inevitable impurities; the cutting machine network structure adopted comprises a cutting machine remote monitoring system with multiple cameras, the remote monitoring system is used as a central control system and simultaneously communicates with a field operation system and a user MES system; and the key process steps are as follows: 1) the MES sends steel plate information to the central control system of the cutting machine to generate a steel plate information library.
[0005] 2) after the cutting machine is powered on, the zero point is automatically searched, and the cutting head and the code printing head are located at the zero point.
[0006] 3) after the steel plate is conveyed to the position of the plasma cutting machine by a crane, an operator inputs a steel plate number, the numerical control system calls the steel plate information from the steel plate information library sent by the MES, and automatically generates a code printing program and a cutting program.
[0007] 4) the cutting path of a sample block and a fixed length and the code printing character of each sample block are automatically generated according to the cutting data information; the sample block content comprises a sample block number, a thickness, a steel type and head, tail and rolling direction arrows.
[0008] 5) the cutting speed is automatically set according to the thickness of the steel plate, or is manually modified according to the actual cutting condition.
[0009] 6) the tail waste is divided into small strips with a length of 400-500 mm.
[0010] 7) the cutting information is returned to the secondary remote monitoring system, and production report forms are saved and generated.
[0011] 8) the machine tool returns to the starting point of the machine tool, and the second step is recycled.
[0012] 9) the cutting sample block is subjected to coloring flaw detection to observe whether there is a crack at the cutting end.
[0013] Further, step 5): for the 500HB high-grade wear-resistant steel plate without adding Mo, Ni low alloy component design, without preheating, the working current of the plasma cutting machine is 250~270A, and the cutting speed is 1100~1300mm / min; for the 500HB high-grade wear-resistant steel plate with Mo, Ni high alloy component and Mo≤0.22%, Ni≤0.65%, the working current of the plasma cutting machine is 190~210A when preheated to 130~190 DEG C, and the cutting speed is 500~1100mm / min.
[0014] Invention principle: The plasma cutting forms a high-temperature (up to tens of thousands of degrees Celsius) plasma arc by compressing the electric arc in a narrow space, so that the wear-resistant steel base is rapidly melted and melted, and then the molten material is blown away by a high-speed plasma flow to complete the cutting. The high-temperature plasma and the material surface interact to cause the material surface to be affected by thermal stress, and the cutting cross section is more prone to fire cutting cracks. A scientific and reasonable plasma cutting process parameter is formulated to reduce the heat affected zone and reduce the cutting stress cracks, thereby ensuring good cutting quality and laying a foundation for the high wear resistance and long service life of the wear-resistant part after cutting. The plasma cutting equipment for wear-resistant steel involved in the present application adopts a Huayuan LG-200HA variable frequency plasma cutting machine, which is light in weight and placed on the cross beam of a numerical control machine tool; is equipped with high-frequency interference reduction technology to realize high load persistence; the gas control unit is in the arc starting controller, the gas path is shorter, the gas pressure is stable, and the cutting quality is better; has a cutting torch cooling system, and is provided with an imported high-flow, high-lift water pump and a high-power heat dissipation structure, which greatly reduces the amount of cutting torch consumables. Mainly used for cutting of carbon steel, alloy steel, non-ferrous metals and other metal materials, and widely used in industries related to metal cutting such as pressure vessels, water and electricity, metallurgy, chemical industry, aerospace, automobile, building, part processing and the like.
[0015] The present application has the following advantages: the NM500 high-grade wear-resistant steel plasma cutting process parameter provided by the present application can cut curves or complex shapes, effectively reduce the heat affected area, improve cutting precision and cutting efficiency, improve the operation safety factor, and at the same time, is beneficial to reduce the residual stress of the cutting part and avoid cutting stress cracks, thereby obtaining good cutting quality. The plasma cutting method adopted by the present application has strong component directivity, small implementation difficulty, strong operability and high safety, and has universal popularization and use value. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 It is a communication network structure diagram of the plasma cutting machine. DETAILED DESCRIPTION
[0017] The following will be further illustrated by examples.
