Q460GJC

Q460GJC is a high-strength steel plate specifically designed for building and construction applications. Its designation follows the Chinese national standard (GB) steel nomenclature system and is engineered for modern super high-rise buildings, large-span spatial structures, heavy industrial facilities, and construction projects with high seismic requirements. It is widely used in critical load-bearing components subjected to extremely high stresses, such as core walls, mega-columns, transfer trusses, main bridge girders, domed roof structures of stadiums, and key support members in nuclear power plants. The "Q" stands for "Qu fu qiang du" (yield strength), indicating that the steel's primary mechanical property is defined by its yield strength. "460" denotes the specified minimum yield strength of 460 MPa at room temperature—placing it in the high-strength category and significantly exceeding grades like Q420GJC—providing exceptional load-bearing capacity and resistance to deformation. "GJ" is the pinyin abbreviation for "Gong Jian Jie Gou" (building structure), clearly identifying its dedicated use in structural construction, distinguishing it from general-purpose or engineering steels. The suffix "C" indicates the quality grade, meaning the steel must meet a minimum average absorbed energy of 27 J in Charpy V-notch impact testing at 0°C, ensuring adequate low-temperature toughness and structural safety under dynamic loads such as earthquakes and wind-induced vibrations.

The main characteristics of Q460GJC steel plate include ultra-high strength, excellent overall mechanical properties, and good weldability. Its chemical composition is based on carbon and manganese, with the addition of microalloying elements such as niobium, vanadium, and titanium. Produced via controlled rolling and cooling (TMCP) or quenching and tempering (Q+T) processes, the steel achieves enhanced strength through grain refinement, precipitation hardening, and phase transformation strengthening. At the same time, careful optimization of the carbon equivalent (CEV) and alloy composition ensures favorable weldability. It is compatible with welding processes such as submerged arc welding (SAW) and gas metal arc welding (GMAW). Welded joints are stable, though preheating may be required depending on plate thickness and welding procedure to prevent cold cracking. The tensile strength ranges from 590 to 740 MPa, with elongation (A) ≥17%, providing sufficient ductility to absorb energy under extreme loading, thereby improving structural ductility and seismic performance. Additionally, Q460GJC exhibits excellent thickness-direction properties (Z-direction properties), effectively preventing lamellar tearing in thick-section welded joints, making it suitable for complex connections and large-section members.

Q460GJC is widely used in major engineering projects with stringent demands for material strength and reliability, including landmark super high-rise buildings, large transportation hubs, exhibition centers, sports arenas, and special industrial facilities. Compared to Q420GJC, it offers higher strength, enabling significant reductions in member cross-sections, lighter structural weight, optimized space utilization, and reduced foundation loads, delivering substantial economic benefits.

The current standard for Q460GJC steel plate is the Chinese national standard GB/T 19879-2023 "Steel Plates for Building Structures", released and effective in 2023. This standard comprehensively specifies grades, chemical composition, mechanical properties, technological properties, impact toughness, Z-direction properties, and inspection rules, serving as a key technical reference for modern structural design and construction. Due to its outstanding performance, Q460GJC has become a critical material in the field of high-end building structures.