Q460C is a high-strength low-alloy structural steel, designated according to the Chinese national standard GB/T 1591-2018. The "Q" stands for yield strength ("Qu" in pinyin), "460" indicates the specified minimum yield strength of 460 MPa, placing it in the high-strength steel category with excellent load-bearing capacity. The "C" denotes the quality grade, meaning the steel must meet specified Charpy V-notch impact energy (KV2) requirements at 0°C, demonstrating good low-temperature toughness. Compared to Grades D (-20°C) and E (-40°C), Grade C is suitable for engineering applications requiring moderate low-temperature performance, but not under extreme cold conditions.
Q460C steel plate is widely used in large-scale engineering structures with high demands for strength and weldability. Typical applications include high-rise buildings, long-span bridges, heavy industrial workshops, tower masts, construction machinery, lifting equipment, mining machinery, large ships, and transport vehicles. Due to its high strength, Q460C effectively reduces structural weight, minimizes material consumption, lowers construction costs, and enhances overall stiffness and seismic resistance. It is particularly suitable for primary load-bearing components subjected to significant static and dynamic loads, such as trusses, beams, columns, and support joints, playing a critical role in modern construction and infrastructure projects.
The key features of this grade lie in the combination of high strength and balanced comprehensive properties. Through microalloying elements (such as niobium, vanadium, titanium) and controlled rolling processes, Q460C achieves high yield strength while maintaining good ductility, toughness, and weldability. Its carbon equivalent (CEV) is well-controlled, reducing the risk of welding cracks. It can typically be welded without preheating or with only minimal preheating under normal construction conditions, facilitating on-site fabrication. Additionally, Q460C offers good atmospheric corrosion resistance and through-thickness ductility (Z-direction properties), which can be specially ordered based on customer requirements.
Currently, Q460C plates are manufactured and supplied in accordance with the Chinese national standard GB/T 1591-2018 "High-strength low-alloy structural steels". This standard specifies detailed requirements for chemical composition, mechanical properties, impact toughness, Z-direction properties, dimensional tolerances, and inspection procedures, serving as the core technical basis for production and acceptance. Thanks to its superior performance and mature manufacturing technology, Q460C has become an essential mainstream high-strength material in modern Chinese structural engineering.
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.