[0018] The network structure of the cutting machine is as followsFigure 1 The cutting experiment was carried out on a Huayuan LG-200HA variable frequency plasma cutting machine. One set of remote monitoring system of the cutting machine was provided with four sets of cameras for monitoring and recording the working conditions of the equipment and the working area, and the recorded data was saved for half a month. The remote monitoring system served as a central control system and communicated with the field operation system and the user MES system. Through the field operation system communication, field information was collected, and the current cutting state, work progress, etc. were displayed on the HMI interface. Through communication with the user MES system, the task data sent by the MES was forwarded to the field operation system, field data was collected, and an EXCEL data table file was generated according to the user's requirements. The table file contains the actual size of the steel plate cutting, steel grade, steel plate number, range size, sample marking and length, etc. When the communication is abnormal, the field operation system is manually positioned, and the data is input to continue the steel plate sampling and sizing operation. Example 1
[0019] A plasma cutting method of NM500 high-grade wear-resistant steel, the 20mm NM500 steel plate is designed with low composition without adding Mo and Ni; the cutting steps are as follows: 1) The steel grade of the steel plate to be cut is NM500, the specification is 20mm x 2000mm x 6200mm, and the MES (Manufacturing Execution System) system sends the steel plate information to the central control system of the cutting machine to generate a steel plate information library.
[0020] 2) After the cutting machine is powered on, the zero point is automatically found, and the cutting head and the code marking head are located at the zero point position.
[0021] 3) After the steel plate is conveyed to the plasma cutting machine position by the crane, the operator inputs the steel plate number, and the numerical control system calls the steel plate information from the steel plate information library sent by the MES to automatically generate a code marking program and a cutting program.
[0022] 4) According to the cutting data information, sample blocks (2 blocks, respectively located at the left and right plate width 1 / 4 positions, sample block size rolling direction x transverse direction is 200 x 600mm, sizing length is 6000mm, and the code marking characters of each sample block include sample plate number, thickness, steel grade, sampling position and rolling direction arrow information.
[0023] 5) According to the steel plate composition design and thickness specification, the cutting machine working current is manually set to 260A, and the cutting speed is 1200mm / min for cutting operation.
[0024] 6) The tail waste is cut into 400mm small strips, a total of 2 pieces, which are transported to the scrap steel recycling area through the waste belt.
[0025] 7) The cutting information is returned to the secondary remote monitoring system, and production reports are saved and generated.
[0026] 8) The machine tool returns to the starting point of the machine tool, and the second step is repeated.
[0027] 9) After dye penetrant inspection of the cut sample plate, no cracks are observed at the cut end.
[0028] The chemical composition is shown in Table 1, and the cutting process parameters are shown in Table 2. Example 2
[0029] A plasma cutting method for NM500 high-grade wear-resistant steel, the 20mm NM500 steel plate is designed with high alloy Mo and Ni components; the chemical composition is shown in Table 1, and the rest is Fe and essential impurities; the cutting process parameters are shown in Table 2. The cutting steps are as follows: 1) The steel grade of the steel plate to be cut is NM500, the specification is 20mm x 2500mm x 8400mm, and the manufacturing execution system (MES) sends the steel plate information to the central control system of the cutting machine to generate a steel plate information library.
[0030] 2) After the cutting machine is powered on, it automatically finds the zero point, and the cutting head and the code head are located at the zero point position.
[0031] 3) After the steel plate is transported to the plasma cutting machine position by the crane, the operator inputs the steel plate number, and the numerical control system calls the steel plate information from the steel plate information library sent by the MES, and automatically generates the code program and the cutting program.
[0032] 4) According to the cutting data information, automatically generate sample blocks (2 blocks, respectively located at the left and right plate width 1 / 4 positions, sample block size rolling direction x transverse direction is 200mm x 500mm, cutting path of fixed length 8200mm, and code characters of each sample block including sample plate number, thickness, steel grade, sampling position and rolling direction arrow and other information.
