Industrial details of 12Cr2MoG high-pressure seamless steel pipe

First, the material characteristics of 12Cr2MoG high-pressure seamless steel pipe
1. Chemical composition: 12Cr2MoG is a low-alloy pearlite heat-resistant steel. The main alloying elements are chromium (Cr) and molybdenum (Mo), of which the chromium content is about 2-2.5% and the molybdenum content is about 0.9-1.2%. Chromium can significantly improve the oxidation resistance and corrosion resistance of steel, while molybdenum enhances the thermal strength of steel. At the same time, its carbon (C) content is generally 0.08-0.15%, which can ensure the basic strength of steel. It also contains elements such as silicon (Si) and manganese (Mn). Silicon can increase the strength and elastic limit of steel, and manganese can improve the toughness of steel.
2. Metallographic structure: The metallographic structure of this steel pipe is mainly pearlite and ferrite. Pearlite is a structure composed of ferrite and cementite lamellae. Under high temperatures and long-term stress, the cementite in pearlite tends to aggregate and grow, while the alloying elements chromium and molybdenum can inhibit this tendency, thereby ensuring the stable performance of the steel pipe at high temperatures.

Second, the production process of 12Cr2MoG high-pressure seamless steel pipe
1. Smelting link: usually electric furnace or converter steelmaking is used. During the smelting process, the amount and timing of alloying elements are strictly controlled to ensure that the chemical composition meets the standard. For example, chromium and molybdenum alloys are added when the molten steel reaches a certain temperature and composition stage to ensure that it is fully melted and evenly distributed.
2. Rolling process: including hot rolling and cold rolling (cold drawing) processes. During hot rolling, the billet is heated to about 1200-1250℃, pierced by a piercing machine, and then rolled by a tube rolling mill to make the steel pipe reach 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. However, the production efficiency of the cold rolling (cold drawing) process is relatively low and the cost is high.
3. Heat treatment process: 12Cr2MoG steel pipes generally need to be normalized + tempered. The normalizing temperature is usually between 900-960℃, the purpose is to refine the grains and improve the strength and toughness of the steel. The tempering temperature is about 700-750℃, which can eliminate the internal stress generated during the normalizing process and improve the comprehensive performance of the steel pipe.

Third, the performance characteristics of 12Cr2MoG high-pressure seamless steel pipe
1. High temperature strength and creep resistance: In a high temperature environment, 12Cr2MoG steel pipes show excellent mechanical properties. Its creep resistance is good. When the temperature is as high as about 600℃, it can withstand higher pressure without obvious creep deformation. For example, in a high-temperature steam pipeline with a design pressure of 10MPa, 12Cr2MoG steel pipe can operate stably for a long time.
2. Corrosion resistance: The presence of chromium and molybdenum elements makes the steel pipe have good corrosion resistance. In an environment containing corrosive media such as water vapor and sulfur dioxide, it can effectively resist corrosion and reduce the corrosion loss of the pipe wall.
3. Welding performance: The welding performance of this steel pipe is relatively good, but due to the presence of alloy elements, suitable welding processes and welding materials are required during welding. For example, preheating is required during welding, and the preheating temperature is generally between 200-300℃. After welding, post-weld heat treatment is also required to ensure the quality of the welded joint.

Fourth, the scope of use of 12Cr2MoG high-pressure seamless steel pipe
1. Use of high-pressure seamless steel pipe: 12Cr2MoG high-pressure seamless steel pipe is mainly used to transport high-temperature and high-pressure fluid media. In the petrochemical industry, it is used to transport high-temperature and high-pressure oil, natural gas, chemical raw materials, etc.; in the power industry, it is used to transport high-temperature steam, hot water, and other media.
2. Application of alloy steel pipes: In addition to being used to transport media, 12Cr2MoG alloy steel pipes are also widely used to manufacture various high-temperature and high-pressure equipment components. For example, they are used to manufacture heating furnace tubes and heat exchanger tubes in oil refining equipment; they are used to manufacture superheaters, reheaters, and other components in boiler equipment to withstand high-temperature and high-pressure steam.