StE315 is a high-strength fine-grain structural steel plate produced in hot-rolled condition, with its designation derived from the European (EN) steel naming system. In this system, "St" stands for "Steel" (from the German word "Stahl"), "E" indicates suitability for "Engineering purposes," emphasizing excellent weldability and formability, and "315" refers to the specified minimum yield strength of 315 MPa. Therefore, StE315 denotes a fine-grain structural steel with a minimum yield strength of 315 MPa, designed for welded and load-bearing structures. This steel grade is typically manufactured using thermomechanical rolling (TMCP), which produces a fine grain structure, enabling high strength while maintaining superior toughness and weldability.
The key characteristics of StE315 steel plate include excellent overall mechanical properties, such as high strength, good low-temperature impact toughness, and outstanding weldability. Its low carbon equivalent (CEV) reduces the risk of cracking during welding, making it compatible with conventional welding processes—often requiring no preheating or only minimal preheating. Additionally, StE315 maintains adequate Charpy V-notch impact energy at temperatures as low as -20°C, making it suitable for use in cold environments or in structures subjected to dynamic or cyclic loading. The steel also exhibits good formability, allowing for cold forming operations such as bending and pressing without cracking.
StE315 is widely used in heavy machinery, construction equipment, commercial vehicles, cranes, building structures, bridge components, and industrial installations—applications where high strength, reliability, and complex fabrication are required. It is particularly suited for designs aiming to reduce structural weight while increasing load capacity and involving extensive welding, making it a common choice in modern engineering structures.
The current standard governing StE315 is EN 10149-2:2023, titled Hot-Rolled Flat Products of High Yield Strength Fine Grain Structural Steels – Part 2: Technical Delivery Conditions. Published in 2023, this is the latest version, replacing the previous EN 10149-2:2013. The standard specifies detailed requirements for chemical composition, mechanical properties (including yield strength, tensile strength, elongation, and impact energy at -20°C), manufacturing process (thermomechanical rolling), test orientation, and surface quality. Notably, the EN 10149 series is specifically designed for high-strength structural steels and is widely adopted across Europe and global markets. As a representative grade, StE315 has become a key material choice in international engineering projects.
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.
