12Cr1MoVR is a medium-carbon chromium-molybdenum-vanadium alloy steel belonging to the family of low-alloy bainitic heat-resistant steels. It is specifically designed for welded pressure vessels operating under high-temperature, high-pressure, and complex stress conditions over extended service periods, offering excellent elevated-temperature strength, creep resistance, toughness, and weldability.
The grade designation has a clear technical meaning:
- "12" indicates an average carbon content of approximately 0.12% (by weight), providing sufficient strength while maintaining good ductility and weldability
- "Cr1" refers to chromium content in the range of 0.90%–1.20%, which significantly enhances oxidation resistance, corrosion resistance, and high-temperature microstructural stability
- "Mo" denotes molybdenum content of 0.25%–0.35%, a key element for improving high-temperature strength and suppressing temper embrittlement
- "V" stands for vanadium, typically added in the range of 0.02%–0.08%, which acts as a strong carbonitride-forming element to refine grain structure and provide precipitation strengthening, further enhancing strength and thermal stability
- "R" is the first letter of the Chinese pinyin "Rong" (meaning "vessel"), indicating its use in pressure equipment
Therefore, 12Cr1MoVR refers to a specialized high-strength heat-resistant steel plate for pressure vessels with ~0.12% carbon and alloyed with chromium, molybdenum, and vanadium.
This steel plate is primarily used in critical pressure-bearing components operating under high-temperature and high-pressure conditions, widely applied in power generation industries for high-pressure boiler drums, headers, and collectors, as well as in petrochemical and coal chemical plants for high-temperature reactors, heat exchangers, and steam generators. Its typical service temperature can reach up to 580°C, making it especially suitable for components subjected to prolonged exposure to high temperature, high pressure, and cyclic stresses. It serves as a key structural material in modern supercritical and ultra-supercritical power units and advanced chemical processing equipment. Key features of 12Cr1MoVR include: yield strength ≥295 MPa, tensile strength 470–640 MPa, and excellent overall mechanical properties; outstanding creep resistance and microstructural stability at elevated temperatures; enhanced thermal strength and resistance to temper softening due to the synergistic effect of Cr, Mo, and V; and a uniform bainitic microstructure achieved through normalizing and tempering, providing good impact toughness (average impact energy ≥47J at -20°C) and weldability. Post-weld heat treatment effectively relieves residual stresses and restores base metal properties.
Currently, 12Cr1MoVR is manufactured and inspected in accordance with the Chinese national standard GB/T 713-2014 Steel Plates for Boilers and Pressure Vessels. Since its implementation in 2014, this standard has established systematic and stringent requirements on chemical composition, mechanical properties, impact toughness, ultrasonic testing, and thickness-direction properties, and has become one of the core standards widely adopted in China’s boiler and pressure vessel manufacturing industry. As a representative of high-performance heat-resistant steels, 12Cr1MoVR has achieved large-scale domestic production and application.
Ultrasonic Testing (UT)
A key non-destructive testing technique that uses high-frequency sound waves to detect internal flaws in steel plates. The probe emits sound waves, which reflect when encountering defects such as cracks or inclusions. The receiver captures the echoes, enabling precise determination of defect location and size. With high sensitivity, strong penetration, and fast inspection speed, UT effectively ensures internal quality, widely used in the production of heavy plates, pressure vessel plates, and other high-end products to guarantee safety and reliability.
Magnetic Particle Testing (MT)
A common surface inspection method that magnetizes the workpiece, causing leakage magnetic fields at surface or near-surface defects like cracks or inclusions, which attract magnetic particles to form visible indications. Simple to operate and highly sensitive, MT is suitable for rapid inspection of surface and near-surface flaws in ferromagnetic materials, widely used for online or offline inspection of plate edges, ends, and welds, ensuring product quality and safety.
Penetrant Testing (PT)
A non-destructive method for detecting surface-breaking flaws. A penetrant liquid is applied to the cleaned steel surface, allowing it to seep into defects such as cracks or pores. After removing excess penetrant, a developer is applied, causing the trapped penetrant to bleed out and form visible indications. Simple and cost-effective, PT is suitable for inspecting surface defects in various non-porous materials, commonly used for welds, castings, and complex components, effectively ensuring surface quality of steel plates.
