First, the chemical composition of
12CrMoG high-pressure seamless steel pipe
12CrMoG is an alloy steel pipe, the main alloying elements are chromium and molybdenum. The chromium content is about 0.8-1.2%, and the molybdenum content is about 0.4-0.6%. Chromium can improve the oxidation resistance and corrosion resistance of steel, and molybdenum can improve the thermal strength of steel, that is the strength and creep resistance at high temperatures. In addition, it also contains carbon, whose content is generally 0.08-0.15%, and carbon can ensure the basic strength of steel. There is also a small amount of silicon, manganese, 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 12CrMoG high-pressure seamless steel pipe
- Seamless steel pipe process: generally adopt hot rolling or cold rolling (cold drawing) process. The hot rolling process is to heat the steel billet to a high temperature, pierce it through a piercing machine, and then roll it through a tube rolling mill. For example, the billet is first heated to about 1200℃, perforated by an oblique rolling piercing machine, and then the steel pipe wall is gradually thinned and rolled evenly by multiple tube rolling mills. The cold rolling (cold drawing) process is based on the hot-rolled steel pipe and is drawn or cold rolled at room temperature to make the steel pipe size more accurate and the surface quality better, but the cost is relatively high.
- Quality control link: For 12CrMoG high-pressure seamless steel pipes and high-pressure boiler steel pipes, there is strict quality control during the production process. Including the inspection of raw materials to ensure that the alloy element content meets the standard; during the rolling process, the dimensional accuracy of the steel pipe, such as the tolerance range of the outer diameter and wall thickness, is controlled; non-destructive testing, such as ultrasonic flaw detection, magnetic particle flaw detection, etc., is also required to detect whether there are defects inside and on the surface of the steel pipe.
Third, the performance characteristics of 12CrMoG high-pressure seamless steel pipe
- High temperature performance: It has good mechanical properties under high temperature environments and can withstand the pressure of high-temperature steam in high-pressure boilers. Its allowable stress can be maintained at a high level at high temperatures. For example, at 500℃, the allowable stress can reach about 100MPa, which makes it suitable for high temperature and high pressure working environments.
- Corrosion resistance: Due to the presence of chromium and molybdenum elements, 12CrMoG steel pipe has good corrosion resistance. In an environment containing water vapor, carbon dioxide, and other media, it can effectively resist corrosion and prevent the thinning and damage of the steel pipe wall.
- Welding performance: The steel pipe of this material has good welding performance. Through appropriate welding processes, such as manual arc welding, and the selection of appropriate welding rods (such as R307 welding rods), the quality of the welded joint can be guaranteed, so that it can still maintain good performance after welding.
Fourth, the difference in the use of 12CrMoG high-pressure seamless steel pipe
- 12CrMoG high-pressure seamless steel pipe: widely used to transport high-temperature and high-pressure fluid media, such as in the petrochemical industry, for transporting high-temperature oil, gas, and other media; in thermal power plants, for transporting steam, etc.
- 12CrMoG high-pressure boiler steel pipe: mainly used for the heating surface of high-pressure boilers, such as superheaters, reheaters, water walls, and other parts. During the operation of the boiler, these parts are subjected to the erosion of high temperature and high pressure steam and flame. 12CrMoG high-pressure boiler steel pipe can ensure the safe and stable operation of the boiler.
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