First, the material introduction of 15CrMoG seamless steel pipe
Chemical composition: 15CrMoG is a low-alloy pearlite heat-resistant steel. Its carbon (C) content is generally 0.12-0.18%, chromium (Cr) content is about 0.8-1.2%, and molybdenum (Mo) content is 0.4-0.6%. Carbon element provides basic strength for steel, chromium element helps to improve the oxidation resistance and corrosion resistance of steel, and molybdenum element mainly enhances the thermal strength of steel, that is, the strength and creep resistance at high temperatures. At the same time, it also contains a small amount of silicon (Si), manganese (Mn), and other elements. Silicon can improve the strength and hardness of steel, and manganese can improve the toughness of steel.
Second, the production process of 15CrMoG seamless steel pipe
1. Smelting process: usually electric furnace or converter steelmaking is used. In the steelmaking process, the addition amount and order of various alloying elements must be accurately controlled. For example, chromium and molybdenum alloys are usually added when the molten steel reaches the appropriate temperature and composition stage to ensure that they can be fully melted and evenly distributed in the molten steel.
2. Rolling process: including hot rolling and cold rolling (cold drawing). During hot rolling, the steel billet is heated to a higher temperature (generally around 1100-1200℃), pierced by a piercing machine, and then rolled by a tube rolling mill to obtain a steel pipe with the required outer diameter and wall thickness. The cold rolling (cold drawing) process is based on hot rolling and is drawn or cold rolled by a die at room temperature to make the steel pipe have higher dimensional accuracy and better surface quality, but this process has relatively low production efficiency and high cost.
3. Heat treatment process: This steel pipe adopts normalizing + tempering treatment. The normalizing temperature is generally 900-960℃. The purpose of normalizing is to refine the grains and improve the strength and toughness of the steel. The tempering temperature is about 650-750℃. Tempering is mainly to eliminate the internal stress generated during the normalizing process and improve the comprehensive performance of the steel pipe.
4. Flaw detection: Eddy current flaw detection and ultrasonic flaw detection are carried out to ensure the quality of steel pipes. Eddy current flaw detection is mainly used to detect defects on the surface and near the surface of steel pipes. It is based on the principle of electromagnetic induction. When the steel pipe passes through the detection coil of the eddy current flaw detector, if there are defects on the surface or near the surface of the steel pipe, it will cause changes in eddy currents and be detected. Ultrasonic flaw detection is used to detect defects inside the steel pipe. It uses the phenomenon of reflection and refraction when ultrasonic waves propagate inside the steel pipe. By analyzing these signals, it is judged whether there are defects inside the steel pipe.
Third, the performance characteristics of 15CrMoG seamless steel pipe
1. High temperature performance: 15CrMoG seamless steel pipe has good mechanical properties under high temperature environments. When the temperature reaches about 550℃, it can still maintain high strength and creep resistance. For example, in the steam pipeline system of some thermal power plants, the steel pipe can withstand the pressure of high-temperature steam to ensure the long-term stable operation of the pipeline.
2. Corrosion resistance: Due to the presence of chromium and molybdenum elements, this steel pipe has good corrosion resistance. In an environment containing water vapor, carbon dioxide, and other media, it can effectively resist corrosion and reduce the corrosion loss of the pipe wall.
3. Welding performance: Its welding performance is good, but some matters need to be paid attention to during the welding process. For example, preheating is generally required before welding, and the preheating temperature is about 150-200℃. After welding, appropriate post-weld heat treatment is required to ensure the quality of the welded joint.
Fourth, the application field of 15CrMoG seamless steel pipe
In the petrochemical industry, it is used to transport high-temperature and high-pressure oil, natural gas, and chemical raw materials. For example, it plays a role in the high-temperature oil and gas pipelines of refineries. In the power industry, it is mainly used for steam pipes, superheaters, and reheaters in thermal power plants to ensure the transportation of high-temperature steam and the conversion of heat energy. In the field of boiler manufacturing, it is a key material for the manufacture of medium and low-pressure boilers, providing support for the safe and stable operation of boilers.
Post time: May-27-2025