12Cr1MoV: Alloy Structural Steel

12Cr1MoV is an alloy structural steel. According to Chinese national standard GB/T 3077, its name reflects the main alloying elements and their approximate content. For example, 12 represents the mass fraction of carbon, which is about 0.12%, Cr represents chromium, Mo represents molybdenum, and V represents vanadium. This is a low-alloy heat-resistant steel mainly used for structural parts in high-temperature and high-pressure environments. Has high oxidation resistance and heat strength.

The main feature of 12Cr1MoV steel is high temperature resistance: 12Cr1MoV steel still maintains good strength and toughness under high temperature conditions, and can maintain high thermal strength and oxidation resistance at around 580°C. Welding performance: It has good welding performance and is easy to perform welding operations, but is sensitive to the normalizing cooling rate. Excellent mechanical properties: high strength, high toughness, good plasticity, long-lasting plasticity, and can adapt to complex stress states and impact loads. Corrosion resistance: Adding alloy elements such as chromium, molybdenum, and vanadium enhances the material's corrosion resistance and high-temperature oxidation resistance.

12Cr1MoV steel. Compared with 12CrMoV steel, this steel has higher oxidation resistance and thermal strength. The creep limit and durable strength value of 12Cr1MoV steel are very close, and it has high plasticity under sustained stretching: Steel technology The weldability and weldability are good, but it needs to be preheated to 300°C before welding, and stress relief treatment is required after welding. 12Cr1MoV steel is a steel type widely used in superheaters, headers and main steam ducts of high-pressure, ultra-high-pressure, and subcritical power station boilers. S still has high thermal strength and oxidation resistance at 80°C, and has high lasting plasticity. The production process is relatively simple and the welding performance is good, but it is sensitive to the normalizing cooling rate. Long-term use at 580°C will produce the second type of temper brittleness caused by the segregation of impurity elements such as phosphorus at the grain boundaries. Pearlite spheroidization will also occur with long-term use.

The chemical composition of 12Cr1MoV steel mainly includes: carbon (C): 0.08%~0.15%; silicon (Si): 0.17%~0.37%; manganese (Mn): 0.40%~0.70%; sulfur (S): ≤0.035%; Phosphorus (P): ≤0.035%; Chromium (Cr): 0.90% ~ 1.20%; Molybdenum (Mo): 0.25% ~ 0.35%; Vanadium (V): 0.15% ~ 0.30%.

Key points of 12Cr1MovG alloy pipe welding process Before welding, the weld groove and both sides should be preheated to 250~350℃, and the preheating range should not be less than 3 times the thickness of the weldment. During the welding process, it should be ensured that the temperature of the base metal (internal and external surfaces) within the preheating range is not lower than the preheating temperature, and the interlayer temperature is not lower than 250°C and not higher than 350°C. Each weld must be completed in one pass. If the welding work is interrupted during the welding process, it should be ensured that the temperature on both sides of the weld groove and within a range of no less than 150mm on both sides is not lower than the preheating temperature (250~350°C) until the welding work is restarted. It must be ensured that both the inner and outer surfaces of the weldment reach the specified preheating temperature.

The mechanical properties of 12Cr1MoV alloy steel depend on its specific heat treatment process, such as quenching heating temperature and cooling method. Generally have high yield strength, tensile strength and good impact toughness.

12Cr1MoV steel can be provided in different delivery states, such as: hot-rolled state, controlled rolling state, quenched and tempered state, normalized state, and fully annealed state.

Due to its excellent high-temperature strength, oxidation resistance, durable plasticity and good welding performance, 12Cr1MoV alloy structural steel's application scope mainly includes: Power industry: widely used in high-temperature and high-pressure boiler pipes in thermal power plants, such as superheater pipes and reheat pipes . High temperature pressure components such as heater tubes, headers, steam pipes, etc. Petrochemical industry: In oil refining equipment and petrochemical equipment, it is used to manufacture pipes, containers, reactor shells, heat exchangers and other components that require high temperature resistance and corrosion resistance. Pressure vessel manufacturing: used to manufacture high-temperature and high-pressure pressure vessels and reactors, especially suitable for oil refining, chemical industry, fertilizer and other fields. Power equipment: also used in high-temperature components of power equipment, such as internal combustion engines and gas turbines, such as turbine blades, nozzle rings, transition sections, etc. Nuclear industry: It can also be used for some non-nuclear grade high-temperature pipelines and high-temperature component plants of auxiliary systems in nuclear power plants. Machinery manufacturing: used to manufacture mechanical parts that work in high-temperature environments, such as bearing seats, support structures of high-temperature furnaces, etc.

To sum up, 12Cr1MoV steel is mainly used for various important structural parts and pipeline systems that need to work in high temperature environments and have high strength and good corrosion resistance.