08Ni3DR is a low-temperature pressure vessel quality alloy structural steel plate. The designation carries specific technical meanings: "08" indicates an average carbon content of approximately 0.08%; "Ni3D" signifies the inclusion of about 3% nickel (Ni) as an alloying element, where "D" stands for "low temperature" performance requirements typical in pressure vessel steels; and "R" denotes "Rongqi" (vessel), indicating its application in pressure equipment. Thus, 08Ni3DR refers to a 3% nickel-containing steel with excellent low-temperature toughness, designed for pressure vessel fabrication.
This steel plate is primarily used in the manufacture of welded pressure vessels operating in low-temperature environments, such as liquefied natural gas (LNG) storage tanks, air separation units, and ethylene or liquefied petroleum gas (LPG) storage and transportation systems. These facilities often operate at temperatures as low as -101°C or below, demanding exceptional low-temperature impact toughness from the material. 08Ni3DR excels in this regard, maintaining high resistance to brittle fracture under extreme cold, thereby ensuring the safety and reliability of such equipment.
Key characteristics of 08Ni3DR include outstanding low-temperature impact toughness (retaining high impact energy values even at -101°C), excellent weldability, moderate strength, and good cold-forming properties. The addition of nickel significantly lowers the steel’s ductile-to-brittle transition temperature, enabling it to maintain sufficient toughness reserves in deep cryogenic conditions. Furthermore, the material is typically supplied in a normalized or normalized-and-tempered condition, ensuring uniform microstructure and stable mechanical properties.
The current national standard governing 08Ni3DR steel plate is GB/T 3531-2023 "Steel Plates for Low-Temperature Pressure Vessels", which was issued in 2023, replacing the previous GB/T 3531-2014 edition. This updated standard refines requirements for chemical composition, mechanical properties, impact testing, and inspection rules, enhancing quality control and technical specifications. In procurement and engineering applications, compliance with GB/T 3531-2023 should be explicitly specified to ensure adherence to the latest technical requirements.
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.
