Steel Cutting – What Is Steel Cutting

Technology name: Steel structure cutting, also known as steel plate cutting.

Definition of technology: The usual cutting techniques include flame cutting, water cutting, plasma cutting, etc. Flame cutting is currently the most widely used.

Steel structure cutting refers to the process of cutting steel structures according to needs in industrial production. Steel structure cutting is for the steel structure to be cut. It generally refers to the process of melting, blowing and dividing the steel structure by mixing industrial gas and oxygen to burn and reaching the temperature required for cutting. The technologies currently used include flame cutting, water cutting, plasma cutting, CNC cutting and so on. The most commonly used is flame cutting, which has the characteristics of low cost, easy operation, mature technology and wide use. It is currently the most widely used cutting technology in the industry. Flame cutting refers to the use of industrial gas and oxygen to burn the metal to be cut. The process of heating to the melting point of the steel and releasing a high-pressure oxygen stream to further oxidize the metal and blow off the slag produced by the combustion to form an incision. The cutting gas currently used mainly includes acetylene, propane, hydrogen oxygen, Xiapu gas, natural gas and so on. Acetylene has the disadvantages of serious pollution, severe injury to staff, easy tempering, and high cost. Now the country has clearly ordered it to be eliminated and used. The cost of propane, hydrogen oxygen and Xiapu gas is relatively high. Natural gas cutting is a new technology developed in recent years. It has the advantages of low carbon, environmental protection, safety and stability, low cost, and abundant gas sources. It is a technology promoted by the country and has a broad prospect. If the flame temperature cannot reach the flame temperature of acetylene oxy-fuel combustion, it is necessary to add temperature-increasing and combustion-supporting additives (such as Shenqi natural gas synergist, etc.) to complex reaction with the fuel gas, and then the natural gas cutting can be realized only after Cuiization, activation and heat accumulation. Required cutting temperature.

Steel Structure Cutting Process

Cutting standard

  • 1. Scope: This standard is applicable to the processing process of raw material cutting. It is suitable for cutting and blanking processes with flame cutting and plasma cutting as cutting methods.
  • 2. Construction preparation:
  • 2.1 Material requirements:
  • 2.1.1 The steel plate used for cutting and blanking should be inspected and accepted by the quality department, and its various indicators shall meet the corresponding provisions of the national standard.
  • 2.1.2 Before cutting the steel plate, the grade, thickness and surface quality of the steel plate should be checked. If the corrosion point on the surface of the steel plate exceeds the negative deviation of the national standard steel plate, it is not allowed to be used in the product. The small area of ​​pitting corrosion can be welded and polished until it is qualified without reducing the design thickness.
  • 2.1.3 When blanking, the grade, specification and surface quality of the steel plate must be checked, and the blanking can only be done after confirmation.
  • 2.2 Construction equipment and tools:
  • 2.2.1 Cutting and cutting equipment mainly includes CNC flame cutting machine, CNC plasma cutting machine, straight bar cutting machine, semi-automatic cutting machine, etc.
  • 2.2.2 Before gas cutting, check that all the equipment and tools of the gas cutting system are operating normally, and ensure that they can only operate under safe conditions, and they should be maintained during the gas cutting process.
  • 2.2.3 The detection and identification tools are: steel ruler, tape measure, stone pen, marker pen, etc.
  • 3. Cutting operation process:
  • 3.1 During automatic cutting, when lifting the steel plate to the gas cutting platform, the distance difference between the two ends of the steel plate and the guide rail should be adjusted within 5mm. When performing semi-automatic cutting, the guide rail should be placed on the plane of the steel plate to be cut, and then the cutting machine should be lightly placed on the guide rail. Make the side with the cutting torch face the operator, select the cutting nozzle according to the thickness of the steel plate, and adjust the cutting straightness and cutting speed.
  • 3.2 According to the different automatic cutting and semi-automatic cutting methods, adjust the distance of each cutting torch, determine the trailing amount, and consider the slit compensation; in the cutting process, the size and direction of the cutting torch angle are mainly determined by the thickness of the steel plate. The relationship between the inclination angle of the nozzle and the thickness of the cutting piece and the cutting margin are shown in the following table:  The relationship between the inclination angle of the cutting nozzle and the thickness of the cutting piece. Gauge cutting method Material thickness mm Cutting gap width (mm) Remarks gas cutting material ≤10 1~2  10~20 2.5  20~40 3.0  40 above 4.0 When gas cutting thick plates, the cutting nozzle and the surface of the workpiece should be vertical. After the entire section is cut through, move the cutting nozzle and switch to normal gas cutting. When the gas cutting is about to reach the end, the speed should be slightly slowed down so that the lower part of the cut is completely cut.

Cutting technology type

  • Flame cutting: Flame cutting is currently the most widely used cutting technology. It mainly uses the mixed combustion of gas and oxygen to generate high temperature to oxidize and melt the steel, so as to achieve the purpose of cutting. The gas used is natural gas, acetylene, propane, etc. Acetylene has been explicitly eliminated by the country. Natural gas and propane are new types of gas technology. Cuihua agent needs to be added, after Cuihua and activation, to achieve the cutting purpose.
  • Water cutting: It is a newly developed cutting technology in recent years. It uses high-pressure water jets to cut steel plates. It has advanced technology and high cutting accuracy. It is suitable for cutting thin, medium-thickness and high-precision cutting steel plates. The disadvantage is that the cost is high, and the general industrial cutting does not require high-precision cutting, so it is not suitable for ordinary industrial cutting.
  • Plasma arc cutting: It is a processing method that uses the heat of the high-temperature plasma arc to locally melt (and evaporate) the metal at the incision of the workpiece, and use the momentum of the high-speed plasma to remove the molten metal to form an incision. Plasma cutting with different working gases can cut all kinds of metals that are difficult to cut by oxygen, especially for non-ferrous metals (stainless steel, aluminum, copper, titanium, nickel). The main advantage is that the cutting thickness of metals is not large. At this time, the plasma cutting speed is fast, especially when cutting ordinary carbon steel thin plates, the speed can reach 5-6 times that of the oxygen cutting method, the cutting surface is smooth, the thermal deformation is small, and there is almost no heat-affected zone.

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