[0033] 5) According to the steel plate composition design and thickness specification, preheat the steel plate to 180℃ with a handheld gas flame gun before cutting, manually set the cutting machine working current to 200A and the cutting speed to 1000mm / min for cutting operation.
[0034] 6) Cut the tail waste into 500mm small strips, a total of 3 pieces, and transport them to the scrap steel recycling area through the waste belt.
[0035] 7) Return the cutting information to the secondary remote monitoring system, save statistics, generate production reports, etc.
[0036] 8) The machine tool returns to the starting point of the machine tool, and the second step is repeated.
[0037] 9) After dye penetrant inspection of the cut end, no crack was observed. It was determined that the cutting parameters of 200 A current and 1000 mm / min speed were not suitable for the high alloy composition NM500 at a preheating temperature of 180 °C.
[0038] The plasma cutting procedure was restarted and steps 1) to 4) were repeated. In step 5), the steel plate was preheated to 130 °C and the cutting machine was manually set to 200 A current and 520 mm / min speed. The cutting operation was then repeated. In steps 6) to 8), no crack was observed after dye penetrant inspection of the cut end. It was determined that the cutting parameters were suitable for the high alloy composition NM500.
[0039] Table 1 Chemical composition of the examples (wt. %) .
[0040] Table 2 Plasma cutting parameters of the examples .
Claims
1. A method for plasma cutting of NM500 high-grade wear-resistant steel, characterized in that: The steel has the following chemical composition by mass percent: C=0.2%-0.3%, Si=0.20-0.35%, Mn=0.9-1.0%, P=0.007%-0.01%, S=0.0013%-0.0022%, Alt=0.035%-0.075%, Cr=0.25%-0.65%, Nb=0.016%-0.025%, Ti=0.009%-0.011%, Mo≤0.22%, Ni≤0.65%, B=0.001%-0.002%, and the rest is Fe and inevitable impurities; the cutting machine network structure adopted includes a cutting machine remote monitoring system with multiple cameras, the remote monitoring system serving as a central control system and communicating with a field operation system and a user MES system; The key process steps are as follows: 1) the MES sends the steel plate information to the central control system of the cutting machine to generate a steel plate information library; 2) after the cutting machine is powered on, the zero point is automatically found, and the cutting head and the marking head are located at the zero point position; 3) after the steel plate is conveyed to the position of the plasma cutting machine by the crane, the operator inputs the steel plate number, and the numerical control system calls the steel plate information from the steel plate information library sent by the MES to automatically generate a marking program and a cutting program; 4) the cutting data information is used to automatically generate the cutting path of the sample block and the fixed length and the marking characters of each sample block; the sample block content includes the sample block number, thickness, steel type, and head, tail and rolling direction arrow; 5) the cutting speed is automatically set according to the thickness of the steel plate, or manually modified according to the actual cutting condition; 6) the tail waste is cut into small strips of 400-500 mm; 7) the cutting information is returned to the secondary remote monitoring system to save and generate production reports; 8) the machine tool returns to the starting point of the machine tool, and the second step is repeated; 9) the cutting sample block is subjected to coloring flaw detection to observe whether there is a crack at the cutting end.
2. The method of claim 1, wherein the NM500 high-grade wear-resistant steel is cut by the plasma cutting method. Step 5): for the 500HB high-grade wear-resistant steel plate without adding Mo and Ni low alloy components, no preheating is required, the working current of the plasma cutting machine is 250-270 A, and the cutting speed is 1100-1300 mm / min; for the 500HB high-grade wear-resistant steel plate with Mo and Ni high alloy components and Mo≤0.22% and Ni≤0.65%, the steel plate is preheated to 130-190℃, the working current of the plasma cutting machine is 190-210 A, and the cutting speed is 500-1100 mm / min.